Pushrod tube seal replacement

[tenderfoot]

On my cafe project which is progressing, albeit slowly, I have an oil leak on the right hand pushrod tubes.

Is there an easy way to replace these.?
Ideally I'm looking for a pictorial walk-through like Bpeckm put together on the front wheel bearing replacement.
Even I could follow that and do the job successfully.

[Wirespokes]

You know, it would be more work for me to write it all up than just doing it.

If you can torque the head bolts, set the valves, and seal up the cylinder bases, and pull the headers, that about says it all.

Snowbum has something to say on this I'm sure. Check him out:

http://bmwmotorcycletech.info/search.htm

I'd do a search on pushrod tube seals.

After reading all that, if you still have questions, get back to us!

[Bigger Al]

Wirespokes is right. It's an easy job, and shouldn't take you more than an hour or two to do. I've done it 4 or 5 times, and can pull it off in about 45 minutes.

The steps:

1.) Bike on centerstand

2.) Mufflers off

3.) Headers off. Use caution with the exhaust nuts, and don't force them. Liberal application oof anti-seize on reinstallation is a good thing.

4.) Bump whichever cylinder you start with to TDC.

5.) Rocker covers off.

6.) Loosen head bolts a bit at a time, then remove.

7.) Put rockers aside, remove pushrods.

8.) Gently, but firmly pull the cylinder out on the piston, but not so far that you slip the rings out of the bore.

9.) Clean up the pushrod tunnels in the block and put the new seals on the tubes.

10.) Apply sealer of choice to mating surface between the cylinder and block. A little goes a long way, and attention must be paid to the oil hole at the top of the cylinder skirt. Don't plug that up.

11.) Slide the cylinder back on.

12.) Reverse the steps.


It sounds like a lot, but really isn't. My assumption (yeah, I kmow how those work out sometimes) is that you have a shop manual of some kind to help guide you with torque values and such.
Just take your time with the first go around, and you'll be fine.

[tenderfoot]

Excellent, thank you very much.

Haynes: Check
Torque wrench: Check
ADVrider for help: Check
4xRubber seals: Check

I think I'm good to go.

[Bigger Al]

Originally Posted by tenderfoot

Excellent, thank you very much.

Haynes: Check
Torque wrench: Check
ADVrider for help: Check
4xRubber seals: Check

I think I'm good to go.

Let us know how things go.

[JonO]

Check out this link:

http://www.pbase.com/dqmohan/prtseals

Very detailed, with lots of photos!

[petefromberkeley]

Man, I've had to do my pushrod tube seals about every 25K miles. And they are definitely toasted- all cracked etc. I must need to find a new seal source.

[tenderfoot]

Originally Posted by JonO

Check out this link:

http://www.pbase.com/dqmohan/prtseals

Very detailed, with lots of photos!

That is very detailed.! And much more involved than I anticipated.
Thanks for the link, I'll save it and use the pictures in conjunction with Bigger Al's method.
For now I'll live with the leak and concentrate on getting the other bits I'm busy with finished in order to get the bike on the road.

Can't I just smear some high temperature silicon around the offending seal to try and stem the flow a bit for the time being.?

[Bigger Al]

Originally Posted by tenderfoot

That is very detailed.! And much more involved than I anticipated.
Thanks for the link, I'll save it and use the pictures in conjunction with Bigger Al's method.
For now I'll live with the leak and concentrate on getting the other bits I'm busy with finished in order to get the bike on the road.

Can't I just smear some high temperature silicon around the offending seal to try and stem the flow a bit for the time being.?

That won't work. Just buy a couple of cans of brake cleaning solvent and spray things down every few days.

[Reryder]

Often there is no need to replace the seals.
You can make a tool out of a piece of pipe with inside diameter just bigger than the pushrod tube and use it to tap the seals back in a few millimetres to make them seal. They are tapered so seal up good when pounded gently in . (Not too far though or they sort of disappear inside.)

You have to cut an angular slice out of the first six inches of the pipe so it slips up over the pushrod tube from under the bike. Then file the end of the remaining pipe to an angle that matches the flange on the end of the pushrod tube. You actually are pushing the tube down a couple of mm too.

Difficult to explain, but if you google around you should be able to find pics, i have seen them on the net before. My buddy used his on mine and they stopped leaking.

[Joerg]

Originally Posted by tenderfoot

Ideally I'm looking for a pictorial walk-through like Bpeckm put together on the front wheel bearing replacement.
Even I could follow that and do the job successfully.

Not as many pictures, but this one is online since 2004, and from what I hear it has served some people well :-)

[Bigger Al]

Hey Joerg, that's a nice stack of information you've got there. Nicely done!

[BillsR100]

Mine are weeping just a bit so I did some googling.
There is a good discussion and tips on trying to reseat the seals rather than replacing them here...

http://www.bmwmoa.org/forum/archive/...p/t-10039.html

[lkchris]

Originally Posted by Bigger Al

Wirespokes is right. It's an easy job, and shouldn't take you more than an hour or two to do. I've done it 4 or 5 times, and can pull it off in about 45 minutes.

The steps:

This doesn't work if your bike has an o-ring sealing the cylinder to the block.

Also, it doesn't permit replacing the o-rings on the cylinder studs.

This rubber is probably just as old as the pushrod tube seals, if not older, and really ought to be replaced at the same time.

This means either taking the cylinder completely off the piston, or detaching the rod from piston by taking out piston pin.

[Bigger Al]

Originally Posted by lkchris

This doesn't work if your bike has an o-ring sealing the cylinder to the block.

Also, it doesn't permit replacing the o-rings on the cylinder studs.

This rubber is probably just as old as the pushrod tube seals, if not older, and really ought to be replaced at the same time.

This means either taking the cylinder completely off the piston, or detaching the rod from piston by taking out piston pin.

Good points. I've had the heads and cylinders off of my bike several times in the last few years for various reasons, and don't usually worry about the stud o-rings, and my cylinders seal at the bases with Hylomar.
I was giving the "quick and dirty" method that some of us Airhead pilots have used at the 11th hour before a big trip.