Help: Brake issue PMu F906 HC+ - Page 7 - Perth-WRX.com

RJ999 · #61 23-05-2014, 01:22 AM

Just been out for bedding in...omg sweet silence, no squeak, so good

magic1 · #62 23-05-2014, 08:13 AM

RJ share with me your sound engineering reason how a shim can cause uneven wear of a disc rotor?

scary · #63 23-05-2014, 08:24 AM

You do know that the pistons in the caliper don't automatically retract when you take your foot off the brake pedal?

Only the pressure is removed and the pads stay in contact or very close to at all times.

If the pads come away from the rotor this is called knock off and is actually an issue to be dealt with - but usually comes when driving hard on a track etc - not something you appear to be familiar with.

Now on to your uneven rotor wear - unless there is something dynamically wrong and things are not straight no amount of shims etc are going to cause uneven wear - think about it for half a second and you will realise that something that is in constant circular motion can't wear out on one side.

If the uneven wear is between the centre and outer edges across the entire rotor that is possible.

So in essence if you have or had rotors that are worn on 1 side more than another I would suggest they are either warped ( this is a cause of pad knock off) or have been machined incorrectly.

Most people would feel this as vibration or through the pedal.

As I remind my children daily - engage your brain before your mouth (or in your case fingers)

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Master D · #64 23-05-2014, 08:32 AM

Also, have you checked to ensure both sets of pistons on the calipers move free and easy? A potentially sticky piston pushing the brake pads could cause uneven wear.

scary · #65 23-05-2014, 08:47 AM

To the pads yes but not the rotor

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strayakent · #66 23-05-2014, 08:49 AM

Quote:

Originally Posted by RJ999

Rossco-Will give it some more time and try your method (I did a hills run in Jan and it didn't help, but have machined discs again now, will give another shot).

Travis-if that doesn't work then B-Specs will go in

Simon-I tried A1RMs before and I hated them as they squealed heaps on braking(more than the pmu), maybe rotor matters. I'm not sure what's on mine, but looks like they might be the 3000s or 4000s.

Taylor-at least yours only squeal while braking, mine squeals while rolling at low speeds without brakes applied lol

ive had this before rj, its to do with the handbrake not 100% disengaged.. usually caused by freight mob ripping it too tight. causes (schink, schink,) disc rubbing noise at low speeds hey. may not be the case for you but its something to check

RJ999 · #67 23-05-2014, 08:54 AM

Thats a very logical explanation too Shane.
Like I said I'm keeping an open mind about this, not blaming anyone for what happened to the rotor(unless pmu gives me reason to) as it may well be that the rotor was fucked anyway but still just annoyed at incorrect parts, and using incorrect parts isn't what should happen when professionals are involved

RJ999 · #68 23-05-2014, 08:55 AM

Dave - there were no sticky pistons, I did check and moves freely no problems

Straya - wasn't handbrakes, been over all that dre..eew

Rossco · #69 23-05-2014, 09:26 AM

WTF is wrong with you?

There were no 'incorrect' parts mate so stop saying that. The old shims 'may' have been re-used (and it's a standard practice if the replacement pads didn't come with new shims (and many brands don't)).

Metal shims do not stop/cause brake noise they are there to act as a heat barrier more than anything.

Glazing causes or lack of pad material transfer to the disk causes noise (bedding in).

Quote:

Originally Posted by scary

engage your brain before your mouth (or in your case fingers)

Quote for the truth!

RJ999 · #70 23-05-2014, 10:07 AM

What is wrong with you lot?
Where in my post have I said that old shims were re-used??? I bought Pmu shims supplied by them to go on the pads supplied and fitted by them. FFS

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