Here you can see the contact areas highlighted with red. You can see how cruddy the clip is also.
You can see the rust on the clip from the pad and the areas circled have scale built up on them.
As gnarly as these look, the pads were still free in the brackets and were causing me no problems.
Remove the pads by sliding them (or tapping with a hammer).
If you have a mounted wire wheel and are CAREFUL, you can clean up and almost polish the contact surfaces of the stainless pieces. (THIS IS TRICKY TO DO ON A MOUNTED WHEEL AND IF THE WHEEL CATCHES AN EDGE OF THE CLIP CAN SUCK THE CLIP AND YOUR HAND INTO THE WHEEL. DON'T WEAR GLOVES) If you don't have a mounted wheel, use a small wire wheel in your drill To do the job.
Here is the back side of the clip prior to cleaning, notice the build up of scale on some of th surfaces.
This is the same surface after wire brushing with a small brush in an air grinder. You could use a Dremel tool or a drill to do the same thing. A hand brush will remove dirt but isn't very effective on the rust as it is imbedded in the stainless. Scotchbrite pads work to some extent.
With a small screw driver or needle nose pliers, remove a stainless clip. Do one at a time, some models they are not identical. On the 1500s they are interchangeable.
Clean the back side of the contact areas. This can be difficult, do the best you can. If the clips are deeply pitted in the areas that the pads slide on, feel free to replace the clips. This rough surface can trap water and rust the mating surfaces. It may also impede the pad travel.
OK, you've cleaned up the clip, now the bracket. This is thee most common cause of brake pad freezing. The contact areas on the bracket build up with scale BEHIND the clips and pinch the pad.
Sorry about the blur, another view of the scale.
Not a clcear pic but you get the idea, file it smooth.
Nice idea having stainless hardware that doesn't rust as your sliding surface BUT the rust is now hidden and just as big a problem.
Depending on how bad the scale is will dictate the removal method. At this point a vise is nice to hold the bracket. If its bad, use a welders chipping hammer or a small hammer and chisel. Don't go nuts on it, just chip the scale. Then grab a file and clean up all of the contact surfaces that the pad would ride on. If you're not sure which areas, grab a pad and put it in the bracket without the clip. Get ALL of the scale! Don't worry about getting rid of all the pits in the surface, though it doesn't hurt to get most of them. If you get rid of all the pits you'll slightly increase the clearance for the pad, not a bad thing but a lot of filing.
Repeat for the 2nd clip and its mounting area.
This step is optional. At the shop we don't do it but I will on my own to see if it lengthens the maintenance interval. Use some rust converter such as Extend or Permatex rust converter on the contact areas of the bracket. You can get the Permatex at Ace hardware in a spray can.
This is what I used, it converts the rust to some sort of polymer that inhibits further rusting. We'll see. I've used it in other applications and liked it. This area is subject to high heat though so I don't know if it will last.
This is what the treated areas look like within a few minutes.
If you do the treatment, do the bracket before the clips to give it a chance to dry. I brushed it on very lightly so as not to create a build up.
One last area to address on the caliper bracket. The slider pins.
Check their boots for tears. If they aren't intact then replace them. Use a brake lubricant on them, it is designed for the environment that it has to function in. You can get it at any auto parts store.
Time to address the pads. If you are not changing them (and even if you are), check to see if they slide freely now in the bracket. Slip one end into the clip and swing the other end in. It should want to rotate right through to the center of the bracket and fall out. If there is a lot of drag (and this is a subjective feel) take the pad to the pedestal grinder and LIGHTLY radius the edges of the contact areas. If this doesn't free it up go back and grind(or file) the areas that can pinch or are pinched by the clips. If its tight now it will just get tighter later when the rust returns. We always do this on new pads also. We've found that the stampings on the pads usually have sharp edges that can dig into the clips.
The picsc of the pads are blurry but I'll include them, hopefully you get the idea from the shiny areas.
This is the pad as it came out of the bracket. They come painted or powder coated but they rust behind the coating. I used a file to put a small radius on the edges of all the surfaces that slide on the clip to eliminate the paosibility of them digging into the clip. I also filed off any scale or flaking paint from the contact surfaces. These are stamped plates and are rough to start with. Don't go nuts here either as you don't want TOO much clearance.
This is also a good time to adjust the E-brake. This is a drum brake within the rotor. I don't know about you, but I use the parking brake most of the time. Mine needed adjusting as it wouldn't hold me if I was in gear. Getting the rotor off can by a bear because there is usually a ridge of rust built up on the outer edge of the drum and you have to get the brake shoe to compress enough to go through it. Mine came right off this time. There was a ridge but not a bad one and my brake needed adjusting so everything was in my favor. I used a carbide burr in my die grinder to remove the ridge before I put the rotor back on. You could use a sanding disc in a drill or a stone in a drill or Dremel tool.
As for adjusting, I took the adjustor wheel out about 3 turns on each wheel. I made sure the e-brake wasn't dragging and that the rotor went on easily. They work great now.
Reassemble. on the 1/2 ton, bracket first, pads in the bracket and then the caliper. Put the wheels on and snug up the lugs. let the truck down and torque to 140lb/ft. On the 3/4 ton you HAVE to assemble the caliper to the bracket BEFORE you mount the bracket. Ask me how I know.
140 lb/ft for the 3/4 on also. Get in and pump the brakes just to make sure they are up before you start the truck.
On a side note, the procedure is very similar for front brakes also be it on cars or trucks. The problem also exists on fronts as well. For example. Thursday I did all four corners on a 2005 Gran Prix with only 17,000 miles. All of the pads were hanging up to some degree. The rears worse than the fronts. The rotors all needed turning, the rears because of rust, the fronts because the outer pads were hung and the inners were doing all the work and had grooved the rotors.
Happy wrenching,
Bob
