wheeping pushrod seal? Replace or push it in?

[jjwithers]

I have a completely rebuilt engine that is about 7 years old with 23k on it.
one of the pushrod seals is starting to leak.
It got me thinking... instead of popping the head off and replacing it (which i've done before)
Can i use a 'drift' and push it in a wee bit?
the seals still look like they are in great shape. The last time i replaced them (different bike), they were rotted and old.

-Josh

[Kurt in S.A.]

Yes, at the risk of pulling the tube out of the head, creating another leak. I've heard of some other stop-gap methods, one being using something like baling wire and wrapping it around the tube but wedging it in between the ring and the seal, thus pushing the seal tigher to the case. Or maybe trying to "paint" on some black RTV around the seal and case.

Are you sure it's the seal? I had a leak down on the left side on my /7. I washed the bike and blew baby powder into the area. Within a few minutes, I saw a small line of oil develop from the seal. However, the next time I went for a ride to confirm, the leak was much worse coming out from the base of my oil pressure sender. I've replaced the sender and now I'm essentially leak free.

Kurt in S.A.

[Major Softie]

I've replaced the sender and now I'm essentially leak free.Kurt in S.A.

And, if there's any leak you don't want, it's a leak in your essentials.

[Garnet]

I have seen a drift made from a piece of pipe that was split up one side and peeled open to fit around the pushrod tube. That was one can contact about half of that collor at once.

It seems like a lot of work to me to make a tool to do a patch job. Then when you go to replace them you have to drive the tube back into the cylinder, which will probably require removing the cylinder.

It should only take a couple of hours to replace all four tube seals, IF the exhaust has been off recently.

Check the condition of the existing seals first. It seems that rubber aint what it was in days gone by. I have found 5 to 8 year old tube seals in as bad a shape as 30 year old originals. Split and hard saels will still leak after being ponded in.

[melville]

I have seen a drift made from a piece of pipe that was split up one side and peeled open to fit around the pushrod tube. That was one can contact about half of that collor at once.
It seems like a lot of work to me to make a tool to do a patch job. Then when you go to replace them you have to drive the tube back into the cylinder, which will probably require removing the cylinder.

It should only take a couple of hours to replace all four tube seals, IF the exhaust has been off recently.

Check the condition of the existing seals first. It seems that rubber aint what it was in days gone by. I have found 5 to 8 year old tube seals in as bad a shape as 30 year old originals. Split and hard saels will still leak after being ponded in.

Haynes had a diagram for making one and I had the impression it was a necessary part of doing a new top end on an earlier Airhead. Up to some time after mine was made, they supposedly had rings that could be moved on the tube, with some effort. So I made a tool:

Cutting the pipe lengthwise:


Putting an angle on the end, refined with the bench grinder:


Checking the fit:


Can't say if it works (doesn't leak) yet, but perhaps in May I can give a report. Also, these were new seals, not old and hard ones.

[richard t]

I have a factory made tool like your making, it works well on /5 & 6's with moveable ring on the tubes, later models not so well, note if your seals are cracked and rock hard you are going to have to remove & replace

[jjwithers]

Cool pipe drift! My seals still look OK. Not super hard. Not dried out... which is why i inquired about giving them a little whack.... hopefully i can give something like this a try over the weekend....

[mattcfish]

I have a factory made tool like your making, it works well on /5 & 6's with moveable ring on the tubes, later models not so well, note if your seals are cracked and rock hard you are going to have to remove & replace

Do the aftermarket stainless PR tubes use the locked or moveable ring?
My /6 had the small tubes with movable rings. You could reseal them by knocking the ring in, but they would eventually work themselves back out after several thousand miles of heat and cold.

[richard t]

I have a factory made tool like your making, it works well on /5 & 6's with moveable ring on the tubes, later models not so well, note if your seals are cracked and rock hard you are going to have to remove & replace

Do the aftermarket stainless PR tubes use the locked or moveable ring?
My /6 had the small tubes with movable rings. You could reseal them by knocking the ring in, but they would eventually work themselves back out after several thousand miles of heat and cold.

I'm not sure about the after market tubes, but would be inrested to know because I'll need a set some day on old Blue

[Duane Ausherman]

Melville has it right, make or obtain one of those tools.

It is only about 35-40 years since these bikes were new and the procedures were fresh. How can we be so ignorant in so short of time? If this is a common human condition, then how can we possibly claim any knowledge of the history of 1000 years ago?

That tool is an absolute necessity. We used it many times a day in my shop. We used it to give a tap to just about every bike with any evidence of oil weepage at the pushrod donuts. Watch it carefully and if the pushrod bounces back, then it is either too loose, or the donut is too hard. On the early ones the collar moved and the later ones had a fixed collar, so the whole pushrod moved. The rubber donuts produced back then would only last about 4 years and needed to be replaced. Be careful to not squish the donut too much, or it will soon split open.

Why didn't someone make them out of silicone? They wouldn't get hard so quickly and would conform more easily. The collar wouldn't need to be tightened up so often. They would actually seal up much better, or so it always seemed to us.

I can't believe I am reading these questions. It shows that I should have anticipated the demand and written this up on my website a long time ago. My error. If/when I get back to posting my huge amount of saved up material, I will add in the info about this tool and procedure.