Braking problems...

[PETRAN]

ok, i searched all the faults and fixes threads and since i found nothing i think i should post this so as to find a solution in here if possible...

As you all understood it's a breaking problem!
I've noticed many many times that my 2003 MCS WORKS Mini is kicking the brake pedal back when braking BUT the ABS doesnt work!
Either its under hard braking or a normal one there are times that for no reason the break pedal kicks back as if the ABS works but the wheels roll normally!

I mentioned this problem to my dealer many times and they could find nothing as long as the electronics show no malfuction..
I asked them to check all the mechanical brake system, including discs, padles, brake fluid and everything but they found nothing...

So i'm asking, has anybody had the same problem cause this one is driving me mad...

Thanx in advance guyz...

[DaFlake]

Could be air in the lines that would cause something like this. Can you bleed them yourself? This would be the first thing that i would try. While you are at it, it might be worth putting in a better brake fluid that is designed for heavy brake fluid. It is possible that you boiled your fluid and got some air in the system.

[PETRAN]

DaFlake thanx for answering...

The fact is that my dealer has allready checked the lines and everything in the system(thats what i've been told) and they said that they found no air or anything wrong going on in the system...

On the other hand i never tried so far a better brake fluid and i think i should give it a try...
The problem is that this "malfunction" shows up even in hard braking or in a normal one which means that the fluid is not boiled...

Anyway i'm gonna try this too..

Thanx again mate...

[Richard Crofts]

I used to get this a lot on stock brakes...cadence brake and the next time you depress the pedel it will brake normally...almost guarenteed. The pumping action part way through braking seems to make the ABS realise its up the spout and then it brakes normally.

Switched to JCWs and I don't get it anymore ??! :?:

[DaFlake]

Yeah, I was taking a stab at the problem.... Hmmm, I'll ask around on this one.

[PETRAN]

Quote: Originally Posted by Richard Crofts (original)

I used to get this a lot on stock brakes...cadence brake and the next time you depress the pedel it will brake normally...almost guarenteed. The pumping action part way through braking seems to make the ABS realise its up the spout and then it brakes normally.

Switched to JCWs and I don't get it anymore ??! :?:

This is exactly the case for me too...

But since it was not there since day one i cant figure out whats going wrong and it works sooo badly...

The fact is that when this "kick back break pedal" happens i can feel it
getting harder to push and i just cant push it all the way till the end no matter how hard i press my foot on it...

[Richard Crofts]

Exactly the fault I had.

You drive along push down hard and the pedal doe not travel it just stops and you can feel the "kickback" sensation of the ABS but with virtually no braking. If you try to press harder the pedal does not move the "kickback" sensation gets worse and the car only slightly improves (almost negligable) the braking....as soon as you let up and press down again the car seems to brake as normal. I drove mine like that with this occuring intermitantly for about 4 months before several terrifying near no stops at roundabouts....I then got some JCW brakes fitted (my pads and discs were all well worn anyhow by that point. The problem has since totally disapeared. I have had it occur once in poor conditions and after driving through a load of muddy crap and water...so i think this was just poor braking caused by contaminants on the disks or pads and so the abs just didn't know what to do...as soon as i had cleared the brakes off by driving through some puddles and using them a few times they worked fine and its not happened again since and i spend a lot of time hard on the brakes!

Good luck as i'd be interested to see what the cause is. PS I had a fluid change just before having the JCW kit fitted (part of my TLC brake services)

[PETRAN]

I'm gonna visit my dealer soon for this case ...
as long i have a solution i'm gonna keep you updated..

any other comments on this kick back brake pedal whould be wellcome!

THANX TO EVERYBODY ...

[oldmots]

The kickback probelm could be in the vacuum servo brake booster. The valve that initiates the booster action may be sticking. The only fix is to replace the booster.

[Peartreeproductions]

My father's old Rover 214 (yeah i know hardly a Mini!) had exactly this same fault. Made driving absolutely life threatening! It was due to a faulty ABS sensor on one of the wheels. But seems odd that your dealer is saying there is no reported fault.

However it does seem to be consistent with driving through very dirty water which might cause a faulty reading from one or more of the sensors. Then as soon as you brake the system thinks one wheel isnt rotating as fast as the others. Sounds like an intermittent faulty ABS wheel sensor to me.

[PETRAN]

up !!!

anybody, please kelp

[MINIMANIAUK]

Oldmots ,could be correct,there have been failures with the booster

[PETRAN]

Quote: Originally Posted by MINIMANIAUK (original)

Oldmots ,could be correct,there have been failures with the booster

got it

thanks

[PETRAN]

ok, one more now,

i've searched in realoem but couldn't find any part with the name of "vacuum servo brake booster" !

any hint ?

i'm asking this one cause i'm gonna ask my dealer to search about this part for any failures .

thanx in advance

[oldmots]

There are many names, but "brake booster" is the generic one. It's the part that the master cylinder is mounted to.