Irregular brake pad wear - check it out!?

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slowlysideways
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Post Fri May 19, 2006 12:00 am

Had a right nightmare with brakes.

Was getting really bad "warped disk" feeling under hard braking on track.

So replaced the disks and pads with brand new genuine BMW parts, but noticed on the old ones, that only the OUTSIDE of the disk was being worn (the inside inch of the the old disk was rusty where no contact with the pad had been made), thus wearing the passenger outer pad into a "cheese wedge" shape, but only 1 out of the 4 pads.

So replaced both disks and pads - done about 100miles in them bedding them in, removed wheel to check them, to find the same has happened :evil: - irregular brake pad wearing, again like a cheese-wedge shape (outside of the pad being used, inside of the pad not even touching the disk!)

The calipers are brand new, so are the disks, and pads - so the only thing left must be a bent brake carrier, which is what the caliper slides on!

Bought a new front passenger brake carrier from eko, and fitting it at the weekend... hope this is the cure! :roll:


Some pics...

Brake pad from the top looks normal
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New & Old disks
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Looking down from the top of the brake pad shows cheese wedginess
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New bits all on!
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eko
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Post Fri May 19, 2006 12:12 am

As PM,surely its the carrier at fault,not much else it can be!

Good luck :)
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Jhonno
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Post Fri May 19, 2006 12:26 am

Does it move freely on the sliders? could be sticking..
Got cable ties? Get diffin..

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slowlysideways
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Post Fri May 19, 2006 12:29 am

I lubricated the sliders loads with GT40 silicone spray, so it should be all good.

The carriers were wirebrushed down, and a little copper grease added to the edges where the brake pads "move" on them
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Markey
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Post Fri May 19, 2006 10:43 am

Do the pistons come out square onto the caliper ? ?
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slowlysideways
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Post Fri May 19, 2006 12:25 pm

onto the caliper? or do you mean onto the pad?

if so - we presume so, because the inner pad is wearing perfectly normal...
Martinaston
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Post Fri May 19, 2006 12:33 pm

Are you sure the mating surface where the carrier meets the hub is clean ?
It seams a bit odd to bend the carrier, i can't even think how it would be possible :?
Was the inner pad sitting flush against the piston ?
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WerkdE30
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Post Fri May 19, 2006 12:36 pm

do u have the spring clamp thing on its missing in the pic i dunno if this would cause that problem tho. u should put brake grease on the slides like the stuff u put on the edges on the pads. try pushing back the piston to see if its seized also.
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Markey
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Post Fri May 19, 2006 1:00 pm

Onto the pad, the piston may be coming out a little bit jerky and applying more pressure to one side then leveling out so the other pad would not get fully applied at this stage.
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slowlysideways
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Post Fri May 19, 2006 3:28 pm

martin - yep, back of the hub where the carrier meets it is all clean and wirebrushed up

also not sure how a carrier could get bent

yep - the inner pad is sitting flush with the piston of the caliper, and nice and flat with the disk

werkde30 - calipers are new, so pistons and seals are perfect (tested them also)

markey - we checked the movement of the caliper piston, and everything seemed spot on.



where the carrier "wraps" around the edge of the disk - there was a large gap between the face of the disk, and the edge of the carrier on the drivers side, than there was on the passenger side - thus us thinking that it must be the carrier at fault

sorry if that descriptions seem sa little hazey!
slowlysideways
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Post Sun May 21, 2006 2:19 pm

More brake woes!

After getting the new brake carrier from eko, it's the wrong one :( didn't realise there were different types.

I'm going to post up several pictures, if anyone could point out if there is anything obviously incorrect with my brake setup - i'd be greatly appreciated. anything from wrong calipers/ carrier/ pads etc.

The calipers were brand new from the previous owners, the disks are brand new BMW genuine items, and the pads are also brand new from local motorfactors.

Think I'm just going to put a wanted post up for 2 calipers & carriers complete, that way it can't be wrong.

