After market brake experts?

Have replaced most all brake components front and rear: rotors, pads, fit kit, shims, flex lines, disassembled, cleaned and properly lubricated the rear drum brake components, removed the glaze, everything is operating very smoothly and correctly unless I try braking with force from high speed where the brakes work but they sort of make a shuddering sound. I wonder if I'm just exceeding the capacity of the stock brake components under certain conditions.

Reply to
Daniel
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Do you have the ABS brake system? If XLE you probably do. Did you use the shims and orange/blue goop to hold them on front pads. Lubricate the pad pins? Bleed lines?

Reply to
Wolfgang

Reply to
johngdole

=============== No ABS. New shims used synthetic caliper grease. Replaced pins with proper lubrication and replaced rubber boots. Bled all the brake lines since I also replaced the calpers and one rigid rear brake line.

Reply to
Daniel

================== Replaced calipers with Toyota remanufactured "new". I'm not really sure what's going on with this sound. Feels like the pads are shuddering against the rotors. Don't think I'm feeling any vibration at the brake pedal. Checked for excessive runout with a dial indicator at the axle hub and disk rotors, both within spec. Rotors were new. I'm generally talking fairly high speed, -- at high speed under very firm braking there's a shuddering noise that just doesn't sound right. I lift off the brake pedal, then reapply and it returns, unless I'm braking moderately, then no problem. In reassembling the brakes every fastener was torqued to the correct spec - really that's only the torque plate and sliding pins, so it's not something loose, and the fit kit included new spring clips to hold the pads in place. I wonder if there's any possibility I got those reversed. The spring clips are at the top, and the flat edge at the bottom of the caliper. I tried to be very careful to reassemble them as removed and seemed to match the drawing in the manual. Wondered if I may be getting into the category of "racing" brake pads, and stock Camry brakes just aren't designed to be driven extra hard. Brake pad out gassing at extreme load perhaps. Perhaps the braking sound is transmitted through the strut mounts. I can hear a whooshing sound even when braking from 30 mph, but it is smooth and unobtrusive. Try changing to some higher performance pads?

Reply to
Daniel

I came across one car with very similar problem once. The "growl" happened only from moderate/hard braking from high speeds. Any light application won't cause the noise. It was a real mystery but I didn't have the chance to work on that one.

Racing pads, like the Hawk Carbon Metallic, Raybestos SPS Ceramic, EBC Yellow/Red Stuffs, can generate a lot of heat with their high coefficients of friction but they hardly ever fade -- they'll only glaze/warp substandard rotors in repeated heavy use.

On single-piston version of the caliper the flat pad supports do look like belong to the bottom.

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My guess is that caliper pistons or pins may not be gliding the best they can so the calipers are not grabbing with full force. When you retract the piston, you should be able to use two fingers turning the (Harbor Freight) disc pad tool with ease. Almost no effort at all. That's why I asked about the condition of the calipers. I'd think the "new" rebults should give no problems with the piston sticking. In fact, the piston should retract slightly (I'd say about 1/16") merely with your hand pulling on the caliper so it'll glide back and forth on the pins.

The caliper pin with the rubber bushing is install on the bottom on

4-cyls. The bushing sometimes causes the pin to stick. After you break it free it will glide just fine but will stick again in a few mintues. But I assume two of these pin bushings were replaced along with four pin boots with your rebuilt calipers.

I assume you bought all these parts from Toyota?

Daniel wrote:

Reply to
johngdole

=============== Yes. Toyota parts. Also replaced the busings on the lower sliding pins. The caliper pins were sliding beautifully when assembled.

I can only assume this is normal behaviour and on occasion I'm just overloading the braking system by braking too hard from too high a speed.

Reply to
Daniel

Noise from 30mph down probably doesn't help ones confidence. It's probably hard to overload the brakes at that speed.

Difficult to think it's the combination of new pads and rotors, then if the caliper piston and pins checked out. The only pads I've managed to fade in normal driving are NBKs (NBK markings). Akebonos (AK markings) can take a lot of beating. No NBKs for me.

Daniel wrote:

Reply to
johngdole

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