LOUD Squealing Brakes

I have a '95 Chevy S-10 4x4. I changed the front pads and rear shoes last November. All seemed well until a few months later when the rear brakes started acting strange. I found I had mixed up the shoes on one side. I replaced them again with new ones.

Ever since I am getting an extremely loud squeal when braking. I put new drums and shoes on the rear again and it made no difference. After sticking my head out the window driving I decided it might be coming from the front. My rotors were quite old so I put on new front rotors and pads. The sound seems just a tad less now but it’s still squealing intolerably.

I’ve never had any brake squeal at all on this truck before and I’ve changed the front pads many times myself. The truck has 176,000 miles. This was my first time doing the rears myself, but I’ve looked at it over and over and can’t see anything wrong there. I think the noise is coming from the front but it’s so loud I’m not positive.

Could this be something else like the wheel bearings or suspension parts? I’m really aggravated now. Any suggestions are greatly appreciated.

Take it out on a deserted street and bring the truck to a stop with the park brake only. If the noise is there you know it’s the rear. If it’s gone, then it’s the front ones.

If it’s the fronts, most squealing is due to vibration of the pad. Worn caliper slides, pad vibrating in the yoke, etc. can cause this.
While it’s seldom done, new rotors should always be thoroughly cleaned with Brake Kleen or a non-oily carb cleaner such as Chemtool to remove any traces of oil or rust preventative that may exist.

If it’s the rears, it’s possible a bent wheel rim can even cause a brake squeal. I’ll save that explantion until it’s determined if the rears are at fault.

Thank you. I’ll take it out tonight and try the parking brake. It starts squealing only after the brakes get heated up. I did clean the new rotors good with brake cleaner. My front calipers are original, I think I had the slides replaced once way back before I started doing it myself, so maybe something is loose there. I’ll post back after trying the parking brake.

I just took ‘the squealer’ out for a drive, I tried just using the parking brake many times at various speeds, it doesn’t squeal at all, so I guess I’m looking at a front problem.

How do I tell what I need to replace? The slide bolts are a little corroded on the exposed area but the ends are shiny, the sleeves looked shiny also. Maybe they are loose though, I don’t know. The calipers both have rusting/corrosion on the inside area but seem to both still be working. Both sides had even pad wear. Should I just replace the whole calipers? Thanks again for the help.

If the calipers are snug on the slides I don’t see that as being the problem, although you should make sure the slides are clean and greased.
Are the pads snug in the yokes; no missing anti-rattle springs, etc?

Maybe the problem is the pads themselves. Lining material can vary a lot. When I worked for Subaru they carried 2 types of brake pads which were identical except for the color of the backing.
One set was hard, more prone to noise, and would last quite a while. The other set was soft, far less prone to racket, and did not last as long.
This kind of put us in a spot sometimes when weighing longevity against noise.

Have you tried any of that disc brake quiet that can be applied to the back of the pads?
What about beveled leading and trailing edges of the pads?
Another more obscure thing that may(?) help is running a diagonal hacksaw cut about halfway through the lining and lengthwise with the pad.
The cut can dampen vibration if that is the cause of this problem.

I change the front pads about every 20k miles, I do a lot of city driving. I’ve used several different brands of pads over the years and I’ve never had any squeal issues. I’ve never had to use anti-squeal compound or anything like that. I had been using Bendix pads for the last 5 years until my parts store stopped stocking them, the current pads I have are Wagner Thermo-Quiet. I looked into them on the internet and they seem to have rave reviews from most people for quietness. And they were working fine for the first few months after I installed them. This noise is so loud, it just seems like something is loose or worn out.

I’m going to take the calipers back off today and inspect them better. I see they sell replacement slide bolts, sleeves and bushings. But a whole rebuilt caliper is only $15 each, by the time I buy all the hardware, it’s almost the same cost. But it would be easier not having to disconnect the brake line for me. I didn’t notice anything missing on the slides when I took it apart before. Has anyone had the slide parts become loose from wear?

If anyone cares, I finally fixed my squealing problem after a couple of months of throwing new parts at it. New rotors, drums, calipers, several sets of pads. Squeal stopped after replacing the rear wheel cylinders. The rear brakes lines crumbled as soon as the fitting turned, so I replaced them also. All I can figure is one of them was not functioning properly causing stress on the front, I dunno, but it’s no longer a squealer. Fortunately, the brake parts are cheap for this, new cylinders were only $10/ea. online.

When you apply the parking brake that is a mechanical system to put the rear brakes shoes against the drums. When you step on the brake petal that uses hydralics to force the shoes against the drums. The squealing must have been something out of place in the hydralic system due to the bad brake cylinders. Anyway, you are all set now. I don’t think the front brakes were ever part of the problem.