Brett San Diego

So I retorqued my CV joint bolts today. I resolved to do this since reading quattrorunner's experience with CV joint bolts backing out on their own:

https://rennlist.com/forums/911-forum/267406-90-mph-and-bang.html

My car is a 1978 911SC with 6 M8 bolts at each CV joint requiring 30 lb-ft of torque. Almost exactly 1 year and 6,000 miles ago, I rebuilt my axles. When checking them today, a few were fine (no movement when torquing), many required 1/8 to 1/4 turn, and a couple required much more than 1/4 turn.

I have a feeling that iceman's comments in the above thread that CV joint grease is responsible for the loosening bolts is correct. When I did my axles, I degreased everything including the bolts and mounting flanges. To clean the threaded bolt holes, I squirted some solvent through them, but this probably didn't completely do the job. Probably better to run a brush through the holes with lots of solvent.

Anyway, I'd say it's worth rechecking your CV joint bolts if you've done work or had work done at some point in the recent past.

Brett

theiceman

Good info Brett

I did mine 2,000 km ago so I am curious , the next chance I get I am crawling under for a look. PS how did you do it ? Did youjack up the entire back end and put it on stands?

ebsalem

The bolts are under a buck each at the local fastener store. For some reason new bolts don't back out like used ones. (trick I heard from Walt or Andy on the mailing list way back.)

Brett San Diego

I did it like this:



But, I followed the suggestion from someone here to leave the wheels on and lay on my back using my knees to hold the tires while I torqued each bolt. It worked fine. Easier than getting up and putting on the e-brake for each bolt.

This lift is my favorite tool. Had it for almost a year now. It has paid for itself already in jobs that I could do myself and not have to pay someone to do. It's a Bend-Pak LR-60P, portable low-rise lift. I bought from www.asedeals.com.

Brett

r911

bolts are a specail high strength fastener - be SURE not to just get anything that looks the same at a hardware store

2 other critical issues are to use new Schnorr washers (the serrated cupped things)
and to clean all grease out of the female threads inside the CV

much data at Pelican so do a search there.

Peter Zimmermann

I'll certainly second Randy's suggestion to use Schnorr washers, even to the point of adding them when they're not there. My memory is fuzzy on this point, but I think that when Porsche went from 10mm to 8mm bolts they also cancelled the lock washers (10mm hardware through '79 had them). Sometime about 1990 my shop started to buy Schnorr washers, in both 8 & 10mm sizes, in large quantities, and we put them on every CV bolt. Good point, Randy!
Pete

Brett San Diego

My bolts did not have any washers on them so I didn't use any washers when reinstalling. For now, I'll just keep up with retorquing and use lock washers next time around.

Brett

spikesdad

Very cool Lift Brett
Need to get one for my two cars.
Makes me feel a whole lot better in earthquake country

r911

The washer issue & also the moon plates was discussed on Pelican a month or two ago. No ones knows for certain of course, but Grady Clay thought the deletion was likely a cost cutting move by the factory - happened during a time of "dollar duress" for example.

My view is to cut myself a nice safety margin - just as if I were doing glacier travel... the results if you err are not that different.

911 Rod

I bought a product called Goop.
It is very similar to the OEM stuff that you put on the bolt where it attaches to the CV.
It not only works like lock tite, you can see if the bolt is backing off.
Anyone try this?

john70t

Some guy ( RoninLB?) center-drilled the heads and saftey wired them together.
It's probably better to use the Schnorr washers because regular lock washes have only one point of contact, and may provide turning resistance to the torque wrench before the bolt head has even started to contact the flange.
Nice pic BTW.

GothingNC

I picked up some new Porsche brand CV bolts from European Performance in Raleigh for my SC yesterday and the Tech guy said that I did not need the end gaskets.

Will I incur any problems not using the gaskets?

theiceman

Well I am no expert and it depends what you are doing. If you are just replacing bolts you will of course not need them. If you are repacking the cv joints you may need something. a mechanic told me to just put a bead oof silicone around it to stop the grease coming out ( THE PURPOSE OF THE GASKET ) but i elected to put the gaskets in.
Having said that Itheorizeda t one point that part of the reason for the bolts having the opportunity to back out is because the gasket will compress and cause the bolts not to be so tight . But all just theory. Bottom line for me was the manual called for them so I put them in.

ice

GothingNC

Finished the job.

Now the slight popping noise I was hearing while shifting gears is gone

I just think it was kind of odd how the outer passager side backed out since the whell turns clock-wise. Usually it would be the P/S transmission CV or the D/S outer CV.

Bolts must have been loose for a while or I have been driving in reverse too fast.

theiceman

Great Job

I checked mine on the weekend while i had the car up for other reasons and my random sample indicated they were still tight ... I have only put 2,000km on but thought it was worth checking.