push rod seal leaking oil

[scottyintex]

While we are on oil.........and oil leaks...............has anyone replaced the push rod seals on their bike. I am getting a few drops of oil from a push rod seal leak.....not enough to make me want jump and fix it yet. However, tiny leaks have a way of getting bigger....so.....some time in the future I figure I gotta do it. How big a job is this? Are there certain pitfalls to be a voided?

[Bob_Roller]

You have to remove the cylinder head to get the pushrod tube seal replaced. So the exhaust system has to be removed, and if the exhaust nuts have not had periodic removal and had an anti-sieze compound applied to the threads, you're in for another 'adventure'.The seals are not symmetrical in cross section, so they only go on one way, make sure you take note the orientation of the seal before you remove the old one. While you're there, it wouldn't be a bad idea to replace the cylinder base o-ring as well, all you have to do is remove the cylinder, change the o-ring and put the cylinder back on.

[Chris_in_BC]

Bob basically describes well what you need to do.
I would add, if you replace the cylinder base O-ring, also get the two little O-rings that go on the top engine cylinder studs. And be careful about putting too much sealant in this area as this is your oil supply for the heads.

Probably want to have new head gaskets available. You don't have to split the heads/cylinder, if you do nothing but replace the push rod seals, but it gives you a chance to check piston and valves.
And the push rod tube seals for the R65 are a different part number and shape  than all the other airhead models.

That said it can take a long time for the seals to become a major leak, sometimes they stay minor.
Not something you have to rush into if minor at the moment.

[Justin B.]

I have done a few of these and it's not that difficult, but you MUST remove the cylinder as the push rod tubes are attached to the cylinder.  You should order the following parts (do it way before hand and you'll have plenty of time to take advantage of Chicago BMW's discounted prices:

Head gasket
Cylinder base O-ring
2 ea. small O-ring for upper studs

** Double the above if doing both sides. **

If you have never had your exhaust nuts off it is likely they will be frozen.  Start soaking the exhaust nuts a couple weeks in advance with Kroil or PB Blaster (or other "REAL" penetrant), but I have never had this work.  Unless you can afford to be down, with engine in bits, for a while it might not be a bad idea to go ahead and order a pair of nuts along with your gaskets.

It will likely take quite a bit of torque to get the nuts moving, but once they start should spin off with the hand.  If they break loose, turn easily for 1/4 turn or so and then start getting stiff you should probably stop right there and get out the saw.

On the older bikes you could make a tool (or use a large flat-blade screwdriver) to re-seat the engine end of the drain-tube but I have never tried that trick on the R65.  I think the Haynes manual has drawings for a "tool".  I have had pretty good luck using engine oil on the tube-to-seal junction and a smear of Hylomar between the seal and engine block.

Good luck...

[Semper Gumby]

<snip> I would add, if you replace the cylinder base O-ring, also get the two little O-rings that go on the top engine cylinder studs. And be careful about putting too much sealant in this area as this is your oil supply for the heads.

Alert Alert Danger Danger Will Robinson....  Be very careful about using ANY sealer around the base near those top two studs and their o-rings.  That is where oil pushes its way from the case to the cylinder head  (Around the top studs!!!!!).  If you get any sealer between the little o-ring and the stud...Bad things will happen to your cylinder head and valve rockers.  For the record the last time I replaced my push rod seals I used NO sealer on the base (Between the case and the cylinder).  The o-rings (The thin large one at the base of the cylinder and the two small ones around the top studs) work very well and have not leaked...ever!

Now about those G@wd D$%N F&*K@NG Worthless pushrod seals...  I may just seal the SH&T outta them.   I'm thinking a little coppercoat or some Permatex red Gasket sealer.

BTW - These top studs are a weak point in the system.  If you over torque and pull one out you are in for big trouble.  Its hard to heilicoil something that has oil flowing about it.  Then you are out a set of cases.  

End of alert.  We now return you to your regular programming......

[Baffo]

BTW - These top studs are a weak point in the system.  If you over torque and pull one out you are in for big trouble.  Its hard to heilicoil something that has oil flowing about it.  Then you are out a set of cases.  

I just have had all 8 holes recoiled with helicoil (1 on each side did come loose and was fed up with them so redone them all), the thread starts a bit deeper than the oil hole, so there is no problem, also the studs are long enough to let the helicoil 'begin' just after the oil-hole, so, no troubles at all

[Semper Gumby]

Wow.  When ever I talk to mechanics about helicoiling those top studs they start hedging - not a good sign.  Glad it worked out for you.  If ever I need this service perhaps I will send my case to you?

[Baffo]

Wow.  When ever I talk to mechanics about helicoiling those top studs they start hedging - not a good sign.  Glad it worked out for you.  If ever I need this service perhaps I will send my case to you?

I didn't do it myself, and I think shipping to the Netherlands will cost you, including time... [smiley=cool.gif]

Take a look here also http://home.jps.net/~snowbum/engineinternals.htm

[its_only_me]

I think you can tap the seals in a bit as a temp repair...

see...

http://www.realclassic.co.uk/bmw06090500.html

[msbuck]

Yep, that's what Graham has been doing on his for a few years now.  There is a special BMW tool to do this.  But you can make up one of your own without too much trouble.  I think Graham's are finally to the point that we're going to try to replace his seals this winter.  (We better get started, spring is just around the corner!!)

[Semper Gumby]

Tapping your pushrod seals???!!!!!  I have never heard of this.  Special tool for this.  Oh no .... more Casual Tool Acquasition!!!!  

I suppose you could cut a slot in a large enough socket to get around the pushrod...hmmmm.

I'm still thinking about "sealing the SH&T" out of it idea.

Ha I read the article and he used a DRIFT!!!  I can't wait...to bad I'm on the road again.

Greetings from Cold but Plowed Boston MA.

TTFN,

[Justin B.]

Bill, I have always used a wide flat screwdriver but I think the Haynes manual has a drawing of one and I think it can be made out of a chunk of conduit.  I still don't know if this does any good on the newer engines.  Didn't sometime in the late 70s bring about push-rod tubes that are permenantly affixed and can't move?

[Chris_in_BC]

 Didn't sometime in the late 70s bring about push-rod tubes that are permanently affixed and can't move?

I agree Justin. In the early 70's the ring around the push rod tube pressing on the rubber was just a press fit on the tube. You could tap the rubber in a little tighter by tapping on the ring, in effect sliding it down a bit. In the late 70's BMW started brazing or welding this ring to the tube. Now if you try to tap down the ring you are trying to drag the push rod tube out of the top of the cylinder. Not easy and probably not a good thing.

Taping the rubber itself in a bit into the block might help for a bit , but I have never had much success. I think the rubber just gets hard reasonably quickly and after that you don't have much luck stopping the weeping. Always been amazed at how hard the rubber is on the ones you take out compared to new ones.