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Calipers twisting off?
Glassguy54
Member Posts: 588 ✭✭✭
Have had this happen twice now. I'm going down the road, then I think I hear clanking noises, pull over and discover the disc brake caliper has sheared off of the mounting plate on the axle! Luckily the caliper is captured between the wheel rim and the rotor so it doesn't come flying off, hitting any other vehicles. When I remove the tire/wheel assembly to extract the caliper, one caliper bolt is sheared off, but the other is missing in action! And one ear on the mounting plate (it is a square piece of steel welded to the end of the axle with a hole in each corner, tho only 2 holes are used to mount the caliper) is torn so that there is no longer a hole, but more like a letter "C" where the open part has torn through the edge of the mounting plate, allowing the caliper to work free and detach. It seems that one bolt must somehow be backing itself out, then with only one bolt left to hold it, the caliper is able to pivot back and forth during braking and fatigue the metal to the point of tearing through. It has been the bottom bolt on both calipers that has disappeared. It is difficult to get a wrench on the bottom bolt to loosen/tighten, so maybe at the factory (Heritage) these don't get sufficiently torqued? Any one else ever have this happen? Its a dual axle trailer for a 246 Captiva. I replaced one caliper in July '13, (first one to tear away) had a caliper replaced Monday in Tennessee because it wasn't releasing all the way and was heating up. Last night outside of Hannibal, Mo. the other one tore free so I've ordered 2 calipers so by next week I will have replaced all calipers. I'm applying thread lock to the bolts and will make darn sure those bottom ones are secure!
Comments
PC BYC, Holland, MI
I'd use red loctite in a heartbeat... It takes heat to release it, and they won't come off without considerable heat. I'd also step up to stainless grade eight, with nylon nuts securing them..
Your problem isn't common, but I bet using the supplied fasteners is, ya know?
Torque spec for lugs would be nice too, if a # is floating around. If not, I'll go to 90.
The floating calipers on my super duty are torqued to 80#, and the caliper housing to 120# and using blue loctite..
Realize when you wet the threads, torque specs are only ballpark... Dry is only way to get a specific torque, unless the manuals call for dressing of some sort... We're not talking about internal engine parts or sealing/marrying surfaces, so my guess is tight is good, so long as it stays tight.
UFP DB-35 caliper mounting bolts for use with UFP Brand DB-35 brake caliper. 7/16" -20 x 1 1/8" mounting bolts with LOCTITE.
PLEASE NOTE: Mounting Bolts come standard with LOCTITE #242 ( torque each caliper bolt to 55 ft. lb.) When LOCTITE is used, star washers aren't required..UFP #33090 Caliper mounting bolt for DB-35 series disc brake caliper - Sold as each.
manufactured overseas head marking on them doesn't match any manufacture I know of in the states. They are only grade five from the pictures I've found. If I were you I would use the star washer and lock tight if you are using these bolts and make sure they are torqued to spec and check them periodically. Good Luck
UFP DB-35 caliper mounting bolts for use with UFP Brand DB-35 brake caliper. 7/16" -20 x 1 1/8" mounting bolts with LOCTITE.
PLEASE NOTE: Mounting Bolts come standard with LOCTITE #242 ( torque each caliper bolt to 55 ft. lb.) When LOCTITE is used, star washers aren't required..UFP #33090 Caliper mounting bolt for DB-35 series disc brake caliper - Sold as each.
manufactured overseas head marking on them doesn't match any manufacture I know of in the states. They are only grade five from the pictures I've found. If I were you I would use the star washer and lock tight if you are using these bolts and make sure they are torqued to spec and check them periodically. Good Luck