I pulled the front diff. on the syncro today to replace the old failed (weak) viscous coupling (vc) with a good used one. Dropping the diff. is in the Bentley manual so I won’t describe that part except to say that it takes a bit of wiggling to get it out. I used a motorcycle lift as a transmission jack. Once out I set it on a container to drain.

See the dark dirt on the input end? Looks like the oil seal there is leaking, need to attend to that. Once most of the oil drained out I humped it onto the bench, just to look at it.

See the speedo drive sticking out? Then it’s on to the floor and off with the 13mm bolts holding the skinny end on.

Some tapping with soft faced hammer to break the seal and it comes apart.

Yup, that’s the vc sitting there, with a spacer on top.

The vc just lifts right off, exposing the speedo drive gear on the pinion shaft.

Closer view of speedo gear.

With the case separated I drained the remaining oil, applied some sealant to the mating surfaces, put the new vc on the pinion (and didn’t forget the spacer) and the skinny part of the case re-installed and torqued down. All well and good, refill with oil in the morning. Now the interesting bit. I had to take the end plate off the old vc, I was dying to see the inside first hand. The big C-clip came out easily.

That end plate should then pull out, but it wouldn’t come. I thought maybe if I drained the vc and also run an awl around the edge of the plate to remove gunk it might help matters. The silicone flowed out, not as viscous as I have seen in those German videos showing refills, and looking like it might have some gear oil in it. BTW, didn’t smell bad.

Got the end plate off.

Removed the C-clip on the shaft (barely visible in above pic) and pulled the first two plates out to look at the adjacent surfaces. Need any more evidence that the plates do come in contact during hump? Upper plate in pic has been flipped over.

Close ups.

Accepted wisdom is that a weak vc is due to the silicone fluid leaking out. One could expect an O-ring to fail with time, but what I found was something else. I had a look at the X-ring that seals around the central shaft (there are two, one on each end, the one shown is in the end plate). It appears that the X-ring is twisted in the groove, look.

Out it comes, yes, it is twisted.

Another view (damned cat hairs, get everywhere).

This surely must have happened at the factory, a lip of the X-ring getting caught on the shaft during assembly. Tsk, tsk,  Steyr-Puch.

Addendum: I’m assuming the vc had leaked some fluid, but even with that folded X-ring I have no proof. The “dirty” fluid from the vc could be gear oil contaminated or it could be metal particles from the plates. Perhaps I can use a magnet to determine?

Thanks to good friend Simon, I have, in my hot little hands, a used viscous coupling. It might be on its way out, getting aggressive after a long hot drive, but it will be great for me this winter.

Here is a view of the front, the front differential end.

A couple of things to note:

-the punch mark up there on the rim between the circlip ends. It aligns with the casting ridge between that screw port and the rim.

– the paint on the screw ports and on the circlip ends.

Closer shot of the punch mark on the rim

The punch marks and the paint on the circlip must have something to do with registration on end cap for balancing. I doubt they were there to help rebuilders, but rather I am guessing the unit was balanced before filling (there are spot welded balancing tabs on the side of the body) and the marks are there to be sure it went back together balanced.

Here is the other end, the one closest to the propshaft.

Coming soon, the install, and perhaps (if I can get my act together) some sort of bench test of the VC.

A week and four (!) attempts later I finally have the leak fixed. It’s a tale of woe and I guess you could say blindness on my part. When I re-installed the cover plate and noticed the drip at one of the lower cover bolts I assumed the leak was coming from a poor seal at the plate. So I drained the oil and left the cover plate off overnight. Next day I cleaned the mating surfaces well with brake cleaner and used Permatex grey RTV on the sealing surface. Filled the transmission and it still leaked, a small drip at one of the cover plate lower bolts. Now I was peeved. Emails to Daryl at AA Transaxle gave me some confidence, he suggested that I make sure that the cover plate was flat and that the 6 mm socket head bolt under the cover plate was good and tight. So once again I drained the transmission (cover plate off again) overnight. Next day I set about making sure the cover plate sealing surface was flat. I tried flat filing but even with the file loaded with chalk, aluminum filings would ball up and scratch the surface.

So I switched to lapping the cover on a bit of granite using a couple of grades of carborundum grit and WD40 as a lube.

Coarse grit:

Finer grit:

You can see a few larger scratches, must have had some coarse grit carried over. But that doesn’t really matter in this situation, what I wanted was the the cover plate sealing surface to be flat.

