Brake squeal

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Cornbread

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Replaced front pads on `99 Jeep Cherokee. Used Wagner Thermoquiet ceramic pads, rebuilt calipers, and re-surfaced cast iron rotors. Lubed, adjusted, and bled properly. Stop quickly, but have annoying high-pitched intermittent squeal.

I`m on the verge of trying a cheaper pad without the word "quiet" in the name. I searched all the brake forums and am about out of "fixes" for the squeal. I have not tried any of the sprays or chemical products. I`ve driven a couple hundred miles.

Anyhow, does anyone have a pad type that has been consistently silent? I will take quiet over long wear.

Thanks!
 
Cornbread,

You might want to try bedding your brake pads. The process is to allow the brakes to warm up with several "normal" applications of the brake, and then to perform some high speed full threshold braking (just before ABS kicks in) from 60 mph to 20 mph multiple times until you start experiencing brake fade, or have made 6-10 attempts. This will heat the pads and rotors, and transfer pad material to the rotors. This will give you better braking and often will quiet the squeal.
 
rpn453: A very interesting link. Complicated, isn`t it? Thermoquiet instructions specifically say not to put anything on the backs of the pads. Apparently they have a built-in shim/shoulder and lube/adhesive compound. No cover to peel off so I guess it is heat activated.

Interestingly, the old and worn out pads were dry as was all the mounting hardware. Never heard a peep from them!
 
Let us know what you figure out! It is strange that those pads would squeal when it seems they've been specifically designed not to.
 
The adhesive type anti-squeal products are no longer recommended for the common "shimmed" brake pads of today. Using the adhesive products on shimmed pads will cause the pad shim itself to separate from the pad overtime, causing increased noise. When installing shimmed pads, apply a thin coat of synthetic brake caliper grease to the shim before installation is about all that you can do.

Anyway, to answer your brake noise complaint:

1. What kind of finish is on your old rotors? Did you use a 100-150 grit sandpaper block for about a minute on each side of the rotor?

2. Did you wash the rotor with hot soapy water and dry with paper towels prior to installation? (This removes any embedded metal dust that may cause noise issues)

3. Are your pads tight within the caliper mounting bracket? Sometimes a slightly loose fit will cause noise. I always lube the "pad ears" and the corresponding points of the caliper mounting bracket.

A formal bed-in is not always necessary. In fact, some pad manufacturers recommend against it as it sometimes heats the pads up to an unnecessarily high temperature and may cause pad glazing. Always follow the recommended pad bed-in procedure given to you by the pad manufacturer. On many of the retail pads, simply driving the car normally for several hundred miles is all that's needed.
 
Critic,

Good answers on this and other recent threads, but I'm a bit confused why you answered that two year old Akebono one!

I think it's time you pull together all that acquired research you've done and post a sticky: Generally Accepted Best Brake Practices.
 
Critic, good list. Did that. I am beginning to wonder about clearance where the pad ears contact the support bracket. There is a notch worn in the bracket, a common problem apparently on high mileage Jeeps. According to the Thermoquiet pad instructions, clearance should be .010-.015 inches. I have one at almost .015, but if I use my thinnest wear clip (which serves as a shim) I have less than .010 clearance. I may go ahead and try this anyway. The pads still seem to move freely on the bracket.

I`m thinking that the pad ear may be getting hung in the worn groove and cocking just enough to negate the dampening effect of the pad back. Over on the Jeep forum it has been mentioned that some folks weld up the wear groove and then grind it level.

I`ll pull it down and see about fitting a clip in the most worn grooves-if I can get my 17 yr old son to leave the Jeep in the driveway long enough!
 
Critic,

re: pad glazing
Typically pad glazing is caused by high demands on the brakes when they are still cold. I believe that the best practice is if they are warmed well and then the bed-in procedure is performed.
 
Quote:

According to the Thermoquiet pad instructions, clearance should be .010-.015 inches. I have one at almost .015, but if I use my thinnest wear clip (which serves as a shim) I have less than .010 clearance. I may go ahead and try this anyway. The pads still seem to move freely on the bracket.

Click to expand...

I think that may just be your problem. Check out this statement from Bendix:

"Pad Fits in the Anchor: Anchor brackets do wear out. The pad should fit very snug in the anchor bracket. The factory maximum clearance is only .010. Most squeal noise is caused by loose-fitting pads in anchor bracket. (Toyota has Technical Service Bulletins that explain lubrication of pad retaining clip for this reason alone.)"

Quote:

Typically pad glazing is caused by high demands on the brakes when they are still cold. I believe that the best practice is if they are warmed well and then the bed-in procedure is performed.

Click to expand...

Maybe, but pad glazing can simply be caused by pad overheat, especially when new.

"Proper Pad “Break In” is Critical. Any time you perform a brake job, you should perform 30-50 moderate stops from speeds lower than 40 mph. There should be a minimum of seven tenths of a mile cool down between stops. Excessive heating or hard use when new will cause brake pad glazing and will prevent proper break-in. The proper break in procedure is outlined in your car’s owner manual.

If the pad manufacturer comes with specific bed-in instructions, always follow them. Otherwise, I'd be cautious about following any formal, aggressive bed-in procedure. Just my opinion.
 
I don't know the answer... but I used the Thermoquiet pads on three vehicles without any squeal and without having applied any compounds. Nor did I surface any of those rotors.

Jeep Liberty, Ford Ranger, and Toyota Camry.
 
CRC brake quiet has been used on evey pad I've changed from cheapos to pricey and I've never had an issue with any of them down the road.
 
Quote:

CRC brake quiet has been used on evey pad I've changed from cheapos to pricey and I've never had an issue with any of them down the road.

Click to expand...

While it may have worked well for you, it isn't the correct product for many of the pads on the market today. The adhesive action of the conventional disc brake quiet compounds may cause shim separation from the backing plate over time. The correct compound to use is the same grease that is used to lube the slide pins. The grease allows for move shim movement.
 
I understand. Just saying, I've never seen it do anything to any of the pads I've used on my SAABs. I've never had the patience to wait for pads to stop squeaking. I'm not a "look at me" type. Perhaps it's because I goop it on that it still allows a decent amount of movement. The CRC stuff just seems to be high temp silicone....
 
Quote:

The adhesive action of the conventional disc brake quiet compounds may cause shim separation from the backing plate over time.

Click to expand...

I just found this on my Jeep. BOTH sides had the shim come loose and actually started to cut into the rotors like a lathe tool!
mad.gif
Will be doing the job myself this time, no glue.
 
After trying almost every anti-squeal tactic I could muster, I removed the ceramic Thermoquiets and replaced them with Bendix semi-metallic. The Bendix pads have been quiet so far. We shall see.
 
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