Stuck Brakes

cheflionfoot

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I have a 2011 AWD CXL which I drove the morning of the last blizzard, "Nemo", and got home before it got bad and parked in the garage. That was Friday morning. On Tuesday morning I went to use the car and when I put it in reverse it would not move. It was stuck. The EPB was disengaging, but the car would not move as if it were stuck to the ground. Called OnStar to run a diagnostic, and nothing was wrong. Called the dealer, they said they never heard of this and if no lights are on in the dash they can't explain, so tow the car in. I called GM road side assistance and there was a flat bed there within the hour. Driver tried to move the car himself and it would not budge. Driver said he could not get the car out because of the angle of the garage and needed to get a tow truck out to drag the car out of the garage and then put it on the flatbed. Second driver came out, a huge guy about 300 pounds, scoots under the car and knocks a couple of this around, gets in the car, puts in reverse and really revs the engine. Car did not move and all of a sudden the car shot out of the garage. Turns out, according to the second driver, that it's very rare, but sometimes humidity and salt would cause the calipers to stick to the rotors on the brakes. I guess the car just needed some man handling to get it on its way. So if ever your car is not going anywhere after you drive in a snow storm, and park the car for a couple of days, you know what's wrong.
 

jft69z

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Western NY
Buick Ownership
'11 CXL-gone, '11 CTS-V Coupe (6M), '13 ZR1 Vette, '69 RS/Z-28 454 cu.in;'15 BMW 550i
I have the same car you do & it occasionally does the same thing, but to a much lesser degree. I usually just give it a little bit of throttle & it pops free. I still cringe a little bit each time...
 

92sub

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997
8
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Motor City
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87GN (gone), 2011 CXS (gone), 98 Regal GS
I have a Yukon Denali XL and it will do the same thing.....it always has the engine torque to free itself but it is interesting. I think it has to do with the amount of metal in the brake linings as to whether it will effect one vehicle as opposed to another. I keep my garage heated to about 60 in the winter so that does not help either.....seems to be the perfect temp for corrosion here in the rust belt.
 

jft69z

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291
4
18
Western NY
Buick Ownership
'11 CXL-gone, '11 CTS-V Coupe (6M), '13 ZR1 Vette, '69 RS/Z-28 454 cu.in;'15 BMW 550i
I keep my garage heated to about 60 in the winter so that does not help either.....seems to be the perfect temp for corrosion here in the rust belt.
Same here with my shop, 50-55 degrees when I'm not working in there, 60-70 when I'm out there. My GMC 2500 HD truck does it too on occasion, not as bad as the Buick though. Been lucky so far with no brake pulsation yet because of it....
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8-track

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All this happens for one reason only and will happen on any vehicle that has metallic pads! Basically the pads rust to the rotors. The worst part that you all should be aware of is this. Most nearly all pads today are bonded to the backing plates not riveted. I have not pulled the brakes on the Lacrosse to know which way these are done, but if they are bonded they can and do break loose from the backing plates under the conditions you all described. When this happens you won’t necessarily know it. The pad can fall completely out or just slide down. If it falls out braking will be less, how much depends on whether it’s a front brake or back or if the loss is enough to pop out the caliper piston thus losing brake fluid. If it only fall down the loss in braking will be gradual over time, but neither is good. If and when this happens you should inspect all 4 calipers for this occurrence and that means both inside and outside pads on all 4 wheels.
One way to avoid this is dry the brakes by some aggressive braking, to build up some heat in the rotors, just prior to parking in the garage. This will help some if the car sits outside, but not much. The other is, one, don’t apply the parking brake if at all possible and two jostle the car back and forth after exiting, this tends to move the calipers away very slightly from the rotors. Other than that the only other remedy is change the pads to an organic compound, which is always my choice when doing a brake job!
 

cheflionfoot

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... The worst part that you all should be aware of is this. ...
Thank you very much for the info. That was really very helpful. I will look into the alternative type of pads becuase I would have hated for that to happen in a street parking space without the space to really rev. Just a note however; because you are well versed in all aspects of car brakes, not all of us are. Some perople are experts in one thing or another and expect everyone to share their knowledge base and can become very condescending when they encounter people that do not share their knowledge. That is like a docotor telling everyone that they should now exactly how to maintain homeostasis in the sinus cavites when incuring an infection.
 

8-track

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Cheflionfoot, I’m not sure I’m clear on your retort, but my statement of,” the worst part that you all should be aware of is this.” ... Was followed by the explanation of what that would be. The two scenarios that I described are not something I would want under me in a situation of needing optimum braking. If I leave something short for an answer please ask, I will always do my best to expound on it further to clarify it.
It’s not that metallic pads aren’t functional from a brake fade condition of heat buildup, it’s that they defy all principals of braking except brake fade. And one of those principals is, when you put two pieces of carbon steel together add water or water and salt their going to rust together. If you had looked at your rotors immediately after your situation when the guy broke the wheels free, you would have seen a rusted pad print on the rotor.
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8-track

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Yes and No! FNC, (Ferritic Nitro-Carburizing) is a little like cyanide hardening. Yes it’s different but the result is basically the same. The Ferritic is the clue, Ferritic I.E. ferrite metal or carbon steel, and all carbon steel rusts! With that said harden steel rust differently and slower than non-hardened steel because of the atomic substructure density. Likewise it re-polishes better and easier, so no you most likely will not see the rusting like other rotors under normal conditions. Still in Cheflionfoot’s case, due to the severity of adhesion, had he looked at the rotors immediately after they broke loose he would have seen the pad imprint, but it may have been on the inboard side of the rotor.
The FNC rotor is a major improvement in the metallic pad/rotor combo, but it’s about 40 years in coming and bikes have run hardened rotors forever. The first order of braking is the coefficient of friction, which means hard against soft. When I raced I ran ventilated cross drilled steel rotors and soft pads (manila color, brass chips), but similar material harnesses, (metallic pads cast iron rotors) is a bad combo period, not a good coefficient and not good for longevity.
 
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