Variator

[Lyndon]

This thread will cover the History, Operation & Maintenance of Snow Trac, Snow Master and Trac Master Variators in approximately 27 Chapters. So that you don't have to read thru the entire thing just to find out the answer to one question, each Chapter will be it's own Reply.

1. History and Theory
2. Daily User recomendations
3. Belts
4. 2 basic versions, Paddel & Spline.
5. Thrust Berings
6. Seals, Top,Side, Front, Rear & "caps"
7. Bevel gears
8. Pins & Dowels
9. Ring Gear
10. Starter Bushing
11. 6 Volt Versus 12 Volt
12. Linkage, Quick Shift Kits, Forks.
13. Fluids
14. Venting
15. Tension Adjustment
16. Sticky Splines
17. 2 Adjustable Spring Assemblies.
18. Special Adjusting Wrench
19. Starter Ground
20. Special starter mounting clamps
21. H20 Damage (Water Damage)
22. the 2 Spline Caps
23. Where it's Metric and Where it's SAE
24. Reassembly, Centering.
25. Rig Steers to one side
26. Parts interchangability
27. Special Mounting hardware.

Feel free to jump in and correct my spelling anytime!

 

[Lyndon]

Re: History and Theory of operation.

The Variator is a Variable Parallelogram or adjustable diameter V belt drive. It depends heavily on the differential around which it is constructed. The Westermaskiner Co. and some others developed it for some pieces of farm equipment that needed multiple speed drives from a single engine operating at a fixed speed. Combines had them since the Threshing cylender needed to operate at a much higher speed than the sickel bar(sissor like cutting bar). It's a pretty ingenious merger of Swedish and German technology. It's pretty obvious how it functions if one can see it in operation. The 2 Variable width pulleys are set up so that one set closes, creating a larger diamter pulley, while at the same time the opposite side opens, to create a smaller diameter pulley. They are not quite the same as a snowmobile drive in that they do not carry the entire HP of the engine. Because you are trying to Crush one of the pulley set smaller, and the belt doesn't want to crush, they can only be adjusted while they are operating. In this contexts 'adjusted' means Varied, not like fine tuning or tensioning.

 

[Lyndon]

Re: Daily User recomendations:

Live and Die by the tag that should be on the dash, right above the stering columb, which says "never turn snow trac when vehicle is not moving". If you do crank the wheel around too hard or too fast ST25 will brake. This is a "C" shaped aluminum casting that is actually designed to break. Most people's reaction to this is why not beef it up? If you do the next thing to break is the parallel bars that press on the thrust bearings. So Beef them up! Now you start breaking the actual Chives (Pulley halves). They are cast, machined and have splines cut in them and are very expensive to reproduce and don't weld or repair very well. If you heed the warning you will never have a problem. I've seen so many machines with the ST 25 casting broken or repaired that I had a mold made, cast replicas and always carried a spare on the machine. But then through the years of operation with my fleet of 13 and my associates machines we Never broke one. Don't Over grease, keep the pulleys free of greese and be gentile on the steering and it will give you many years of good service without a problem.

 

[Lyndon]

Re: Belts

The Variator belt doesn't actually carry very much Horse Power. It's a hundred horsepower belt, that only see's about 5 to 10 HP when your turning and almost none when the machine is going straight. I have never even heard of a case of breaking this belt. What does happen is that over the course of time it grinds down, the surfaces get glazed up and it slips. Most owners first reaction is to always carry a spare, so over the course of time I accumulated tons of spares that never actually got used. The way to determine if the belt is worn out is to measure across the back, a new one is 2 & 1/8 " and it will operate down to about 1&1/2". The operators manual shows only a half inch of flex as the tension adjustment. However the US importer's nephew, who probably saw 500 to 800 machines come into the US, working as a mechanic for his uncle, observed that leaving the belt a little loose actually made the machine turn better. How can this be? Well it turns out this gives the pulleys the most room to adjust. Our own experiments seem to confirm this. Thru some catalog searching and a bit of trial and error I found a substitute belt that is readily available, probably listed elsewhere on the Forum, as 200 people have asked me about it. It's a 2926V646. This is the Dayco, Gates, and Goodyear number and even though the sides are at a minutely diferent angle, it works at least as well as the original, if not better. We have tested one on a machine with a much larger than standard engine and it held up superbly. The bottom line is that the belt technology has improved in the last 50 years. Because the new belt is a bit more flexable than an original, the machine rolls a bit easier and get's a tad better fuel milage.

