Leaking Inner CV Joint

[wake74]

In the next of the after the first weekend with the car questions:

The right hand inner CV joint is leaking some grease that is spewing radially out onto the rotor. Obviously not the ideal place for grease. The bolts on the right hand side were definitely not fully tight. Tighten and send it? Figure out how to take it all apart and add sealant? Are these bolts loosening up normal and I should check them between each track session?





Thanks!

Glenn

ps. Now I have a good excuse for being so far off the pace. I don't suck, the cracked headers and leaking CV joint were easily costing me 10 seconds a lap :-)

[Rick Kirchner]

Having a hard time telling exactly because the pics are so close up, but that does not look like a leaking CV. It looks like it's the seal in the bearing at the side cover of the gearbox, and looks like gear oil. Inboard rear brakes?

[Fred Michael]

You should disassemble, clean and seal the joint or it will continue to leak.
As for the bolts being loose, that should not be happening. It could be that you just need new nuts or it's possible that everything wasn't totally seated when they were last tightened.
With the amount of thread showing outside the nut it's also possible that the bolts are too long

[Fred Michael]

Having a hard time telling exactly because the pics are so close up, but that does not look like a leaking CV. It looks like it's the seal in the bearing at the side cover of the gearbox, and looks like gear oil. Inboard rear brakes?

That's definitely cv grease

[wake74]

You should disassemble, clean and seal the joint or it will continue to leak.
As for the bolts being loose, that should not be happening. It could be that you just need new nuts or it's possible that everything wasn't totally seated when they were last tightened.
With the amount of thread showing outside the nut it's also possible that the bolts are too long

Good point on the bolts. It could be that the nuts are bottoming out before it reaches full compression on the joint. I'll double check that and order up some new AN bolts if necessary.

It's definitely CV joint grease, not tranny fluid. Much different smell and consistency.

And for Rick, yes, they are inboard brakes on an RF81.

[Fred Michael]

Another thought on the bolt length is that it's possible that there should be a spacer between the brake bell and cv housing that is missing. I have had a couple of cars set up that way to allow for proper axle movement

[tlracer]

How flat/smooth are the faces of the disc where they contact the CV and drive flange? Might he worth having a machine shop give them a very light skim to take off any roughness, so there's better metal-to-metal contact.

[jrh3]

Check if the metal lock nuts have worn the bolts or the nuts are worn and loosen.
AN bolts are superior to these commercial bolts but grip length is important.

[alangbaker]

Another thing that helps the bolts from loosening is to use 8mm metric hardware if the CVs from a VW or the like.

The 5/16" bolts in holes sized for 8mm bolts have too much room to move as the whole mess vibrates.

I switched from 5/16-24 (all new AN-grade hardware) to M8-1.0 and suddenly my joints stayed tight all weekend.

[Phil Creighton]

Alan is right about the metric bolts but unless you feel like going into the gearbox to change the bolts I would pull the cv - seal the faces with silicone or hylomar check you have enough grease in there and bolt it back together with new nuts - torqued!
Its not unusual for CV bolts to loosen up a bit on the inboard brakes - its one of the constant items we check before,during and after a weekend.

[Rick Kirchner]

Ah - so the bell is sandwitched between the drive flange and CV. I couldn't tell what I was looking at, but now it makes sense. I've never had an inboard brake car. Yeah, it seems there should be something between the CV and the bell. I guess with a CV there's no snubber so there could just be a big center hole there to let the grease through.

[alangbaker]

Alan is right about the metric bolts but unless you feel like going into the gearbox to change the bolts I would pull the cv - seal the faces with silicone or hylomar check you have enough grease in there and bolt it back together with new nuts - torqued!
Its not unusual for CV bolts to loosen up a bit on the inboard brakes - its one of the constant items we check before,during and after a weekend.

I second all of this.

But what I did when I wanted to change over to using M8 bolts was carefully cut the heads off the 5/16 bolts that were between the flange and the gear case. Then I reassembled everying and carefully sized my replacement bolts so that they'd fit with just a couple of complete threads beyond the locknut. But I'd say that I had a little more space to work between the flange and the case on my LD200 than there is on Glenn's car.

[wake74]

I got it all disassembled. Had to pull off the back of the gear case to disassemble the shifter rod. The brake rotor wouldn't clear the rod to pull it off. Will have it cleaned up, hylomarred and reassemble later this evening. Will use new jet nuts.

Will check on it between the sessions at the next weekend to keep an eye on it. I'm hoping not to have to pull the case apart to swap those bolts out. The nuts weren't bottoming out, my guess is they were just loose enough to allow some squeeze out of the grease.

The outside cv bolts are actually the allen head M8 bolts on both sides.

[alangbaker]

I got it all disassembled. Had to pull off the back of the gear case to disassemble the shifter rod. The brake rotor wouldn't clear the rod to pull it off. Will have it cleaned up, hylomarred and reassemble later this evening. Will use new jet nuts.

Will check on it between the sessions at the next weekend to keep an eye on it. I'm hoping not to have to pull the case apart to swap those bolts out. The nuts weren't bottoming out, my guess is they were just loose enough to allow some squeeze out of the grease.

The outside cv bolts are actually the allen head M8 bolts on both sides.

If the outer drive axles are sourced from VW or the like, that's not surprising. It was the fact that the outer bolts were M8 on mine that started me thinking about this.

[Rick Kirchner]

Is there any compelling reason to put the bolts through the drive flange from the back? If you goober a thread you're really screwed as to now you're into disassembling half the back of the car to get the side cover off, the flange out, and the bolts changed.

One of the first things I did to my car was put the bolts through from the outside and I've had no issues.

[alangbaker]

I think the only issue is whether or not you have sufficient space. The head of a bolt is pretty much always shorter than a nut with the couple of threads that need to stick out past it.

[stonebridge20]

I think the only issue is whether or not you have sufficient space. The head of a bolt is pretty much always shorter than a nut with the couple of threads that need to stick out past it.

Jetnut with no washer fits just fine.

[wake74]

Is there any compelling reason to put the bolts through the drive flange from the back? If you goober a thread you're really screwed as to now you're into disassembling half the back of the car to get the side cover off, the flange out, and the bolts changed.

One of the first things I did to my car was put the bolts through from the outside and I've had no issues.

There appears to be sufficient space to do this using jet nuts and accurately sized AN bolts. When the gearbox comes out for a refresh at some point, I'll swap the bolts around. It's probably going to stay as-is for now, and I'll keep an eye on the nuts between sessions.

[jrh3]

Anyone using AN5 , drilled shank with castellated nuts and cotter pins?

[problemchild]

make sure that there are not unused holes in the brake rotor (from its original application) that will allow grease to escape. Silicon plugs will stop that.

[wake74]

I guess I didn't circle back and close out the thread. Between weekend 1 and weekend 2, I took the inner CV apart, and sealed things up again with some Hylomar (or more technically I guess the US equivalent). And used new jetnuts. Checked over the second weekend, no leaks, and the nuts are still tight.