Occasional loss of brake pedal pressure

[bogan bob]

Just wondering if anyone can shed any light on what is going on.

Sometimes when braking heavily at lights or in the hills, ill hit a man hole or reflector or bump in the road and the brake pedal pushes in another couple of cms and im not braking as heavily as before - very worrying when you are quickly approaching the backend of the car in front.

Pushing the pedal harder in this instance wont stop the car any quicker, i have to let go of the brake pedal and jump back on it if i am really struggling for braking distance.

Is this an annoying quirk of the abs (ive never owned an abs car before but have driven abs fitted work cars and when their abs kicks in it is very different to this) or is it a function of hard coilovers, 17" rims and/or dodgy brake lines or something?

 

[naughtika]

have you done any bleed for all 4 corners?

if you have.. what type of fluid are you using?

 

[Guest]

If it were me, first I'd do a full flush of the brake system with new fluid and being sure to purge all the air out. After that then start to look at other possible causes, for example master cylinder failure.

 

[Guest]

Have you checked the recall has been done on the brake system as brake failure is the possibility if this hasn't been sorted.

 

[bogan bob]

cheers guys. I havent done a bleed at all, but that was on the list of things for the next service, along with new rotors, pads and braided lines.

How do i check the recall has been done?

 

[bradc]

The recall is only on auto's, yours is a manual isn't it, so nothing to worry about.

What happens if you are on gravel or something slippery and you intentionally get the ABS to kick in, does it work as it should?

 

[bogan bob]

cheers Brad, she is indeed manual.

Its very hard work to get the abs to kick in, but it does seem to function normally

Another thing i noticed tonight was when it happens, one AYC bar turns on momentarily. Ive also noticed this happen when i hit smaller (but still substantial) bumps under braking (but the brake pedal prob doesnt have to happen), is that normal?

 

[Guest]

I get this phenomena sometimes too, you go to hit the brakes and it feels like metal on metal until you quickjly let off and normal pressure applied braking is resumed. will be interested on your findings, next on my list is a bleed.

Mike

 

[bradc]

I only had the AYC lights come up under braking when I had different tyres installed. I ended up pumping one of them up 1psi higher than the other and it fixed the problem. The tyres must have been worn very slightly differently.

 

[bogan bob]

Ok ill look into pressures, but i do keep them similar and the tyres were pretty evenly worn when i last checked