Club 80-90 Forums

For second time this year, I've experienced bolts working loose on driveshafts and just had to be towed home because one bolt was bent and prevented me from refitting CV to gearbox on the spot. Any ideas to stop a repeat??

genuine bolts rather than the cheapo ones that come with new cvs and new washers they are only pennies. Genuine bolts seem obsolete from VW but check with your dealer they may have been superseeded.
Oh and use a torque wrench when tightening to spec. I've sheared two of the cheap bolts, which whilst being multispline which is good are not 10.9s like the VW hex heads. The perfect bolt would be a multispline VW 10.9 as fitted to some syncros when they had some about, which doesn't seem to be often.

CovKid,

Perhaps these people stock something suitable. They were recommended in a post quite a while ago.

http://www.namrick.co.uk/browse.asp?PCID=10

Just googled the tensile strength of 12.9 grade .............
Nominal tensile strength =1200 Newton/mm2

Mike

go to a good bolt supplier, and get some tab washers.

Threadlock maybe? Not undone any driveshaft bolts myself, but it might work.Maybe there's some wheel vibration thing going on that's helping them work loose?

I would recommend a decend bolt, torque up to correct specification and use threadlock and hopefully that will solve the problem.

If a bolt is over tighened, either two things can happen without a visable display or shear. The pitch of the thread of the bolt can be stretched and the actual thread in the housing could be stretched, and no matter how much threadlock or the correct torque is applied they will work loose.

As mentioned earlier also, do you have any vibration in the assembly that could couse vibration into the bolts etc.

:Process of elimination i'm affraid.

Dickspanner

I'll give spring washers a go this time. Might afford more bite than tab washers. Bolts seem fine, well, except the bent one which I think I'll have to grind off to get out tomorrow

Recovery guy was great. Anyone else beat £29 a year for breakdown cover?

sorely tempted I can tell you. Couple of tack welds just to make sure.

Two different types of steel and you would most probably get heat/cooling internal fractures in the weld, or a fracture straight after the weld.

I have looked at problems like that before when we have built stupid conversions and I know how you feel

CovKid wrote:For second time this year, I've experienced bolts working loose on driveshafts and just had to be towed home because one bolt was bent and prevented me from refitting CV to gearbox on the spot. Any ideas to stop a repeat??

I haven't acually been under to see if this would fit but I retain a shear pin in my boat drive system (Howling Hot 1600Xflow) with a three inch diameter Jubilee clip with a second wormy bit screwed on at 180 degrees so as to achieve balance. I wonder if such a device could be set round the six heads and tweaked up so as to prevent loosening? When I took my gearbox out my screws were barely over finger tight but unless they were just about to come adrift had presumably been like that for years. You ain't go a big humping V8 or something in there pulling big fat soggy dragster tyres have you?
Cheers
Ken

You are not alone, this happened in Nice, after 1100 miles in three days.

Last bolt out bent, all other o.k.

[IMG1680]http://i199.photobucket.com/albums/aa28 ... 040103.jpg[/img]

aha - same scenario then Simon. Mind you, the last bolt on mine is so bent on the mating surface side, its not gonna shift without an angle grinder. Weather so hot I haven't ventured out as yet....

Ken Simmons,
You wrote

a three inch diameter Jubilee clip with a second wormy bit screwed on at 180 degrees so as to achieve balance. I wonder if such a device could be set round the six heads and tweaked up so as to prevent loosening?

Or how about the usual aircraft practice (with drilled heads) of safety wire locking in pairs. Couplings on outboard ends could prove a little difficult to access, but many aircraft jobs were only just possible.

Mike

Grun wrote:Ken Simmons,
You wrote

a three inch diameter Jubilee clip with a second wormy bit screwed on at 180 degrees so as to achieve balance. I wonder if such a device could be set round the six heads and tweaked up so as to prevent loosening?

Or how about the usual aircraft practice (with drilled heads) of safety wire locking in pairs. Couplings on outboard ends could prove a little difficult to access, but many aircraft jobs were only just possible.

Mike

I have done that in other applications and found it easier to get started with the drill if you grind a little flat on so as to cut through the surface hardening. Tough suff so best buy a few 2mm drills though!
Cheers
Ken