Brakes - Caliper Stuck?

[Klink]

I have a 2008 Suburban and I just left to come home from a weekend away with the family and the truck started to act really weird. I got a real bad vibration in the steering wheel at about 55 and I can feel the brakes pulsing. I turn around and drive the 15 miles back to the place I was staying and raise up the front end of the truck and the drivers side wheel I can't even budge. The passenger side spins freely. I open the bleeder thinking this will release some pressure on the caliper. This did not work. I pull the caliper off and cool everything down and grease the pins thinking they might be sticking. Put it back together and the wheel spun freely. I took it for a test drive and again I smell brakes and raise the front of the truck and yep, wheel wont spin.

 

Any ideas here? I will be going to chevy in the AM as the truck is still under warranty. Not happy about extending my vacation another day.

[rockcrusherrevived]

I have a 2008 Suburban and I just left to come home from a weekend away with the family and the truck started to act really weird. I got a real bad vibration in the steering wheel at about 55 and I can feel the brakes pulsing. I turn around and drive the 15 miles back to the place I was staying and raise up the front end of the truck and the drivers side wheel I can't even budge. The passenger side spins freely. I open the bleeder thinking this will release some pressure on the caliper. This did not work. I pull the caliper off and cool everything down and grease the pins thinking they might be sticking. Put it back together and the wheel spun freely. I took it for a test drive and again I smell brakes and raise the front of the truck and yep, wheel wont spin.

 

Any ideas here? I will be going to chevy in the AM as the truck is still under warranty. Not happy about extending my vacation another day.

 

do you feel the steering wheel pull to the left or right when braking

[Klink]

No pull at all. I can hit the brakes and let go of the wheel and it just vibrates left to right. Not enough to pull.

[Matt_]

Are you able to compress the caliper?

 

If not, can you compress it with the bleeder open?

[rockcrusherrevived]

No pull at all. I can hit the brakes and let go of the wheel and it just vibrates left to right. Not enough to pull.

 

on the old chevys like my 82 the clamp on the control arm holding the flexable line would rust and sqeeze the flexable line so the brake fluid had a hard time flowing but on the gmt900 the flex line is so short there is no bracket to secure it so that can't be the problem

[Klink]

I can compress both pistons with a "C" clamp with bleeder open and closed. I am completely baffled with this. Everything moves free and nice. I drive it and I am hard on the brakes. Pull it in the garage, jack up the front end and pass side spins with little resistance. Drivers side has that god awful hot metal on metal sound. Just creeks as I fight to turn the wheel.

[Klink]

No pull at all. I can hit the brakes and let go of the wheel and it just vibrates left to right. Not enough to pull.

 

on the old chevys like my 82 the clamp on the control arm holding the flexable line would rust and sqeeze the flexable line so the brake fluid had a hard time flowing but on the gmt900 the flex line is so short there is no bracket to secure it so that can't be the problem

 

 

I thought it could be a collapsed brake line but fluid will go back if I compress with a "C" clamp. That and if I open the bleeder it does not free up the caliper.

 

Is there a proportioning valve that could be playing games here?

[Matt_]

Ok a few more things...

 

How hard is it to compress? Noticeably harder than the other side?

 

With the caliper compressed, it slides back and forth on the arbor alright and doesn't get hung up?

 

Are the pads free to move? Make sure the pads aren't jamming up.

[rockcrusherrevived]

No pull at all. I can hit the brakes and let go of the wheel and it just vibrates left to right. Not enough to pull.

 

on the old chevys like my 82 the clamp on the control arm holding the flexable line would rust and sqeeze the flexable line so the brake fluid had a hard time flowing but on the gmt900 the flex line is so short there is no bracket to secure it so that can't be the problem

 

 

I thought it could be a collapsed brake line but fluid will go back if I compress with a "C" clamp. That and if I open the bleeder it does not free up the caliper.

 

Is there a proportioning valve that could be playing games here?

 

i haven't had my gmt900 long enough to know whats on the under side

[Klink]

Ok a few more things...

 

How hard is it to compress? Noticeably harder than the other side?

 

With the caliper compressed, it slides back and forth on the arbor alright and doesn't get hung up?

 

Are the pads free to move? Make sure the pads aren't jamming up.

