Juddering Brakes! GRRR!

chrisash32 · Post by **chrisash32** » Sun Jan 27, 2008 7:20 pm

Hi All!
Just about had enough of the brakes on Stacey's car now....
When the peddle is depressed the whole car shakes violently! (its very scary).
Its slowly been getting worse over the past few months. Stacey and her mum were insistent that the car never did it when it was running on my old alloys.
So that made me think it was the steel wheels that are on it at the moment.....
Had a check around today and noticed that the front drivers side was bucked, so out came the spare and i swapped them.

I thought that would fix it but they are just the same. The car had new discs about 1-2k ago as we thought a warped disc was the cause, but this proved not to be the case. Also the pads are fine.

When you press the peddle you can hear something pumping, its quite an odd noise to describe. Like pressurised air being compressed and released.
Took the car back to ATS where the discs were done and they have had it on the ramp and are insistent there is nothing wrong!! Madness!

Just wondering now if anyone on here has any ideas?

Many Thanks

Chris

RUM4MO · Post by **RUM4MO** » Sun Jan 27, 2008 8:36 pm

Sounds like you are activating the ABS - that will be what the pulsing that you feel - back through the pedal. Has this car got the brake assist option fitted by the way - this was meant to sense emergancy braking and whack on and hold the brakes "full" on regardly of brake pressure. I specified it on my wife's car but have never been aware of activating it as these cars brakes are a bit agressive anyway in normal use. Of course the brake assist, if fitted, could be faulty.

chrisash32 · Post by **chrisash32** » Sun Jan 27, 2008 10:16 pm

RUM4MO wrote:Sounds like you are activating the ABS - that will be what the pulsing that you feel - back through the pedal. Has this car got the brake assist option fitted by the way - this was meant to sense emergancy braking and whack on and hold the brakes "full" on regardly of brake pressure. I specified it on my wife's car but have never been aware of activating it as these cars brakes are a bit agressive anyway in normal use. Of course the brake assist, if fitted, could be faulty.

Hi,
thanks for the reply. The car doesn't have the brake assist option fitted and i don't think its the ABS thats kicking in as my old 9n3 used to do that now and again and it just doesn't feel the same.

chris 9n · Post by **chris 9n** » Sun Jan 27, 2008 11:21 pm

could it be a warped disc?

iv had this problem. i had to slam on then ever since the car juddered whilst braking .all sorted now new discs

chrisash32 · Post by **chrisash32** » Mon Jan 28, 2008 12:22 am

chris 9n wrote:could it be a warped disc?

iv had this problem. i had to slam on then ever since the car juddered whilst braking .all sorted now new discs

but they were replaced not that long ago... think probably 1000 - 2000 miles? think they could have gone again?

ihpj · Post by **ihpj** » Mon Jan 28, 2008 9:17 am

IMHO it is likely to be a worn bush/ball joint or something suspension related especially if SWMBO managed to buckle a wheel, she must have ht something with some force to do it damage. This would then surely have a knock-on effect on the suspension components.

Just my 2p worth mate. Let us know how you get on tho' ...

chrisash32 · Post by **chrisash32** » Mon Jan 28, 2008 10:33 am

ihpj wrote:IMHO it is likely to be a worn bush/ball joint or something suspension related especially if SWMBO managed to buckle a wheel, she must have ht something with some force to do it damage. This would then surely have a knock-on effect on the suspension components.

Just my 2p worth mate. Let us know how you get on tho' ...

Thanks for the reply. This is one thing i have not checked and also i wouldn't have a clue how to find if it was worn or suspension related!

Before i get shouted it, it have to make the point that it was her dad that bounced the car up a kerb! lol. (used to driving company vans and not caring about them!)

I did a few tests last night, the car don't judder at any other times, when accelerating or at a constant speed it doesn't pull to any particular side or judder.
Under breaking, judders violently and pulls ever so slightly to the left...

Would that help any diagnosis?

Thanks

RUM4MO · Post by **RUM4MO** » Tue Jan 29, 2008 6:56 pm

I had this once with a 1994 Fiesta 1.6Si - car was okay before going abroad for a weeks holiday. On our return I took the Fiesta out for a run and got a fright when it showed these same symptoms - took the front wheels off and discovered that one of the vented discs was starting to crack although not worn down to "replace" thickness. Fitted new discs and problem solved. If you took to it to someone with a rolling road then they would soon sort it out for you. By the way what original symptoms lead you to believe the discs needed changing. New discs being fitted to "not cleaned" hubs could cause this problem - but ATS should have done this disc change okay (?). Maybe wrong size of pads were fitted (?). Finally in my case, there was a lower speed limit that I could brake at without this shuddering - less than 30MPH.

Jamo · Post by **Jamo** » Wed Jan 30, 2008 5:19 pm

Did you change the pads with the discs? If not I'd start afresh with new discs and pads!

neil_dubgt · Post by **neil_dubgt** » Thu Jan 31, 2008 12:47 pm

sounds like a warped disk to me, even if there new disk and pads they still warp....in fact i may be right in sayin that when there new there more prone to warping

PoloRally · Post by **PoloRally** » Mon Feb 04, 2008 4:33 pm

Alright mate most common problem is that the discs have been changed but the disc flange is covered in rust and corrosion it should be cleaned when ever the discs are changed! Easy job to do.