Chattering brakes?!

[BlackCaprice]

Hi all, got a bit of a brake pad query. When I purchased my Caprice it needed the rotors replaced and I'll admit I just bought a set of the cheapy ebay ones so I'm prepared to cop a bit of 'you get what you pay for' (although I also fitted the same combo to the BA family wagon with no probs/issues at all)

ANyway, I fitted 4 new rotors and all new pads and the car stops fine etc, HOWEVER I notice I'm getting a sort of chattering sound coming from under the car and the only reason I'm assuming it's brake related is it stops chattering when I apply the brakes then comes back when I'm not braking.

Someone suggested putting grease on all the contact areas of the pad to caliper (obviously not on the actual disc rotor surface) so the only thing I had handy was some Timken bearing grease. I put it on the back of the pads where the piston contacts and also in the grooves where the pads sit and to my surprise it actually worked. They were quiet for a day or so but the chatter is coming back now.

So I guess what I wanted to know was has anyone else had this issue and seeing as though the grease thing worked a bit is there a better grease that may be more suited for the job?

(btw - I reckon it's more the rear pads as when I removed the caliper to apply the grease the rear pads seem to move around in the groove a lot more then the fronts)

Thank in advance for any info

[Not_An_Abba_Fan]

Did the noise start straight away or did it come in over time?

I think you have run out in the rotors. Commodores, particularly VT onwards, need to have the wheels torqued up correctly or they will cause run out in the rotors.

One thing you could try is to remove the rotors and refit them in a different position, then torque the wheels up in a star pattern in two stages, first stage to 60nm, then up to 110nm. See how that goes.

[Morton]

You can buy specific anti-squeal compound to apply on the back face of brake pads. It's often red, and dries into a soft kind of rubber

[BlackCaprice]

Sorry I missed these replies (stupid thread subscribe didn't work).

Turns out it's the rear pads. I got sent the wrong ones when I ordered them and didn't notice because they still fit and brake fine. The tabs on the ends of the pads aren't big enough and allow the pad to move forward and backwards (along the axis of the car if you like) rather than in and out as you would normally expect and that's what is making the racket.

Simple fix is new decent quality brand name pads.

Thanks all for the input!