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Rear Diff Breather

Posted: Fri Jul 05, 2013 7:10 pm
by little_pete
I have a leaking front seal on my diff (though it's a good excuse to look for a 3.7 diff) On my searches for said diff I read that someones leak was exaggerated by a blocked diff breather. I investigated mine, the cap on my diff breather appears to be solid, no way to breath with it. Is this normal? I've pulled it off it will hold water no problem with no leaks. One other thing to mention is it has been painted on the outside. Could this fill some small breathing hole? Should I drill a little hole in it?

Re: Rear Diff Breather

Posted: Fri Jul 05, 2013 7:33 pm
by philthehill
The diff breather should be clear as there is nothing overly complicated about it. It is just like a tube with an umbrella over the top.
If it has had excessive paint put over it could be blocked and yes the axle tube does need to breath as any build up of pressure could cause the oil seals and/or gaskets to leak.
If in any doubt replace £2.50 plus vat and postage from ESM Minor parts Part No: DIF206.

Re: Rear Diff Breather

Posted: Fri Jul 05, 2013 8:00 pm
by little_pete
Ok I cleaned the plastic tube, which initially I thought was metal, tried to unscrew it with pliers and lots of black paint cracked off to reveal two decent sized holes :-) Also great to see that on taking the filler cap off oil gushed out, so can't of lost too much. From the little drips and the spray underneath. I thought I might be loosing loads at speed. though probably only done 80 miles since filling up. I'll just keep an eye on it until a nice diff comes along.

Thanks for the part numbers though

Re: Rear Diff Breather

Posted: Fri Jul 05, 2013 8:13 pm
by philthehill
Some of the early breathers were metal.
If the car was level and oil gushed out when you removed the filler/level plug that indicates that the axle was overfilled which in itself can cause oil leaks.
Always fill the axle with the car level and let any excess drain off into a container whilst you go and have a cup of tea/coffee.
Remember to put the plug back in after finishing your tea/coffee otherwise the oil level will go down rather faster than you intended !!!!!!!!!!!!!!

Re: Rear Diff Breather

Posted: Fri Jul 05, 2013 8:53 pm
by little_pete
Ah It was reasonably level but I filled it with the nice thick EP90? which I noticed once squirted through the nossle took a while for the level to react (on the cold morning I filled it up), I thought the more the better and bunged the plug in once I started to get it pouring out.

Re: Rear Diff Breather

Posted: Fri Jul 05, 2013 9:17 pm
by bmcecosse
More is definitely NOT better in this case - drain it down to the correct level. Too high will leak out over the rear shoes.....although leakage from the front seal is a useful anti rust treatment for the rear floor pan........