So my buddy's C6 has an overwhelming burning smell coming from the front driver's side brake pad even after a short drive and the rotor is noticeably hotter than the other 3. We removed the caliper and the piston compressed easily enough so there's not something blocking it's release. The pad, when not engaged, wasn't in contact with the rotor any firmer than the passenger side. We tried a search but didn't find any recommendations. Any ideas? Thanks

 

how's the right rear wheel/pad/rotor/caliper?

 

Man you work fast! haha. You must've got on CF as soon as you got home Thanks for posting.

Didn't notice any problems with it or smell coming from it. It's strictly the left front wheel that gets hotter and smells. I pressed the pistons back a little when we had the caliper off and they didn't seem any more difficult to move (thought there might be something clogging the line??) and when I put the caliper back on and it had a little play in the grip I moved it back and fourth and it seemed to move smoothly on it's mounting posts. The pads don't have any obvious portions that seem to be wearing unevenly... I'm stumped (though that's not saying a whole lot considering my level of experience with brakes hehe).

I've got ceramic pads sitting in the closet waiting on a nice spring "mod" day, and was planning on having the calipers zinc coated. Maybe this is the time to do it... then again I'd hate to ruin the new pads if there is something that's going to cause them to rub/burn off excessively as soon as I put them on... decisions decisions....

 

my reason for asking is that I think the brakes are tandem diagonal, and if there was something wrong with the system, it would affect front left/right rear. I could be wrong on the tandem diagonal thing, tho.

If I'm correct tho, that means it's something specific to only the front left brake as you've noticed.

My off the cuff guess is possibly some blockage in the line as you suggest, a wheel/brake sensor (abs?), or contaminated fluid.

In line with that, have you checked, changed the fluid recently? How many miles, how old is the car?

 

Hey Bill - I got your PM so I came over to take a look at this thread to see what Robbo's problem is.

I think you're correct about the diagonal thing - the brake bleeding sequence is something like LR - RF, then RR - LF because the system is divided into 2 circuits for safety (if the LR - RF blows a line and loses fluid, the RR - LF brakes should still work so you can stop).

At first I would suspect a leak of some brake fluid onto the pad, but it sounds like the caliper has been removed and hopefully any seeping would have been detected.

So, if no brake fluid is getting onto the pad, I would think that maybe the left front wheel possibly splashed through something on the street that got some kind of fluid or grease on the pad and when that pad heats up and heats up that substance that it's giving off smoke.

Robbo says that the floating action of the pad mounting bracket on the sliding pins seems to be smooth, so it sounds like that's not a problem.

The big concern is that Robbo says that it's hotter than the others. That might indicate that the pad is not retracting when brake pedal pressure is released. He reports the pistons don't seem to be sticking, but maybe there is some junk in the brake line that is holding pressure even when you take your foot off the pedal.

Maybe a brake bleed of just that one caliper would flush that line and take care of the problem. The LF is the closest to the master cylinder and wouldn't take much fluid at all to completely flush that line.

So....all the above is just speculating what the problem might be, but I'd do a quick bleed of that caliper and see if that made any difference.

Good Luck Robbo!!!

Bob

 

Robbo/Torch, reason I asked Bob to stop by is he knows a few things about brakes (see post #10: http://forums.corvetteforum.com/c6-c...-question.html)

Thanks, Bob!

 

Thank you for the help and suggestions AO & Bob.

I have in-laws on their way to the house for a couple day visit right now, so I probably won't mess with the car until Sunday or Monday, but will report back when finished bleeding to see if it resolves the problem.

Thanks again,
Rob

 

Wow time flies it seems. Got busy and 20 days pass and haven't bled or drove the vette haha. Finally got to bleed the caliper today. Fluid came out just fine right away (ie - didn't seem blocked). Got it all buttoned back up and went for a drive. No change. Still smelled brakes.

I'm out of ideas. I'm going to keep an eye on it for the next few days and check every time I get out of the car. I have some new ceramic pads in the "mod closet" and have wanted to get the rotors zinc coated for awhile. I think next week while the wife is out of town and I can use her car I'll take it apart and drop off the rotors and really scrub down all the calipers while they're off and put the new pads on and see what happens.


Rob