Yes, the pads were the only brake related part that the shop replaced. Could this at all possibly be related to me bleeding the brakes, and getting a new abs light? Because this squealing began right after the bleed, and about 5 days after the new pads.
But I will take it back to that shop and see if they can set it right. So, just to clarify, my possible situation there is rust built up on the surface that the pad mounts to, and now that it has new pads, the rust has built up enough thickness make the pad not seat all the way down, and it now rubs on the rotor?
Rust impeding the precise movement of the brake pads in any area is a cause of concern and something
to be on the lookout for. But in my previous reply I was specifically focused on the internal parts of the
caliper being bound up by relatively small amounts of corrosion closing up the clearances on the 'puck'.
By the way, the proper term for the part that I was referring to is the brake caliper hydraulic piston. Here's
an illustration of the front brake caliper overhaul procedure for our trucks from the '99 FSM:
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If you want a more descriptive real-world photo, here's a brake caliper thread started by Schurkey. The first photo is exactly what I'm talking about: (brake caliper rebuild)
And for more solid info on our brake calipers, after looking around the internet the best discussion was again found in this forum: ('94 front brake caliper rebuild)
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As for the sound showing up after you bled your brakes, I don't think that this was the root cause. It
may have been coincidence, having to do with the pads breaking in/conforming to the existing rotors, and
thereby changing the interface between these 2 surfaces, and possibly moving the pads into a audible
resonant frequency? (Disclaimer: The previous is conjecture on my part, please take with a grain of salt. :0)
In English, I don't think you did anything wrong with your brake bleed procedure. And a quick check
as to my troubleshooting theory being the right one would be to jack the truck so that the tire/wheel/rotor
assembly in question can be turned by hand. IF all this turns quietly with little drag then the problem is elsewhere.
On the other hand, if this assembly is draggy and noisy (as if the brakes are being lightly applied) then this
needs to be corrected.
Another test for sticky/draggy brakes is to drive for a few minutes, get out and check the relative temps of
all 4 wheels against each other. Oftentimes you will find 3 brakes slightly warm, while the 4th brake assembly
is radiating a lot more heat than the others. (And depending whether your wheels are open or closed,
there may be a lot more brake dust on the suspect/draggy wheel.)
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I'm not saying that this is the only possible source of the noise, but it *is* one source that I've troubleshot
to several times in the past.
Hope this clarifies what I was describing in my previous post.
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