Lower pushrod tube footprint

[58panman]

My 58FLHF has a leaking rear intake lower pushrod tube. I've put a older (seemed fine) set of corks in, still leaks. Put a new set of I believe James Gasket in still leaks. New Springs, still leaks. I looked at the footprint of the bottom where the tube sets on the cork, just the outer edge of the tube seals as the tube footprint is concaved, maybe to bite into the cork? Should the bottom of the tube be flat? I don't want to remove the exhaust one to look and create another leak. Thanks in advance for any advice.

[Rubone]

The footprint is correct, very slightly concave. What pushrods do you run? Some of the large diameter aftermarket contact the tube making it flex slightly and leak. Is your breather line restricted at all? overpressurized case manifest themselves as lower pushrod leaks.

[58panman]

Not sure on the pushrod, will check. Bought it with them in and did not leak. But then I adjusted. It wasn't run for 30 years, but didn't leak there then. Restored and leaked (no motor work), figured corks dried out, ran a few miles, maybe 50, changetd, still leaked, I knew they were old stock, changed to new ones, same. Will look into breather issue, but I hadn't changed anything since I last rode it.
Thanks so much for the help!

[JSB55]

I've cured leaks on both 65 Pan and 99 Evo by putting in an extra washer/spacer below the spring.

[dukekleman]

If it didn't leak with the same parts in its earlier years and does now with new corks, I'm going to blame the new corks.
Here's what I've seen...
Certain new corks aren't manufactured to proper tolerances. The center pushrod cork of certain brands can have a larger OD to it which binds inside the spring cover cap. This binding causes a loss in applied spring pressure to the upper and lower pushrod cover seals , which in turn then leak.

Hope this helps,
Duke Kleman

[58panman]

Thanks I'm planning on checking it out in the morning. I will try and move the lower and see if it moves with less than adequate tension. Good advice. I hope that is it.

[dukekleman]

I hope I describe this well in text...When you fully compress the spring cover, it should "spring back" quickly. Some times with the wrong dimensioned center cork, it stays in place compressed and doesn't spring back. This can also cause the center tube to not telescope smoothly.

Duke Kleman

[58panman]

You described very well. Checked tension by pushing lower tube back and forth, moves easier than the exhaust one. Pulled apart. The upper cork seems fine, no sticking when compressing assembly. The lower cork however doesn't have hardly any imprint at the low end of lifter block. I added one washer and checked side to side resistance, better but not enough. Added one more washer, and put a little EZ Turn lubricant on the mating surfaces. Rode about 25 miles, better, but not quite sealed. Will look ad impression on lower gasket, and go from there. Sure seems like flat flange on the lower tube would seal better than a concave that would only have a narrow footprint.

[58panman]

Photo of footprint

[jim d]

I had a 86 CI 74 XLCH Sportster that used to leak at the bottom of the pushrod tubes also for no apparent reason. I turned the lower tube upside down because the top end does not have the funnel shape but was shaped with a flat flange on the end. I then used an additional thin washer like is used in the center to put on the funnel end. But I didn’t use the corks for sealing. I used o rings that I think were used on later Shovels for the tubes if I remember correctly. So I put one o ring on the bottom. In the middle I put the one extra washer on top of the lower tube with the funnel end up. Then I used a the o ring with the original washer on top. The extra washer keeps the o ring from slipping into the funnel. And I used another o ring at the top to finish off. Your results may differ. But for me that took care of the problem. And being a big bore stroker with all the extras it was not babied.

[dukekleman]

I do have 2 tubing sleeves I made years ago. One for the inner pushrod tube, the other for the outer pushrod tube. I slide the tube inside the sleeve with the sealing flange facing upward. I set the assembly in my arbor press and "square up" the ends of the tubes using the press. Many tubes are not perfectly square, even new tubes. I then run them lightly on my flat plate just enough to give me a 360 degree view of the sealing area.
I didn't mention this earlier because it sounded like you hadn't had a problem with them before but perhaps it's worth checking?

Hope this helps,
Duke Kleman

[duffeycycles]

The narrow face of contact is the same as valve grinding,oil pump check valve & many other "seals". Narrow face means more pounds per square inch of contact = better seal without heavier springs.I designed liquid flow valves for production filling,same thing there.

[58panman]

Thanks all, I will check squarness as the lower tube is not sealing squarely. If it's OK I'll check the upper. Thanks all for the help.
Having a hoot riding this thing, already have 700 miles on it riding around this small Wyoming City.

[Carl Olsen]

I coat the corks with grease for a leak free fitment, softens up the cork and seals perfectly every time.
Carl

[otis71]

I don’t imagine this will help if there’s other issues but I bought a set of lower seals made of rubber, maybe nitrile in the early 90s for my 64. Same ones in it leak free to this day after countless times having the tubes removed and reinstalled. I never measured them but I believe they’re a bit thicker also.