After coming back from a ride up in the hills last sunday, about 1/2 mile from home my passenger rear caliper came off!
To be specific, it came off the rotor and was dangling inside the inner wheel rim. It was pretty much being held there by the SS brake line. Anyways, I was able to limp home. Further investigation showed that the caliper bolts were still in the caliper sleeves but had backed out of the knuckle. After repairs were made I checked the driver-side rear caliper and the upper bolt had also backed out of it's knuckle! (It had been hanging there by one bolt)

So, this is my concern: I tightened mine by feel. (what I felt was snug/tight) Obviously it wasn't enough I did not use torque wrench specs.

What about you? How did you tighten yours?

Kit (86 GT)

quote Originally posted by Kitskaboodle: So, this is my concern: I tightened mine by feel. (what I felt was snug/tight) Obviously it wasn't enough I did not use torque wrench specs. Kit (86 GT)

snug/tight? that's for oil drain plugs

brake calipers and stuff, german torque specs: Gutentight

...ok I just had to

just keep in mind what grade bolts you have, what it's holding on and what it's bolting to

...or you can get the book and check torque specs and get the torque wrench out

The caliper bolts require loctite, otherwise they will back out after a period of time.

The manual is calling for 40lbs , I should check mine, lock tight is a very good idea, there was a thread a day or two ago --about what type of lock tight to use , I guess they have several different grades of it..

quote Originally posted by Kitskaboodle: What about you? How did you tighten yours?

Torque wrench.

I've never had a caliper bolt loosen. In fact... even when I wanted it to come out.

Found that post on all the different types of lock tight --its by perry rhodan---he knows his lock tight.


Loctite, or thread locking liquid are good to secure thread on fastener, but be carefull to use the correct strenght. Blue locktite or "243" is enough for aluminium. Its of "removable" or dissasembly type.

Purple or "222" loctite is for very fine thread.

Red (291 or 271 I dontt remember) loctite is too strong...It's only good for big bolt with big thread or for bolt that will not need disasembly and generally need the heating of pieces. It will tend too shear thread on aluminum wgen disasembly causing the thread to strip.

Use primer (Loctite primer T or S ) to help it cure. The loctite react only with ferrous material like iron,steel ....it's an anareobic cure material. Since ferrous material absorb oxygen and aluminium not, this will help the loctite to bond correctly.

quote Originally posted by ryan.hess: Torque wrench.

I wholeheartedly agree. With decent quality Asian-made torque wrenches selling for less that $20 these days, there's no excuse not to have one in your tool box. And once you have one, use it religiously!

While necessarily anecdotal, I too have never had a properly torqued caliper bolt loosen on my '88 Fiero. When I bought my Formula in 2002, one caliper attach bolt was missing and at least one other was dangerously loose. After replacing the missing bolt, replacing a loose one that was badly worn, and inspecting the rest I tightened them all to the torque specified by GM. I have checked them every six months (or whenever I have a wheel off in the shop) ever since, and not one has loosened. Still, the next time I remove the calipers I will use a drop of blue Loctite on each of the attach bolts. Simple to do and cheap insurance.

[This message has been edited by Marvin McInnis (edited 05-08-2006).]

quote Originally posted by Marvin McInnis: While necessarily anecdotal, I too have never had a properly torqued caliper bolt loosen on my '88 Fiero.

I've never had one loosen up but I did find that someone had installed one of the sliders backwards which meant the bolt was mounted too far out away from the knuckle, and not enough turns of the threaded part were seated in the knuckle. That would have been the one to loosen up on me had I not noticed it I guess! Ah the joy of owning used cars.

What I should have included in my first response to this thread, is that if you purchase an OEM replacement caliper bolt, you'll find it has loctite on it. Naturally, if you loosen or remove the bolt, you should clean it an re-apply loctite to it. As mentioned above, a Torque Wrench should be used.

This is nothing to "play around" with, if the "wrong" bolt backs out, it allows the caliper to swing into the wheel acting like a can opener. It will carve a drench/hole into the wheel, then lock the wheel up faster than you can imagine. The other bolt backing out, just allows the caliper to drag on the wheel, with loss of brake performance to that wheel, although I'm sure something worse could happen.

Those not using loctite have been either lucky, or living on borrowed time.

Here's the text of my caliper bolt story: https://www.fiero.nl/forum/Archives/Archive-000002/HTML/20040223-1-035542.html

The links to pictures in that archived thread are no longer valid, so here are the current pics:









Long day that was...

JazzMan

[This message has been edited by JazzMan (edited 05-08-2006).]

I did all four brakes in the spring of 2005.. I checked the bolts twice that year... Once in the summer and again in the late fall.

I haven't checked them this year....... Not yet

------------------

1988 Fiero Coupe 2.5L
1990 Trans Am GTA 5.7L

quote Originally posted by California Kid: The caliper bolts require loctite, otherwise they will back out after a period of time.

Yeah, but SPARINGLY use the blue stuff not red. Use red and they'll never come out again!

Sounds like good advice. My question is, when checking the bolts, you find them very tight, do you still proceed to loose them and then add a little blue loctite? Yes? NO?

Thank you!


Steve

quote Originally posted by solotwo: ... when checking the bolts, you find them very tight, do you still proceed to loose them and then add a little blue loctite? Yes? NO?

Here's how to check them. Use a torque wrench just as if you were installing the caliper attach bolts in the first place ... in the "tightening" direction ... but don't over-torque them. If the bolts move, even a little, before you reach the specified torque, they have loosened. (If they move, it's also possible that they weren't torqued correctly when originally installed, but since there's no way of knowing for sure you have to presume that they have loosened.)

If the bolts have not loosened (i.e. they don't move), leave them alone. If any of them have loosened, remove them, clean the bolt threads, apply a drop (only a drop) of blue Loctite, and reinstall to the specified torque.

[This message has been edited by Marvin McInnis (edited 05-10-2006).]

Most of the time I use blue loctite but some times I didn't. I always torque them with a torque wrench. Never had a problem but I usually touch them (rear ones) often to drop the cradle. Use the blue stuff!

Thank you for the information!

Steve