 

[Lyndon]

Re:Splines versus Paddels:

This would be a nice place for someone to jump in and post the 2 correct pages out of the service manual. Besides I'm getting tired of writing. Early machines have early bug or bus transaxels that have Paddle ends on the shafts that come out of the differential and originally went to the wheels. These shafts have been cut off, milled down to accept the bevel gear, had a keyway cut into them( Woodruf Key, you know, the half moon kind) then had splines milled on the end and lastly they are threaded to accept the small, 11,12, or 15 tooth chain sprocket. After a certain year VW and Porsche switched over from the "Paddle end" to a Splined end where it goes into the transaxel. These shafts can be damaged as they are not that hard. It is wise to put the nuts back on after removing the small sprockets to protect the threads. These shafts come in a Right and a Left that are not the same. If you have to replace the transaxel make sure your getting the correct one to match your shafts, Paddle or Spline.

Edit by Bob: sorry to be so slow in the addition of these, but I was out of town for 24 hours!


Here are the Variator pages from the 1972 Parts Manual . . . the first 2 pictures show the SPLINE version.

The final page below is from a 1966 Parts Manual, it shows the PADDLE type version.
​

 

[Lyndon]

Re:Thrust bearings

Most of the snow track OEM bearings and seals are SKF part numbers and are actual SKF parts. The number series has been changed in some cases, but can still be cross referenced by a baering supplier. The Thrust bearing that pushes the pulley halves closed is readily available and I use a Check republic copy from ZKL, it's a 51110A. This bearing appears to the naked eye to be the same on both sides, but actually one side is slightly smaller than the other. One side fits snugly on the Chive, over a collar. The other side pops in the cap and the race goes in between. The 'cap' is ST14A, the Bearing Bracket and the 2 parallel arms press against it. The top one has a zerk fitting, the lower one, on the other side of the variator has a hose barb, short hose and the Greese Zerk fitting that bolts on a bracket on the side of the engine compartment. The lower one rarely if ever goes bad, where as the upper one gets wet and will likely have to be replaced so you only have to buy one when you do a rebuild.

 

[Lyndon]

Re: Seals

There are seals where the chain sprockest go in that must not leak. Their in the manual and are readily available, as are the bearing right next to them.

There is a seal where the splined shaft that is the input shaft to the transmission that is a VW Part. On the opposite end ot the Trans, where the shift shaft comes out old models don't have a seal and later years do. I haul my machines at an angle and the old style wants to leak transmission oil out this one. When it does it runs down the floor matt. This entire "nose" casting can be replaced with one that accepts a seal and it is also a VW part.

There are 2 bearings in each Tower (ST11A, Bearing Housing) the lower one is a single roller and the upper has dual races and acts to asorb some thrust. The lower one gets oil from the tranny, the uppper one has a greese line going to it. Theese are SKW, american sizes. There's also a seal here. It does not have an ST part number but it's a 345212 or a BA 345210. I'd take this one with me to the bearing House. The transaxel has in the side of the nose cone where the shift shaft comes out, a set of 3 tiny caps that look like a tiny invrted bottle cap. The cross shafts slide inside these holes. On old tranny's the 3 tiny caps were plastic plugs that would fall out when the tranny got hot. In later years they are aluminum and don't give trouble. Have a VW tranny guy put the new style in and your tranny won't leak when you go up long steep hills. These are strictly a VW part. There are Vent holes in the tranny that will be discussed elsewhere.

