New rear main seal STILL leaks - 95 540i

[BrianH]

OK, so I replaced my rear main seal on my M60 engine after it started leaking and causing clutch slippage. I've done all the other "usual" stuff recommended when you remove the tranny, like the center bearing, guibo, trans seals, new clutch, etc. I was all ready to re-install this stuff and thought "maybe I should hook up the exhaust, install the flywheel, and test-fire this sucker. I'd hate to put it all together only for it to leak again." Well, for once I had a good idea! Sure enough, the new main seal is leaking! Crap! How can this be? It's definitely leaking around the seal, not the seal housing or the oil pan gasket. I read a post on another board saying that when you install the new seal, you should position it a little deeper or shallower than the original so that you're not on the same wear spot on the crank as the original. My crank seems a have a raised spot, not a groove, where the old seal was. Anyone have an idea what I could have done wrong? I lubed the new seal and crank before installation. Also, I have the new seal out again and it looks fine, so I didn't damage it during the install. Any ideas?

Thanks,

[SoundsandBytes]

OK, so I replaced my rear main seal on my M60 engine after it started leaking and causing clutch slippage. I've done all the other "usual" stuff recommended when you remove the tranny, like the center bearing, guibo, trans seals, new clutch, etc. I was all ready to re-install this stuff and thought "maybe I should hook up the exhaust, install the flywheel, and test-fire this sucker. I'd hate to put it all together only for it to leak again." Well, for once I had a good idea! Sure enough, the new main seal is leaking! Crap! How can this be? It's definitely leaking around the seal, not the seal housing or the oil pan gasket. I read a post on another board saying that when you install the new seal, you should position it a little deeper or shallower than the original so that you're not on the same wear spot on the crank as the original. My crank seems a have a raised spot, not a groove, where the old seal was. Anyone have an idea what I could have done wrong? I lubed the new seal and crank before installation. Also, I have the new seal out again and it looks fine, so I didn't damage it during the install. Any ideas?

Thanks,

It seems that I too have a main seal oil leak....... and we all know that none of that 15W50 or 20w50 oil plus Lucas Stabilizer is going to stop that sort of leak..... do we? Man I cannot believe I just bought the 94 525i and I did not catch that.....live and learn, and besides I put up with a lot more off of my 90 Corrado G60 then this so far.... ;)

[Anton CH.]

I have a similar experience with my front seal. The new one started leaking after being replaced. Bill recomended regrinding the crank to get rid of that groove.

[Craig in Davis]

shallower or did you just read about it? Unless things have changed, yes, you should put it just a touch deeper to provide a good seal. Did you replace the carrier gasket? Did you damage the oil pan gasket when removing the carrier? Both of these gaskets can leak and look like a rear main seal. Fortunately, I've never had this problem when I replaced a rear main so that is about all the help I can offer.

Good luck,

Craig



I read a post on another board saying that when you install the new seal, you should position it a little deeper or shallower than the original so that you're not on the same wear spot on the crank as the original. My crank seems a have a raised spot, not a groove, where the old seal was.

Thanks,

[Bill R.]

A. Oil varnished or coked up and left a buildup on this area
B. The rear main seal got hot enough for some of the rubber to deposit on the crank, either way you should be able to take some 400 grit emery cloth and polish it out, then when its all cleaned up you should be able to tell if the crank actually has a groove in it or not, if not then , inspect the seal housing to make sure that its not cracked and the gasket as robin suggested.. I would then put another new seal in. Don't reuse the new one that you have already had in....





OK, so I replaced my rear main seal on my M60 engine after it started leaking and causing clutch slippage. I've done all the other "usual" stuff recommended when you remove the tranny, like the center bearing, guibo, trans seals, new clutch, etc. I was all ready to re-install this stuff and thought "maybe I should hook up the exhaust, install the flywheel, and test-fire this sucker. I'd hate to put it all together only for it to leak again." Well, for once I had a good idea! Sure enough, the new main seal is leaking! Crap! How can this be? It's definitely leaking around the seal, not the seal housing or the oil pan gasket. I read a post on another board saying that when you install the new seal, you should position it a little deeper or shallower than the original so that you're not on the same wear spot on the crank as the original. My crank seems a have a raised spot, not a groove, where the old seal was. Anyone have an idea what I could have done wrong? I lubed the new seal and crank before installation. Also, I have the new seal out again and it looks fine, so I didn't damage it during the install. Any ideas?

Thanks,

[Bill R.]

harmonic damper not on the crank...





I have a similar experience with my front seal. The new one started leaking after being replaced. Bill recomended regrinding the crank to get rid of that groove.

[Derek A.]

Are you sure its not the front seal on the trans ? I had that problem on my 535i. It was so bad that the clutch was eventually swimming in trans lube. As it turned out there was a bur on the input shaft and it cut up the trans seal. I got the warranty history from the dealer - and it was a problem from the factory.

[winfred]

possible problem with the pcv system making pressure? i think those later style seals are teflon and need some break in time on a clean non oiled crank, a oiled surface supposidly pisses them off because they can't transfer teflon to the crank, i've not done too many of that style seal and have had no problems yet