CV bolts come loose

[cmcfaul]

Is there any down side to using Loctite on CV bolts?

Found a cv bolt on my driveway this weekend even though I have been pretty good at checking them when under there. Consider myself lucky for having it fall off on the driveway of all places. I have star washers on the ends but they obviously don't work.

Thanks,

Chris

73 911 E

[r_towle]

You need to clean out the threads in the flange with a good cleaner to make sure the loktite does something valid.

You can also get race wired bolts and tie off the heads...just more insurance.
Use new washers when you put the bolts back in.

Rich

[cmcfaul]

Whats the correct washer to use?

[Stan Gillis]

I believe the name of the washers are Schnoor.

[Packy]

Originally Posted by r_towle

You need to clean out the threads in the flange with a good cleaner to make sure the loktite does something valid.

You can also get race wired bolts and tie off the heads...just more insurance.
Use new washers when you put the bolts back in.

Rich

Use schnoore washers for sure, and +1 on safety wire. I rebuilt my CVs like 3 times before I decided that the ridiculous amount of cleaning wasn't worth it. Safety wire makes is so much easier IMO.

[cmcfaul]

How do you attach the safety wire? Those bolts are made from really strong steel. Can they be drilled easily?

Those look like the washers I used from Home Depot. Do they have to come from the Porsche gods?


Chris

[RWebb]

safety wire is not needed if the correct fasteners are installed and done so properly

safety wire will NOT maintain the correct torque on the faces of the CV assemblies

Schnorr is the correct washer - always use new - they are NOT at Home Depot

carefully clean both male and female threads with brake cleaner & Q-tips

do a search to find a thread that explains it all

[JeremyD]

Brake cleaner - q tips - correct torque with new Schnorr washers or go with the stage 8

World's Best Locking Fasteners & Locking Nuts and Bolts STAGE 8

you don't want a CV joint coming loose - makes a hell of a mess.

[burgermeister]

schnorr washers are available from mcmaster-carr for a very reasonable price. As is most other metric hardware.

[Grady Clay]

While long, this thread will have everything you need to know.
Reconstructing Constant Velocity (CV) Joints
This is worth studying end-to-end.

Best,
Grady

[Packy]

I drilled the bolts for the safety wire. It is just a back up. RWebb is right that the safety wire won't keep the torque spec, but it prevents them from backing out more than a 1/4 turn or so. It isn't fun when the CV bolts come out going 100 mph, ask me how I know.

[gtc]

I'm a recent convert to these Nordlock washers. I've used them on my car and another Pelican's, and haven't seen any loose bolts since. They are also reusable, whereas Schnoor washers are not. The only caveat is that they are a bit thicker than schnoors - 2.5mm or so.

[MysticLlama]

I have the other car with nordlocks, and haven't had a problem with any of them after a thousand miles or so.

And yeah, because of the thickness we had to play with bolts and shuffle them around a bit along with some extras to get the right length ones everywhere, so have to keep that in mind.

[Hendog]

I just repacked my CVs. I removed the old bolts, which were never removed before (100K Km). I replaced with same size (new) bolts. There were no Schnorr washers originally nor did/do the new bolts extend by any amount out the other side. This has lasted 24 years and 62K miles.

But I won't rest easy now until I replace those bolts with longer ones and install Schnorr or Nordlock washers. In the meantime I'll keep an eye (and torque wrench) on them.

[burgermeister]

Hendog, I think CV bolts backing out is an 8mm bolt issue. The 10mm bolts torqued to 60 ft*lb (which an 87 should have) probably takes care of the issue - that's twice the clamp load of the 30 ft*lb (or therabouts) 8mm bolts, which is a lot of headroom.

[Tut]

Chris,

I have Schnoor washers by the piece. What size are your bolts?

[JJ 911SC]

Originally Posted by Hendog

... But I won't rest easy now until I replace those bolts with longer ones and install Schnorr or Nordlock washers. In the meantime I'll keep an eye (and torque wrench) on them.

Henry

Did you had any washers? When I drop the engine (86 from a 83SC) there was no washer and no plate either (PP indicate its use for the 10mm bolts).

The bolts are M8 by 50mm (60mm with the head), so now I've got no smuck what suppose to be there...

[Hendog]

Originally Posted by JJ 911SC

Henry

Did you had any washers? When I drop the engine (86 from a 83SC) there was no washer and no plate either (PP indicate its use for the 10mm bolts).

The bolts are M8 by 50mm (60mm with the head), so now I've got no smuck what suppose to be there...

There were no Schnoor washers but there were/are the half moon washers which span two bolts. The bolts on my car are M10x50mm.

[1976 TN Porsche]

I got mine at Fastenal.

[uwanna]

Originally Posted by JeremyD

Brake cleaner - q tips - correct torque with new Schnorr washers or go with the stage 8

you don't want a CV joint coming loose - makes a hell of a mess.

Here's the "Stage 8" solution I bought after finding in a post on the forum. They are a great idea and should prevent unwanted "incidents" I especially like the 12pt socket heads instead of allen head bolts!

Ideola's Garage: Stage8 Fasteners for Porsches

Found that link in the old post below. Seems there was some sort of "group buy" going on, but I think you can still buy them from the link above. Read this post for more info.

Stage8 Locking CV Bolts for ALL 911/912