Rear Crankshaft Oil Seal

[mintex]

Bugger, that's not good 

[Mics126]

that is a horrible crack. have you been able to see what has caused it to go like that, its not a common site.

[Bambino126]

Thanks for the offer Rusty, but I've just bought a 2nd hand Bis gearbox off Ebay for £130. It should come tomorrow. I'll take the broken one out today and see what went wrong with it. Think I found the leak though!

[Bambino126]

I've taken the gearbox out now, but a bit disappointed to see that the bell housing has got oil in it again. I've only done 50 miles since I changed the clutch and cleaned out the bell housing. While the engine was out I changed the crankshaft rear oil seal and the O-ring that goes around the rear main bearing carrier.
I know that its engine oil in there not gearbox oil because I recently changed my engine oil but haven't changed my gearbox oil for a long time. The oil that leaked into the bell housing was golden brown not black so it must be engine oil.

I'm starting to doubt myself now because I've looked at the Fiat parts diagrams and they show a 6-hole paper gasket rather than an O-ring sealing the bearing carrier to the engine so have I fitted the wrong part?

So I ask you BIS experts, should the rear bearing carrier be sealed to the engine crankcase with....
this?


or with this?

[Bambino126]

The only reason I fitted the black O-ring is because when I disassembled the bearing carrier, a large O-ring came out, and in bad condition, but the car's previous owner may have fitted the wrong part and I have simply copied his mistake. 

[Pete126]

By the look of the rear bearing cap nearly all of the white metal has worn away, The oil will be leaking out of the new seal because of the play in the old bearing.

[Bambino126]

Arr that explains it then. Thanks Pete.
I have ordered a new whole bearing assembly now. But still confused which type of seal to install it with?

[Rusty's Uncle]

What Pete says may be true but bearings that are nicely "run in" can look similar and if the bearing was that knackered you would probably have had no oil pressure . The paper gasket was used on the 500s up until the later 126s so I think the Bis would be the o-ring. In a full gasket set there are two large o-rings. The thicker one is for the oil filter. Before I realised this I once fitted the thin one in the filter and ended up spraying the engine bay with nice clean oil  
From memory there should be a chamfer on the crankcase which is designed to accommodate the o-ring and form a seal. I have also come across cracked main bearing housings.

[Pete126]

What Pete says may be true but bearings that are nicely "run in" can look similar and if the bearing was that knackered you would probably have had no oil pressure.

Not sure i agree with that statement The white metal tin/zinc layer is there to reduce friction and heat,

This was my rear bearing which was running without loss of oil pressure but was leaking oil through the new oil seal..

[Bambino126]

Wow that bearing looks much better condition than my one. I have ordered a brand new one which will arrive on Monday. There was the option to buy undersized bearings but I went for the standard size because I hope I won't need to have the crank re-ground. I hope this will be ok.
So the conclusion on the seal is to use the O-ring style not the paper one. Thanks Rusty.  Shame I just ordered the paper one Doh!

[Bambino126]

Does anyone know where I can get the "thin" O-ring from? I've used my last one, and don't want to buy another whole gasket set for £40 just to get one O-ring! Does anyone know a supplier that does them individually? Or if I fitted the paper one would it still be oil tight?
Thanks again for the advice guys.   

[Rusty's Uncle]

Does anyone know where I can get the "thin" O-ring

Think I know a man 
Just pulled one out of one of my gasket sets. Out of interest I offered it up to a main bearing housing and I can see that if it does not seat flat then it could easily be damaged by the sharp edges on the bearing housing. I think that I would hold it in place with a dab of instant gasket when you refit the bearing.
PMAPM&ICP
That stands for ping me a pm & I can post 

[dadandlad]

For my O-Rings and shaft seals I use Fluid Power Equipment really helpful and no order too small
I use the Doncaster branch as they seem to have more of a idea

http://www.fpe-ltd.co.uk/default.aspx

[Bambino126]

Does anyone know where I can get the "thin" O-ring

Think I know a man 
Just pulled one out of one of my gasket sets. Out of interest I offered it up to a main bearing housing and I can see that if it does not seat flat then it could easily be damaged by the sharp edges on the bearing housing. I think that I would hold it in place with a dab of instant gasket when you refit the bearing.
PMAPM&ICP
That stands for ping me a pm & I can post 

Thanks Rusty PM sent

[Rusty's Uncle]

O-ring sent