Spongey brake pedal?
Discussion
If your pads and fluid are OK try this next (it's just happened for the second time on mine)
Remove wheel(s)... (it was my Left Rear both times)
[pic]http://img.photobucket.com/albums/v520/V6GTO/WheelHub1.jpg[/pic]
...and make sure this sucker is FT.
[pic]http://img.photobucket.com/albums/v520/V6GTO/WheelHub2.jpg[/pic]
It had come loose by about 1/2 a turn,allowing the disc to push the pads apart slightly, hence spongey pedal.
While you're there clean out your disc holes!
[pic]http://img.photobucket.com/albums/v520/V6GTO/WheelHub3.jpg[/pic]
Martin.
Remove wheel(s)... (it was my Left Rear both times)
[pic]http://img.photobucket.com/albums/v520/V6GTO/WheelHub1.jpg[/pic]
...and make sure this sucker is FT.
[pic]http://img.photobucket.com/albums/v520/V6GTO/WheelHub2.jpg[/pic]
It had come loose by about 1/2 a turn,allowing the disc to push the pads apart slightly, hence spongey pedal.
While you're there clean out your disc holes!
[pic]http://img.photobucket.com/albums/v520/V6GTO/WheelHub3.jpg[/pic]
Martin.
I've never seen pad knockback caused by the driveshaft nut being lose before, but it's entirely possible - it's normally a lose wheel bearing that does it though.
Apparently the spongyness is the pistons taking up the slack between where they are and where they should be (touching the disk)...which means the initial pedal travel does nothing to stop the car.
Normally when you re-apply the brakes they are nice and firm again...until you go around a corner, then you're back to square one!
Good post though. I think there should be some kind of techincal archive somewhere, where posts like this should be kept. Joust with his infinate webspace perhaps?
BTW lots of reading about pad knockback here: www.stoptech.com/tech_info/wp_knockback.shtml
Apparently the spongyness is the pistons taking up the slack between where they are and where they should be (touching the disk)...which means the initial pedal travel does nothing to stop the car.
Normally when you re-apply the brakes they are nice and firm again...until you go around a corner, then you're back to square one!
Good post though. I think there should be some kind of techincal archive somewhere, where posts like this should be kept. Joust with his infinate webspace perhaps?
BTW lots of reading about pad knockback here: www.stoptech.com/tech_info/wp_knockback.shtml
As the only way to check pad wear on the rear wheels is to take them off you might as well add this one to the check list, and after all that effort cleaning out the holes in the disks is worth doing at the same time. Very useful info Martin.
There seems to be no substitute for taking the wheels off and doing a proper inspection when your brake fluid light comes on.
--
Richard
There seems to be no substitute for taking the wheels off and doing a proper inspection when your brake fluid light comes on.
--
Richard
If replacing and tightening up the nut (to 250nm) doesn't solve the problem then you can safely assume the underlying cause is a worn hub carrier.
In my case, final diagnosis of the problem only occurred when a broken drive shaft was replaced, as once the hub is fully dismantled it's easy to see the damage from the hub moving around in the carrier.
HTH
Andrew.
In my case, final diagnosis of the problem only occurred when a broken drive shaft was replaced, as once the hub is fully dismantled it's easy to see the damage from the hub moving around in the carrier.
HTH
Andrew.
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