lionj

Hi Guys,

I changed my front and rear brakes today on my 92 sc400 and took it for a drive and to my amazement my car still squeeks, can someone tell me whats the problem, I detest hearing the squeeking noise everytime I hold brakes, thanx guys.

Forever Lexus,

VQT

Describe the squeeking sound. Sound like metel scraping metal? or does it stop after a couple of brake (the pad warmed up)?

Did you changed the pads yourself? Did you put anything between the back of the pad? and the clips? (some kind of grease or glue I think)

Did you or your mechanic cleaned and lube all the sliding pins?
Did you replace all the sliding O rings?
You may even have to replace all the brake hardware (those metal clips that stay between the caliper and the pads)

lexcoupe94

This situation is common with disc brakes on many cars. The problem is the pads vibrating in their mounts at a high frequency, usually rubbing against their mounting clips. The following are methods I've used to combat this annoying problem.
-Do you hear the squeak with light pedal pressure, which goes away when you press the pedal harder? If so, remove the pads and file off the sharp 90 degree edge of the pad surface so that the leading and trailing edges are rounded. My theory is that the sharp edges of the pad sometimes cause the pad to skitter or skip across the disc surface under light pedal pressure, causing the pad to vibrate; when you press harder, the pressure stops the vibration. I used a low-tech method - scraping the pad against the concrete driveway.
-Do you hear the squeal no matter how hard you brake? The pads may be glazed, or not completely flat. You'd be surprised how often new pads are concave or convex. Roughen up the surface of the pad until it is no longer looks shiny. The low-tech method works for this too. I've found that if I do both of the above tips, the squeal goes away 95% of the time.
-Still have squeal? The mounting clips may be misaligned or old and weak so that they do not hold the pad in the caliper firmly. Try bending the clips slightly to tighten the pads in the caliper, or replace the clips if in doubt.

moshlub

You are most likely missing the anti-squeal stuff. With disc brakes, some better shops give you this stuff with the pads when you purchase them. If you didn't get any, you can purchase it for about $2 a package. This stuff acts like glue when you're putting them on, holding the shims to the pad. But also, it stops the squealing from happening. The squealing is a result of vibration.

Anyway, I would not recommend bending any shims or any other modifcations, as you're tampering with the original design of the brake assembly. This could give you headaches in the future.

Red93sc400

The SC400 shop repair manual, in the break sections, show anti-squeal clips or springs and anti-squeal shims. I dunno for a fact but if you did not install them or also if the springs or clips are weak them maybe the anti squeal system is less effective?

Just for comparison, my SC's OEM break ALWAYS squeak when I first pull out of the garage in the morning and at the end of the street. After that, they perhaps tend to warm up and do not sqeak. Or maybe there is a fine patina of rust that forms on the rotors overnight that causes the squeak.

Out in Arizona, where my parents live, they have constant break squeal problems. The micro-fine dust from the desert and roads coats the brake rotors and causes the squeal. If you wash the rotors down, you have no squeal for perhaps a few weeks until they recoat themselves. Bummer.