Please note that the following refers to a 1980 924, non turbo tube and the rebuilding of same. It would appear to me that one could use the same methods to rebuild a 924 T, 944 or 928 unit as well, but I cannot say for sure.
Obviously the project begins with the removal of the transaxle and then the tube itself with the required rear suspension work as noted in the Haynes book. There are others, but this is the literature that I have and know best. As a sidenote, one of you noted a gasoline smell and commented that this is an opportune time to rectify same. My experience too!, and I also removed the fuel tank and changed the vent hoses. Sometimes I still have the vapors, but to a much lesser degree since the changing of the hoses.
Now bear with me as this may seem crude! The first step is to remove the shaft itself from the torque tube. The shaft must be driven out along with the bearings and their holders (four of them in a 924 tube). There is also a vibration damper (large piece of cast iron) in the center of the later model 924. The method that I adopted was to rip a 2x4 down the length to fit inside the tube and ‘pursuade’ the shaft and bearings out the other end with a sledge hammer. This would have looked a whole lot more sophisticated with a press of some sort, but I did not have access to one.
Upon removal of the shaft and bearing holders, you will find that the bearings are a press fit into the bearing holders. In addition, there are small rings that fit into the bearings metal to metal, but have plastic inserts where they fit onto the shaft itself. You will need to remove the rings and bearing holders from the shaft; stripping it entirely.
The bearings come out of the holders easily with a drift and hammer. The replacements appeared to be standard off the shelf items as my supplier had no trouble finding them. I took one of the old ones and had them match it up. The 924 T and 944 will likely need larger bearings so even if I had sizes they would not help everyone anyway. The new bearings fit into the bearing holders one way only. The plastic lined rings will need to be installed into the bearings; but here is where things start to become interesting. Lay the bearing/holder so that you are pressing down to install the bearing (on the floor and tapping with a drift & hammer if you do not have a press). Be sure that you are seating the bearing by pushing on the outer race so that the bearing itself is note damaged. Obviously you reach a point where the bearing is fully seated. You will need to install the bearing/holder in this direction only otherwise the bearing will slide out of the holder during instal!
lation!! Without moving the bearing/holder, install the plastic lined ring into the inner race of the bearing with the flange facing up. Again, look at it if you are in doubt and note that while installing the ring, you are not able to push the bearing out of the holder. You are also not able to push the ring out of the bearing; it too will reach a point of being fully seated squarely into the bearing. Proceed with the same procedure with the other three bearing/holders.
Now turn the bearing/holder upside down and take the drift and peen the plastic lined ring in four places on the back side of the bearing. This will prevent the ring from coming out of the bearing as the ring is not a really tight fit in the bearing. The bearing to holder fit is fairly snug, but again will come out if you install it from the wrong direction.
You will notice there are marks on the shaft where it did not rust indicating the locations of the bearings. Make measurements of these locations and write them down. Lubricate the inside of the torque tube and the shaft with WD-40 and install the first bearing/holder at the first mark on one end of the shaft. Probably the best way is to install the transaxle end bearing first, installing from the engine side. Position the bearing on the shaft so that as you push the shaft toward the trans. Direction there is no way for the bearing to come out of the holder. Push the shaft into the tube and stop when you are about two inches (50MM) before the flange as measured with a straightedge across the transaxle flange (details in Haynes, 924 manual p. 185). You will need something sturdy to push against with a spacer to keep the shaft that two inches inside the flange. The bearing has probably stopped moving inside the tube somewhere due to resistance from rust, etc. That’s OK. !
You will need a steel pipe (3/4” for 924) that is of a size to fit over the shaft, but not so large as to touch the bearing or holder. The goal here is to push on the flange of the plastic lined ring and slide it along the shaft into the tube. This may require some considerable effort, but the resistance is what keeps the parts in place after assembly! Push the bearing to the point of your measurements and stop. Take the measurements in four places around the perimeter of the bearing. This is important! Remember that the plastic lined ring can cock during installation and if the bearing is installed crooked it likely will not last. Making sure that the shaft is not free to move in the tube (two inch spacer and something to push against as above), install the second bearing with the pipe to the measurement previously noted. Again, take four measurements and straighten the bearing. If you go too far, you will have to remove everything and start again as you cannot push!
the bearing or the shaft backwards- this might dislodge the bearing from the holder.
Continue with the third and fourth bearings as above. Finally, the Haynes recommends a 19.5 MM +/-.5MM recession into the flange for the driveshaft. Gently tap the shaft from the previous 50MM to this specification; you CAN go in this direction without unseating anything. Again, if you go too far your in real trouble and can’t really be sure that you haven’t unseated one of the bearings in the process.
A couple of notes: This is a lot of effort for a part that takes hours to remove and replace. That is the reason why I have emphasized the need to carefully install things so that the bearings cannot be pushed out of the holders. If the unit failed shortly, I know that I would not have tried this a second time but have called the project a disaster. This took me two tries myself- even after I had installed the tube back into the car. I was glad I took it out as one of the bearings was approx. half way unseated. Check the fit of the tube to the transaxle on the floor and not installed in the car!!
You may note that no mention was made of the vibration damper in terms of installation. This is due to the fact that I never re-installed mine. I can feel the difference (I think) too and would re-install one if I ever do this again. The damper would also be measured for location and pushed into place between the second and third bearings (early pre-’78, this is not applicable to you). You would need a larger pipe for this. I did not install mine as it appeared to be a lot more work and I did not have a whole lot of confidence that this whole thing was going to work. This is also the reason that I have never mention this until I had the opportunity to log some miles on the rebuild. 29,000 now and counting!!!
Jag har bytt lager i "torque tuben" på min 924S och det var faktiskt en smula krångligt.
Jag provade först en metod som beskrivs i "Clark´s Garage" men den är lite brutal mot axeln och fungerade dåligt för hopmonteringen. Dessutom så stämde inte måtten på de bussningarna som beskrivs till lagrens innerbanor om man nu vill göra nya sådana.
Efter att ha provat några olika mindre bra varianter så byggde jag en enkel fixtur för att kunna linjera axeln med "röret" och så använde jag en liten hydraulisk press (en riktsats från Jula) för att pressa in axeln. Om man inte linjerar axeln ganska noga vid monteringen så nyper den i innerbanornas bussningar. Och även om axeln inte nyper i lagren när den pressas i så tenderar lagren att flytta sig. För att förhindra detta så använde jag distanser av 75mm plaströr mellan lagren för att låsa dem i rätt läge.
/Per S
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Jag såg att bakre lagret i transaxelröret slängt ur sej lite fett,
så jag demonterade det och kollade om det fanns fettkvar och om det kändes bra för övrigt, och det var i utmäkt skick så sen var det bara ett pressa tillbax lagret i axeln.