shooftie

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.