I think I may have a locked up caliper

[TurboDiverArt]

Hi All,

I changed the pads about a year and a half ago. I used the severe duty pads from NAPA. Since installing them about 40,000 miles ago I have checked them two or three times. I was concerned about the heavy metallic pads causing excessive wear on the rotors. I never noticed any rotor wear. About two weeks ago I started hearing a squeak from the left front brake. Over the past week it progressed to a constant squeal while moving. Tonight I noticed when hitting the brakes hard I would gear a grinding noise which had not happened before. Got under the truck and felt the outside of the rotor and I can tell there is a gouge in the rotor. I don

[rjschoolcraft]

There are several threads on this topic. You should probably search for them.

I know on the 2001 trucks, the rotor will slip off. Don't know about the 1999's.

On my 1995, it's a big job. The hub and rotor must come off of the truck. This is accomplished by removing four bolts that hold the hub to the steering knuckle from the back side. They are 15 mm hex but very large shank bolts (close to 15 mm major diameter from memory, never checked, though). The 36 mm axle nut must also be removed. Once the hub and rotor assy is off the truck, drive out the wheel studs and the rotor will fall off.

[TurboDiverArt]

Originally posted by ronniejoe:
There are several threads on this topic. You should probably search for them.

I know on the 2001 trucks, the rotor will slip off. Don't know about the 1999's.

On my 1995, it's a big job. The hub and rotor must come off of the truck. This is accomplished by removing four bolts that hold the hub to the steering knuckle from the back side. They are 15 mm hex but very large shank bolts (close to 15 mm major diameter from memory, never checked, though). The 36 mm axle nut must also be removed. Once the hub and rotor assy is off the truck, drive out the wheel studs and the rotor will fall off. I had done a search on Rotor removal and found two threads. One was not helpful, the other said the rotor could be taken off with a BFH. Looking at the picture of the rotor on the NAPA site it's not real clear if it slides on/off but it looks like it does.

Art.

[HammerWerf]

This is long.

Art,

Your description of sound, and gouge on the rotor face is a duplicate of what my wife's suburban had happen last June.

I replaced the original factory pads at 22k miles with Raybestos Brute Stop pads. We got about 55k miles out of these till the noise started.

She told me that the brakes were making a squeeling noise. Given the length of time in service, I figured the wear noise maker was starting to touch. No problem, check them on my day off. Come home from work on day, told the noise has changed to GRINDING, and I would check it out NOW. Drove the car around the block, Wife was right. Isolated noise to Right Front. Pulled the tire, found the gouge. Looked in the inspection spots. Pad thickness looked thin, but not this thin. Off to AutoZone to buy their DuraLast brake pads. As I am trying to push the piston back into the caliper, fluid out the bleeder, I notice the caliper is not moving easily. Finally get enough fluid out to pull the caliper. When I checked the pads, found the inner one was worn down to the backing plate. Nothing left. The adhesive holding the material to the plate was almost all gone, and a few high spots were machining the disc. Upon inspecting the sliding surfaces, found that dirt, and brake dust had locked the caliper in position. The outer puck had about half of its material left. Cleaned up the surfaces to very clean, put some synthetic brake grease (CRC product) on the sliding surfaces, per a CarQuest maintance note, and put it back in service. Did same to the other side, too.

My observations on this.

The suburban was not braking like we would like it to. Seemed like it would not stop in time. All the usual complaints. We had adapted to the braking requirements. Upon doing front brakes, the truck stopped like it should. It could throw your up against the seatbelts. Have not tried to activate the ABS. Prior to c/o, I don't think the ABS could have been activated.

Maintance (at least for me) appears to provide the best assurance of fully operating front brakes. Have to pull the calipers off at least once/year to clean the sliding surfaces, and to check the actual thickness of the inner pad. I remember a post where the member said he did this every year, and his brakes worked great.

HammerWerf

[rob1681]

check your break lines,they may get soft and will not allow fluid back to the master cylinder.I changed everthing on my truck and it turn out to be the front rubber brake lines bad.

[TurboDiverArt]

Did either of you have to replace your rotor? I definitely have to replace one. The other is marginal in my opinion. The drivers one is just downright rough and it's deep.

