Re-packing a CV joint and heat shields Q

[RDBx]

Heading off on a long trip in a few days and typically leaving things to the last minute I need to sort a couple of issues before we go.

Firstly, giving everything a quick check over I spotted an outer CV joint has lost the large fixing band and it's grease, I've got a pot of molybdenum stuff and some large zip ties, how much grease should I pack in after cleaning the joint out? No time to get to a garage unfortunately and I’m sure this will only be a temporary solution.

Also, a couple of the exhaust heat shields underneath have come loose and buzz like mad on the motorway, I’d prefer to re fix them before we drive 2k miles. The fixing studs are there but have corroded away to a degree so the retaining clips no longer hold fast on them. Is there anything out there that could do the job or a reasonable bodge that’s worth trying?

Thanks.

[V8 FOU]

I usually pack a cv joint until it is full. You should really use the special cv grease, but what you have should be ok. Zip ties are fine - but make sure that they won't catch on anything.

Heat shields can be fastened with something like locking wire or baling wire. Or even a large hose type clip. Failing that drill a small hole through the heat shield and silencer and use a self-tapping screw.

[zcacogp]

V8 FOU said:

I usually pack a cv joint until it is full. You should really use the special cv grease, but what you have should be ok. Zip ties are fine - but make sure that they won't catch on anything.

Pretty much this, but the moly grease will be fine. If there is crud in the joint then you will need to dismantle it and clean it out before re-packing it. Also, it's well worth dismantling the joint anyway so you can pack grease into it while reassembling it. It's a very messy job, but strangely satisfying.

When re-assembling, make sure you 'burp' the gaiter. What you don't want is an air bubble in there as it will mean the grease isn't packed into all the working parts. To ensure this doesn't happen, assemble the joint with lots of grease, put the gaiter over it and lift the edge of the gaiter slightly with a small screwdriver. Then squeeze the gaiter until all the air is out of it and it is oozing grease around the screwdriver. Then put the cable ties around it and re-fit it to the car.


Oli.

[RDBx]

V8 FOU said:

Heat shields can be fastened with something like locking wire or baling wire. Or even a large hose type clip. Failing that drill a small hole through the heat shield and silencer and use a self-tapping screw.

Cheers. Should have explained myself better. The shields are mounted on studs, underneath the car.

On the CV Joint, think you're found the flaw in my plan. Hoping to re pack it in situ. Doubt that'll be possile if air bubbles need to be avoided. I've not got a breaker bar long enough to shift that nut. Bugger.

[anonymous-user]

zcacogp said:

Also, it's well worth dismantling the joint anyway so you can pack grease into it while reassembling it.

Do NOT dismantle your CV joint! Each ball is precision honed to the socket in which it sits. If you dismantle it, the chances are it will not be re-assembled exactly as before, one ball will take ALL the load and the CV will be toast in about 10 miles of driving.

If it is full of grit / debris, remove it, soak it in degreaser in a bucket. Carefully articulate the joint WITHOUT popping the balls out, to try to wash the dirt out. Dry, regrease liberally, and re-assemble onto driveshaft & car.

[aww999]

Is that true of all cars Max? Your expertise in all things automotive is evident across the forum, but I've been swapping axles, CV's etc around for years doing various engine swaps and never had a problem like you describe.

[anonymous-user]

aww999 said:

Is that true of all cars Max? Your expertise in all things automotive is evident across the forum, but I've been swapping axles, CV's etc around for years doing various engine swaps and never had a problem like you describe.

Generally speaking yes. Because CV joints are multi elements (ie the load is shared between more than 1 ball/socket) load sharing is extremely important. (because the balls & sockets are so stiff, being made out of extremely high grade steel, tiny dimensional differences make ENORMOUS differences in the proportion of the load being carried by each element). To avoid this, the balls are graded, installed, and finish honed in situ. if you swap balls about, so to speak, you stand a good chance of negating this attempt to even out the load sharing, and typically find the joint will fail a lot faster than if it had not been disturbed.

However, it's worth noting that as the joint is used, the natural process of wear actually tends to level out the dimensional differences anyway, so often, with old, well used joints (that will feel noticeably less "tight" than new ones), sometimes you can swap around individual components without issue.

But, as a general rule, don't disassemble CVs unless you absolutely have too!

[aww999]

Useful info, thanks!

[OldBuoy]

RDBx said:

Also, a couple of the exhaust heat shields underneath have come loose and buzz like mad on the motorway, I’d prefer to re fix them before we drive 2k miles. The fixing studs are there but have corroded away to a degree so the retaining clips no longer hold fast on them. Is there anything out there that could do the job or a reasonable bodge that’s worth trying?

Thanks.

I'd be inclined to "lose" the heat shields. Or maybe a big repair washer would hold it firm.

Edited by OldBuoy on Thursday 28th August 12:52

[zcacogp]

Max_Torque said:

Do NOT dismantle your CV joint! Each ball is precision honed to the socket in which it sits. If you dismantle it, the chances are it will not be re-assembled exactly as before, one ball will take ALL the load and the CV will be toast in about 10 miles of driving.

Interesting, thanks. I was the one who gave the advice ... as has been said, I've dismantled old CV's several times to clean and re-lubricate them and never had a problem with premature failure. But perhaps this is because, as you said, they were old and fairly loose and hence the tolerances were looser.

Every day is a school day .... OP, you may be able to re-lubricate them while on the car but it'l be a boat-load easier if you can get them off.


Oli.

[RDBx]

Yep, no doubt zcacogp just not sure I'll be able to in the time. On a positive note, I guess whatever I'm able to do when it's on the car must be better than having a dry joint and it being open to the elements.

[V8 FOU]

You should be able to re-pack in situ. Just force the grease in with the car on full lock and turn the joint as you pack it.
FYI, if the joint is off the shaft, the easy way to re-pack is to put huge gobs of grease into the middle where the shaft goes, then press with a finger and the grease will be forced through the joint. Repeat until it is full!

[RDBx]

V8 FOU said:

You should be able to re-pack in situ. Just force the grease in with the car on full lock and turn the joint as you pack it.
FYI, if the joint is off the shaft, the easy way to re-pack is to put huge gobs of grease into the middle where the shaft goes, then press with a finger and the grease will be forced through the joint. Repeat until it is full!

Ta, think I'll pick up a new box of gloves on the way home.