Back at the transmission I removed the old silicone sealant which what I thought was squeeze out from the original install of the cover plate, right adjacent to the cover plate hole rear side. This was where I was blind, I should have thought more about why there was so much clear silicone there. I also carefully filed what I thought were slight ridges around the bolt holes on the cover plate sealing surface. Here is an example (you might guess that I was grasping at straws here):

Filed:

As another example of me being gormless, I even smeared some RTV on the area where I removed the old silicone caulk on the case seam. Why did I not put more on and further up the seam? I don’t know.

Cover plate was caulked and put into place.

I was generous with the caulk – well that’s what I have been told 🙂

I let the stuff cure for about 5 hours before I filled the transmission with oil. Can you guess what happened? Yes, still a little drip. Chagrin does not adequately describe my feelings at this point. I went under the van and looked carefully and I noticed oil seeping out from the top edge of the little it of RTV I smeared on the case joint (pictured above). If I put a corner of a rag on that spot the drip at the lower bolt would stop. Why had I not noticed this before. More info from Daryl and a sinking feeling that I might have to pull the transmission and reseal the case joint. But I decided to make one more attempt. Again, an overnight drain of the oil and this time I scrubbed and degreased the case joint all along the side of the cover plate hole. I bought some of the expensive RTV sealant, “The Right Stuff”, it had a few good recommendations and is a fast curing goop.

Picture here of the cleaned area (cover plate sealing surface was later cleaned of the old grey Permatex):

I also gave that socket head bolt another bit of twist. Then I smeared on sealant over the case joint, and on the cover plate sealing surface, not very pretty:

I let the stuff cure for a few hours then refilled the transmission and went into town on errands. I was not optimistic about success, but I’ll be dammed if the damn thing is now sealed tight! One day later and it is still dry. I’ve come to the conclusion that the original silicone caulk that I removed from the case joint area was put on to stop a leak. I bet it was done when the transmission was rebuilt.

I learned a few things from this fiasco. Apart from being more observant I discovered that when putting on the skid bars/plate on the syncro, install the bolts loosely until all are in place, before tightening. That makes it so much easier. I also found that my Snap-On transmission wrench (17 mm hex) was awkward to use on the fill plug (but very good on the drain plug) so I cut a section off my 17 mm allen key and used the short bit on a 17 mm socket, and even better, on my 17 mm ratcheting spanner.

A very brief overview of a transmission oil change in my ’86 syncro. I had not changed the oil since I bought this van almost 2 years ago and I noticed a very slight oil leak/seep at the bottom edge of the reverse gear cover plate. I figured it would be worthwhile when I had the chance to drain the oil and look at the cover plate. I bought some regular run of the mill 80/90 wt gear oil with the idea that I would put in the fancy gear oil later after I fixed the cover plate leak. As it turned out, this was a smart move.

The oil fill port is on the right hand side of the van just above the shift linkage rear bushing. The drain port is near the rear near the midline. Important to first see if you can unscrew the fill port before trying the drain port. To get at the fill port easily I found it best to remove the rear skid plate/bars;  2 X 17 mm nuts and bolts at the engine carrier bar, 2 X 17 mm bolts and 2 X 17 mm nuts and bolts at the forward end of bars( actually there is a 15 mm nut on the upper left hand skid bar mount),  and to detach the shift linkage rear bushing housing; 2 X 13 mm nuts and bolts.

Kinda silly picture of skid plate out.

Oh, I should mention the tools I used to remove the drain and fill plugs. A 17 mm allen key, and a nice Snap-On tool with 17 mm hex. I needed the allen key to help the Snap-On tool at the fill plug, there was not enough space to fully swing the wrench (you know what I mean).

And more obvious advice: clean out the hex recess in the plugs with dental pick, toothpick, compressed air, whatever. Ya gotta have the wrench make a good fit. I squirted penetrant/rust buster on the plugs, more out of habit than expecting that the damn stuff actually does anything. Next pictures shows the fill plug (shift linkage still up in place) and the wrench in in the plug, riveting story eh?

Thankfully the fill port plug unscrewed with no problem. Next, on to the drain plug. The wet spot is the penetrant fluid stain.

It too came out with no trouble. The magnetic plug had a bit of fuzz on it, but I think this is a pretty normal coif.

While the transmission drained, I removed the weeping cover plate. It seemed to be leaking at the bottom edge.

