Hi all,
Since picking up the car, I have felt that the brake travel and performance hasn't been 100% despite all calipers having been refurbished and good condition discs and pads installed.
When depressing the brake pedal, the top "portion" of the pedal travel has very little resistance before firming up and getting actual braking force. I know the ABS models are known to have a slightly longer travel but I don't have the utmost confidence in the car's stopping power currently and I do have to put on quite a bit of pressure to stop from speed.
The car is a Rev3 with ABS. I am using Mobil DOT4 brake fluid.
A friend and I have bled the system using the 2 person method (tried engine on and engine off) and got a considerable amount of air out of the bleed nipples (which I have also replaced as a test) but when no more air is coming out from any corner, there is still this dead/soft spot near the top. When the engine is off, we can get the pedal really firm but as soon as the engine is on and the brake booster comes into effect.... soft/dead spot again!
Any ideas? I read somewhere that handbrake setup can cause this issue but the handbrake works flawlessly so I'm not quite sure if that would cause issues?
Thanks in advance dudes and dudettes
[Mk2] [Turbo] Brake pedal issues (soft/dead spot and long travel)
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Re: [Mk2] [Turbo] Brake pedal issues (soft/dead spot and long travel)
mines the same, always been like that.
Re: [Mk2] [Turbo] Brake pedal issues (soft/dead spot and long travel)
I'm sure it's not supposed to be like that though!
Re: [Mk2] [Turbo] Brake pedal issues (soft/dead spot and long travel)
Really surprised to see you got air from the system. As I may have mentioned to you I had a lot of bother after replacing the calipers getting the pedal to firm up but after replacing the flexis it was pressure bled and they were spot on. Or so I thought as driving that and 2 modern cars back to back I thought the mr2 was always going to feel under assisted.
The handbrake cables were replaced and reset last September. The flexis probably around may last year.
So if the air has got back into the calipers and not through the nipples then how else would it have got in? Master cylinder? I don't know.
Have you read about resetting the brake pedal itself? Not the actual height but the rod on the back. The one I bought of km on here had that done and they always felt sharp to me but then that was a good few years ago now and I was driving a escort estate as a daily workhorse at the time. That had bad brakes and mostly because of the master being on the passenger side connected by a horizontal bar.
The handbrake cables were replaced and reset last September. The flexis probably around may last year.
So if the air has got back into the calipers and not through the nipples then how else would it have got in? Master cylinder? I don't know.
Have you read about resetting the brake pedal itself? Not the actual height but the rod on the back. The one I bought of km on here had that done and they always felt sharp to me but then that was a good few years ago now and I was driving a escort estate as a daily workhorse at the time. That had bad brakes and mostly because of the master being on the passenger side connected by a horizontal bar.
Re: [Mk2] [Turbo] Brake pedal issues (soft/dead spot and long travel)
my brakes were pin sharp until servicing them as all 4 corners had sticking pistons of various stages of broken.
Bled them using a cheap 1 man vac bleeder and they were rubbish. did it again with 2 people as you described above, first with engine off and then again with engine on. This made them much better. However the pedal isn't perfect and not where it was before.
The step I missed out was to remove the handbrake cables during the bleeding and then stamping on the brake pedal 30+ times to wind the rear pistons out.
My handbrake used to be 2-3 clicks, now it's all the clicks. but I never reset the rear pistons as I should have. Maybe this is the step that is vital and making the brakes feel a bit sub standard.
Going to give it another go tomorrow evening.
The other suggestion was that the master may need bleeding, not tried this either. The fluid did drain down to zero as it stood for a few days with no calipers on. Not even looked at the ABS pump to see if that has a bleed point too.
Bled them using a cheap 1 man vac bleeder and they were rubbish. did it again with 2 people as you described above, first with engine off and then again with engine on. This made them much better. However the pedal isn't perfect and not where it was before.
The step I missed out was to remove the handbrake cables during the bleeding and then stamping on the brake pedal 30+ times to wind the rear pistons out.
My handbrake used to be 2-3 clicks, now it's all the clicks. but I never reset the rear pistons as I should have. Maybe this is the step that is vital and making the brakes feel a bit sub standard.
Going to give it another go tomorrow evening.
The other suggestion was that the master may need bleeding, not tried this either. The fluid did drain down to zero as it stood for a few days with no calipers on. Not even looked at the ABS pump to see if that has a bleed point too.