 

[Lyndon]

Re: Bevel Gears

There are 2 bevel gears in each side of the variator. One on the horizontal shaft and one on the verticle shaft. They don't seem to wear out, usually out lasting the transmission by quite a bit. The one on the output shaft that drives the sprockets is on a Woodruf Key and will slide off by hand. It is kept in place by stacking a hollow sleve a bearing and then the sprocket, a thick washer and a huge castel nut. On some machines they added a shim here to get the 2 bevel gears to mesh properly. Don't loose it if there is one there!The smaller bevel gear on the verticle shaft is splined and has a castel nut and washer. About the only thing I've seen go wrong here is that the cotter pin comes out and the bevel gear falls off. The rig will still drive, but it won't steer. You can tell if this has hapened besides the fact that it quits steering, by removing the variator belt and trying to turn each pulley. It should be trying to move the track on that side of the machine. If it spins freely the castle nut has fallen off. When you try to steer the machine it lifts the shaft up, drops the nut, washer and gear into the housing for the axel shafts. Then it all drops back down and looks OK, but won't steer. Usually the parts are OK and can be fished out and reassembled with a new cotter pin. I've only seen this show up once but heard about it hapening from a dealer.

 

[Lyndon]

Re: Pins & Dowels

Variators are easy to work on because of their simplicity. They are primarily held together, or more correctly the "joints" where all the action takes place are Dowels. They are all the same diameter, it's 5/8 I believe. Anyway they are all held in place with cotter pins. There are 2 short ones that link the steering box to this bizare "Arm" called ST501. It in turn rides on a dowel that sticks in a hole on a welded bracket and has a bolt going thru it on the other end. The part number is ST3008 for this dowel and it's the only one not held in by a cotter pin. The bolt that holds it in is 3/8 and needs to be Grade 8. It's the only grade 8 bolt on the whole machine. It bolts to the ST25 "C" casting, and on one machine I found it had a small sleve to reinforce ST25. There are some more dowls held in place with cotter pins that support the parallel arms. A wire brush for dressing copper plumbing fittings is good for dressing out all the holes that these pins ride in. The pins them selves should be dressed with steel wool or scruff pads.

When reassembling a Variator get some boat wheel bearing greese, the blue water repellant stuff, and a solder paste brush and coat every shaft as you assemble it. These parts tend to never get oiled and often seize up. There are some unusual reinforcing washers, about 12, that many of these shafts and dowels ride in. They are supposed to be tight in the cut outs where they rest and the dowels are supposed to turn freely inside them. It's part #ST 3014. They pop out of the punched holes fairly easily. If you repaint the steel pieces they will be a bit tight pressing back in.These washers don't usually get painted.

 

[Lyndon]

Re: Ring Gear

The main Ring gear in a VW transaxel is reversable. Installed one way you get 4 forward speeds and one reverse speed. Flipped over you get 4 reverse speeds and one forward. It needs to be in the second way since the tranny is in the Snow Trac is backwards from how it goes in a beetle. Busses up to 1965 had some gear reduction boxes in the wheels that required the axels to rotate the opposite way the wheels turned. Snow Trac's usually used Bus transmissions. If your case is shot and you replace it with a different one, make sure the ring gear is in LIKE a Pre 65 BUS. Make sure you tell your tranny guy that too! You Want the 4 reverse gears and 1 forward.

 

[Lyndon]

Re: Starter Bushing

The brass bushing that supports the end of the starter shaft is pressed into the bell housing. This should be inspected and replaced if worn. They are different sizes for 6 Volt and 12 Volt. The 6 volt is much larger inside and on the outside. VW places have a special aftermarket brass busing that converts an old 6V bell housing to adapt to the New, smaller diameter 12 Volt shaft. Put a dab of grease on the shaft end sticking out of the starter before you plug it back in to it's hole. Starters are very difficult to remove from an ST4 when the Variator pulleys are on. It's possable, but difficult, so have the starter rebuilt and plug it in while your doing the over haul, when it's easy to get at. Even if your starter seems to be working good have a starter guy go thru it anyway. Having one rebuilt is cheap and saves a lot of hassels later. As previously stated: " You can't call Triple A for a tow from Mt. Mckinley".

