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Discussion Starter #1
Just installed my 4 Pot AP Racing kit ( 330mm discs ) and my steel braided hoses in front. At the back, i only have my standard 2.0lpt brakes with rubber hoses. Was testing out the brakes and realized that at braking over 60mph, there was slight jittering / vibration on the steering wheel and brake padel ( if my legs arent hallucinating! ) Just wondering if that is normal in high performance brake setups or is my brake set faulty? Or is it a simple case of braking imbalance between front and rear? Thanks mates!
 

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No, it's not normal, and indicates a problem somewhere. Judder is normally caused by uneveness of the discs (did you say the kit was second hand?), but may in this case be caused by something not being true. I would re-check all the mounting info and make sure everything is properly aligned as a first step.
 

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Discussion Starter #3
Yeap got the kit second hand ... My discs dont look warped though ... mabbe i got the mounting wrong?! .. Bought the brackets from Abbottracing but i realized that the brakes had to be mounted differently from the Saab ones. Will do a check again ... Thanks Mark!
 

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you can get them resurfaced for not to bad of a price...id try that being that they were previously owned...
 

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just my 2p I have had a few probs with my big disc conversion (not AP )with vibration...
couple of things to make it better
the conversion made the disc edge inboard to the pad so any little run out caused a huge vibration

cured by "chamfering" the pad back past the disc line

also the Aluminium bell moves the wheel out slightly so that the wheel is not centred by the hub lip
so care is needed offering up the wheel and making sure that the wheels are torqued evenly

when these things are done they do run smooth again...

good luck
 

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Discussion Starter #7
You were mentioning aluminium bell? I also have an occasional loud squealing sound when my wheels are turned and brakes applied at the same time. The Abbott guy told me that i may need bells. Whats that and does the AP kit require that?
 

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You'd know if you didn't have the bells- they are the aluminium bits that the discs bolt to in order to be fixed to the hub
 

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Discussion Starter #9
Hey .. just had my brake disc resurfaced ( or "skimmed"?? ) and the brake judder / vibration is gone! Didnt cost much too abt 20 quid. I still have the squealing sound though .. comes on when my brakes are warmed up ( hot ) and when my wheel is turned and brakes applied at the same time .. lets off a loud high pitch ( metal grinding metal ) squealing sound My brake pads are 2nd hand and have been lying around unused for over a year prior to installation. Could that be the reason? Or is my disc / pads misaligned when my wheel turns?? Help !!!!
 

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Second hand pads??


If you've skimmed the discs I would put on new pads straightaway. The ones you have will likely not be seated parallel (or flat) to the surface and they will have all the ridges from the old dics surfaces still in them!! They may not be in the same caliper or the same side etc.etc.


The squealing could be due to a wear indicator???

Did you put anti-squeal grease on the back of the pads?


Is there clearance between the caliper and the wheel itself? Are there any marks of shiny metal on the inside of the wheel??
 

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Apart from the alignedment issues, which do actually sort themselves out quite quickly as the AP discs are drilled or grooved, using new pads and following the bedding in procedure on AP's site here is essential to temper and bed the disks in properly.
 

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Discussion Starter #12
I dumped my old Mintex brake pads for brand new Ferrodo DS2500s .. ( cost me more than 200 quid! ) and guess what? The sound got worse! And now i have a second WHISTLING sound which is softer than the squealing ones. I figured that my old pads were chamfered at the edges and so did not cover the AP discs fully. The new ones cover the disc fully and the squealing sound might be coming from the rust on the edge of the discs? Gonna bed in my pads now .. will report back! Thanks mates for ur advice but I am seriously starting to regret fitting this brake kit in .. it has already cost me nearly 600 quid for the hoses, brackets, pads, labor and it would be foolish to give up now?
 

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£200 for a set of DS2500s! You were robbed!! I only pay about £90! I'm sure shipping to Singapore shouldn't cost over £110.

The whistling/squealing has got me stumped tho. It may get better when the pads/discs are bedded. DS2500s do sometime have a littel squeal in operation, but not to much. Does the noise chnage depending on pedal pressure? And as sgould says, have you given the back of the pads a good coating with coppaslip or equivalent.

Keep at it, it should be fixable without too much more work, and they are definitely worth it!
 

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Discussion Starter #14
£200 for a set of DS2500s! You were robbed!! I only pay about £90! I'm sure shipping to Singapore shouldn't cost over £110.
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OMG ... I am so gonna kill that shopowner if it turns out that i had been ripped! Well the sound gets better under hard braking. If i drive normally and then slow down at traffic junctions or at carparks, it makes a rather loud squealing sound. But under hard braking / spirited driving on the highways, the pads are dead silent when i slow down Havent had the time to bed in my pads yet ... currently in the midst of my exams! Whats that Coppaslip thing about?
 

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Coppaslip is a trade name (in UK at least) for high melting point anti-sieze grease. It's a grease with a lot of very fine copper "dust" in it. It can be used on bolt threads and between alloy wheels and the steel hub and also as a thin smear on the back of brake pads where they contact the piston or calliper. On the brakes it allows a bit of slide as the pads are pressed and helps to stop, or dampen, the squeal.
 

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Discussion Starter #16
Finally solved the problem mates! I needed to fit in the Anti-squeal shims to my pistons. Its stuck on the back of the pads .. Took advice from the Saab mechanic who helped another guy with his Hirsch brakes. Bought my shims from Porsche ... the squeal is 99% gone .. only get it at certain slopes and when my wheels are turned .. shims probably misaligned then ... the squeal comes from the sound of air between the pads and discs when the brakes pedal is released .. the shims keep the pads near to the discs even when the pistons are withdrawn
 

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Discussion Starter #18
I would love to! .... Esp since i just installed my Saab Remus sports exhaust ) But i dont know how to upload pics into this forum though
 

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I've just joined www.photobucket.com its free and easy to upload pics and then to link them to the forums.
All you do is copy the photobucket link (shown under your pictures once you have uploaded them) and using the IMAGE button paste the link in and it should show on the forums.

There are other picture hosts but this one is really easy to use
 
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