Pushrod oil leak

[georgesgiralt]

Hello !
When I put the R65 back on the road, I bought her new rings and replaced all gaskets because oil was all around.
Now, a little more than a year after, I still have a leak at two of the push rod tubes. Even with the correct tool, I can't suppress the leak. And the rubber was new.
So I plan to remove the barrels soon and address the issue.  I was wondering if it could be wise to put some Drei bond seal or some Permabond A136 (I have both products) to solve the leak once and for all ?
Should I push the tubes into the heads before mounting the new rubber, and press them in on the crankcase with the tool and a hammer or should I use the current position hoping for correctness ?
I must admit that I'm somewhat ... hum... to have to remove the barrels, use a new seat of gaskets after one year... So a good and permanent way to solve this will make my garage floor and myself happy !
So your wisdom and experience will be appreciated !
Thanks

[Rob Valdez 79 R65]

The tool was a stop-gap measure back in the days when the metal ring on the pushrod tube was not fastened to the tube.
When you smacked the ring with the tube, the ring moved on the tube.  It can't do that on the R65, as far as I know.
All you would be doing is trying to pull the tube out of the cylinder, and I don't know if that is possible, with the tool.

The leak is a pain, I know.  I don't know if sealant will work or not.
Make sure every thing is clean, you have the correct rubbers for the Type 248 engine, and make sure you have them installed with the top "up".

[georgesgiralt]

Well, a local BMW Guru repairing airheads (and airheads only) since the late seventies solved one leak by using the BMW tool on the ring. So I think it could be useful, sometimes. But it failed on two places which are still leaking.
The rubber I installed were of unknown origin (I can't remember who supplied them)  and installed by the Haynes Manual. Now, I've bought BMW parts with the correct P/N. So I may be lucky this time ?

[montmil]

Snowbum has an excellent article on push rod tube seal replacement. Read what he has to say about sealers, installation lubricants and alignment. Also, the R65s do not have the "adjustable" compression rings as did the earlier marques.

On something as labor intensive and gasket pricey as a tube seal replacement, I would recommend staying with fresh OEM rubber from a BMW dealer. I seem to recall that the raised 'seam' on the rubber bit should be installed with the seam down.

A frustrating re-do, I'm sure.

[Mike V]

George,

You don't mention what side of the motor is leaking.  Left?  Right? Curious.

I wouldn't recommend using a hammer on the Tubes and collars.  Theoretically you should have adequate compression on the PTS's with the correct head torque and pressed installation depth of the tubes.

Were the PTS's installed correctly as far as you know?

[nhmaf]

I've heard from more a couple sources that using a little bit of the gasket dressing/cylinder base sealant can be helpful - do make sure that things are perfectly clean beforehand, too.  

Ridge/seam on the bottom side is also what I understand to be the correct orientation.

[Julio A.]

The last time I used the pushrod stop gap tool, I inadvertently made the metal ring loose on the pushrod tube, loose enough to enable my bare hands to move the rings back and forth and made the leak worse. I fixed that by replacing the tubes, which is a very annoying and time consuming job to do.

My r65 had the press fitted metal rings on the pushrod tubes. Post 81 models have brazed or welded tubes I believe, and the use of the the tool on these types would actually do nothing more than to possibly damage the tubes.

[georgesgiralt]

Hi !
thanks for your advices, but things did not turn out as I planned today.
Both side are leaking. On the left side it is the exhaust tube, and on the right side there is only a weep on the intake tube.
Left cylinder leak a lot at the base and the right one only a drop once in a while.

Heads where and are torqued well, and as I assembled everything myself, I'm pretty sure the jointing surface where clean and free from burr or trace of previous rubber.
This part of the maintenance is delayed a bit, see my posting about the fork..

[georgesgiralt]

Hello !
This morning, I was cleaning the shop and thought I could have a very detailed look at the right hand leak (by far the most important).
Guess what ? The push rod seals are quite dry but the base of the barrel is painted with oil. So I surely have a torn O-ring or something like that.
Of course I will dismantle and address this, but....
I'll call Permabond to the rescue !