metal rattling noise from brakes, right front when going over bumps

There should not be any rattling from your brakes... there should be nothing that is loose, no play, no gaps between any moving parts. If you do see a gap, then you have a problem with your brakes. The way brakes are designed, the caliper should always be in contact with the pad, and the pad should never be any further than 1/8th of an inch (approx) from the disc.

Shims are not part of this equation... you should never have to shim a brake assembly to achieve the correct fit. By design, disc brakes are self-adjusting. Problems with fit indicate the brakes are not working properly.

A noise that goes away when you hit the brakes could also be caused by the suspension. When you apply the brakes, the braking force gets transmitted through the brake pad to the caliper to the front steering knuckle to the lower arm & strut, etc. If there is something loose in this assembly, it could be held tight under braking. You might look to see if something is loose... you can start by jacking the car up, gripping the wheel and seeing if it wiggles in any direction, side to side, front to back, up or down...

 

When you take the brake pads out - FIRST disconnect the 12 v battery. (some people advise you to also pull 2 relays in the fuse box). If you don't the brake accumulator can activate and blow the piston out of the caliper.

 

NO, the accumulator pump will not apply pressure to the brakes when running if car is not in Ready and brake not pressed..
Pressure only applies when brake paddle is pressed.

 

I will quote Britprius

The Prius has a capacitor bank as a backup "the black plastic box next to the battery" this is why Toyota say to remove the two relays and wait 2 mins for the capacitor bank to discharge.

John (Britprius)

Read more: http://priuschat.com/threads/bleeding-05-prius-brakes-the-old-fashion-way.115607/page-3#ixzz2QrGujio2

 

You were talking about the "anti-squeal" plate. Completely different part.

I've done loads of brake jobs and have never seen a broken clip. Guess you got a bad one! Glad your problem's solved.

 

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I know this is an old thread, but just wanted to chip in a few thoughts on the disc pad's rattling. In my '07 the issue was the abutment shims, which prevent the pads from moving up and down, were worn out. These are typically included in the "disc brake hardware kit" sold by the major auto-parts sites.

The symptoms i had were that the front brakes emitted a loud "chatter" or "rattle" kind of noise when driving over bumps. The noise would go away when pushing the brake pedal enough to engage the disc brakes, even when riding over bumps.

These hardware kits contain the abutment shims, as well as sometimes the slider pin boots. These shims are sometimes called slider shims, or anti-rattle shims. they are NOT the same as the clips that go on the back of the pads.

One word of caution for these hardware kits: i bought a kit from Dorman, and it included 4x identical shims. This is NOT right. These kits should have 2x of two different types of abutment shim. one shim has a "P" shaped edge, which contacts the pads, and prevents rattling. The other 2x shims don't have this "P" edge. These should be paired together with 1x P shim on each side. Get this kit from Warner or Bosch instead of Dorman junk.

i've included pictures of these shims below.

I advise putting the "P" shaped shim on the top. This should prevent it from wearing out prematurely, as it won't be constantly compressed when you actuate the brakes.

 

If you buy the parts from Toyota, what you're showing here as "abutment shims" make up what Toyota calls the "fitting kit". There's a "shim kit" (the flat ones that go behind the pads, and that kit includes a packet of shim grease), and there's a caliper rebuild kit, which is all the rubber parts (piston seal, piston boot, slide pin boots, bleeder cap) and the rest of the miscellaneous bits and bobs, and that kit has a packet of the red grease that they specify for all of the rubber parts around the piston and slide pins. (Each of these kits includes all of the corresponding parts for two calipers.)

The aftermarket parts in your photo look like they are just bright metal plated. The "fitting kit" pieces from Toyota come with a dry, Teflon-like coating that allows the pads to be applied and released easily, without needing a grease (which would pick up lots of grot, considering how exposed those pieces are).

It is possible to also get rattles if the flat shims (behind the pads) don't have enough of the supplied gray shim grease applied to dampen their motion. On the other hand, I haven't reapplied that stuff yet, and mine aren't rattling, or at least not in any way that bothers me.