Caliper Bolt - 986 Forum - The Community for Porsche Boxster & Cayman Owners

pompous · 04-11-2010, 02:42 PM

One side is done and doing the passenger front brake now. Of the two caliper bolts, the lower one comes out just fine (just like the others), but the upper one will rotate 2 or 3 times and then is stuck. I've tried penetrating oil and wrenching it a couple turns one direction and then back the other direction, but that's as far as it'll go. Anybody ever run into this or have any ideas?

Mike_Yi · 04-11-2010, 03:11 PM

Try tightening it again a bit, then loosen it again. Keep working it like that.

I've had trouble before with caliper bolts. I've always had luck with putting th eallen wrench in the bolt, then smacking it with a hammer until it loosens. A safer way to do it would be to put a pipe over the end of the wrench to get more torque. The first method is safer, but takes a while, and doesn't always work. The second method is tricky. It either works, or destroys the bolt.

ppbon · 04-11-2010, 03:25 PM

... put some anti-seize paste on the threads.
The braking components are subjected to continuous and high temperatures that can bind the bolts if left in there many years.
Happy Boxstering,
Pedro

pompous · 04-11-2010, 04:16 PM

I broke the head off!! $%$@

landrovered · 04-11-2010, 06:32 PM

I have always used blue loctite on caliper bolts, I had one fall out on me once, won't allow that to happen again. I would not personally use anti sieze on a caliper bolt but that is just me perhaps.

jmatta · 04-11-2010, 06:41 PM

I've always been taught not to re-use caliper bolts...once and they're done. The use of anti-seize not only makes removal easier, but lubricates the threads to get a proper torque setting...never dry.

pompous · 04-12-2010, 04:28 AM

I'm in the market for front calipers. Anybody have em' laying around?

ppbon · 04-12-2010, 05:56 AM

Quote:

Originally Posted by landrovered

I have always used blue loctite on caliper bolts, I had one fall out on me once, won't allow that to happen again. I would not personally use anti sieze on a caliper bolt but that is just me perhaps.

Your caliper bolt was loose because it was not torqued properly.
Most likely because the threads were dry!
A properly torqued bolt will stretch a bit giving the threads more area for friction, which is what holds it in place.

Happy Boxstering,
Pedro

sd_boxster · 04-12-2010, 06:10 AM

That sucks, man, sorry to hear about the broken bolt.

Quote:

Originally Posted by pompous

I'm in the market for front calipers. Anybody have em' laying around?

landrovered · 04-12-2010, 06:16 AM

Not to open a great debate but I use a torque wrench on all critical components. The caliper bolts are subject to heating, vibration, expansion, contraction and torque. They can work loose if they are not torqued properly or if thread locker is not applied.

Then there is the debate concerning what proper lubrication is when torquing bolts to spec. Some manufacturers suggest dry, some lightly oiled and some with loctite of other thread locker depending on the application.

The bolt I mentioned was on a different brand of car but the lesson was learned and learned well.

The mechanics that have worked on my car before me are top rate race mechanics and there is green thread locker on every bolt that I have removed from the car.

It seems that they use it as a matter of course.

I am continuing this practice where it makes sense to do so. Any rotational parts (cvs) are obvious places but also those that might endanger my life if the component fails (brakes) are on my list as well.

Like I said it may be me, I may be paranoid but I will not take a chance with a caliper failing in a critical situation.

RandallNeighbour · 04-12-2010, 03:17 PM

The tips on the top front caliper bolts are exposed in a cup-like recess in the wheel carrier. My thinking is that they are exposed so as not to build up pressure with the anti-seize accumulating at the bottom of a hole.

Because of this situation, these can corrode due to water accumulating there. I think mine rusted because the car was in Utah for a bunch of years as a DD and the road salt probably got in there and wasn't washed out regularly.

Two years ago, some of you probably remember me moaning over the fact that both top bolts up front on my MY97 took nearly 2 hours to remove (each one!) with the same back and forth loose, tighten motion recommended earlier...and the bolts when finally removed completely sheared off the threads in the wheel carrier. It was as smooth as a machined hole.

I would imagine that this is what will happen when you finally get that bolt out of yours too.

I had to buy a time-sert kit, drill it out bigger, put in a new insert, and then put in new bolts. The brand "time sert" is like Helicoil, btw.

That was a nightmare. And an extra $200 and week at my buddy's house I had no desire to spend on my brake job.

pompous · 04-13-2010, 06:59 AM

Quote:

Originally Posted by RandallNeighbour

The tips on the top front caliper bolts are exposed in a cup-like recess in the wheel carrier. My thinking is that they are exposed so as not to build up pressure with the anti-seize accumulating at the bottom of a hole.

Because of this situation, these can corrode due to water accumulating there. I think mine rusted because the car was in Utah for a bunch of years as a DD and the road salt probably got in there and wasn't washed out regularly.

Two years ago, some of you probably remember me moaning over the fact that both top bolts up front on my MY97 took nearly 2 hours to remove (each one!) with the same back and forth loose, tighten motion recommended earlier...and the bolts when finally removed completely sheared off the threads in the wheel carrier. It was as smooth as a machined hole.

I would imagine that this is what will happen when you finally get that bolt out of yours too.

I had to buy a time-sert kit, drill it out bigger, put in a new insert, and then put in new bolts. The brand "time sert" is like Helicoil, btw.

That was a nightmare. And an extra $200 and week at my buddy's house I had no desire to spend on my brake job.

This is exactly my situation. I ended up putting it back together and taking it to a local shop. They drilled it and then used the helicoil and i'm out the door for ~$150. It crossed my mind to do it myself, but it would have been my first time doing such w/nobody experienced to help me. I figured such an integral part of my box's safety, it probably is not the best time for me to "learn" and take a chance at compromising the braking system. Just glad its over now lol

Mike_Yi · 04-18-2010, 02:21 PM

Quote:

Originally Posted by pompous

This is exactly my situation. I ended up putting it back together and taking it to a local shop. They drilled it and then used the helicoil and i'm out the door for ~$150. It crossed my mind to do it myself, but it would have been my first time doing such w/nobody experienced to help me. I figured such an integral part of my box's safety, it probably is not the best time for me to "learn" and take a chance at compromising the braking system. Just glad its over now lol

Damn. Sorry it broke on you. That sucks!

Drilling out a bolt like that is tricky. It's not as big a deal if it's just a screw or bolt through sheet metal. Then you only have to drill the head off. If you have to drill into something, then it is VERY important that you drill perfectly straight, or you're going to have problems. Taking it somewhere to get it done was probably the best way to go.