DerbyDad03

2007 Civic LX, 91K miles, bought used about a month ago. A visual inspection of the front brakes indicated no issues, lots of pad left. A week after we bought it, it passed the required state inspection.

First the background, then my question.

Recently, the front passenger brake started to smell burnt so I pulled the wheel to check the caliper, etc. The slider pins moved freely and the caliper compressed with absolutely no problem. However, the pads were stuck in the bracket so tight that I had to pound them out with a rubber mallet. Lots of rust on the pad tabs and under the clips. Even after I got them out with the mallet, when I tried to put them back in (just as a test, on the workbench) they just jammed up tight.

I checked the driver's side and the pads were just as tight, if not tighter. Once again, the caliper compressed with very little effort and the slider pins were free.

I used the wire wheel on my bench top grinder and cleaned the pad tabs, the caliper bracket channels and the clips. When I lubed it all up, the pads moved freely and everything went back together as it should. A test drive with some hard braking resulted in no odor and no heat. I'll be keeping an eye on things over the next few days.

So here's my question:

If the pads were so jammed up that they didn't even move until the rubber mallet was applied, how were they moving enough to stop the car? Obviously they were doing something because they were heating up and smelling and the car was stopping fine. I'd find it hard to believe that the rear drums were doing all of the stopping, but even if they were doing most of it, the pads must still have been moving inwards otherwise they wouldn't have gotten hot.

Can anyone share some knowledge on how some seriously jammed up pads were still doing their job?

Thanks!

ezone

Even though they feel stuck to your touch, they probably were not really seized as much as you think.

Hydraulic force is much greater than your hand pressure and WILL move them against the rotors,

but when hydraulic force is removed, the caliper piston retracts slightly but the pads do not 'relax' and move away from the rotor....so they drag a little bit constantly...


I see this all the time in the rust belt.

The rust buildup behind the stainless clips is usually what causes the pads to bind and stick. The rust 'swells' as it forms and causes the clips to effectively move against the edges of the pads.

Sometimes one pad may be stuck so tight it causes the other pad to wear rapidly. Occasionally I see this cause a soft pedal, and rarely completely quit working altogether.

I make a habit of removing the stainless clips and grinding the rust out of the caliper brackets, then greasing the casting I just ground the rust from. Wire wheel the stainless clips, and grease the slide pins.

Before cleaning:

DerbyDad03

What you show is basically what I had. Thanks for the answer, that's kind of what I thought.

In all the years of doing my own brakes I've never seen pads that I had to hammer out. The pads look too new to have rusted in as firm as they did. That was even more surprising than the fact that they actually worked. Even the ex-Honda mechanic that inspected the vehicle after I bought it looked at the lack of wear on the pads and just assumed that they were fine.

Well, they really are fine now.

Thanks again.

CraigW

iTrader: (1)

3rd party parts.