 

[Lyndon]

Re: 6 Volt vs 12 Volt

VW up graded from 6 volt to 12 volt in 65/66.Snow Track followed suit shortly after. 6 V flywheels have larger teeth and fewer of them than 12 V and are not interchangable. However a 6 V starter will preform nicely on 12 volts, so some years of Snow Trac that are 12 Volt have a 6 Volt starter that has been retrofitted with a 12 volt solenoid. Actually it's lots of years of the machine. I guess VW must of had lots of old 6 volt 1600 Industrial engines to get rid of left over and the Manufacturer of Snow Trac's bought'em all. I'm quite sure they did this with a bunch of the other parts. It appears that they would buy up all of last years stuff, like the tail lights or steering wheels that were not going on to next years model of VW and were therefore surplus. Anyway if you have the older tranny with the 6 Volt larger bushing, you have to get the special adapter bushing for the starter if you put in a new engine that has a 12 Volt flywheel. Also the starter won't bolt in the way VW originally designed it because of the variator towers. One of the bolting 'Ears' has to be hacksawed off. This is another reason why it is better to have your starter rebuilt, rather than buying a new one. These special angle iron clips actually just pinch the starter in place. And that lower stud for mounting the starter is Metric, same size as the lower engine mounting studs. The two top bolts have been substituted with standard 3/8 SAE bolts, and the long one of these also should have an "L" shaped clip that pinches the starter in to place.

 

[Lyndon]

Re:Linkage, "Quick Shift Kits"

There are 2 generations of ST4 shift lincage. the ealry machines had a ball cup on the shift shaft, and a standard VW bug shift lever, mounted on a sheet metal housing. In some extreem cases if you backed the machine up a steep hill the tranny would twist in it's rubber mounts and since the shifter was supported by the floor, not the tranny, it would get stuck in gear. Later to rectify this problem they made a pressed sheet metal mount that grips on to the nose of the transmission housing and had a couple of reinforcing bars for additional support that attached to the tranny. The Ball socket also got an up grade, with the addition of a spring. There is a shift guide plate, not shown anywhere in the ST4 literature, that is a stock VW part. It can be installed 4 different ways, for a snow trac it should go with the raised part up and on the left side. Some forcing of the shifter eventually wore or bent the shifting forks in the tranny. This makes the shift real sloppy. I just finished rebuilding 2 of these VW Transaxel/Variators. They needed new forks. A partial fix is to buy a VW "Quick Shift" kit. This has a plastic or metal half sphere that slides over the shift handel before you put the top mounting plate on and raises the fulcrum point. They are a bit tricky to adapt to an ST4 because VW's had bolts to hold down the shift plate, and ST4's have studs sticking out that are not long enough to accept the adapter. No problem. Get an "ALL Thread Coupling" available at hardware places like Home Depot. It's like a machine hex nut, about an inch long. The size is 5/16 SAE. You'll have to cut or grind it down about a 1/4 of an inch and use 5/16 X 3/8 long hex head bolts to mount the plate. Since the mounting holes in the shift plate are oval and a bit larger, you will find that some adjustment and a little tinkering you can get good results. The thing needs to be bolted down good and tight so you just have to try it in several positions.

 

[Lyndon]

Re: Venting

To allow for expansion of the gear oil there was a little hole on the top of the nose cone of a VW tranny. It's just above where the shift shaft comes out. A regular VW Tranny held a couple quarts of oil, Variators hold 7! When going up steep hills or long up grades this pee'd out oil. So Snow Trac put a small aluminum rivit for a plug. Then they drilled one 1/8 hole in each variator tower, about 2/3 or the way up, on the inside.Thats facing each other. It's hard to even find, but it works. Oil will still come out if you turn the machine up side down. Early machines didn't have the holes so you have to add your own and plug the hole in the Nose cone yourself. A self tapping screw will work as a plug. I usually tap it out to 1/4X20 and put a set screw in it.

