• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Push rod tube seal 1986 R80

Hello all, I was wondering if there is an easier way to replace the tube seals? I looked in the haynes, it does not really cover replacing them, just looking at it it looks like i have to remove the cylinder jug to replace them. If there is a way that I do not see, please let me know, It looks like fun from my view.
 
Oak sells a pamphlet that is a step by step guide to this. $25 last I checked. Worth it...email him at
askoak at aol dot com.
 
My 86 R80's tube seals leak with sythetic oil but they don't with conventional. It has been leak free for the last 13+ years.
 
Funny thing is i changed the oil due to oil pan gasket leaking, it was crispy, i replaced the oil with standard non synthetic oil, now it leaks from the tubes, it was at first leaking badly past the dip stick o ring, had to replace that as well. after wiping down the new oil leaks and test driving it after replacing the o ring, the passenger side push rod tube is leaking, i do not think any of it has been replaced, 26 years old, somethings bound to leak. if there are any step by step procedures to replace that i do not have to pay for thatll be better.

Looking at Oaks pictures of topend disassembly your almost rebuilding the motor if you have to replace the seals, your removing the piston from from the rod. is there a way of replacing the seals without having to go that far and still be done correctly?

ALSO is there a crankcase vent I am not seeing in the manual that might cause excess pressure to leak?
 
Actually . . . .

In bringing my R100RT back I had to replace the push rod tube seals. Of all of the projects it was one of the easiest jobs.
Follow the directions in Haynes and buy a ring compressor or a big radiator clamp and you will be OK. Note arrows on top of piston.
Campbell Tellman II
:thumb
 
Here is a recent thread talking about pushrod seals and the involvement (or lack there-of) needed: http://forums.bmwmoa.org/showthread.php?t=62620&referrerid=51262

I recently replaced mine but only needed to slide the cylinders from the engine casing and then slide them back. My 78 has no cylinder o-rings or gaskets, just Hylomar (which is available but not that easy to get). The push rod o-rings were in good shape, so I left them alone. I am not sure what subtle differences there are for a '86. I read Oaks guide carefully, but have taken the cylinders off before many moons ago -before Oaks guide existed. It's not that tough, but Oak does have some good pointers. One point he makes is not using any hammer other than rubber. I needed to use a rubber hammer (mallet) to coax my cylinders away from the engine housing. Cleaning off and reapplying the Hylomar was the biggest part of the job.

Here is a pic of the job mid-way through:
 

Attachments

  • pushrod seals replacement.jpg
    pushrod seals replacement.jpg
    74.2 KB · Views: 170

Wow, that's a great step by step photo guide, but..........

I only slide the heads/cylinders back a few inches to access the seals
Note: there is no gasket or Hylomar bwt head & block just o-ring on cylinder head bolt.
(92 GS)
Have fun.

<a href="http://s1089.photobucket.com/albums/i358/brittrunyon/?action=view&current=P9262310.jpg" target="_blank"><img src="http://i1089.photobucket.com/albums/i358/brittrunyon/P9262310.jpg" border="0" alt="Photobucket"></a>
 
The answer to the original question is ... there's no easier way.

It's simply foolish to not replace the cylinder stud and cylinder base o-rings at the same time.

And, I wouldn't call the process "difficult" in any event.

A push-on-from-bottom ring compressor is < $30 from Snap-On

RCL30.jpg


http://buy1.snapon.com/catalog/item...roup_ID=675642&store=snapon-store&dir=catalog
 
The answer to the original question is ... there's no easier way.

It's simply foolish to not replace the cylinder stud and cylinder base o-rings at the same time.

And, I wouldn't call the process "difficult" in any event.

A push-on-from-bottom ring compressor is < $30 from Snap-On

RCL30.jpg


http://buy1.snapon.com/catalog/item...roup_ID=675642&store=snapon-store&dir=catalog

Wow. Really?

If someone feels the need for complete disassembly to replace the seals, the previous site linked is the way to go: http://www.pbase.com/dqmohan/prtseals or read a Haynes, Clymer or BMW repair manual.
 
Easiest way to to remove exhaust headers, bundgie carbs away from head, remove spark plugs, remover rocker arms, pull entire head and cylinder assembly away from block until wrist pin is visible,,remove one of the keepers, push wrist pin out till rod if free (make sure rod doesn't slam down and dent the mating surface), slide assembly rest of the way off.