Plate off, evidence of silicone caulk as a sealant.

Close up of the bottom corner that I suspected the leak was coming from. No smoking gun that I can see, minor scratches, almost a crack like line there though, no?

At this point I was advised by my son that I need to drive him to some sort of “date”, grrr. I should have let the transmission drain overnight and degrease the mating surface of the cover plate before applying rtv silicone  and re-assembling (as per Daryl of AA transmission’s advice). So I slapped on the the silicone and the plate, and set about filling the transmission. I made a fill hose with some pvc tubing and a funnel.

All filled and the skid plate back on, the shift linkage re-installed, and the damn cover plate leaks more than before. So, tomorrow I’ll do it all over, this time properly letting the cover plate area drain and be de-greased. Daryl also advised flat filling the cover plate flange to make sure it is flat.

Courtesy of Bill M.

R. Jones pushed me into this, he wanted to see how it all goes together. I’ll go through it on point form, pictures and text. Bentley has an exploded view and instructions for back up.
On the way out to the workshop I noticed a cool spider on a leaf of one of the jade plants we put outside for the summer. Got a quick snap before it moved. If you want good pics, head to A. Gordon’s Wordlessme.

Back to the job, first unscrew gear lever knob and pull off the rubber shifter boot. Then mark the position of the upper plate on the lower plate. I scratched circles through the two holes in the upper plate.

No need to remove the two 10 mm nuts you see there right now, we will be taking the two plates out together. Then it’s under the van to drop the spare and remove the shifter box, four 10 mm nuts and washers, careful, they drop easily 🙂

Box removed

Now remove the vertical from the horizontal between the “ears”. It’s a 10 mm stover nut and a washer on one side, and a 13 mm headed bolt on the other.

Now you can get back into the van and pull up the plates and shifter, and take it to the bench for disassembly.

There is a set screw on that metal collar on top of that spring, hold it tight as you back the screw off and remove collar and spring. The shift lever will slide out of the housing assembly. Look at the “T” end of the lever, remove the 2 plastic bushings. These are wear items and it would be a good idea to replace them.

I didn’t as I did not have any on hand, and I couldn’t be arsed to make some up. The bolt that rides in there looked a bit worn and I suppose the small amount of play in there does contribute to the overall feel of the shifter. Here is the bolt back in the bushings.

And the wear.

Back to the other parts, now you can remove the two stover nuts holding the upper and lower plates together, you did mark position of the two plates first right? The white plastic collar on the underside of the upper plate is pried out.

Then the entire inner workings, rubber collar and all, can be pushed out from top to bottom. It might be tight, but palm pressure is enough to do it. Careful not to break the upper plastic.

The two white plastic bearing shells can be pried out of the rubber and that will allow an internal spring to sproing things apart.

Now clean all the parts.

Reassembly is pretty straightforward, first squeeze the split shells into the rubber collar, might be a bit of a struggle.

Then the one inner bearing with the protrusion is pushed in from below until it snaps into place. Good time to put a little grease on the rubbing surfaces. Not too much, Bentley makes no mention of lubricating the plastic assembly and I have seen some that are caked in grease and dirt, so it is probably best to go light with the schmalz. Do, however, put a dab of grease on the gear lever where it goes into the plastic assembly and in the bushings on the “T’ at the end of the lever. Note that the rubber collar has a “top”, the little ridge, see? Sorry about bad focus in the next couple of pics.

Then put the larger of the two springs on.

And press the upper bearing into place, again it snaps in. The rubber collar allows the split shells to spread.

This assembly is now pushed into the upper plate.

Followed by that plastic collar.

Put the upper and lower plates together and secure (in the right place using your marks) with the two 10 mm stover nuts. I risked Zinc and or Cadmium poisoning and buffed up the shift lever. The lever is inserted into the bearing assembly, the spring put on, and the collar locked down in place (there is a dimple on the shaft).

Out to the van, and pop the gubbins in.

Then under the van to connect the shift lever to the ears using that bolt and bushing arrangement. Bolt the box back on and put the spare tire and tray back in place. Back upstairs and rubber boot and shift knob back on.

That’s it. Oh, I suppose I should have mentioned that you can get replacement plastic parts for the assembly from the usual suspects, Van Cafe, Go Westy, Bus Depot etc. I re-used the old parts, they seemed to be in OK shape.

