65tripleblack

Trans is a Kiesler 5 speed. Trans yoke is leaking but not the seal. Appears to be 2 pieces. Is that right? It's leaking from the inside steel where it's machined by a lathe. Could it be cracked there?

JohnZ

Some of those Keisler yokes had a tiny vent hole drilled in the end of the splined housing; does yours?

Big Hit

Funny....
Just had the same issue with 4L75 Yoke.
Remove the drive shaft with Yoke, but the yoke in a vise, spray brake clean inside the yoke and watch it leake.

I mixed a small amount of fiberglass resin and poured it into the yoke center...let it dry in the vise...all fixed.

In my case the HD yoke end cap was not 100% welded.

Frankie the Fink

Are you talking about the Welch plug in the bottom of the yoke? If so, that's been a problem for these conversion for 10 years - I thought it was fixed a while back.

I fought the issue for a year after my conversion in the '61.

65tripleblack

That's exactly it. Welch plug? It looks like the yoke is 2 pieces but never examined it.

Today I take the car on the road for the first time since August 2016.

Maybe over the winter I'll pull it out and have it welded up.

65GTO

Note... you may or may not want to do this, but the tranny yoke in my 64 Eldorado Biarritz rag top was doing the same thing. I cleaned up the area real well, and laid some 2 part epoxy over that area (not JB weld. I actually have a aerospace epoxy donated to me via a friend in NASA, but JB would probably do just as well).

That was about 8 years ago and it has not leaked a drop there since. And that is thin, hot auto tranny fluid.

Frankie the Fink

Keisler's fix was to JB-Weld the plug and stand the yoke up and fill it with tranny fluid and see if it leaked after a day or so....if it didn't then it was a 'good' fix.

But that was utter BS ... the spline in the tranny tailshaft is like a fluid pump as it moves in and out over the road bumps and it pushes fluid down the one missing (intentionally) spline slot into the yoke and you have a big messy leak even if the rubber seal is good...

I went through 3 yokes to get a non-leaker.

I would have thought SST (Silver Sport Transmissions) would have corrected this by now.
If so, maybe you just buy one of their yokes and save yourself some grief.

65tripleblack

OK thanks all. Glad to hear it's fairly common and not a crack. I always expect the worst, and usually get it.

Since it's not stressed, I'll deal with it over winter and either JB Weld it, bronze braze it or arc weld it (if it's not a Welch plug which might not hold up to welding).

I can't understand why a Welch plug would be there. I would think the splined section is solid steel.

GearheadJoe

Hi Joe:

I had exactly this problem with the yoke that came with my TKO-600 from Keisler. The leak was small but persistant, and it took me a couple years of trying other things before I figured out that the leak was actually coming out the center of the yoke.

I called Keisler and they immediately recognized the problem and said that their early yokes had this issue. I asked them for advice on how to fix it myself and they said most do-it-yourself repairs eventually start leaking again.

They insisted instead that I send it to them for a no-cost repair. It came back with a 360 degree weld *and* some sort of sealant that looked like clear epoxy. It has not leaked since.

I don't know if Silver Sport is still doing this repair to old Keisler yokes, but if not, you may just want to buy a new yoke. Keisler told me that the design of the yoke had been changed to eliminate this problem.

SilverOverdrives

I would recommend welding the welch plug in the slip yoke and be done with it. You could use a sealer but the sealer could fail again at some point down the road.

I've seen the welch plugs come completely out so I would do this sooner instead of later. *This applies to the Keisler era slip yokes specifically*

Jeff

65tripleblack

Can you explain how those slip yokes were made? Why a Welch plug?

Instead of paying my welder friend, I was thinking of cleaning the seam with acetone and bronze brazing it with my MAPP torch.

SilverOverdrives

Well, I don't know really. I assume it's a requirement of the casting/machining process and I don't know that I've seen a slip yoke that does not have a welch plug. They are typically pressed in and most do not give any trouble.

Brazing would probably do the trick just the same. I've seen epoxy sealers work too, just don't get any on the inner splines.

Frankie the Fink

Yes, My first Welch plug was completely blown out on my Kesiler upgrade. Remember, that transmission rear splined shaft is a pump working in and out of the yoke during road bumps, just like a piston in an engine cylinder.

It never sleeps and is constantly applying pressure on that plug...

GearheadJoe

Hi Joe:

Don't forget that the yoke is likely made of forged steel and may have received some form of heat treatment. Given how hard that yoke works (especially in your car!), it would be a shame to weaken or distort it in any way.

65tripleblack

Thanks Joe. Didn't you say earlier that Keisler 360* welded the plug on yours? I'm thinking about the heat and brazing needs less heat than welding. If I were absolutely certain that I could get everything, including the seam clinically clean, then I'd have no problem using JB Weld on it. Sometimes heat is used to press out frozen u-joints as well.

Westlotorn

I would take it to a shop that welds every day. They can lay down a bead that will look like an artist welded it for you and eliminate leaks. For a small job like that it will take them 5 minutes and I bet no more than $30.
Playing around with lesser skills might cost you a lot of time.
I weld things all the time and have a nice Miller wire feed but I see what a pro can do and realize some jobs need to go to them. 2 cents from the peanut gallery.

65tripleblack

Duly noted.

Some good ideas here and I have time to think about it.

My friend Ken Capraun is an artist of a welder. Typical German **** retentive perfectionist. A really, really great guy of about 72, who asks me how much I should pay him for his work! Doesn't seem to like money as much as he likes his vintage gas dragster.

One of his customers runs classic TVR racers and Ken made a jig to create beautiful hand made frames for this client.

GearheadJoe

Hi Joe:

Yes, Keisler put a 360 degree weld on the yoke. However, I don't know whether they pre-heated the whole yoke to a certain temperature and/or did anything after it was welded to help it retain its strength.

One thing you might want to check is how much Silver Sport charges for the yoke they use with their kits. Presumably this leak issue has been resolved in that design, and there wouldn't be any concerns with possible effects from brazing or welding.

I'm not a metallurgist so maybe my concerns are misplaced, but I know that you sometimes run your car hard, and a failed yoke at speed is not something that anyone wants to experience.

Frankie the Fink

I suggested contacting SST several posts back.

SilverOverdrives

Keisler did nothing regarding heat treat before/after they were welded. I don't recall if they would run a solid bead or go in short runs to minimize heat soak. It's been a while...

That being said, none of them have ever failed as far as I know.

The old Keisler yokes were made by Emmbros of India. The quality was good other than the welch plugs leaking or coming completely out. Our shaft uses a different strap arrangement/C-C length which prohibits it from being a direct swap.

Sealing or welding will be the best options.

Jeff