Brake failure

[CruisinVx]

Well it's been a bad day for cars for me today... Cooked my amp then on te way home my brakes decided to fail... Oh yeah it's a VX Berlina series 1

I noticed the beak pedal get very spongy after about 1.5 hours of mainly highway driving and 30 minutes in very congested city stop start.
it always was a bit spongy, but since I bought it a year ago I hadn't had any issues until now.
So while trying to brake I pumped the pedal and it seems to apply the most amount of brake with say 0-30% of the brake being pushed in, anything past that was pretty well useless.

While pulled over I had a look at the pads and rotors and there's about 7mm of pad and the rotors were fine. Turned the car back on pumped the brake and couldn't see any noticeable leaks, and the brake fluid was full.

I waited for my mum to come so she could follow me home, took about 15 minutes and when I headed off, the brakes were fine...

Any ideas what it could be? I'm gunna try bleeding the brakes on the weekend, hoping it's not a master cylinder... If it is what do u reckon I'd be looking at to fix it?

 

[Drewie]

Sounds like the brake fluid needs changing, the fluid should be changed every 2 years as it absorbes moisture and the boiling point of the brake fluid drops, the fact they recovered after sitting for 15 minutes indicates that is more than likely the problem. When was the last time the brake fluid was completely changed?

 

[vc commodore]

Sounds like the master cylinder is failing....Replace it before it fails totally

 

[CruisinVx]

Well I bought the car about 9 months ago and haven't done it since then.

Any way of testing of the master cylinders ####ed or on its way out?

 

[Drewie]

Similar thing happened to my Father-in-law, he left my place in his Toyota towing a 6x4 trailer and after about 30 minutes or so driving in stop start traffic his brakes failed the pedal went to the floor, he called the RACV and by the time they arrived he had a perfect hard pedal again, the RACV guy said his brake fluid had boiled and needed changing, he had the car towed to a workshop and had the brake fluid changed and has never had a problem since, this was several years ago.

 

[SS-REX]

Yeah as Drewie stated above your fluid needs to be replaced it's probably absorbed moister over the years and the boiling point has dropped a fair bit. I'd start with that then look at components after if that doesn't remedy the problem.

 

[gm1961]

Hi All

7mm is not much brake pad left, change them , also is the rotor clean . or does it have black / blue / grey spots ( heat marks ) or any corrugations / lines in it

Hard driving , or continual driving will warm up the rotors >> pads >> calipers thus the brake fluid

I think its time for new pads , machine rotors at lease and new fluid

Pump up brakes = fluid leaks or air bubble , but you would not have 100% fluid level ( ok a leak would drop the level, but air bubble would not )

regards
george

 

[vrsprspt]

3mm is minium brake pad thickness for roadworthy, but yes if there is signs of excessive heat on the discs or worn lines or deep lips on discs then discs will need machining/replacing and pads replaced, I wouldn't replace them unless there was a real need to. Do the fluid change first then if the problem continues look at your pads and discs

 

[st3r3otyp3]

M8 the fluid is now almost water so change it here is all the info you will need.

https://forums.justcommodores.com.a...ving-stuck-wheels-flushing-brake-fluid.214269

 

[colourmesilver]

check booster and vacuum leaks, also if your on your own you can do a gravity bleed.