Hello , I know this is beating a dead horse , but My 54' Bel air with TCI ifs has MAJOR brake squeal when applying brake s , hard or soft pressure . Everything is BRAND NEW. Have scuffed rotors , pads , tapered pad edges ,anti squeal backs of pads . Still squealing . I didn't see anyone mentioning Ceramic pads . Are Ceramics a bad idea , seems to me cheapy asbestos are worse to use . Another thought was brake bleeding , is it possible to have a weakened applied pressure if brakes need bleeding . Even with lumpy can sound , Squeal is loud as Hell . Gotta get this one figured . Many ideas , but No luck so far . Be safe my Brothers & Thanks for Any & All help !!!
Might be a 'bedding in' issue as everything is new, so the squealing might lapse eventually. How much use has there been so far? It might be worth checking out the bedding in procedure on, I think Wilwood, or it might be Baer. It's brutal, but I'd be thinking what the heck, what have you got to lose - it'll be kill or cure and if it fails you'll probably be replacing the pads anyway. Comparison of organic, ceramic and metallic brakes here. Metallics seem to be the noisy ones. https://www.bridgestonetire.com/tre...are made,their friction and heat conductivity. I've just replaced the brakes in my daily driver and they're working great, except for an annoying squeak but only in light applications in reverse! Chris
Thanks , Yes bent tabs over . About 65 miles on pads now , checked in with Kev @TCI . Says antisieze on back of pads & where pads contact caliper as squealing is a vibration sound . Also pads are S10 98' pads , maybe get better pads . I went to Napa & found old can of "Stop Squeal" in brake section , shits like a sticky CAT cement , that get applied to edges of pads & between piston & pad . Let dry 20 min & install pads . Will let ya all know . If not , going to try NAPA Ultra premium ceramic pads . Trying to wrap my head around squeal being a vibration sound , To me it would seem a rotating friction would cause a squeal , but live & learn . THANKS Brothers , I will chime back with result tommorrow.
The cause of a squeal is the fact that the coefficient of static friction, is higher than that of dynamic friction. What that means is that it is easier to move something when it's already moving. What happens on brakes, is the pad and rotor "stick" together for a very short time, then unstick, then stick, then unstick, etc. This sets up a vibration in the parts, which is the squeal that you hear. You have to either dampen the vibration by using the glue, etc. or else prevent the pad and rotor from being able to stick, by adjusting the surface finish, or you have to make everything so rigid that it can't move enough to squeal (which is impossible, since the materials are all elastic, to some extent). Understanding the theory of squealing usually does little to help you solve the problem, unfortunately.
One shop I used to deliver parts to often had new pads sitting on the bench with some kind of liquid soaking into the friction material. When I asked about it back at the store, I was told it prevented squeal, and come backs. I don't know what it was but somebody here must know. Gary
I've always used anti-seize on any metal to metal contact area between the pads and the caliper with good results. A frustrating situation to be sure!
I've used anti-seize for a number of years with pretty good luck. When was doing brakes every day back years ago I found out that the cheapest brake linings and pads usually were the quietest. They didn't last all that long but they were quiet. Those don't last as long or stop as well or have the fade resistance that higher quality do though.
Look for pieces of steel in the brake pads. When you see it, grind it out of the pads. Use some good pad adhesive..
I fought a brake squeal issue on a car back in the late 70's that I would fix and two days later the owner would bring it back with the brakes making noise. Each time the brakes were real dirty. A check with some who knew the area she lived in confirmed that she lived three miles down a gravel road from the pavement. It was the dust from the gravel road that was making the brakes make noise.
There is a tab on each end of the outer pad on many GM disc brakes. The tabs need to be bent, or crimped, so they are tight to the caliper. Use a large pair of Channellock pliers, apply force to the pad at both arrows, till the pad cannot move around any more. Do both ends of the pad, I only put arrows at one end, but the other end has a tab, also. This is just on the outer pad. Also, the inner pad should have an locating spring clip holding in position, this spring clip fits over the pad, then into the hole in the piston. and there need to be O rings in the grooves in the caliper, at each end of the bolt holes. One big, one small, for each bolt. The large one goes around the sleeve that is on the threaded end of the bolt.
I don't think asbestos has been used in brake pads/shoes in many years. Some have claimed that's why rotors warp.
Thank you very much. That is a great explanation. I put mid 70s chevy brakes on my 55 a couple years ago and have had an intermittent noise ever since. I will take your advise and check the pads and hardware.
