Rear main seal question

[Codfish]

Is this seated correctly ??? The front is flush with the housing.

[john_a]

Is this seated correctly ??? The front is flush with the housing.

I'd want the seal seated fully. You do not want it to be off-square, and bottoming it in the recess helps avoid it getting tilted.

Yours, as pictured MAY still be fully seated, if there is the factory spacer ring behind the seal (and hidden in the picture view.)

That spacer is 0.060" thick & only 5 mm wide, so it would not show up in your pciture that shows the gap.

If there is no spacer present, then the seal would be better off seated fully.

If your crank has a wear line from the old seal, then get a hold a spacer or two to move the seal off the wear line.

[Codfish]

The problem is, it will not go any further in and still be flush with the front of the housing. Or should I not be concerned with that ??? I looked at another engine I have, and it's flush.

Is this seated correctly ??? The front is flush with the housing.

I'd want the seal seated fully. You do not want it to be off-square, and bottoming it in the recess helps avoid it getting tilted.

Yours, as pictured MAY still be fully seated, if there is the factory spacer ring behind the seal (and hidden in the picture view.)

That spacer is 0.060" thick & only 5 mm wide, so it would not show up in your pciture that shows the gap.

If there is no spacer present, then the seal would be better off seated fully.

If your crank has a wear line from the old seal, then get a hold a spacer or two to move the seal off the wear line.

[john_a]

Why do you think it is important to be "flush" on the front side?

BMW provides the spacers if needed to move the seal off the wear line, but even when using those it is always based on the machined lip inside that you are to bottom the seal against. Forget the front, this is not a through-hole where you have to control the depth based on a feature at the front. Do you have a spacer in there? Do you need a spacer in there? If not, then get the seal pushed in all the way.

[Codfish]

Let me start with THANK YOU FOR RESPONDING !!!

I have 3 m-10 engines in my garage (1 I am putting together the other 2 are for future use). When I look at the other engines it seems like the seals are flush with the housing... So naturally I though that the seal has to be flush... I dont see a spacer of any kind and I fear "tapping" it in further (to seat it) that might make me ruin the seal...

Any chance anyone has a pic of what the spacer looks like???

or

what about a pic of a properly done seal in the housing ???

Thanx in advance

Wayne

Why do you think it is important to be "flush" on the front side?

BMW provides the spacers if needed to move the seal off the wear line, but even when using those it is always based on the machined lip inside that you are to bottom the seal against. Forget the front, this is not a through-hole where you have to control the depth based on a feature at the front. Do you have a spacer in there? Do you need a spacer in there? If not, then get the seal pushed in all the way.

[john_a]

Any chance anyone has a pic of what the spacer looks like???

or

what about a pic of a properly done seal in the housing ???

Wayne

Wayne, you can see an illustration of the spacer in any of the online BMW parts catalogs, same page that shows the rear main seal.

Not much more to it than the dimensions I gave in my first reply.

If you look at your seal closely it has the size visible on it, the OD is 110 mm. The spacer is a thin, flat metal ring the same OD (110 mm) as the seal. I alluded to the other dimensions earlier, so the whole thing would be 110x100x1.5 mm like it shows in the parts catalog.

Now I really don't think any picture is going to help you confirm your seal installation. Because you still won't know if yours has a spacer or not by looking at any other pics, right? So how can you compare the two? The only picture that could help you would be if you could go back in time and photograph what was there when your seal went in. You've got two engines to look at, but that does not tell you anything about what the part in your hand has.

Seat the seal, if it won't go any deeper, then it's already seated.

Read the numbers on the seals, there will probably be 90, 110, 12 (ID, OD, thickness.)

Does the new seal have the same thickness number (12) or does it show 90x110x10?

Or 90x110x15? that could make it look different when installed.

But just seat it and be done with it, it does not matter how it compares visually if you can't be sure which ones have a spacer present, or don't know the seals are the same thiickness.