Caliper Bolts Missing - Brake Caliper Separation

[ComputernerdBD]

Hey everyone. Happy new year and well this is a night to remember.... So last night I changed the oil, differential/t-case fluids and rotated the tires. Just basic stuff as I was planning on driving it on a 350 trip next weekend. Noticed no issues with anything with the brakes when I did the tires (I don't touch the brakes anyway, I have items like that done professionally for safety and time reasons but I do take a brief look when I do oil changes), so seeing what happened here was a huge surprise. Except for other small issues like some residual power steering fluid from a recent repair and the front axle fluid looking like silver car paint, it was otherwise a flawless night of fluid changes and also painted the power steering lines and a couple other places where it needed it on the frame to stop rust.

I drove the car 20 miles after that maintenance, even taking it up to higher speeds, on hills and even having to slam the brakes on a couple times hard for deer in the middle of the road and the truck had no problems. Everything was running and stopping very well and with all the hills any brake problem would be immediately a serious event. I just had the brake pads/rotors/calipers/rubber lines/pins/bolts replaced in early October and since then it has driven thousands of miles without issue even on several longer high speed trips. Tonight I went to drive to New Year's dinner and after about a mile or two at slower speeds on flat highway, I started feeling the brake pedal travel increase and it started to get spongy which is highly unusual since the truck stops like new. Tapping the brakes will stop it no problem normally. For a second I almost didn't think much of it since it was raining, but then it got worse and I heard a metal on metal banging noise. I immediately got the truck off the road. I popped the hood to check the brake fluid thinking maybe a line broke (unlikely). Fluid was full and still like new. Then I broke out the light and checked the front wheels first. No leaks, everything looked fine. When I went around to the rear right wheel and what I saw almost gave me a heart attack. The brake caliper literally separated from the bracket, started banging against the inside of the wheel (which now has fine silver aluminum powder residue on it from the contact) and I could see 1/2-3/4 of the piston on the inside.

Both of the bolts (which were brand new gold/brass colored AC Delco ones) holding the caliper onto the bracket were completely missing, felt like the pins were still there. I was able to slide the caliper almost completely clear of the bracket and it would have come completely off if the wheel was not on the truck. The bolt hole on top was still intact as far as I can see so except for whatever damage was done to the caliper post-separation from banging around and the piston popping most of the way out it looks like it was in good shape. I was able to slide the caliper back in and move the car about 20 feet to give space for the flatbed tow truck and had the car towed, I asked the shop to investigate, check everything and get a new GM OEM caliper to replace this one. I am wondering also if I should also have the brake hose replaced as well if that would have been on the leading edge and hitting the wheel...

Has anyone ever seen this before with brake caliper bolts just coming undone at the same time? I even drove the route I took when the issue started happening using my other truck and checked the parking space where the truck was and could not find the bolts anywhere so they are long gone. Considering the time and distance the car has driven, I hope this is something that can be explained by mechanical failure or something similar, I don't even want to think about the alternatives... Thanks

 

[Mooseman]

It could happen. I had the bracket to knuckle bolts back out on my Montana SV6 van years ago. One fell off, the other hung on to dear life. Was able to drive it to the nearby dealer where they charged me $26 for the bolt + labour. I had done the brake job myself on it a while back. I don't think I missed torquing them down but since then, I use blue Loctite and torque them to hell.

The caliper to slider bolts aren't known to back out but if they weren't torqued properly, they could back out. I'd get it redone on their dime as they were the last ones to touch it. Because the caliper was basically held there by the hose when it was banging around inside the wheel, I would get that replaced as well. I could only explain this one as improperly torqued bolts.

 

[ComputernerdBD]

Really? Interesting... Yes, I am going to ask them to replace the caliper, hose and all the hardware. That would solve the immediate problem but in terms of the bigger issue of why I am still wondering how bolts could go from being screwed in (with the small distance, wouldn't they have been on their last threads the day before if they were walking out?), surviving hard stops and driving for a long time and then 2 miles into a 50 mile drive after they were last checked they are completely missing. Bit disturbing really.

I actually walked some of the back roads today to see if I could find out where the bolts let go if they did on the road since the roads are crowned significantly here. They would have rolled right off after being ejected if they did and gotten in the dirt beside the road. Nowhere to be found. I am also hoping this was not a deliberate act, if I get concrete info after the inspection that gives me reason that may be the case I am going to get the authorities involved. Both trucks are now protected by video after this event (not directly related to this, I was looking into doing that eventually when I had time.) so if that is the case and it happens again, I can see what happened around it. Thanks

 

[Mounce]

Well they'd probably rather blame it on someone setting you up... But it's their fault in the end.

Plus if someone really wanted to set you up and had the idea to mess with the brakes then they would know that the fronts do the majority of braking and would've loosened them. Or just punctured a brake line so it'd be a slow degradation until lack of brakes. Not all criminals are that smart but yeah, shop is to blame if you haven't touched them..

 

[TequilaWarrior]

Interesting timing...
I just had a pad completely sheer off on the driver's rear wheel. When I went to replace the pads, I found that one of my caliper bolts was gone. I do usually do my own brake work - too many negative experiences having meineke/midas do it. It could be that I messed up with torquing the bolts, but it's been almost 2 years. Also, I'm very deliberate when I do brakes. The other bolt on that caliper was as tight as could be without breaking it. I was able to insert a stud and nuts/washers to make it driveable until I can get replacement hardware - slider pins, boots, bolts, etc...
The other interesting thing to note for my issue is I had my PA inspection a few days beforehand - and one of the requirements for inspection is an actual measurement of the brake pad thickness. I know they pull the wheel, but I don't know if they pull the caliper and mic the pads or have some other means to do so.

 

[Mooseman]

Nah, there are brake pad measuring tools to do this, kinda like feeler gauges.

 

[ComputernerdBD]

Ok appears to be fixed now.... OEM caliper and brake hose replaced. Going to drive it and verify everything. Did notice a small amount of brake fluid on the brake line threads but hoping it was residual from when it was installed. Wiped it off and going to recheck. They could not determine the cause of the issue, so a little interesting and scary at the same time. Thanks

 

[mrrsm]

Don't ignore your instincts if you believe that you are in conflict with anyone... Widen your gaze... at least for a little while and observe any obvious signs of tampering henceforth and look for signs such as impressions in fresh snow fall around the vehicle that perhaps someone has been creeping about with "A Chip on His Shoulder...". If you are around local neighbors that you trust... inquire of them about anything odd happening nearby as well that may not be public knowledge.

They sell inexpensive Trail Cams now that can be set up to record only when movement occurs within the field of view. Perhaps it is just me... but I have worked too many real cases involving or presaged by similar bizarre things not to keep my wits about me... without being paranoid in the process. Just remember... It is always better to Act... than to React.... and You'll solve the Mystery here... if there is one to be found.

 

[Mooseman]

Now the real question... who paid for it?

 

[ComputernerdBD]

The investigation continues. I don't think it was the neighbors, I barely know them around here anyway and it certainly isn't a conflict going on. I even take small courtesy steps to avoid problems since I drive in and out of the area during late hours like shutting my lights off if the truck is pointed toward windows at close range and making sure the radio is off so I don't wake anyone up. I have a camera system now with one pointed toward both trucks and investigating motion operated dashcams for inside them. Eventually I will move now that I have a better job...

I paid for it, the shop could not determine it was intentional or human error (and they are honest, they have made mistakes before and made good on it without having to escalate the issue further than a calm discussion, I was cool with them and they returned the same keeping my business) but there is not much it could be.