Moderator: Tech-II
frootloops wrote:So I took a day off to get the car through to Central Saab yesterday. They said it was the brake hoses, so replaced them. I got home and it's made zero difference. None. The three wheels that were getting hot are still getting hot (including the one with the brand new caliper). I jacked the car up after a gentle 10 mile countryside/town run and could barely turn the passenger front.
So the calipers have been checked and aren't sticking. Hoses have been replaced. Fluid has been replaced.
So frustrating.
david chies wrote:Fairly astute diagnosis ..Might even be right .
Odd that Pro Mechs didn't twig though.
Name and shame the brand of pads ???
For all to know & avoid .....IF ....swapping them out finally cures the problem.
I put the pads in with the piston fully retracted at which point there was mm's of clearance on both sides. I took it for a drive and after the brakes had been engaged the pad is effectively skimming the disc, literally touching it but without much pressure (when cold certainly). I assume there should be a clear air gap?
david chies wrote:But.. In the past, on a 'mechanical car' a pedal continuing to the floor under constant pressure indicated a leaking Booster.. and /or a bad master cyl.
david chies wrote:You clearly have massive patience .. I would have 'lost' the car by this point.
sounds wrote:Have you had the yaw and steering angle sensors checked?
david chies wrote: Easily tested by Removing the manifold end of the booster vac hose and applying suction.. to see if it holds that vacuum (doesn't leak ).
david chies wrote:Name and shame the brand of pads ???
For all to know & avoid .....IF ....swapping them out finally cures the problem.
frootloops wrote:What else in the system could be failing to release pressure?
beardydave wrote:My bet now would be on either the master cylinder binding, or the brake booster not releasing the master cylinder, but both of those I would normally expect to see a pedal not coming back up.
beardydave wrote:Unplug the ABS module, and bridge (paperclips work well) the 4 small pins at the bottom end of the plug. The bridge needs to go across the plug, not along the length of the plug. I can post some pictures if you like when I get home.
beardydave wrote:nb, you can achieve almost the same by starting the car then unplugging the abs module. But this second way you also loose the rev counter, temp gauge, boost gauge and fuel gauge.
frootloops wrote:beardydave wrote:My bet now would be on either the master cylinder binding, or the brake booster not releasing the master cylinder, but both of those I would normally expect to see a pedal not coming back up.
Definitely no issue with the pedal, it comes back up fully every time. Would removing the vacuum from the brake booster help prove anything? I haven't yet worked out how to remove the pipe from the front of the booster, I think it might just be a pull hard situation, as it doesn't appear to have any 'disconnect-able' parts?
frootloops wrote:beardydave wrote:Unplug the ABS module, and bridge (paperclips work well) the 4 small pins at the bottom end of the plug. The bridge needs to go across the plug, not along the length of the plug. I can post some pictures if you like when I get home.
Ooh this sounds a bit scary! Some pics would be very much appreciated. What do the bridges do exactly?
frootloops wrote:beardydave wrote:nb, you can achieve almost the same by starting the car then unplugging the abs module. But this second way you also loose the rev counter, temp gauge, boost gauge and fuel gauge.
Does yanking the abs module (or the bridged pin approach) have any other risks to the electronics? I assume it will also flag up loads of issues on the dash if I do this? Is the plug you mean the one that looks like an oversized scart plug, and pulls up vertically from the abs unit?