4 pot brakes very poor - pedal feels too hard!
23 July 2007, 07:21 PM
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4 pot brakes very poor - pedal feels too hard!
Really hoping someone has had this before, and any help is greatly appreciated.
The brakes have always needed excessive pressure to get any real braking effort, but as i had 2 pots on, i put it down to them, after reading all the threads. Now i have recently fitted the subaru 4 pots, but there is no difference whatsoever!
It feels as if there is no servo assistance, remminisant of my old mk2 escort. After having a go in a friends car with identical set up... 4 pots, red stuff pads, grooved discs, we are now cetain something is not right somewhere, as his are 10 times better, and acually have feel and are progressive.
This weekend we changed the servo and master cylinder... No difference! It bled up no problem, the pedal initially bites alot higher than on my friends and definately feels harder, and you really have to force the pedal to get it to stop at any decent rate.
The only thing we could think of was that there may be a restriction in the brake pipes (braided flexibles all round) but considering it bled up no problem. i can't see it.
Oh and the servo is holding vacuum, as you can here it release if you pull the pipe out.
Please help.
The brakes have always needed excessive pressure to get any real braking effort, but as i had 2 pots on, i put it down to them, after reading all the threads. Now i have recently fitted the subaru 4 pots, but there is no difference whatsoever!
It feels as if there is no servo assistance, remminisant of my old mk2 escort. After having a go in a friends car with identical set up... 4 pots, red stuff pads, grooved discs, we are now cetain something is not right somewhere, as his are 10 times better, and acually have feel and are progressive.
This weekend we changed the servo and master cylinder... No difference! It bled up no problem, the pedal initially bites alot higher than on my friends and definately feels harder, and you really have to force the pedal to get it to stop at any decent rate.
The only thing we could think of was that there may be a restriction in the brake pipes (braided flexibles all round) but considering it bled up no problem. i can't see it.
Oh and the servo is holding vacuum, as you can here it release if you pull the pipe out.
Please help.
24 July 2007, 03:57 AM
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With the engine turned off, having built vacuum in the servo, does the pedal get progressively harder as it is pumped?
It should do, as the vacuum decays. This will confirm servo action.
Maybe question the pad material?
It should do, as the vacuum decays. This will confirm servo action.
Maybe question the pad material?
24 July 2007, 04:14 PM
#4
Are you sure all of the pistons are free in the calipers.
To test servo switch engine off and pump pedal until it gets firm.
Now with foot on brake pedal start the engine, the pedal should now drop a little, this will also test the non return valve, when you switch the engine off pump pedal and it should go hard as E46 m3 has stated.
To test servo switch engine off and pump pedal until it gets firm.
Now with foot on brake pedal start the engine, the pedal should now drop a little, this will also test the non return valve, when you switch the engine off pump pedal and it should go hard as E46 m3 has stated.
24 July 2007, 08:17 PM
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Thanks for the reply guys, yes we done the servo test, and it checks ok, even swopped the pipe and the non return valve just to be sure.
I think we are going to take the calipers and pipes off this weekend, swop everything in turn, pipes, pads, calipers, and see what is actually at fault.
Nice to have a spare car at our disposal. I will keep everyone informed, thanks.
I think we are going to take the calipers and pipes off this weekend, swop everything in turn, pipes, pads, calipers, and see what is actually at fault.
Nice to have a spare car at our disposal. I will keep everyone informed, thanks.
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