Clean all surfaces, check cam followers for perfect surfaces, apply very thin layer of Hylomar to base of cylinder. (personal preference, I use assembly lube when installing pushrod seals since they have to move very slightly due to temp differential). Never had one leak. Install large (if needed) O ring and the 2 small ones..the Hylomar will hold them in place.

make sure the small top O rings are in place,,push head/cylinder assembly back on the rods until you can position rod in piston..push wrist pin back in..make sure it's all the way in and seated, install NEW wrist pin keeper, push head until cylinder is closely seated against block, install pushrods back in same holes,,install rocker arms..torque properly (3 stages), install headers, install carbs. Leave rocker arm covers off when restarting engine - oil passages are part of the top engine studs so you want to make sure any HYlomar or crimped small O ring hasn't clocked the hole..run engine for maybe 30 seconds and you should?better have a small stream of oil running down each rocker arm.

Place Teflon cookie pans under each head to catch the oil..if you want to run the engine like this for a couple minutes...you can then wait for a total cool down and retorque the heads..then go for a 3K mile ride and check the heads then.
 
Funny thing is i changed the oil due to oil pan gasket leaking, it was crispy, i replaced the oil with standard non synthetic oil, now it leaks from the tubes, it was at first leaking badly past the dip stick o ring, had to replace that as well. after wiping down the new oil leaks and test driving it after replacing the o ring, the passenger side push rod tube is leaking, i do not think any of it has been replaced, 26 years old, somethings bound to leak. if there are any step by step procedures to replace that i do not have to pay for thatll be better.

Looking at Oaks pictures of topend disassembly your almost rebuilding the motor if you have to replace the seals, your removing the piston from from the rod. is there a way of replacing the seals without having to go that far and still be done correctly?

ALSO is there a crankcase vent I am not seeing in the manual that might cause excess pressure to leak?

You don't have to take the head off of the cylinder. Just undo the 4 bolts that hold on the rocker arms, carefully pull the cylinder back with the head attached until you can just see the circle clip on the connecting rod/piston and go no further. The piston pin will only push out one way and is identified by the notch in the piston. Carefully remove the circle clip ( shouldl be replaced with a new one, most don't ) and then gently tap the piston pin out and remove the piston with the cylinder head assembly. You don't want to disturb the rings, if you pull it out so far that the rings are exposed then they should be replaced. As you slide this back on the head bolts stop and as the pushrod tubes are clear of the seals they are easily replaced. Repeat the above to get the head/cylinder/piston back into place.
 
Do you have any concern for leaving the 12 and 6 o'clock bolts fully torqued while the head/cylinder is off? I would be for possible head warping if it is left that way for too long. Hard to say what is too long...unevenly torqued can't be good.

For the price of a set of head gaskets, undo all bolts and pop the head. Now do the circlip/wrist pin thing. You'd even get a chance at decarbing the head.
 
Do you have any concern for leaving the 12 and 6 o'clock bolts fully torqued while the head/cylinder is off? I would be for possible head warping if it is left that way for too long. Hard to say what is too long...unevenly torqued can't be good.

For the price of a set of head gaskets, undo all bolts and pop the head. Now do the circlip/wrist pin thing. You'd even get a chance at decarbing the head.

The gurus seem to think that two hours is the time limit if going the rocker bolt route. No idea how they come to that conclusion. Seems best to me if you just do the rocker bolt route then a stone cold engine would be a good idea, and work briskly! Many pushrod tube seals have been replaced this way and I have not read/heard of any problems.
 
Last edited:
I see where Snowbum says he "approves" if not more than 2 hours. One minute, two hours, 24 hours...untorqued is untorqued but I suppose it could be done. My issue is the work "briskly" note! I hate to rush myself on these kinds of things. Inevitably, something comes up, I don't have the part, or have to get onto something else in the meantime...then I'm working every more briskly, heading for a possible ef-up.
 
I see where Snowbum says he "approves" if not more than 2 hours. One minute, two hours, 24 hours...untorqued is untorqued but I suppose it could be done. My issue is the work "briskly" note! I hate to rush myself on these kinds of things. Inevitably, something comes up, I don't have the part, or have to get onto something else in the meantime...then I'm working every more briskly, heading for a possible ef-up.

Regardless of whether you chose to remove the head completely or go the "rocker" bolts only" route, this job is certainly one where preparation and following the script is important. I guess the fall back position if something goes egg-shaped during a "rocker bolts only" job and it is going to be much longer than anticipated would be to then separate the head from the jugs.
 
Back
Top