 

[Lyndon]

Re: Fluids

Looks like I messed up on the order. Well anyway, what I call the Tower is ST11A. As previously mentioned, Variators should hold about 7 quarts of oil. Generally it's 90 weight hypoid gear oil. I prefer the lighter 75 weight. If you live above the arctic circle or run your machine in exstreemly low temperatures you can run ATF. Synthetic is always better in oils. It doesn't thicken up at low temperatures as bad and the machinery tends to last about 2 & 1/2 times as long. This also applies to the engine. It will last longer and start at a lower temperature. There are 3 plugs on a VW transaxel, 2 on the bottom and one in the side. When filling the transaxel, fill it until oil starts to run out the side hole. Thats the proper level. It takes a 17MM allen wrench which can be obtained from a VW'b place, or you can sometimes get a thick 17 MM nut and a box end on it. On several ST4's I found a 90 degree plumbers "L" force threaded in to facilitate filling. IF you have the tranaxel out and apart you can just pour the oil in one of the variator towers right when your assembling it. When it's in the machine, you can access the fill port from inside the cab. There's a removable plate on the passenger side of the floor/firewall at 45 degrees. This plate is for: Adjusting the lower variator adjusting nut, filling the transaxel, and adjusting the clutch. But you have to be a real contorsionist to accomplish these tasks this way. I put the oil in before reinstalling the variator, adjust the clutch as soon as I put the engine in, and adjust the lower variator adjuster with a special wrench from the top with the air induction cone out. I'll post pictures of the special 1" wrench.

 

[Lyndon]

Re: Sticky Splines

The 2 chive halves slide up and down on a splined sleve that rides on a smaller splined shaft. When you go to dissemble these assemblies there is likely to be a build up of hardened greese that wants to keep you from pulling it apart. It's OK, it's just greese, not some hidden "C" clip. Do not use a pulley puller on the chives. They are cast and will brake. I've seen a lot of broken ones, some attempts had been made to weld or braise them, with limited success. Don't pry on them with big bars or 2X4's. If you have one that just won't come apart, see the next section, there is a way without breaking them.

 

[Lyndon]

Re: The 2 "Spline Caps"

I know I'm goinh out of order, on the index this is #22, but logically it should fall here, right after "sticky splines". The 2 spline caps, are ST7210 & ST 7211. They are a mushroom shaped splined hollow tube that bolt to one half of the variator chives. If you inspect them closely one has the internal spline at the Cap end, the other has the interior splines at the shaft end. Do Not get them mixed up. Puting one on the wrong way can result in serious damage to both the internal splines on this piece and to the shaft it mounts on. I've seen the weld where the top flange attaches to the shaft fail. Get a machinist to deal with this, don't try any home remedies on this part. These should slide freely in and out of the pulley half that is not bolted to them. If they don't try dressing them with a wire brush or whire wheel. The internal spline of the chive can only be dressed with a steel or brass "Tooth Brush". Greese them before reassembling them. If you have a pulley that won't release ST7211 or ST 7210 don't panic. Spray all the spline that is exposed with penetrating oil, let it sit for a day, then set the whole mess on 2 four by four's and tap on it with a brass hammer or put a piece of wood on the end and give it a few good blows with a small sledge hammer. Eventually it will move. Spray more penetrating oil on it and knock it back the other way. A pulley puller, a large one can be employed, but don't crank it down too tight and breakk the chive. Your best bet is to tighten it fairly tight and strike the bolt head of the puller with a hammer. If this process fails, take it to a machine shop, before you damage it and let them try. Machinists have some pretty good tricks up their sleves. When reassembling the variator chives, make sure that you use the correct length bolts to attach this part to the chive. The holes are not always tapped into the chive all the way through. It will mess up the threads on the 9/16 bolts (3) that hold the 2 pieces together.