Here are the pics

Wheel removed
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See gap between pad and disk on inside edge
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Side of caliper & carrier
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Back
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Top
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See here, only the outer inch or so actually being used
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Caliper removed, carrier remains with pads in situ
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Note gap again, starting to form a cheese wedge shape of pad
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New caliper - are these correct ones? (im guessing so, as the drivers side is perfect!)
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fromt the back - Existing carrier bolted on, with new wrong carrier held up next to it? all holes in incorrect places for caliper mounting
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Same again, but from the front - new carrier doesnt have the "hooks" on the edges
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Martinaston
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Post Sun May 21, 2006 5:01 pm

Have you tried fitting the new carrier to see how it lines up to the disc ?
DanThe
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Post Sun May 21, 2006 7:32 pm

Ive never seen the hook type before, has that caliper got an 11 digit part No on it?
DanThe
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Post Sun May 21, 2006 7:43 pm

Heres what it should look like

Image

these are for sale BTW :wink:
slowlysideways
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Post Sun May 21, 2006 8:30 pm

DanThe - PM me with how much you want etc, i take it they are in good working order?
Taylor325i
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Post Sun May 21, 2006 8:31 pm

See gap between pad and disk on inside edge
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Those caliper brackets look quite rusty - could be that the faces of the bracket where the pad should sit evenly against are distorted with rust and not allowing the pad to seat properly. Either that or the bracket is indeed bent.



fromt the back - Existing carrier bolted on, with new wrong carrier held up next to it? all holes in incorrect places for caliper mounting
Image


Same again, but from the front - new carrier doesnt have the "hooks" on the edges
Image[/b][/quote]


The calipers and brackets in the 2nd and 3rd pics that are fitted to the car are ATE. The bracket that you are holding is a Girling item.


Taylor.
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Bob_S
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Post Sun May 21, 2006 8:43 pm

are your wheel bearings ok?
Bollocks to this 24v scrap!
slowlysideways
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Post Sun May 21, 2006 8:43 pm

So the calipers I have are brand new ATE items then?

They are genuine BMW ones I know that much as it's punched into the casting
Taylor325i
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Post Sun May 21, 2006 8:58 pm

slowlysideways wrote:So the calipers I have are brand new ATE items then?

They are genuine BMW ones I know that much as it's punched into the casting

BMW used two different setups on the E30 - ATE and Girling. My 1988 325i track car has ATE front calipers and my 1990 325i road car has Girling front calipers. I don't know why BMW changed the setup because in my experience there is no difference in performance. Must have been a cost issue.
Your calipers may have BMW stamped on them but they were made by ATE.


Taylor.
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slowlysideways
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Post Sun May 21, 2006 9:49 pm

I'm confused...

Have I got an incompatitable setup?

Either way, hopefully bought a set of front calipers & carriers together, so hopefully will end this brake fiasco! winkeye
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Post Sun May 21, 2006 10:04 pm

caliper differences look v similar to what vauxhall did on the gte.. the calipers look the same as the ones that came on them.. the new style you have bought new are better on the vauxhalls.. they sieze up less n stuff
Got cable ties? Get diffin..

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slowlysideways
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Post Sun May 21, 2006 10:09 pm

front new calipers & carriers should sort me out lmao
slowlysideways
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Post Mon May 29, 2006 12:00 pm

hiya gang

just to round this thread up

got my new calipers & carriers from Alan - thanks lots!

fitted them, and all seems A-OK, however I have just one question... are my pads right?

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Brake disks, before, new calipers/ carriers on
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Pad in carrier
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Slight gap?
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They work fine, so I'm guessing they're OK - however I know there are 2 types, one with brake pad sensors, one without - I have the ones without....

Does this matter? are they different shape etc?

Thanks

and one last glory shot up in the air
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Brianmoooore
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Post Mon May 29, 2006 7:07 pm

Both types of caliper use the same pads, and the pads in your pics fit the wear sensor, not that this is important on a track car.