Clutch started slipping a few weeks ago.

 

Got gearbox out today (its a really tight fit)  plus clutch and DMF.

 

Oily contamination on the friction surfaces is the obvious cause of the slipping. But the crank seal and engine side of hte DMF are as dry as a bone.

The inside bellhousing is covered in a thin layer of black oily residue all the way to the gearbox input shaft and release bearing. So its coming from either the gearbox or the clutch slave. I dont know which though.

Anyone know how to tell which is the source of the leak? Unfortunately, Ive no idea if the hydraulic fluid has been going down in the reservoir as its not been kept here.

 

These gearboxes have an internal Central Slave Cylinder (CVC). Ive not come across these before. Is it possible to test the CVC for leaking ? By connecting it to the hose in the engine bay with some plastic tubing and genrating a bit of hydraulic pressure with the peddle maybe ?

 

If I remove the CVC will I be able to tell if the gearbox shaft seal is leaking.

 

The CVC s seem expensive and not listed on Euro Carparts. Anyone know where best to get one at non-dealer prices? - in case I need to replace it.

 

Any help would be much appreciated.

 

 

 

 

Actually ive found loads of CVCs on the internet , at a variety of prices. From £35 to £120.

 

Any ideas on how to tell where the contamination is coming from ?

 I'd renew the slave cylinder and the gearbox input shaft oil seal. I'd probably renew the crank oil seal as well whilst it's dismantled. You don't want to have to take it all apart again.

Same as above but iirc you need to remove some sump bolts to change the crank one.

Change the whole lot, you need a clutch as well so you should also do the DMF, oil seals are very cheap and the concentric slave is also not expensive. Don't muck about, do it all while it's in bits and top the gearbox up as well.

The rear main oil seal (VAG calls it a 'rear sealing flange') is about £55 retail, as the actual radial seal is not available separately :(

Same as above but iirc you need to remove some sump bolts to change the crank one.

+1

To get a good seal on the sump, you need to remove it and run a new bead of sealant, but you would me amazed at how many people miss the two bolts that go through the sump as they try to remove the seal first.

It's worth replacing (or at least inspecting) the oil pickup/o-ring whilst the sump is off. It's unusual for it to be blocked on a diesel, but it does happen.

Also could be the tandem pump leaking down onto the bell housing . if it was the slave cylinder you would have been losing fluid from the resiviour.

cheers for all that info.

im pretty sure its leaking from the gearbox drive shaft seal. im replacing that and concentric slave/release bearing 

As above I would do the lot while it's in bits.

 Drop the box oil to imo

 

 

The rear main oil seal (VAG calls it a 'rear sealing flange') is about £55 retail, as the actual radial seal is not available separately :(

 

If there are sizes on the seal it should be easy to find one.

Plenty of suppliers on E-Bay.

Just priced one up from Yamaha for my R1 engine,£30.

Typed the size in on E-Bay and it was under £5 delivered

...If there are sizes on the seal it should be easy to find one...

IIRC, the reason why the radial seal was dropped as a separate item, is that it was very difficult to fit to the flange plate. This lead to it being damaged and leaking.

IIRC, the reason why the radial seal was dropped as a separate item, is that it was very difficult to fit to the flange plate. This lead to it being damaged and leaking.

 

Ah right,can be damaged easily.

Most cars don't have the luxury of a removable plate though with a seal in it,so plenty of seals are replaced properly without damaging them

Ah right,can be damaged easily.

Most cars don't have the luxury of a removable plate though with a seal in it,so plenty of seals are replaced properly without damaging them

I always assumed that the flange plate was someone's bright idea that would let you use a press to replace the seal.