Failed Brake Systems

[Daves Blue SRi Vectra]

I would like to know if anyone has had a similar problem to my car at the moment. The model is a ELITE V6 Turbo (Petrol).

2 Weeks ago, on my way home, the brakes failed all of a sudden. Although I could stop the car on the footbrake, it took both feet pressing down very hard to do so, and had to use the handbrake to prevent a collision.

The car is now in a Local Dealers (Perrys of Bury) who are doing a good job, but have so far come to no conclusions. They are being led by Vauxhall Technical who so far have asked the to change:

Master Cylinder
Servo Pump
Brake Modulator

The exact syptom is that if you press the pedal half way, the brake force slowly creeps to zero. If you cycle the pedal, you have braking for a limited time, but annoyed people behind you.

If you turn the engine off, and press the pedal hard, you should have a rock hard pedal, mine simply goes to the floor with decreasing resistance.

Has anyone else had any similar experience / fault similar to this that does not involve mechanical failure of pad/disc's or loss of brake fluid?

Cheers to all !! And i will let you know the eventual outcome!

[benny]

i would say a servo problem of some kind ....

[Caterman]

Sounds like a leaking servo m8

[badge25]

Never had it in a car but my brakes did fail in my truck the other day 44 ton loaded with dangerous chemicals stationary traffic ahead and me doing 50 mph foot on brake and nothing. foot to floor nothing. took my foot off and back on again and had full brakes and locked up. Had to ditch onto the grass to avoid a collision. Stopped about a foot past the front of the car i had to avoid with the trailer at 45 degrees. Went for repair and they cant find a problem. I'm petrified incase it happens again.

[Daves Blue SRi Vectra]

Nope - Servos has been checked and replaced. Must admit, that was my first thought.

The technicians @ Perry's checked all the components and then blocked off each section of braske systems and tested it individually. They could not find fault with individual components.

I think this is why Vauxhall Technical have got involved and have taken over from the garage technicians.

Strange eh?

[rushy]

Blocked or disconnected vacuum system from inlet, or does that come into the servo category?

[Gsi3.2]

they'd have checked that with the servo Rushy ( or at least i'd hope they would have )

well; as VX are throwing the kitchen sink at it, it should come back 100% okay..they could test the modulator by not only TECH", but also by disconnection..

Did the pedal stay rock soild at 1/2 way down or sink to the floor?..if it stayed 'firm' then it points to either failed servo internals or the modulator.

[Daves Blue SRi Vectra]

No, the pedal would bite initially, but then braking force would be lost evenly over time, and the pedal would move to the floor slowly. So to maintain braking force you have to chase the pedal down, until you get to the bottom and revert to sheer will power.

When the systems was not energised (with main power off) the pedal should have been rock hard, getting increasingly harder everytime you try to cycle the pedal. But it was just the same as driving. The pedal was mushy to the touch and you could plant it all the way down, take of the handbrake and the car would eventually start to creep forward as the force of the calipers on the pads reduced to lower than the desire of the car to move under gravity.

I tried turning the main power on / off / on / off to see if it was a computer glitch that would reset, to no avail.

[plasma]

wonder if the fluid has been boiled?

[Daves Blue SRi Vectra]

Okay, the plot thickens.

Today they changed the Brake Modulator (what ever that does) and no surprises, no change.

So they have now said that next on the list is the vacuum pipe, followed by a replacement of the Servo.

Then that's it - game over / surrender !

Every part of the system would have been replaced with no change, so I really have my fingers crossed on this !