I need to figure out if I can slide the rotor off or have to disassemble the hub. Not sure how to do that if I have to. Just too darn dark and cold to pull the wheel off and play with it to determine this. I'm hoping someone with a 1999 truck knows.

Thanks,
Art.

[Tony Mattingly]

Yes, do not forget the brake line. I pulled my hair out one time because of the brake line. Actually what happened was, rust started building up inside the metal clip that helpd the rubber hose. As the rust built up and slowly sqeezed off the line. Finally, fluid would go in, but it would not let it bleed off. Similar to what a "stuck caliper" would do.

[JTodd]

I recently changed mine, both sides. Most likely, yours are not slide off. AutoZone lists the same part numbers for front rotor and wheel hub for the 96 and 99 K2500.

There are two big issues. 1)Getting the four bolts out of the back and 2)getting the hub off of the steering knuckle. I believe the bolts are 15mm, use a 6-point socket that is in pretty good condition. The threads are severely coated in lock-tite at the factory and they are in there tight, plus they are prone to round. If you have access to an impact gun, use that, otherwise a long breakerbar. I don't mean to scare you off. I pulled both front and rounded 1 because I was not using a tight-fitting, 6-pt socket. It is hard to get penetrating oil to the bolts because they are recessed and have an expanded shoulder to them. Besides that, the bolts go through the knuckle and thread into the hub, so even if you get oil past the shoulder, you have another inch or so before getting to the threads.

Once the bolts are loose, spray PB-B into every nook and cranny you see. The red straw really comes in handy. Keep spraying! (go make a sandwich, spray more, each sandwich, spray more . .you get the picture) The problem is the hub not only bolts to but slides into the steering knuckle. Due to heat and the elements it corrodes, making it difficult to come out. With plenty of PB-B I was able to work the hub out with a large crowbar. Let the PB-B do the work. I decided the BFH did not work as well as lots of spray, time and a long bar.

Be patient! This is not a 30-minute brake job, but it is certainly do-able.

I actually may need to do one of mine again. I am pretty sure one of my new rotors has warped.

Good luck.

[ANXIOUS-SUBMAN]

I beat the crap out of my old rotors trying to get the hubs off. One method that has been used is to back the bolts out about 1/4" then use a drift pin or punch on a pneumatic impact driver on the heads to push the hub off. When the heads bottom out again, back them out some more and keep driving. You may have to replace the bolts afterwards.

Another tip: As soon as you get the hubs off, remove your abs sensors for safe keeping while swapping the rotors out. Apparently I damaged one of mine in the process and then had to take it to the dealer to have them scan the abs computer to determine which sensor was bad.

[JTodd]

I tried the method of backing out the four bolts and hitting them with a hammer. The space was tight enough to not get a good angle, but enough to let me ruin the bolt heads.

Here is another method mentioned in a previous thread
I'll pass on the trick I use to help loosen rotors. With the weight of the truck on a floor jack, I put a hardwood block under the bottom of the rotor. I then let about 3/4 of the weight of the truck onto the block. Tighten the floor jack and put a jack stand under the frame too for safety.

That gives about 1,200 pound to bear on the problem. At this point, a few stiff whacks with my favourite hammer, and the rotor gives up its grip.

Guaranteed to work. Just be safe, because the truck will want to drop a bit when the rotor comes free. I would say that this method might pull the rotor away from the hub before the hub came away from the knuckle. To prevent this, put the lug nuts back on.

The thread is here. (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=007858#000000)

[TurboDiverArt]

Anyone got a diagram of the brake setup? I must be missing something. Been raining for days here so I can't just go out and loot at it at night. I'm just not understanding the bolts needed to get the hub off and the rotor separated from the hub.

Does the hub connect to the spindle/knuckle with bolts from the back or the front? The 4 problem bolts in the back, are they for the hub or rotor?

The link posted about the floor jack method, is this a method of doing it with the hub staying on the truck? Wondering if the 4 bolts in the back are to detach the rotor from the hub and then letting it down breaks the rotor lose from the hub and it sort of slides off? Or, do you still have to remove the hub?