No problem. This info has been hiding in the Chevy chassis service manuals for 50 years..you'd think somehow it would make it to the internet? Huh.
If the outer brake pad is loose, bend the long tab up. It's kind of hard but make sure you don't crack the lining. Just bending the two little tabs like in the example above will not work in the long run, they will loosen back up and rattle again. I put a piece of clean plywood against the lining and put them all in the vise. Then use a heavy mallet with a big chisel and give the long tab a couple raps. Then see if its tight. I like to get them so I have to use a pair of channel locks to get the pad in the caliper.. On some brake pads I can get them in the vice and bend them up. I prefer this method over the hammer. I use Porterfield brake linings. Besides being one of the best pads for stopping, they usually fit tight and no bending is needed.
How is the rotor finish? Too shiny coupled with today's pads, you may get a squeal. I have a can of Permatex pad spray, have used it for years. I bend my tabs too, now I do them with big pliers before I install them, so the outer pad will snap into position and stays tight. You can also do them installed, use a big screwdriver as a wedge between the rotor hat and under the bad, knock the ears down with a big punch.
Jim pointed out the main points. If the contact areas are not lubed and the hardware is worn or junk these calipers will squeal, squawk, wear unevenly and not provide optimum stopping power. Watch out for the amount of paint that is on the pad backing plates. Raybestos, and a few other brands, sometimes but a thick coat of paint on the backing plates. Remove any excess paint and verify the pad is square. Ears on the inner pad may be to tight and cause the pad to hang up. There should be lube on sliding surfaces and the pad should sit square and be able to slide on the caliper. 'Anti-rattle/squeal' shims on the back of these pads can be fairly useless. I have melted these as I like to get into the middle pedal while having fun on the back roads, it also adds a bit of squish to the pedal. I chuck those and simply use a coating of caliper grease where the pad contacts the caliper and piston. Use the caliper spring clip. As mentioned the outer pad has a large flange that should square the pad to the caliper. I've had these not fully bent or cockeyed a bit. Same for the fingers that need to be channel-lock clamped. Verify the two fingers are properly goose-neck shaped to grab the caliper and keep tension on the caliper. You don't want the bend in the fingers to be mashed flat as you lose the clamping feature. They act as a spring to hold the outer pad on. You may have to tweak the fingers to provide the proper clamp load as well as keeping the pad tight to the caliper. Ceramics can be finicky to bed in on non-OEM applications. If you follow the procedure in this whitepaper you should be fine. https://centricparts.com/getmedia/f...Whitepaper_C4-Bed-In-Performance-8-2018_1.pdf
Make sure the calipers ride easily on the caliper bolts without high temperature lube. Most times I had to grind the bolts down some. This will help keep the calipers from getting hung up. After grinding and getting the right fit, number the bolts to the caliper so they don't get mixed up...
I "saved my sister some money" by changing rotors and pads on her Ford Focus by using the cheapest of the cheap and they (apparently) made a terrible squealing noise. She had them swapped for better quality and squeal gone. I daily an early 80's Regal (G-body) as well as having had multiple other G-body cars, I have always done my own brakes and I have never had to bend anything on the pads as I have never had a squeal (this is actually the first I have heard of adjusting the pads themselves). I'd say scuff the rotors (to clean off any remains from the existing pads) and change the pads to a different brand/quality.
you should crimp the ears on the pad whether or not they squeal...it's part of the design. Not doing so won't necessarily make it squeal, but you might hear a slight clunk occasionally.
X-2! ^^^^^^^^^^^^(Pep Boys parts-counter-monkey) 'Cheap'(softer) pads tend to stop better too..compared to the ceramics and such. Ceramic pads just make lighter-colored-dust so that is why most people like them. That and they are sooo hard they last longer too. Try the cheapest pads they sell AND...when trying out the new brakes DO NOT take'm out and panic-stop the crap out of them!! Start off at a low speed and gently apply brakes a few times to "seat/bed" them. Be sure and scuff-up the discs some to give the pads a fresh(er) surface to work with. If this doesn't work......... your-on-your-on!! 6sally6 PS.you prolly already know all this stuff but it might help somebody else
I use a hi-temp white grease on any metal-to-metal contact point with any brake system. Caliper slide surfaces, the threaded pins, the steel GM caliper bushings. Even on drum brakes, the shoe contact surfaces on the backing plates, star wheel, e-brake lever through the rear shoe, etc.
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