 

 

The two pistons on the drivers side....the top one moves more freely than the bottom one. I did not pull the caliper on the other side.

[Matt_]

The two pistons on the drivers side....the top one moves more freely than the bottom one. I did not pull the caliper on the other side.

 

Try compressing both at the same time. You can put a brake pad in there if you dont have a dual piston compressor... just put a wooden shim or something in between the c-clamp and the pad so you don't damage it.

 

It should go in easily with little effort on the c-clamp.

 

And how many miles do you have?

[Klink]

The two pistons on the drivers side....the top one moves more freely than the bottom one. I did not pull the caliper on the other side.

 

Try compressing both at the same time. You can put a brake pad in there if you dont have a dual piston compressor... just put a wooden shim or something in between the c-clamp and the pad so you don't damage it.

 

It should go in easily with little effort on the c-clamp.

 

And how many miles do you have?

 

 

I only have the one wheel off right now and I did compress both at the same time and you do have to crank on it a bit to get it to go in. More than I would think.

 

Truck has 42k on it and I bought it last November as a certified so I should be covered through 48k.

 

I really think something funky is going on with that caliper. Unless there is something with the ABS system that regulates fluid that could be faulty. I am not familiar with how the ABS system works on here but I have narrowed it down to the caliper unless there is something with teh ABS. I would think if it was something with the ABS I would get an idiot light.

[Matt_]

Its not likely anything in the ABS or proportioning system.

 

Seems like the caliper from what you're describing.

 

If you haven't already done so, make sure that it doesn't get any easier to compress with the bleeder open. Although if you're replacing the caliper, it's generally a good idea to do hoses too.

[NV5600]

I had almost the same thing happen to my '05 Z71....twice. The first time (in February), both front rotors got extremely hot within about 5 miles from my house. I got it home and looked at it and found two scorched rotors so I replaced them both and put new ceramic pads on too. All was fine for a few months and the truck's braking was very good. Then it happened again on the return leg of a 200 mile trip (in July). I had the same steering wheel shake like you did. I got it home and found the front passenger side wheel almost impossible to turn and the brand new rotor was red hot. The driver side seemed to be ok. I opened the bleed screw and let some fluid out and the wheel released. I let it sit for a few minutes and the wheel got tight again.

 

It makes no sense. Logic didn't lead me to any one cause. It wasn't a bearing because the rotor will turn freely without the caliper on. The caliper pistons compressed easily when I installed the new pads. The calipers themselves slid easily on their sliders. SOMETHING was causing pressure build-up in my front braking system. I'm a transmission mechanic by trade and was not in the mood for this to happen again. I ended up replacing everything from the firewall forward to the calipers except for the steel brake lines which look like new. That means the vacuum booster, master cylinder, flex hoses and calipers. My bad luck continued when I discovered the bleed screws on the rear wheel cylinders (drum brakes) would not open so I had to replace the rear wheel brake cylinders too I had some trouble getting the brakes bled and the rears adjusted to my liking so I ran to the dealer for them to put the final bleed and adjustment on them.

 

As bad as this sounds, the actual cost of the parts was not all that bad. The worst part of the job was replacing that vacuum booster. Picture stuffing yourself under the dash of your truck on a 95 degree day with 80% humidity and then trying to get to the 4 brake booster nuts that you can barely see let alone feel way up behind your brake pedal. Get the idea? Anyway, I have driven hundreds of miles and the brakes are the best they've ever been......and I'll always wonder if it's fixed or not but I honestly think it is. I can't help but wonder though if my problem was somehow caused by moisture in the brake fluid. Could both the cold and hot temperatures cause the moisture to expand thus pressurizing the system? I know that's a stretch. In any case, my old fluid is long gone now. I was considering trading in the truck but would not do it without fixing that brake issue first. I can trade it in now with a clear conscience.

[Klink]

Holy crap! not sure about replacing everything from the firewall forward.

 

I am convinced it has to be the caliper. When it gets hot I open the the bleeder and just a couple drops come out. Which is correct because there should be no pressure on the system. Doing this does not release the brakes. The only way the pressure comes off is when I put a fan on it and it cools down. The caliper has to be sticking.

 

I guess I will find out tomorrow. I am goign to guess this is not the way my wife wanted to spend out anniversary.......sitting at chevy.