(Update!) Caliper bolts missing!

[drno4]

I read it and agree that it could be a culprit. I have seen many many many many times were there was a seized caliper and warped rotors and still the bolts were not loose. I would keep checking because there may be a problem with the female hole the bolt goes in to.

Maybe it was one of the female bolt holes causing the issue, based on your experience. Thankfully, then, I went ahead and replaced not only the calipers but also the brackets (which the missing bolts threaded into), and included new yellow zinc bolts. (The larger caliper bolts that fasten into the rear of the wheel assembly have never had any issues.) Hopefully everything now is good to go!

 

[Trey Hardy]

Edited 11/11/23:

Checked the bolts again the other day. Top bolt loose. Bottom bolt tight as all get out. I had just tightened them both equally 10 days ago.

My theory is that one of the two caliper pistons was fully or partially seized, and therefore putting uneven pressure on the rotor, which in turn caused the bolts to get out of torque. 20-year-old original calipers, showing some rust. Upon further inspection, that left rear rotor had warped slightly, possibly also due to uneven caliper pressure over time.

Solution: new rear rotors, calipers, and pads (on both sides), and a brake fluid change--all installed last night. Also installed new parking brake shoes and hardware while I was at it, which has made our parking brake functional again! Winning!

(original post and thread now follows, below)

+++++++

Hey all,

2003 Yukon Denali XL. 198K.

Heard a scratching/rubbing noise from the left rear wheel today.

Got home, removed the wheel to inspect. Got ready to remove the brake caliper and bracket, to inspect further. Then I noticed the two smaller bolts that tie together the caliper bracket and caliper WERE MISSING! Gone. Not just loose...they were not THERE. (All bolts on the right side were in place as usual.)

Went to Lowe's and got two M-8 1.25 25mm bolts to replace the missing parts.

Last time I worked on those brakes was one year ago. Zero problems since then. I have NEVER had this happen to any of our vehicles before.

I will likely never know what caused the bolts to disappear...but I am curious to hear your theories.

I had the caliper bracket bolt fall out coming over a bridge and locked my passenger side wheel up. I pulled off on the side road by the port and by the grace of god less then 5 min later a black preacher coming home from working on the port stopped to me. He said “man that just happened to me last week hang on I got the bolt you need in the tool box!” And had a crescent wrench to get it tight enough to get home! Diddnt want a dime for the help or his time waiting for me to get done! God works in mysterious ways!
My theory is like yours the caliper locked up and put too much uneven pressure on the bolt possibly. Or my unga bunga torque spec weren’t good enough so instead of the 3ft cheater ima use the 6ft cheater pipe next time!

 

[drno4]

I had the caliper bracket bolt fall out coming over a bridge and locked my passenger side wheel up. I pulled off on the side road by the port and by the grace of god less then 5 min later a black preacher coming home from working on the port stopped to me. He said “man that just happened to me last week hang on I got the bolt you need in the tool box!” And had a crescent wrench to get it tight enough to get home! Diddnt want a dime for the help or his time waiting for me to get done! God works in mysterious ways!
My theory is like yours the caliper locked up and put too much uneven pressure on the bolt possibly. Or my unga bunga torque spec weren’t good enough so instead of the 3ft cheater ima use the 6ft cheater pipe next time!

God is good. All the time. Glad you had a heaven sent helper in your time of need.

I'm surprised the torque on the smaller bracket bolts on my rig (03 Yukon Denali XL) is only 31 ft lbs on the rear. That said, the caliper-to-wheel-assembly bolts are big, and torqued to 148 ft lbs!

 

[jdpber]

 

[OR VietVet]

View attachment 416122

If my legs ever get to lookin' like that, in shorts, someone shoot me, unless I am the two ****** drinker, like the second one from the left. At that point I don't give 2 s*h*i*t*s!