 

[Lyndon]

Re: @ Adjusting springs

The 2 adjusting springs are almost the same except for the piece they are mounted to. They consist of a threaded hollow sleve, 2 large washers, a short thin wall pipe sleve, a big spring, and 2 large fine thread nuts. A special EYE bolt(ST7021) screws into this assembly. The whole assembly turns when you adjust the variator belt pressure. It takes a 1" wrench. The top one is easy to get at, the bottom one is "a whole nuther story"! A real short 1" wrench will work if you have real strong hands and the assembly isn't too rusted up. The double locknuts holding this unit together have been peened, usually 2 or 3 places. I don't usually recomend taking this unit apart, but you can do it with some difficulty. Make sure when you go to reassemble it that the nut that was originally on top, goes back on top. If you swap the nuts, or put the top one on upside down you will ruin the threaded sleve(ST3006). I usually just clean em up and repaint them. The lower one has to be dissassembled if you want to get the arms off to clean and repaint. By arms I'm talking about the 2 flat bars that push up on the thrust bearing. These Adjusters should always be turned in pairs. If you tighten one a half turn, tighten the other a half turn. They determine the Variator belt tension. To tighten or increase the variator belt tension, the adjusters get backed out, for the top one that translates to counterclockwise. Turning it to the right, clockwise, loosens the belt. Lots of folks see the easy to get at top one and mess with it but fail for whatever reason to adjust the lower one. This is a BIG mistake! They MUST be adjusted in pairs. Failing to do so causes the rig to steer OK in one direction and not so good in the other. You'll need a good pair of vicegrip welders clamps and a large vise to reassemble the spring assemblies. Don't forget to Re- Peen the top nut on the double nuts or the whole thing will come apart the first time you go to adjust it. Setting one up form scratch will be covered in a later section.

 

[Lyndon]

Re: Special Adjusting Wrench

It's a cut off one inch 12 point box end wrench welded to a long L shaped handel. I'm at the office as I write this so the picture won't get posted until I get home and make a picture of it. It allows you to adjust the hard to reach lower variator adjusting nut, from the top and is pretty easy to fabricate.

 

[Lyndon]

Re: Starter Ground

Hey, it looks like I might actually get to the end of this thing! The starter pulls about 200 Amps. Since the tranny is on rubber mounts, sometimes it doesn't connect so well with the chasis. Since the body is aluminum which is a good conductor you usually don't have much trouble with lights that depend on the body for ground. The normal ground hook up for an ST4, hooked to the body. If you experience all sorts of seemingly unrelated problems with the lelectrical system, check to see that there is a small braded strap under the machine bolted between the end of the tranny and to where one of the rubber tranny mounts bolts to the frame. If you are putting a variator back into your Snow Trac or Snow Master, make sure it get's hooked up. I have on ocassion abandoned this strap and run a brand new piece of welding caple and bolted it to the tranny direct. There is a hole that was for lifting the tranny at the factory or some how use in manufacturing, that doesn't do anything that will accept a 5/16 bolt. This is a convienient ground point and means running a fairly short piece of the large cable to the battery ( for the Neg side). I like to ground here for my 2nd ground when I do the dual battery set up. The short version is: If you don't have a pretty good connection between the Tranny and the battery, it won't start.

 

[Lyndon]

Re: Special Starter clips

There are 2 "L" shaped pieces of metal that hold the starter in place. they originally were bent heavy guage steel. If you loose one, just make a copy of the other one out of a piece of angle iron. Drill the hole to fit the proper size of metric bolt for the lower one. I don't believe this part is shown anywhere in the service manual. The nose of the old style starters have various reliefs cast in to them. Only this type of starter will work. Don't let your VW Guy sell you a new style. It won't work. The old style came in a steel nose version and an aluminum one. Either will work, but the steel one is better. The clips that hold it in are not biteing into soft aluminum. Even though it looks like a cheesey installation, it works fairly well. On our most recent overhaul one clip and it's nut were completely missing and the starter had stayed in place and worked that way for quite a while.

