Rotor destroyed by pads, what do you think I should do?

[briantf]

I was swapping muds onto my wife's truck and found the rear passenger-side rotor totally chewed up by a disintegrating pad.

The truck has not quite 60K on it, I replaced front/rear pads and flushed the brake fluid at 40K (my recollection). I put Raybestos heavy-duty front pads on and standard rear pads (the heavy-duty were special order).

At first I was very concerned that I had a sticking caliper (fires are possible in such situations). However, only the outside pad was gone - the inside pad (with the scraper) was perfect, though both sets of pads on that axle were very worn down for only 20K - probably due to increased loading to compensate for the bad pad.

The rotor was destroyed - huge grooves cut into it by the rivets. I went and bought two heavy duty Raybestos replacement rotors and a new set of pads, slapped them on. The other rotor was still perfect, nice and smooth (never been turned, either!!). So, I figure I have a spare.

I figure we lucked out that I saw, that it was the outside pad not the inside (NOW I know why the scraper is on the inside!!), and that it wasn't a $200 caliper but a $55 (x2) rotor and a $35 set of pads.

I'm not mad at Raybestos - I've used their pads exclusively on all my cars for 15 years - but I think they should know they had a quality control failure and it could have been a real problem.

I took digital pictures and obviously have all the parts, but taking it to the local Kragen's would be a useless exercise. I looked at their website and they didn't have so much as a phone number to call. just email forms (not really appropriate for this).

Things I learned:
Brake maintenance includes close inspections at a reasonable interval, including pulling the wheels off (dumb luck I was putting muds on for hunting).

Rotors do NOT need to be turned whenever you put pads on (60 K and perfect rotors front and rear) but you do need to torque lug nuts to spec every time. I'd always heard that, now I've got proof.

Factory rotors cost $105, aftermarket rotors cost $55.

Any suggestions would be appreciated!!

Best,
Brian in CA

 

[RON COX]

I think quite a few have had that experience. After two new rotors I switched over to Performance Friction. You can get them at Autozone. No problems since then. Not sure why my Explorer had the problem and not the Ranger too. Must be the weigh difference. Brute Stop pads are just that to rotors, brutal.

 

[mrboyle]

The number one cause of outside pad wear like you experienced is lack of proper lubercation of the caliper slides.

 

[briantf]

98's don't have caliper pins like 92's do

Mike,
The 98's don't have replaceable caliper slider pins like the older trucks do. The pins are hollow and slide over the caliper bolts, and have rubber bellows that are permanently lubricated (kinda miniature CV boots). The way these calipers are setup, they can't exert any more force than the opposite pad supplies. The pad that grenaded chewed up the one side under braking, and the opposite pad was clean but very worn because of the excess braking force required.

Ron, you're right, the Explorer brakes get a serious workout. My Ranger has rear drums that were practically new at 45K when I replaced my front pads - I would up taking the shoes back because I couldn't see replacing them - and I'm the type to replace it if I have it.

Anyone have a suggestion about how to get in touch with Raybestos?

Best,
Brian in CA

 

[mrboyle]

Brian,
Not to step on your toes, but ALL floating calipers have slide pins. Some are different than others. I happen to work on brakes for a living and see the same thing as you described happening to your X in a daily basis.
The bolts that hold the caliper on to your X also serve as the slide pins. The little "bellows" are part of the guide bushings that allow the caliper to slide. Although they have grease in them, due to the heat created from braking, the grease breaks down and solidifies. This causes the caliper to "stick." In other words, when you apply the brakes the piston forces the inside pad to make contact with the rotor. Once the inside pad contacts the rotor the hyduralic force causes the caliper to move in the opposite direction of the piston. This causes the outer pad to contact the rotor. When you release the brake, the piston retracts (very slightly) releasing the inside pad. Once the force of the piston releases the caliper will slide away (very slightly) from the rotor, releasing the outter pad. If the slide pins are not functioning properly (sticking) the caliper will not release completley, allowing the outer pad to maintain contact with the rotor. The pressure isn't always enough to notice, but leads to premature outer pad failure, just like you experienced.

 

[briantf]

Ah, so!

Mike,

No worries, I wouldn't be asking questions if I already knew the answer!!

The caliper slid easily by hand, but I can see how even moderate contact over what is designed in would be a thermal nightmare.

Given that the pins were sticky, how the heck am I supposed to lube the darn things?? The bolt bodies are narrower than the threaded part, slightly, but they didn't appear to be greased from the factory. Should I pull them and grease them with synth or the high temp grease?? If so, I'll definitely need to do the same on the front calipers on this truck and my Ranger (same caliper/rotor setup).

Best,
Brian in CA

 

[Robert]

Brian, when I did my '97s caliper slide pins I used brake cleaner to clean the pins (bolts) completely removing all traces of grease. I also sprayed the cleaner into the hole that the pins go into and used several cotton swabs until they came back out white. I used "caliper slide-pin lubricant". It came in a small, clear plastic pouch similar to the type a sample of shampoo would come in. There were two pouches to the package and ran about $3-$4. It looked like dark green hair gel. It is possible that you could use something else, I would be cautious in doing that though. If it doesn't work properly it may make things worse. It has to be able to provide the right amount of lubricity and withstand the heat that brakes can generate.

 

[mrboyle]

Brian,
Robert just explaind the process better than I could (though I use shop rags instead of Q-tips). You can pick up the caliper slide lube at any auto parts store. If there is more than one choice use the silicone since it won't deterioate the rubber.

 

[01EB5.0]

I lubbed my pins with synthetic bearing grease and have had 15,000 miles of flawless performance. The pins are VERY vulnerable on the explorers and some even grease as often as every 5,000 miles.

 

[espnfreak]

either get new pads or rotors

 

[Brian1]

I have run my grooved rotor in the front for 3 years on the same pair of brake pads. I have had no problems. When i first got the xplor the rotor was grooved (2 grooves) so I replaced the pads and i have had no problems with it. I would not recommend this however. I am due for new brake pads and I will be changing the rotor at the same time - it is already sitting in my garage.