I'm pretty mechanically proficient but for some reason I can't seem to visualize this.

Art.

[rjschoolcraft]

Originally posted by TurboDiverArt:
Does the hub connect to the spindle/knuckle with bolts from the back or the front? The 4 problem bolts in the back, are they for the hub or rotor?

Originally posted by ronniejoe:
On my 1995, it's a big job. The hub and rotor must come off of the truck. This is accomplished by removing four bolts that hold the hub to the steering knuckle from the back side. They are 15 mm hex but very large shank bolts (close to 15 mm major diameter from memory, never checked, though). The 36 mm axle nut must also be removed. Once the hub and rotor assy is off the truck, drive out the wheel studs and the rotor will fall off. The four bolts hold the hub to the knuckle from the back (inside in vehicle orientation). The rotor is held to the hub by the lug bolts and must slide off to the inside after the hub/rotor assembly is off the truck. There is a flange on the hub that the rotor sits up against that won't let it slide off to the outside.

I would advise against the weight of the truck on the block method. That is rather dangerous. A slide hammer is the official method, but Moondoggie has come up with a home made tool that works well. I've never had any trouble getting my hubs to separate from the knuckle.

[TurboDiverArt]

Originally posted by ronniejoe:
I would advise against the weight of the truck on the block method. That is rather dangerous. A slide hammer is the official method, but Moondoggie has come up with a home made tool that works well. I've never had any trouble getting my hubs to separate from the knuckle. OK, I think I'm starting to get this now. If memory serves there is a couple of holts holding a cover over the axle nut, it

[redbird2]

I just did one of my 1998 this morning not bad job.

1) remove center cap from wheel
2) loosen axle nut with wheel still on the ground
3) jack up truck
4) place jack stand under truck A MUST!!!!!!!!!!!
5) remove front wheel
6) depress caliper so you can remove it
7) remove caliper bolts take caliper off (make sure to support it so not to damage brake line)
8) disconnect the ABS wheel sensor wiring at plug and free wire from it retainer clips
you asked how the sensor can be attached and the wheel still spins the hub base plate doesn't move the bearings are mounted to the hub base and the hub is mounted to the bearing they turn whick always the wheel to spin
9) from back side remove the 4 hub mounting bolts very tight. 15mm head bolts
10) remove hub assembly from the truck
11) place rotor face up on couple wood block so not to pinch ABS wire lead
12) drive out wheel studs (perferable with brass drift so not to damage threads)
you will have to twist the rotor around and it will come off from the rear

put back togeather in reverse order.
make sure to torque all bolts to proper specs,
and retorque wheels after first 500 miles


One note if you have had the wheels off alot high miles and lots of tire rotations now is the time to replace those wheel studs very cheap insurance especial if you are hauling the kids with you

[ 02-03-2006, 09:40 PM: Message edited by: redbird2 ]

[tom.mcinerney]

I put on cheap Chinese rotors from NAPA. Another , departed member had experience with some NAPA Chinese that was reminiscent of
>>I actually may need to do one of mine again. I am pretty sure one of my new rotors has warped.

Mine ok , but still low (10K) miles, mostly light running.

[JTodd]

I am going to see what is going on with a possible warped rotor this morning (as soon as it gets light out). I will take some pictures to help give you a better idea. Look for them in a couple hours.

When removing the 36mm nut, don't totally remove it. I used that to hold the hub/rotor on when it finally broke free.

[TurboDiverArt]

Thanks so much to all, great info. Very clear to me now! Now I have to just brave the cold to get it done. I

[TurboDiverArt]

OK, project done. Was not as difficult as I thought. I only ended up having to replace one rotor so that make the project a lot easier. Replaced both calipers and hoses. Using a 2-foot breaker-bar, all the bolts came out very easily with a 6-point impact socket. The 36mm axle nut came off with the impact gun, the hub bolts needed the breaker-bar. The hub slid off pretty easy, no need for a pry-bar. I was able to wiggle it out by hand. Hub was off the truck in about 30 minutes. Removed the speed sensor, knocked the studs out, flipped the hub over and knocked the rotor off. I