Thread: Rear main seal TDi300

I haver never removed a TDI but have a 3.5 and i find it easiest to move the engine straight forward rather than remove the t/c and g/box.

A couple of things -
1. If the leak is at the junction of the block and transmission bellhousing, then it's not necessarily the rear main seal. The last main bearing cap (that usually holds the seal on a old v8) has two rubber t-pieces on the sides. I had mine go - and you can replace them in situ, sump off. But it is difficult and you have to use a fair amount of good oil proof silicone on the face that joins with the rear main seal, and really clean the mating surfaces of the sump so it seals as per spec.

2. If it is the main seal, it may be possible to move the gearbox backwards on a trolley jack, (after taking off the handbrake assembly) take the flex plate off and replace the seal. Fiddly but do able. If you do replace the seal, consider using decent silicone (I use dow corning 732), doing the 2mm bead and wait 5-10mins routine, and discarding the supplied gasket.

3. If you have a shed and an engine crane forget what I said and just take the engine out.

Originally Posted by langy

A couple of things -
1. If the leak is at the junction of the block and transmission bellhousing, then it's not necessarily the rear main seal. The last main bearing cap (that usually holds the seal on a old v8) has two rubber t-pieces on the sides. I had mine go - and you can replace them in situ, sump off. But it is difficult and you have to use a fair amount of good oil proof silicone on the face that joins with the rear main seal, and really clean the mating surfaces of the sump so it seals as per spec.

2. If it is the main seal, it may be possible to move the gearbox backwards on a trolley jack, (after taking off the handbrake assembly) take the flex plate off and replace the seal. Fiddly but do able. If you do replace the seal, consider using decent silicone (I use dow corning 732), doing the 2mm bead and wait 5-10mins routine, and discarding the supplied gasket.

3. If you have a shed and an engine crane forget what I said and just take the engine out.

Thanks for the response, was aware of the possible side seals on bearing cap & yep Ive got the means to lift motor out, & figured that was going to be the best way just thought I might be wrong. Fact is my patience with the Disco is wearing thin, Ive had it 3 years & spent more time on it than all the other vehicles & gear put together.
Ray

Originally Posted by langy

A couple of things -
1. If the leak is at the junction of the block and transmission bellhousing, then it's not necessarily the rear main seal. The last main bearing cap (that usually holds the seal on a old v8) has two rubber t-pieces on the sides. I had mine go - and you can replace them in situ, sump off. But it is difficult and you have to use a fair amount of good oil proof silicone on the face that joins with the rear main seal, and really clean the mating surfaces of the sump so it seals as per spec.

2. If it is the main seal, it may be possible to move the gearbox backwards on a trolley jack, (after taking off the handbrake assembly) take the flex plate off and replace the seal. Fiddly but do able. If you do replace the seal, consider using decent silicone (I use dow corning 732), doing the 2mm bead and wait 5-10mins routine, and discarding the supplied gasket.

3. If you have a shed and an engine crane forget what I said and just take the engine out.

I have taken your tip and removed all the bits (engine in)to get to the seals on the bearing cap. Any idea how to loosen the cap once the side bolts, starter motor etc have been removed. i reckon you are right about this for various reasons.
cheers

Loyd

Tap cap with hammer. Serious. Use a small hammer, and gently tap it on the side and it will fall out.


You're going to need a couple of bits of plate (steel or alum) and a g-clamp to get the cap back in once the t-pieces are in. Much like compressing piston rings, if you compress the t-pieces, after having smeared the sides of the cap with 732, then the wet silicone acts like a lubricant and you should be able to tap the cap in without stretching the t-pieces too much. Use plenty of silicone against the face of the cap that butts onto the main seal, and it should work. My sump is still OK (and it's been almost a year)