For Doug M., wanted to see the wear patterns. Looks in good shape for being almost 25 years old and god knows how many shifts.

I’ve been noticing that I sometimes have  a little difficulty shifting into 1st and 2nd. Spraying grease on the exposed wear points on linkage under the van makes the difficult shifting go away for a while, so even I got the message that it needed some attention This diagram shows the linkage, my van has neither the shift linkage protective tube, nor the rubber boots protecting the rear bushing.

Another difference is that as well as the roll pin that secures the horizontal linkage to the vertical link right at the transmission, my van also has a horizontal bolt and nut securing the two. The linkage at the rear comes off pretty easily, except that the skid rails on the syncro does restrict access to some nuts and bolts. The roll pin is tapped out with hammer and small drift from the inside of the vertical link, that link drops from the ball link which is attached  (13 mm nut) to the shaft coming out of the transmission.  On the bench, the manky, dirty bunch.

Then all cleaned up.

The brown ovoid shaped bushing was packed inside with a mixture of old grease and grit, took a few minutes to get that clean. The roll pin is worn, I think I should get a new one  ( have a spare bit of linkage so I can get the right size at the shop).

Then it’s grease them up and put it all back into the van, with a spritz of Fluid Film. Not really happy about the rubber boot that covers the transmission selector shaft. It does grab onto a ridge on transmission, but outboard end of it doesn’t seem to attach to anything. You can see a glint of exposed shaft in the pic below.

Shot of the linkage U-joint, which seems/feels pretty good, and the forward bushing which takes a bit more effort to get to.

No road test done to see if the shifting has improved, but parked, it goes into all gears nicely.

While I was in the mood, I had a look at the linkage/joint right under the gear shift lever. You know, hidden by that box above the spare tire. I had been reading this thread on the Samba and was curious.

The plastic ears are in place, and not too badly worn. Trust me, you can’t really see because to the grease.

Cleaned off the old grease and put new stuff on.

Still buggering around wondering how to raise the front of the transmission to reduce the output flange downward angle. I supported the front of the transmission and pulled the left hand side mount off. The mount on the other side is much less accessible, coolant lines restrict access. I guess I have to say that this is pretty dull blog stuff. Maybe it helps other folks doing the same thing, but mainly I am treating it as a journal, recording what I have done and reminding me what to do if I have to do it again.

So the rubber mount there is attached to a bracket which is bolted to a beam under the van, and to an ear on the transmission.

It is hard to get a wrench up to the nut on the top of the rubber mounts, but an angle head ratchet wrench (17 mm) can be squeezed in there, and the other end attacked with a socket. I found that loosening the three 13 mm bolts that hold the bracket to the beam allows the ratchet wrench to get up there easier. One funny thing, the EKTA-like diagram above show those bolts coming in from above, they don’t. So the rubber mounts and bracket were pulled out. Here is the bracket on the bench.

I sprayed some white paint on the rubber mount bolt and transmission ear just in case the transmission shifted aand I had to get things back in the right spot. As it turned out, the other mount held things in place.

I compared the rubber mounts, upper and lower (above and below the bracket). The upper one is marked with “U”.

Looks a bit collapsed, saw the same thing with the front diff. mount. The bracket was a bit rusty so I scraped off the rust and slapped some POR on it. While the paint was drying, I had a look at the part of the transmission that was exposed with the mount removed. I found the transmission breather hole which, in the syncro, has a plastic tube leading somewhere higher so that the vent won’t take in water if wading in the van. Sometime in the van’s history the transmission was rebuilt and the breather tube was reconnected to the hose barb on the transmission via a short length of rubber hose. It came off too easily so I used some clear PVC tubing to connect it (heating the stock tubing with heat gun and trying to get it on the hose barb was not a success).

It really is a tighter fit than it looks in the picture, I’m confident it will stay in place. I reassembled the mount, with the lower rubber now on top, and had a few minutes of “quality time” re-installing. I did not succeed in finding any new ideas on adjusting the transmission angle, but I am glad I got the breath line better secured.

PS I also re-installed the “new” propshaft I was babbling on about a few posts back, I had replaced one of the U-joints since. Well, the upshot of all of this was that the driveline vibrations are pretty well gone. Still a very, very slight vibe at 50 kph, but it is really acceptable.

