New pads, calipers, rotors. Now I've developed some sort of brake noise
03 Blazer. About a month and a half ago I finished up replacing rear backing plates, axle seals, rotors, pads and calipers. Also overhauled the parking brakes. Everything seemed fine, until a few weeks ago. I've developed a noise that I can't figure out. The noise itself is best described as a low pitched squeal or groan. It kinda of sounds like the noise my rear brakes made previously when I was having an issue with a sticking caliper. As far as I can tell it's not sticking this time. After I park I check for heat at the rim and see if I can smell burning brake pads but everything seems normal. The noise happens when the truck is about to come to a stop, with moderate pedal pressure.
Have you re-assembled all in the drum brakes with new components? New springs? New retainers?
Do you have the noise while driving or while braking? Can you tell if it is from the front or from the rear?
I had such an issue with rusted retainer pins. Then a spring broke and wedged between a shoe and the backing plate and pushed the corner of the shoe against the drum.
If you have access to a lift I would check the whole underside and the full drivetrain front to aft for any signs that may cause the noise.
At that time you can turn all the wheels by hand and check for noise of vibration. Also check for clearance issues on the wheel bearings and axle supports.
Then I would take the drums off and have a very careful look for such traces as rubbing of metal against metal.
As you have driven it already a bit it may have a slight dust cover but where it rubs will be blank spots.
Have you re-assembled all in the drum brakes with new components? New springs? New retainers?
Do you have the noise while driving or while braking? Can you tell if it is from the front or from the rear?
I had such an issue with rusted retainer pins. Then a spring broke and wedged between a shoe and the backing plate and pushed the corner of the shoe against the drum.
If you have access to a lift I would check the whole underside and the full drivetrain front to aft for any signs that may cause the noise.
At that time you can turn all the wheels by hand and check for noise of vibration. Also check for clearance issues on the wheel bearings and axle supports.
Then I would take the drums off and have a very careful look for such traces as rubbing of metal against metal.
As you have driven it already a bit it may have a slight dust cover but where it rubs will be blank spots.
Sorry, maybe I should have specified, I have rear discs, not drums. And the noise is definitely coming from the rear brakes.
Even on the rear disc brakes, the parking brake is a drum brake inside the rotor, so error_401 may not be far off, don't rule out the parking brake shoes/drums.
How are you checking the temp, just by hand, or are you actually using like a laser temp gun? Use a laser temp gauge, and after a few minutes driving they shouldn't be more than about 25-30 degrees off from each other (comparing the same areas, like caliper to caliper, disc to disc, or drum to drum, etc). If you find one is like 40+ degrees warmer than the other, then you have a dragging brake, and you have to dig further to see if it's the parking brake shoe or the disc and caliper.
When I overhauled my rear end (same as you, backing plates, parking shoes, calipers, pads, rotors, etc), the first replacement caliper I put on was sticking... Checking the temps of the rotor disc after just a short drive, one side was 100 degrees warmer than the other... Had to replace the replacement lol, then all was well after that. But aside from the smell of hot brakes, there was a low "grown" when coming to a stop, but it wasn't dragging enough to make the truck veer off in any direction at all, either while just driving or when getting on the brakes hard.
I'm thinking about taking the truck for a ride without the parking brake shoes installed, in order to rule them out. I'll see if I can get to it this weekend.
I'm thinking about taking the truck for a ride without the parking brake shoes installed, in order to rule them out. I'll see if I can get to it this weekend.
Drove the Blazer around with the brake shoes taken out. Now I'm more confused. The sound is still there, but it's definitely not as bad as it was. I was doing some pretty aggressive braking with it, and couldn't really get it to make the noise that much. Before it was every time the truck came to a stop. Now with the parking brake shoes out it, it will only make the noise occasionally, except way quieter.
Also bought a temp gun like was suggested, though it was after I had taken the parking brake shoes out. I didn't find any noticable temperature difference at the rotors.
I did notice when taking things apart that the passenger side rotor had a spot of discoloration on the inboard side. I could have sworn the noise was coming from the rear driver's side, but could be wrong.
So now I'm still not sure what the culprit is. Maybe a little of both? Sticking parking brake shoes and caliper?
I stopped rebuilding calipers about ten years ago. Back in the 70’s we just replaced the seals, pushed the pistons back in and everything was good. I started having too many problems with sticking calipers so now I always go with rebuilds. I don’t know if it’s warping, crappy seals ... That said even some of those rebuilds are crap. On the last brake job the caliper pins were ever so slightly out of parallel and the assembly was sticking. I needed to finish that day so I got out the old surgical tools (ball peen hammer) and smacked the pins until I got them parallel with good smooth movement. Point of all of this is that brake jobs can need a lot of checking and “finesse” with today’s cheap parts. Try coasting down to under 5 mph, take the truck out of gear and see what happens as you coast to a stop. It should be a smooth really slow stop with no last minute grab at the end. Also you can get on jack stands spin each wheel while someone pumps the brakes and as they release you see the wheel is still nice and free. Also look at the thin shield and make sure it’s not distorted and rubbing. Next as you spin the wheels listen for bearing noise and check lateral play for loose bearings in the rear by rocking the wheel up and down with a bar and 6 and 9 o’clock play in the front. Next did you get any fluid on the pads because that can make then noisy. Some pads are noisy even when dry, I now use Wagner thermo quiet ceramic on everything and have not had any pad noise for over a decade.
Also, make sure that your rotors are still true. A magnetic clamp and a runout gauge is the high tech method. Very light pedal on the brakes is the low tech method, feeling for pulsing. Modern rotors are more prone to warping, especially if you had them turned. Cheap rotors can be out of true out of the box. I stay with good rotor brands. As I mentioned oil on rotors can be noisy as can polished grooved old rotors. Good luck.
Decided to order a new caliper and return the old one under warranty to rock auto. The passenger side caliper, the side I saw discoloration on the rotor. I swear the noise was coming from the driver's side, but besides the noise this is the only evidence I have that something is wrong. I'm still not even sure if a sticking caliper is the source of the noise. No burning smells, no excessive heat or temperature differences, I tried what George above suggested and let it coast to a stop in neutral. Stopped smoothly. Thing is too, it's intermittent. Sometimes there's no noise at all and sometimes it's so bad you can feel the vibration in the floor of the truck. Like metal on metal.
I don't understand why if it is a stuck caliper, why does it only make noise when the brakes are applied (just before coming to a stop) versus when the brakes aren't applied. Feels like I'm just firing the parts cannon at it.
Also, George mentioned brake fluid/dirt on rotors. Everytime I've taken the brakes apart I've been sure to clean the rotors thoroughly with brake cleaner and a cloth, so I don't think it's that.
The noise is so bad at times I wonder if the pads themselves are the issue, or maybe I screwed up the hardware or something. I've checked and double checked, but who knows
01-06-2021, 02:09 AM
New pads, calipers, rotors. Now I've developed some sort of brake noise
