Contour Enthusiasts Group Archives Forums General Troubleshooting Brake Problem/ Question

Hi. I have a 95 Mercury Mystique GS that I recently replaced the front brake pads on. I finished replacing the brake pads on the front (disk pads). The right side of the brakes work fine, on the left the caliper seems to be grinding the rotor. I had both rotors resurfaced (turned), and I cannot seem to find the problem of why the left brakes are grinding. Everything was put in correctly, etc. I took them to an AutoZone to get them resurfaced, so I assumed that they had enough depth on the rotor. Before I had replaced the brake pads, the front-left rotor was "skipping" when I started to brake, I assumed it was warped. I don't know if I need to replace the rotor, perhaps tighten the guide bolts in the back of the caliper... or what to do. I've asked around, and a few people assume that the rotor is too warped, while others swear that couldn't be the problem. I seem to have enough depth on the rotor. I can post pictures if anyone is interested. This is my first post, so thanks a lot for the responses.

Perhaps the caliper is sticking. That could be an internal problem with the caliper piston and seals or it could be (more likely) the caliper slide pins.

A caliper that is stuck can, in extreme cases, feel like a warped rotor. Did you lubricate the caliper slide pins when you installed the new pads? Proper lubrication of anything that slides and any part of the pad backing plate that contacts the caliper is one of the most neglected but important items of a good brake job. It makes the difference between a mediocre and a great break job.

I didn't lubricate the caliper slide-pins, but I used some sorta brake grease on the back of the brake pads. Where are the caliper slide pins located? Are they the pins located in the back of the caliper that need adjustment with the hex wrench? And what could I buy to lubricate the slide pins? Thanks a lot for your reply too....

Most any parts store sells disc brake caliper grease. I have even seen it recently in small packets near the cash register. Most any reputable brand will be just fine as long as it is specified as brake caliper grease. Ford actually uses dielectric grease and labels it for both uses. My personal favorite is the stuff Volvo uses.

It sounds like you found the caliper slide pins, but the hex is not an adjustment. It is part of the bolt. If the slide pins are removed, you will need a 7mm hex wrench to remove them.

Hey. Thanks a lot for helping me out with this. I am wondering, so if the caliper slide pins aren't adjustable, is there any benefit in removing them what so ever? I'm not sure, I was reading my Haynes manual and it was talking about them, but not too specific on what to do with them. I thought maybe they were adjustable, I wasn't too clear on it. I talked to a friend and he said perhaps the caliper is bad. I'm not sure, I just hit 80,000 miles and got my timing belt replaced 2 weeks ago and now this happens. But anyways, thanks a lot for your help in all this.

If you remove the pins, the caliper will fall off. The pins hold the caliper on to the backing plate but allow the caliper to slide back and forth to stay in alignment with the rotor and to account for wear of the pads. If the caliper isn't sliding easily, you may get the same affect as a warped rotor. In addition, your pads will wear unevenly and often, the pads will overheat as the brakes don't release properly. Make sure those pins are tight. If they are loose, that would account for the caliper not sitting straight on the rotor.

Might want to check that the retainer springs on the front of the caliper got put back on correctly and that the pads are seated flush with the caliper. If the pad shifts out of position it wont press flat against the rotor and will make a grinding noise instead of a smooth rubbing noise.

What you probably originally used was a anti-rattle compound (blue in color?) on the back of the pads.
Clean the pins and use a good high temp grease (synthetic) or silicone (dielectric) grease.
Did you thoroughly bleed the brakes after changing pads?

I did use an anti-rattle compound, it was red. I didn't bleed the brakes afterwards because I never removed the caliper. Do I need to bleed them even though I never removed the caliper? Thanks for your previous feedback, it's very useful.

Yes, you should always bleed after changing pads (or shoes) to eliminate any trapped air in the system.
Also bleeding will remove old fluid which becomes saturated with water, rust, etc. in fact many recommend a thorough bleeding every year or two, regardless of pad change for this same reason.
I use a "one man bleeder" made by Lisle. It consists of a clear hose and semi-sealed cup, along with various size rubber fittings that attach to the bleeder screw. It makes it easy to bleed the system by yourself.