Took apart 2 stock propshafts. The rusty red one is an ’86 model, the black one is from a later van (I don’t know the year). You can see that there are a few minor differences. One important one is the machined end that houses the internal bushings. Note the thickness of the internal bushings, the newer shaft has much thinner bushings. Both units have shafts that are the same diameter so it’s the bushing housing that is a smaller diameter in the newer shaft. Also the shaft lengths differ, the older one being longer. The newer shaft has the o-ring in a groove, the older one has a rebate to hold ring.

Some more trivia:

1. the black (newer shaft) had one U-joint that looked stock and one that had a blanked off grease nipple. I am assuming orig. U-joint was replaced
2. The rusty red one, from my van and I am confident that is stock, does match the diagram I posted in previous blog entry. The black one does not match in some details.
3. both internal shafts are same diameter
4. overall length of shafts differ by a couple of millimeters. The black, (newer), shaft being shorter.
5. all the socket cap screws are the same
6. I haven’t found, and this does not mean none exist, any vw part number on both shafts
7. giubos are identical
8. the part of the joint that mates to the trans/front diff, on both shafts are as identical as machined sand cast parts can be
9. the diameter of the propshaft proper is pretty well identical on both shafts (3.155″)
10. both shafts assembled with U-joints out of  IN phase

I played around with a spare propshaft that I got the other day (thanks again SImon). I installed it in the van as is and it did have a vibration at around 50 kph. Wasn’t a huge vibration, but it wasn’t acceptable. Believe it or not, but it felt like the vibration was to the rear rather than the front. I took the shaft out and set about taking the giubo end apart. First thing noticeable was the U-joint had slight axial play in one of the crosses. I took off the circlips at that joint and they measure approx 0.050 in thickness. I installed a pair of 0.060 circlips and that eliminated the play. The ears of the joint look a little beaten. Also, doesn’t look like the circlip is fully in the groove does it? But it is… I think 🙂

I still could detect play at that end and guessed it might be from wear in the internal shaft and bushings. So the giubo and end u-joint had to come off.

First, here is a pic of the end of the shaft.

If you look closely you can see the head of a bolt in the inside face of the U-joint. This is to plug a grease nipple port and indicates the joint is not stock. Close up of that area.

Before taking things apart, I sprayed some paint on the works so I could put it all back together in the same orientation.

Then off with the bolts that hold the giubo to the propshaft. The giubo and joint pull out. The shaft doesn’t look too bad on the end.

Then remove the bots holding the giubo to the joint.

That end doesn’t look too bad either. You can see the shaft is thicker in the two spots, that’s where it rides on the internal bronze bushings in the prop shaft. Have a look in the hole in the propshaft. There’s an o-ring in a groove at the end. My other propshaft had the o-ring in a rebate, not a groove.

Now the giubo, sitting roughly in place, and it had washers on either side. Pretty cruddy washers, and my other propshaft did not have them.

With the giubo removed from the joint, I reinserted the shaft into the hole and tried it out for size. It felt pretty good, no slop. So where did that looseness come from that I felt when it was all assembled?

I decided to lube it all up and put it back together. I used a band clamp to squeeze the giubo into shape to let me get the bolts back in to attach joint to rubber.

And same technique when attaching assembly to propshaft.

Well, all assembled (minus those washers) and it feels nice and tight. No play like before. So I put it back into the van and had a test drive. It still has some vibration (again around 50 kph) but it is less. I had to say that didn’t I? Honestly it is better but not what I want. So the shaft is coming off again and I’ll take it to the driveline shop for spin balancing.

Addendum: In the comments Rob advised replacing that U-joint. I agree and I should have mentioned this in the post. I’ll ask the driveline guy to do it this time.

More addendum: Diagram of the end of shaft. Does it look to you like of some sort of cap at the end of the internal tube or is it integral to the inner bushing? I’m thinking the former is the case. Also note that it is a nut and bolt that holds the giubo to the U-joint yoke. In the propshaft above its a bolt, with the propshaft yoke having threaded holes. My other propshaft has same attachment method shown in diagram. No washers between giubo and shaft shown on diagram either. I bet there were some minor changes made to the shaft during production.

As I mentioned a couple of days ago, I had my prop shaft balanced and I finally have it installed. I drove about 10 km with the front diff. mounts loose to allow it to “settle in”. Today I tightened them down and I can report that the propshaft is pretty smooth. Of course your kind of hyper vigilant in this sort of situation, and I can feel a very very slight vibe at around 60-70 kph, a little like having deep lugged tires. I’m happy with the result.