Aardwolf

I just got done checking my brakes after my last event and the top bolt on the C5 caliper was umm not there..

I'm not sure what happened, the brakes work very well. I drove home from the event. There are minor scars on the wheel, so the caliper did flop up some. I used thread locker on that bolt!!! I was careful and prepared the car very well. I remember putting thread locker on there and tightening the bolt. It had to have busted, I don't see signs of damage from debris.

So if you really want less weight.. only use one caliper bolt, it works good and weighs less.

dvandentop

happened on a guys c4 at auto x, he had his brakes worked on recently

longdaddy

of course you do

Jason

I've had one back out (the big 21mm ones) and have always used loc-tite since.

c4cruiser

Did you clean the bolt threads and chase the threads in the guide pin before applying the threadlocker? The old dried stuff can prevent a good seal in the threads. Also, did you immediately re-torque the bolts after the initial tightening down? IIRC, the bolts are tightened to 25 ft-lbs.

Sometimes it's hard to hold the guide pin and keep it from turning as you tighten the bolt.

The OEM replacement bolts come with a threadlocker applied. I reuse mine and apply Loctite blue after cleaning the old bolts and the threads on the abutment bracket. With a good even coat of threadlocker and torquing the bolts to the specified torque value, I've never had a bolt come loose.

davidfarmer

ANY bolt can come loose........I've not had that happen, but goes to show the importance "nut &bolting" your car between each and every event.

ghoffman

You need a $.50 Nordlock on each one. So called Locktite does not work, and especially at an elevated temperature. No, sorry, my error, this would not work.

BrianCunningham

steel bolts into AL =

Aardwolf

It's steel to steel there, the pin is not aluminum. The grease around the pins had started turning clay like and I replaced it all then used locktite on the bolts. I sprayed the pin off and the threads out with brake clean.

I inspected the brakes more and there isn't a broken part of the bolt stuck in the pin. So I don't think it broke. I wonder if debris had anything to do with it. I did hear a thump at one point and slowed down but felt nothing odd with the car. The OPR on this track was insane, I could literally reach in the nose of the car and grab a handful of shreds.

Where is a good place to get nord-lock washers? I could use several sizes. (good idea, thank you!)

ghoffman

Actually, if he is referring to the M8 that I think he is, it is a steel fastener into a steel slde rail pin, but it goes through the aluminum caliper. This wonderful design precludes the use of a Nordlock or safety wire because both sides can rotate, and Locktite does not work at these temps. So, I suppose your only solution is to chase the threads internally and externally and make sure it is torqued to spec, and inspect it frequently.

Aardwolf

There would be room to use a nord-lock washer on both sides. I could just get a new bolt that is slightly longer. Would that work?

ghoffman

Yes, I think so!

JVetthead

I had one of the big bracket bolts come loose.. the lower one...
Wasnot pretty.. The caliper rotated up and cam locked into the CCW wheel locking the RF wheel up. The car would roll backwards but not fwd. Lucky I was 2 blocks from the house. Lucky it did not happen on track.....

ghoffman

Now, that is a Nordlock kit I do have:

http://hardbarusa.com/hardbar/index.php?cPath=21_35

BrianCunningham

actually I meant this bolt



I've seen those come loose

ghoffman

Yes, that is the Nordlock kit application I have listed above. The M14's are expensive, but the kit listed above is all of $20 a car set, C4, C5, C6 (all)

Shrek

SPLIT LOCK BOLTS solved my header bolt problems. Wonder if they could be adapted for brake applications.

ghoffman

Those do look very good, but I would like to see them tested like in this German TUV test:

http://www.nord-lock.com/video/nl_us.wmv

Aardwolf

Are there any other places that should have nord-locks?

When I do brake prep before an event I do check the car over for loose bolts but have yet to find anything wrong.

C5 Hardtop

Thanks for posting that video! I had no idea about the NORD-LOCK, but I've been educated about them now