 

[Lyndon]

Re: Water Damage

As it sits directly under the hood line, the variator tends to get water on it. Machines that are stored outside get wet. This rusts up lots of joints that are supposed to move on the variator. Westerasmaskiner, pronounced: VER-ter-hous-ma-skien-er means literally 'Hill top' or 'Ridge top', machine works, didn't allow for much in the way of lubrication for many of the moving parts. Eventually the greese gets washed out and rust forms. The Top thrust bearing develops problems, and the various pins and moving arms sieze up. Any attempts you can make when you store your machine to keep water from running into the engine compartment such as putting a strip of rubber at the hood to widnshield joint, will help. Even just throwing a tarp over this area helps. A little snow during normal operation isn't a problem. All the manual wants you to do is oil it with an oil can. This Would have worked fine if you did it every year since the machine was new, but I have a suspecion that none of you are "Original Owners". It would be worth the effort to at least take just the top parts off one time, dress all the Pins and Dowel surfaces and greese them. You don't have to actually tear the variator out, or even remove it from the machine, just yank off the pulleys, pull all the cotter pins, clean the moving parts, regrease them and reassemble. It turns out not to be very hard. The shear simplicity of them is probably why they were so effective. They are not clock like precision, more of an erector set design. The other place on the machine that doesn't like water is the cab frame in front above the windshield. It's steel and along the wing windows it was spot welded together. Water gets inbetween the 2 layers and the rust will eventually push the metal apart at this spot welds. It's a paine to fix. If your's is in good shape, keep this area painted and it won't develop cancer.

 

[Lyndon]

Re: Where it's metric and where it's SAE.

The 2 large top nuts that appear to hold on the chives, the 3 bolts that hold each spline Cap to the pulley half, and the nuts on the other end of the towers where the bevel gear is are all SAE. So are the 2 large castel nuts that hold on the sprockets. For some unknown reason I think they used metric nuts for the 3 studs that hold on each tower. All the hardware on the VW Transaxel is metric, including the lower starter mounting stud. All the loose hardware, that is the stuff used to secure the transaxel/variator to the chasis that is huge,5/8, is SAE. The rubber tranny mounts on the sides are metric, the rear tranny mount where the shift linckage is, is metric where it attaches to the transaxel and SAE where it attaches to the frame. The clutch adjuster is SAE. The Greese fittings are 13MM and you'll need 2 wrenches for them. The bearing caps on top of each tower are SAE, the bearing caps where the small sprockets go are metric. That's all I can remember off the top of my head, but most are listed in the service manual.

 

[Lyndon]

Re: Reassembly and "Centering"

IF you have taken the variator apart, or the 20 mechanics before you didn't know that you have to adjust the springs in similar incraments you will want to follow this proceedure: Put the machine up on jack stands so that the track is just barely hitting the ground. Start it up, and put it in any gear. make sure that no one is in front or back of the machine just to see that it's not goning to fall off the jack stands and run over them! Make sure that you didn't leave any parts or tools on the track either. If you have the tracks off you don't have to worry about this. This operation can be done with or without tracks on. The steering box is a 3&1/2 turn "Lock to Lock" steering box. With the belt moving, turn the wheel all the way to the left, then all the way to the right, Slowly! Now pick a reference point on the dash, such as straight up, and turn the wheel 1 & 3/4 turns so that it's centered. It's a 3 spoke wheel which makes this easy but if your confused, put apiece of tape on the steering wheel. It is best to do this with 2 people so that one can watch while the other stays at the controls in case you want to shut it down quickly. With the steering wheel centered this way look at the belt. Are the 2 sides of the belt parallel? Are the 2 pulleys open about the same amount? If they are not, then you need to loosen one spring a turn and tighten the other a turn. You can measure with a variety of measuring devices, wood block, tape measure, calipers, whatever.. either of the 2 places, at the belt, or the width of the opening. When the belt is parallel, or the pulleys are open the same amount, the Variator is properly centered. From now on adjust both springs the same amount to tension it. It doesn't need to be too tight. Don't attempt to adjust the springs while it's moving. Shut it off each time or at least have the driver put it out of gear. This is a "one time" procedure that you probably won't ever have to mess with again. Remember, loosening the springs tightens the belt. tightening them loosens the belt. They are both standard right hand thread.

