Had a scary experience last week; I was having a great drive through the peak district until my brakes did something weird. I had to brake for a junction but when I pressed the pedal, it went really hard and I couldn't stop the car. Luckily nothing was coming!

 

I was pressing as hard as I could and the car was hardly slowing down. The strange thing is, the brakes were fine again afterwards and have been ever since. I wasn't really thrashing the car and I certainly wasn't working the brakes very hard so what could have happened?

 

I had only just had new brake discs and pads fitted and they seemed to work well before the incident. I have read on here that the pistons can stick in the calipers. Could this have happened? Thing is, they are fine again now.

 

Does anyone have any idea what could have caused this? Any suggestions as to what I should do because it has seriously shaken my confidence in what is otherwise my favourite possession!

 

Thanks

Matthew

Was the pedal really stiff, not much movement? this happens if the brake servo isnt working, like if you pump the pedal with the engine off. It goes really stiff and very hard to stop in that situation.

 

But whats odd is that its working fine now?!?!?!?

Yes the pedal went very stiff. I think. It pushed down part way but then seemed to go solid. I think that's what happened - was just praying nothing was coming down the road at the time.

 

I spoke to a mechanic who suggested that but it is strange that they seem fine again! Don't think I'm happy about chancing it though!

Leaky servo valve, this is a common problem and can be be bought seperately.

 

Daveman

Thank you for replying. I'll look into that then.

sure it wasnt brake fade? if u were baking about for a while before u used the brakes then they could well be over heated.

I never brake particularly late or hard. I had been driving around for about an hour before it happened but to be honest, I brake much harder in my crappy 206.

 

What does brake fade feel like? I can't believe I drove the car hard enough to cause it - if so, I'm really unimpressed!

Doesn't sound like brake fade? brake fade is when you put your foot down and there's nothing there as the fluid has overheated. You have to pump the brake to get any stopping power. Also it would still be like it for a little while afterwards until it cools down again. Also if you have new discs and pads then the fluid should have been renewed anyhow (has it? :) ) as otherwise you wont get the most out of the new bits. I've not seen a zed get brake fade on the road with new pads/discs and fluid.

I had 3G 10grooved discs fitted with Porterfield R4-S pads fitted all round a few hundred miles ago. Do these need running in?

 

I took the car out for a run (carefully) along the A537 yesterday and on a straight, I broke from 60 to see if the brakes were working and I have to say, with my foot hard down, the braking performance was pathetic. I could stop my girlfriend's ancient 106 with drum brakes far quicker and it's brakes are awful!

Yes they deffo need running in but should be performing well after a couple of hundred miles (although you should still go easy for at least another 2 or 3 hundred IMO).

If you rag them without running in you risk warping the discs as (I'd imagine at any rate) they would get hotter in some areas than others and expand in those areas and warp.

You didn't say if you bled the brakes? This can make a massive difference and should be done every couple of years or on fitting new discs/pads.

 

It's not the answer to your original query though, davemans answer seems the most likely place to start.

I didn't get the brake fluid changed. I'll get that done - didn't occur to me!

 

I definitely didn't rag them - don't trust my driving enough.

 

I shall look at the leaky servo valve.

 

I don't really have a clue about changing brake fluid and looking at the servo (don't even know where it is) so I'll take it to a garage.

 

Thanks for the suggestions!

Bleeding the brakes isn't that hard mate. There's good write ups on here and in the workshop manual. To improve things you can bleed at the calipers but keep the reservoir topped up with new fluid . This will bleed the system of any air and will pull the new fluid through. You will see a good improvement doing this. As long as you keep the reservoir full up you wont pull any air into the system. Its deffo worth doing.

hmm. ok I'll have a go this afternoon. Thanks Royal