My car's brakes have been getting progressively spongier and less effective over the past year or so, and I want to fix it now before it gets any worse. Just wondering what the common things that fail in an E30 brake system I should check for first.
First thing I did after I noticed them getting spongy was bleed my lines with fresh fluid, which had zero noticeable effect on braking performance, even though there were a decent amount of bubbles in the old fluid that I removed. One weird issue I ran into while bleeding them was one of my rear brakes would not bleed any fluid with the nipple open, me and a friend were both pumping the brakes as hard as we could and nothing would come out. Let the car sit for a few days, gave it another try, and it bled as it should. That really weirded me out but I couldn't think of a good reason for it to happen, unless the entire line was full of air and somehow wouldn't allow fluid through. Since we were able to get it to bleed normally after a few days I just kind of stopped thinking about it, but maybe it is a clue to the source of the problem.
The brake fluid level doesn't drop either, so it doesn't seem like I have a leak, but is it possible somewhere there is a leak that allows air to be sucked into the system but doesn't allow fluid to leak out? (or at least not a noticeable amount of fluid.) I suppose if air was getting in it would have to be displacing some of the fluid, but maybe this is a possibility.
I am thinking the master cylinder, is there a way I can test it before rebuilding/replacing? Also the car does have ABS and after doing some reading on here I have come across some threads where people mention that air can get into the abs module and mess things up. Not sure if it matters but I was recently driving the car in snow, and the ABS kicked in a few times and seemed to function as it should.
I have also read that a bad caliper can cause spongy brakes, how would I go about testing that? Also thinking of ordering some new SS brake lines just to rule that out, but ideally I just want to replace the broken part, not just throw money at the entire braking system to find the problem.
Anyway I've got some time off work and I'm eager to get under the car and start looking for problems, where do you guys think I should start?
First thing I did after I noticed them getting spongy was bleed my lines with fresh fluid, which had zero noticeable effect on braking performance, even though there were a decent amount of bubbles in the old fluid that I removed. One weird issue I ran into while bleeding them was one of my rear brakes would not bleed any fluid with the nipple open, me and a friend were both pumping the brakes as hard as we could and nothing would come out. Let the car sit for a few days, gave it another try, and it bled as it should. That really weirded me out but I couldn't think of a good reason for it to happen, unless the entire line was full of air and somehow wouldn't allow fluid through. Since we were able to get it to bleed normally after a few days I just kind of stopped thinking about it, but maybe it is a clue to the source of the problem.
The brake fluid level doesn't drop either, so it doesn't seem like I have a leak, but is it possible somewhere there is a leak that allows air to be sucked into the system but doesn't allow fluid to leak out? (or at least not a noticeable amount of fluid.) I suppose if air was getting in it would have to be displacing some of the fluid, but maybe this is a possibility.
I am thinking the master cylinder, is there a way I can test it before rebuilding/replacing? Also the car does have ABS and after doing some reading on here I have come across some threads where people mention that air can get into the abs module and mess things up. Not sure if it matters but I was recently driving the car in snow, and the ABS kicked in a few times and seemed to function as it should.
I have also read that a bad caliper can cause spongy brakes, how would I go about testing that? Also thinking of ordering some new SS brake lines just to rule that out, but ideally I just want to replace the broken part, not just throw money at the entire braking system to find the problem.
Anyway I've got some time off work and I'm eager to get under the car and start looking for problems, where do you guys think I should start?
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