 

[Lyndon]

Re: Rig Steers to one side:

So your not rebuilding your variator, in fact it seems to work OK. but the Snow Trac or Snow Master favors turning one way, and doesn't turn very well the other. It's likely that someone adjusted the top spring which is for tension and didn't adjust the bottom one. Follow the proceedure on centering just before this. These springs need to be adjusted in pairs, and usually just a 1/4 or 1/2 turn at a time. If you adjust the top one, adjust the bottom one the same amount.You must adjust them in opposite directions, so that you are backing off both or tightening up both. If after you've gone thru the centering proceedure your machine still wants to go better one way than the other, you likely have a brake dragging. The Brakes can only be correctly adjusted with the track off and the drive chains in the engine compartment off. It's such a hassel that it's the first thing I rebuild as soon as I've stripped a machine down. Also everything is easier to get at. The complete set of parts , wheel cylenders, master cylender, and brake linings, which are all VW except the Emergency brake bands on "Big Wheel" or New style machines, will set you back around 100 dollars. You won't have to mess with it again for another 20 years and by then you will have sold it or given it to your Nephew.

 

[Lyndon]

Re: Parts interchangability

All the parts on a variator will fit on another variator with one exception and that is the Axel Shafts. Early ones are "paddel Type" later ones are Splined. Along with this one can substitute almost any bug or bus tranny. Paddel for paddle or spline for spline. Read the section on ring gears, and check the section on starter bushings to make sure you set it up right. If you put a bug tranny in without flipping over the ring gear, you'll get 4 reverse speeds and 1 forward. You don't really want to have pull the engine and tranny back out once you've put it all back in do you? You'll need new paper seals that go where the variator cast housings mate up to the VW Transaxel. VW'b shops and the guys that rebuild VW tranny's will have them.

 

[Lyndon]

Re: Special Mounting hardware

There are 2 long bolts that go back to the second frame cross member. They are 5/8 SAE. They are there to counter the strain from the drive chains. With out them the castings would pull off the VW transaxel. Look at the diagrams in the service manual. These castings are ST10 & ST37. The 2 long bolts are not actually bolts at all. They are a piece of bar stock that has been threaded at both ends. It's ST 7078. The nut on the variator end is braised or welded on. The other end of this bolt or threaded rod goes thru a hole in the frame on the underside of the snow cat. This cross member is just folded sheet metal and isn't especially strong. There are 2 flat rectangular nuts. These are important! If you put a regular hex nut here it will pull right thru the frame. This special nut is ST1208. It's just a piece of flat stock with a 5/8 SAE Course thread hole and one edge beveled. The beveled edge goes in toward the top to accomadate the rolled inside corner. If these are lost or missing, make new ones out of flat stock, grind off one edge so that they will lay flat in the channel. When installing a variator it is best to tighten all of the other mounting hardware up first, then have someone watch while you tighten one side then the other. You want them tight, but not too tight. If the variator starts to move much stop tightening. Have your spotter watch right at the sprockets. After they are in and tight, a standard 5/8 hex nut can be tightened on as a lock nut on top of the special flat rectangular nut. You may have to hold the variator end of this long bolt when tightening the lock nuts. They are 15/16 I believe.

 

[Lyndon]

Re: "Live Long & Prosper"

Generally if you take care of the variator, don't abuse it too much, keep it out of the rain and lubricated, it will preform flawlessly for years. If you go thru the rebuild process you won't find yourself doing it over and over. Variators are pretty tough. Keep oil in it, don't crank the wheel too hard. I've seen lots of machines, probably 200, so approximately 1/10 of all the machines built, and all had there original variator, and most of them had the original belt.

 

[Lyndon]

Re: Corrections & Additions

Where previously stated that the steering box was 3.5 Turns 'Lock to Lock' it should be 2.5 turns. Just finished one today. Also the thread pitch for the Eye Bolts, ST 7021, are Metric, Not SAE. 12X1.75 MM. Made some additional pictures today. Just finished a complete variator and engine reinstallation. Takes about 2 days.

 

[Snowcat Operations]

Link to a thread with pictures of a Variator being disassembled.

http://www.forumsforums.com/3_9/showthread.php?t=4487

A Thanks to Lyndon is in order. We forget he took 5 DAYS to write this article. With his knowledge we as a group have gained YEARS of experience from someone lived breathed Snow Tracs. Thanks Lyndon.