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MuddyWinny

300Tdi Rear Main Oil Seal Replacement Failure

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I very much doubt I'm the first person to experience this but I'm feeling somewhat distressed at the moment as this afternoon was the first time I started the 90 after replacing the rear main oil seal and it didn't take long before there was a pool of engine oil underneath it (few minutes) :(, say 5cm diameter.

I'd taken the gearbox out to replace the core plug at the back of the engine that was leaking coolant. While there I changed the clutch etc and since the rear main was an unknown I changed it as well (oh how I regret doing that now).

I used a genuine seal from LRDirect. I also used a gasket as one was originally fitted.

I was very careful not to touch the seal and progressively tightened each of the bolts so it went on as square as possible. It did suddenly move into place as it came off the plastic guide if that makes sense.

There was a little surface rust on the rear of the crank (in front of where the old seal had run, i.e. further back to flywheel,  if that makes sense). Not being sure if this would damage the new seal I cleaned the surface with P1500 wet and dry.

Since the rear was of the crank had oil on it I cleaned it with brake cleaner (My understanding is that it leaves no residue on the surface cleaned).

The only other thing that comes to mind is whether I fitted the gasket the right way round. 
It is formed at the bottom such that one side there is a groove and protrudes the other and I can't remember if I fitted the groove to the block or oil seal. I think the grove went to the block.

So I'll do another rear main oil seal but I'm really concerned that either I've damaged the seal journal by cleaning it or something else it wrong.

I think the t-seals are weeping but I wasn't brave enough to change them. Chances are they did get brake cleaner on them when I cleaned the rear of the block.

 

Any advice is welcome.

Is it likely I have damaged the seal journal on the rear or the crank?

Would t-seals cause such a leak?

Finally, would someone confirm which way round to fit the gasket?

 

Thanks

Mark

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How annoying! If the crank is damaged a speedisleeve might provide a solution. It sounds like there is something wrong with the gasket to leak at that rate. If you do use abrasive paper on the journal make sure it is only around it and never across it. 

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Thanks for replying.

I never knew speedi sleeves existed and would be worth a look.

I'm sure I only went around journal and not on the bit the existing seal had 'polished' (it was a few weeks ago now) but i obviously did something wrong.

I have bought a new seal from Turner Engineering. They have advised me that the gasket is now obsolete and to use sealant (which I also purchased).

I'm hoping to take the transfer box and gearbox out this weekend and replace the seal again. I also plan to let the sealant set overnight.

Fingers crossed...

 

Mark

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was the seal one of the ones that comes with the alu housing too?

The turner ones come with the installation cone, now something that took me a few attempts at working our was that the plastic inner cone that is installed in the seal lip, make sure you keep it in the same orientation as it comes to you, i.e the wider part of the plastic thing almost sits over the crank boss, you then give it a firm but confident push which forces the plastic seal holder through the seal allowing it to expand momentarily allowing it to snap onto the flange shoulder, its a tad unnerving but it works.

Even if there is a polished ring from the old seal, unless its a deep groove it will be ok, like previously said as long as polishing was done around the shoulder of the flange and not perpendicular to it, should be ok.

When you take the thing apart you should be able to identify straight away if its leaking from the seal you installed.

I'd probably haul the engine out... I find it easier than faffing around underneath unless you've got a nice pit, or ramps that is. 

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Quick update...

Yes, it is the seal in the aluminium housing, and yes, it was the seal.

In the end I was really OCD about keeping the seal journal clean and made 5 guide studs by cutting the head of bolts and putting a chamfer on the end.

I fitted a seal from Turner Engineering and had the engine running on the drive for an hour and 15 minutes without it leaking so fingers crossed all is well.

 

Thanks for all the replies.

Mark

 

 

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SUCCES !!!

Well Done.

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Thank you :)

It was a bit disheartening to see oil pouring out and know you need to take the gearbox and transfer box out again.

 

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Know the feeling.....

Mine came out 3 times...

 

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I know this thread is old but arjan what did you do if anything differant each new seal you fitted? I am now about to put my third seal in soon due to repeated failure. Have don't it once with the gasket and ince with just RTV, have used a bearmach seal and a victor reinz for the recent one, shaft the seal sits on its lightly emery clothed and cleaned but looks to be leaking again

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I found a genuine one worked for me on the second attempt after the pattern replacement failed. I'd stick to genuine, more costly but pulling the engine out again is such a ball ache.

Mo

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The genuine seals are made by DOWTY and it can be seen on the aluminium housing. 

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