Brake squeal

[belvnmx5]

So my new to me 1999 Miata has developed a brake squeal on the left front drivers side (I am pretty sure). I replaced the pads and rotors last week which seemed to cure the issue, but I had returned. Fluid is full, the lines seem to be intact. My next guesses are the bearing had gone bad on the wheel or the caliper is not working properly. Any thoughts from anyone?


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[Dynra Rockets]

Bearings are not a squeal, they are a growling hum and typically only heard in turns unless you have a lot of negative camber.

brake.jpg

[kung fu jesus]

Took me a moment to figure out the pic, then I smiled.

Before replacing the caliper:

Clean and regrease the caliper slides.

Look for torn, cracking dust boots.

Inspect piston boots and seals.

Use new pad hardware if you already didn't.

Lightly coat the backing plates with high-temp grease.

Throughly brush and clean brackets & calipers, especially the saddles the ears of the pads ride on.

Inspect old pads for uneven wear.

Inspect rotors for hot spots.

FWIW, I just replaced the FL caliper on Saturday, $64 through Amazon, no core charge, included the bracket and hardware. I have spares, but I haven't made time to rebuild them yet.

[belvnmx5]

Took me a moment to figure out the pic, then I smiled.

Before replacing the caliper:

Clean and regrease the caliper slides.

Look for torn, cracking dust boots.

Inspect piston boots and seals.

Use new pad hardware if you already didn't.

Lightly coat the backing plates with high-temp grease.

Throughly brush and clean brackets & calipers, especially the saddles the ears of the pads ride on.

Inspect old pads for uneven wear.

Inspect rotors for hot spots.

FWIW, I just replaced the FL caliper on Saturday, $64 through Amazon, no core charge, included the bracket and hardware. I have spares, but I haven't made time to rebuild them yet.

Thanks guys! I will check those things first! I bought this car so I could wrench/learn on it so will be slowly trouble shooting this myself.


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[kung fu jesus]

Good luck!

Maybe not for everyone, but if you have the means, rebuilding the caliper is really easy. A little compressed air can pop the piston out of the bore so you can replace the seal and boot. A little light abrasive work on the cylinder and bore, if necessary, a can of brake cleaner, a pick tool, and a bottle cap full of brake fluid are all you need. Seals are $5 or less, even replacement pistons are ~$5. You could take the caliper castings and bake high-temp paint on them if you wish before reassembly.

Sometimes I rebuild spares together and have everything hot tanked, then I build them and seal them in bags until needed.

[gmjantar]

Autozone has it for $43.99 with core exchange. If you play stupid and question the pre-core exchange price they might drop it a bit more.

[belvnmx5]

Brake squeal

Has anyone ever used these before? They look like a decent deal for powder red coated OEM type calipers.


Power Stop (S1704) Performance Calipers, Front https://www.amazon.com/dp/B00TPG9X6M..._XL4gzb1DSG5PH


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[kung fu jesus]

I just mounted a Centric/Powerstop caliper. Non-painted, it was one of the nicer remans I've seen. I usually just paint mine black.

[iscariot]

Eh, those look like powdercoated OEM calipers. I wouldn't spend money on them for the powdercoating - they inevitably get coated in dust and grime.

Nothing in the brake caliper should cause it to squeal. If the caliper failed you would feel a pull to one side while braking, brake fluid level going down, wetness, pedal weakness, odd/accelerated wear on the pads.

When you did the brakes - did you replace the brake hardware? Put the springs that push the pads apart back in? Brush off and apply a thin coat of hi temp grease to where the pad makes contact on the slider tabs? Did the slider tabs have an indentation?

Is the squeal constant or cyclic depending on speed? Only when the brakes applied or always?

[eyeballs]

In my experience the most common cause for brake squeal is brake dust buildup. I find the squeal often goes away after a good car wash. The only times I've used brake grease on the backing plates were to troubleshoot noise issues, and so far that's never proved to be helpful. The slide pins can get pretty bad sometimes though.

[belvnmx5]

Eh, those look like powdercoated OEM calipers. I wouldn't spend money on them for the powdercoating - they inevitably get coated in dust and grime.

Nothing in the brake caliper should cause it to squeal. If the caliper failed you would feel a pull to one side while braking, brake fluid level going down, wetness, pedal weakness, odd/accelerated wear on the pads.

When you did the brakes - did you replace the brake hardware? Put the springs that push the pads apart back in? Brush off and apply a thin coat of hi temp grease to where the pad makes contact on the slider tabs? Did the slider tabs have an indentation?

Is the squeal constant or cyclic depending on speed? Only when the brakes applied or always?

The squeal is cyclic. It get louder/more constant as I drive faster. The springs did seem to have a decent amount of tension left in them still. New backing plates came with the Hawk HPS Pads. One of the slider pins MIGHT be stripped. It didn't seem to be catching well when I put the caliper back on. I have 6 day old baby, so it's going to be a week or two before I can pop back out into the garage to work on anything to verify.


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