MTFCA Forum

I'm going to have the happiest hogshead on the block with these new pedal cams!
I'm putting in O rings to help with the oil leaks at the pedals.
The transmission book shows how an O ring, spring, and washer can be installed on the clutch control shaft to stop the oil leak there.
Has anyone done this? Is it effective (or really needed)? Or just something to get carried away about? Any reasons not to do it?
Of course for the early hogshead the clutch control shaft goes all the way through to the outside on both sides, so I'd have to use two O rings, springs, and washers.

Should I do it? Yes or no?

: ^ )

Keith

I would Keith, considering the early clutch throw-out arms use bolts which make the task that much easier !

I have had better luck with thin lip seals. .875 OD?
If you O-ring the insides with springs, the washer holding the O-rings should be 80+% counter bored to retain the seal & the inside HH contact points should be smooth & square to the shaft.
Yes, this is another leak point to plug.

I've done this as well on my '22 and it's worked quite well. For anyone considering doing the same on the later hogsheads where the shaft doesn't go through, it may not matter but it makes sense to me to use a spring on both sides of the clutch fork to keep the fork centered.

old_charley wrote: ↑

Fri Jun 10, 2022 6:33 pm

I've done this as well on my '22 and it's worked quite well. For anyone considering doing the same on the later hogsheads where the shaft doesn't go through, it may not matter but it makes sense to me to use a spring on both sides of the clutch fork to keep the fork centered.

I think It does make a difference using 2 springs to center the throw out bushing & retain its ability to float, enough so to use 2 springs myself.

Dont forget to manually oil your outer cams & shafts.
They can actually get stiff & lock up if they get dry.
Seen it.

An O ring is an easy fix, of dubious effectiveness, especially in an alloy cover. Most times the holes are well worn and the shafts also, meaning the clearance between shaft and cover is way over spec. I hand ream the cover holes to take a thin walled bronze bush to get the size back to spec. I have made a tool with a fly cutter to cut a seal land in the outside of the cover. It is driven with a carpenter's brace. The I use use a proper oil seal, as John does. This allows the shafts to still be oiled. When new shafts are used, this makes really nice job of it.

An added bonus is the open end on the clutch fork rod can be properly sealed. I leave that bush protruding outside the cover, and plug it with a cup type freeze plug. All this is achievable with hand tools.

Allan from down under.

I've done it a few times. A second spring is unnecessary unless the right side of the shaft goes all the was through. There isn't enough pressure on the spring to cause wear on the fork.

DON’T DO IT ! The spring & o-ring on the clutch shaft is a poor choice if you drive much. The spring keeps the bronze ring loaded against the steel collar in one direction instead of “floating” and wears out its inner diameter.

I concur with John and Allan. Mike Bender had an informative post on doing the job with lip seals but I can't seem to turn it up. Attached are a couple of his pictures. I use a mill as well but don't have an angle head. I stand the cover on its side bolted to a large angle plate. Be sure to retain alignment, especially on the clutch shaft. And, as John mentioned, take care that the outer pedal cams are lubricated. The Timken seal is #253747. Can be cross referenced to any brand.

Use a 5/8” Id X 1/16 Oring. Chamfer the edge of the bore. Grease and install.
Use a long reach cutter and make a groove leaving the Oring proud on the shaft.

Have seen this once or twice on a grooved shaft.

This is what I feared cutting a clutch or pedal shaft. Common sense warned me away.
I had not seen an actual failure until now. Thanks.

O rings are not meant to be used between components which move. At best, They will block the passage of oil between stationary components, but between moving, and sliding parts in this application, the best they will do is slow down the leaks. Here they are being asked to do the work of a lipped oil seal.

Allan from down under.

O -rings installed. I had to do both sides because on the passenger side the shaft goes all the way through. It also gives equal spring force on each side. I like that. All safety wired and ready for installation.
: ^ )

Keith

Allan

O-ring design parameters exist for both static and dynamic applications. They vary somewhat and do indeed work with moving parts and seal remarkably well when designed correctly and surface finishes of the parts are correct. All that information resides in many places, but my design favorite is the Parker Seal O-Ring Handbook. That said, just squishing them between the support and the hogs head in a home-made chamfer, well, under those parameters, I'd agree with you wholeheartedly. It's better than nothing, and "better" has a wide-open definition from shop to shop.

In any event, my personal preference is for a lip seal, but that's beyond the vast majority of owners with minimal access to the equipment necessary. In the absence of equipment, these work very well for that job and can be used with a 3/8 speeder and I've taken them with me to help folks who can't get to a shop or just didn't have the time to send the work out...they are built up from commercial counterbores and have pilots which mimic the pedal shafts:

KWTownsend wrote: ↑

Mon Jun 13, 2022 5:46 pm

O -rings installed. I had to do both sides because on the passenger side the shaft goes all the way through. It also gives equal spring force on each side. I like that. All safety wired and ready for installation.

20220613_143130.jpg

: ^ )

Keith

Just using flat washers wont work. The hot oil & pressure will expand the rings.
You would need to make a cup to retain the OD pressure on the O ring.
The face inside needs a counter bore kiss to smooth the sealing surface.
Learned this the hard way.

I used real shaft seals.
O-Rings are not intended to function as a seal on a rotating shaft.
 

when someone says "you can't do a particular thing", it usually means THEY can't do a "particular thing"

shockingly, but not surprisingly, they often yell at the sky in utter disbelief when someone shows them that it is done all the time: https://promo.parker.com/promotionsite/ ... land,EN.EN