Changing gearbox output seal
- Thread starter Padge
- Start date
Bendy toy
Registered user
Mine is also in pieces.
The rear swing arm has to come off, but you can then check those bearings, drive shaft UJ couplings & splines and FD trunnion needle bearings.
Take off the clutch top cover and use a torch and maybe a small mirror on a stick to check the input bearing for signs of leaks. You can also check the clutch plate thickness. Service minimum is 4.4 mm.
The Haynes manual method with self tapping screws works well. Just keep the drill 25% in form the outer edge as the metal reinforcement ring isn't very deep.
I will be using 17-40-12 2RS angular contact bearings with 1mm shims on the swing arm. The original 17-40-13 2RS FAG taper rollers are costly and have the standard burnished patches with flatted rollers. There is no sign the seals have failed.
If there is sign of a leak on the inner seal, the clutch has to come off. Tube dowels are used at top left and bottom right. The bottom tight can be levered against a Purpose placed?) lug on the gearbox case. Use wood blocks to protect the paint. The top left on mine was absolutely solid. I got it off by using a wedge from the inside. Its not a solution Im happy to use but there was just no other way. However once it was open I could see than the dowel and bolt hole could be tapped out to M10.
I've tapped mine M10 right through so next time I will have a jacking point to push the gearbox off it's dowel. I believe it could be tapped in-situ, but with it all assembled could not take the risk of chewing the engine case threads. However with it opened up, I believe tapping it could have worked in place. Measure the unthreaded hole depth and go in with M10 taper tap to the point where it would hit the M8 threads in the engine case. Then go through with second taper and plug taps. A long M10 bolt should now go through and jack the gearbox off the engine. Screw it in until it stops and take it out again to check the threads are not binding. If they are, you will need to file or turn the threads off the first few mm.
Its all gone back with lots of copper grease on the dowels, the bolts full length and into the newly tapped dowel. Corrosion in there would not be good.
The rear swing arm has to come off, but you can then check those bearings, drive shaft UJ couplings & splines and FD trunnion needle bearings.
Take off the clutch top cover and use a torch and maybe a small mirror on a stick to check the input bearing for signs of leaks. You can also check the clutch plate thickness. Service minimum is 4.4 mm.
The Haynes manual method with self tapping screws works well. Just keep the drill 25% in form the outer edge as the metal reinforcement ring isn't very deep.
I will be using 17-40-12 2RS angular contact bearings with 1mm shims on the swing arm. The original 17-40-13 2RS FAG taper rollers are costly and have the standard burnished patches with flatted rollers. There is no sign the seals have failed.
If there is sign of a leak on the inner seal, the clutch has to come off. Tube dowels are used at top left and bottom right. The bottom tight can be levered against a Purpose placed?) lug on the gearbox case. Use wood blocks to protect the paint. The top left on mine was absolutely solid. I got it off by using a wedge from the inside. Its not a solution Im happy to use but there was just no other way. However once it was open I could see than the dowel and bolt hole could be tapped out to M10.
I've tapped mine M10 right through so next time I will have a jacking point to push the gearbox off it's dowel. I believe it could be tapped in-situ, but with it all assembled could not take the risk of chewing the engine case threads. However with it opened up, I believe tapping it could have worked in place. Measure the unthreaded hole depth and go in with M10 taper tap to the point where it would hit the M8 threads in the engine case. Then go through with second taper and plug taps. A long M10 bolt should now go through and jack the gearbox off the engine. Screw it in until it stops and take it out again to check the threads are not binding. If they are, you will need to file or turn the threads off the first few mm.
Its all gone back with lots of copper grease on the dowels, the bolts full length and into the newly tapped dowel. Corrosion in there would not be good.
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