Gearbox drive flange/CV joint thread stripped

[AdrianC]

Oops.

After last summer's CV joint replacements, I religiously checked the driveshaft bolts were tight. At least twice. Then, the other day, during some extreme provocation up a long rough steep unmade road in 30+deg temps, the clacking started to return on hairpin bends.

A quick check underneath showed that the RH side gearbox-to-driveshaft bolts were all a tidge loose but for one which was a good four or five threads undone. The gear linkage has a good coating of grease. Four of the five slightly loose took about a quarter of a turn to tight, and the really loose one went back in just fine - but the last one stripped its thread almost immediately.

It's totally stripped. I can pull the bolt in and out with no effort. There probably is no bolt any more.

The proper fix is almost certainly a replacement flange, right? How urgent would you say this is? The clacking seemed slightly worse for the first few miles after re-tightening, but seems to have gone away completely now.

I dunno if I've somehow turned into a gorilla or what - but when I was putting the bolts back in last year, I managed to shear one of the triple-square headed bolts, now this - and I was only using a 1/4" ratchet, whilst lying on the ground under the un-jacked van - so not exactly swinging off a breaker bar.

[sarran1955]

Hello,

You really must stop taking the gorilla tablets..

CV joint off and helicoil the flange

Drill oversize and tap at M8

Or even run it with 5 bolts, and we'll do it here...eventually

Is that the one that did not get replaced..by the way..

Cordialement,

[Ian Hulley]

Drill oversize and tap at M8

They are M8 thread to start with ... the CV bolts are M8 x 48mm.

[AdrianC]

Hello,

You really must stop taking the gorilla tablets..

Yep, reckon I must.

Or even run it with 5 bolts, and we'll do it here...eventually

Yeh, I think that's the best bet... Just suck it and see. I'm a bit short on helicoil kits in the cupboard, and my Montenegrin isn't really up to asking around for one.

Is that the one that did not get replaced..by the way..

I can't remember for sure, but I think so - it's the one that got a good wash-out with gearbox oil from the missing grease cap, anyway. There's the second-best old joint in the cupboard, anyway, so we've got a spare if the worst happens.

[toomanytoys]

If you havent got the propper "aircraft" style serrated washers under them then thats part of the battle.. but you need to make sure they are clean when installed, you can reuse the originals as they are top quality.. the chocolate bolts supplied in some kits wont help tho....
Helicoil.. it might do as a fix to get you home.. You can ask Aidan if he will sell a good used one..

[AdrianC]

If you havent got the propper "aircraft" style serrated washers under them then thats part of the battle.

Ah... The driveshaft kit that we bought from Serial-Kombi in France didn't have those - it had three curved plates per CV, which fitted under a pair of bolts each - and the bolts bit into them really badly.

This is the kit we used - you can see the fittings clearly. S-K describe it as "OEM quality"...

http://www.serial-kombi.com/volkswagen- ... 11943.html" onclick="window.open(this.href);return false;

the chocolate bolts supplied in some kits wont help tho....

We've got a mix of bolts - the Allens supplied with the CVs and the triple-squares which we bought separately, also from S-K. It was a triple-square which I sheared.

Helicoil.. it might do as a fix to get you home.. You can ask Aidan if he will sell a good used one..

A good used was my first thought - what else do I need to replace, gaskets, seals etc? If the answer's "nothing", then I can probably pick one up locally, assuming it's just a case of "a flange", rather than them being specific to different box specs. T25s are common around these parts. If there's seals etc required, then a delivery may be easier. Or a combo - big heavy flange locally, small light bits via post.

[Aidan]

flange for any t3 is ok, air or watercooled, only thing to replace normally is the circlip, unless seal surface of 'new' flange is scored or very rough and rusty, and tbh most rebuilders reuse the circlip after a suripticious squeeze in the vice (I always replace with new 40p why not apart from you haven't got any or a vw dealer to hand), flanges are quite hard forged so helicoiling tough, recutting thread often successful in combination with some threadlock, M8x1.25 standard pitch

[max and caddy]

i would say that good as they are, helicoil is not really suited to this application..flange is quite thin and it would only be maybe 5 threads of coil...not very durable..the flange hole could be welded up and re tapped but once its removed it might as well be changed i reckon.

oh, and the seal cap in the center will need to be replaced normally..

[AdrianC]

<phew>

It's not stripped.
It's "just" a broken bolt. Turns out the bolts in the Serial-Kombi CV joint kit are only 8.8 grade, although that still doesn't explain how come I managed to snap it so easily.

[sarran1955]

Hello,

Right: No more Gorilla tablets...

Oh, we've done that one already..

I'm preparing a CV joint video, (did them on Steve's van)

His was VW all original.....little washers and matt black hex head socket cap bolts.

Is there a heavier grade of CV joint/bolts available, as you have been quite adventurous, and have a (relatively) powerful motor..

We have BERNER and WURTH socket cap bolts at work, 10.1. but only in hex head.

Send you some plus contact washers if you like.

Cordialement,