Catastrophic Brake Failure
Discussion
So yesterday I got to enjoy a new driving conundrum. What do you do when the brakes fail.
Exciting! Not half.
I'd decided to do a small B road route after some hours of motorway travel. So I came off the M4 at junction 14, for Hungerford if you head south, but headed north to where I intended to take the B4000 over to the A34. Its a lovely little road. Camera free. Lovely to drive and with pretty villages and pubs along the way. No need to hoon (but fun if you do).
I headed up the road. Looked around and saw no traffic. There's the junction I need on my right. Okey dokey time to brake.
BANG! Brake pedal drops another couple of inches. Braking effect reduced massively.
I think to meself. Oh ho. Not going to make the junction. Keep foot on brake, keep steering wheel straight, try and make the corner following. Phew! Did it.
Apalling grinding sound from the rear driver's side of the car. Yup - the brake pad has pretty much disintegrated. I'm in a very windy twisty road - bit of a dangerous spot so instead of call from where I was I limp a mile or so at less than 20mph to a nearby pub and call the RAC to get it recovered.
Interestingly I did have "some" brakes - after all, the fronts do most of the work, but I didn't want to ruin the caliper or try any emergency braking by trying to get home.
Got home very late and not just a little disturbed.
I have to tell you: spinning on track, spinning on the road (as a passenger), coming off in a kart and breaking a rib - all these things are significantly less scary than pressing the brake pedal and it NOT doing what its supposed to.
Damnit. I service the car regularly and change the discs and pads whenever required.
Moral of the story? Sometimes shit happens. And sometimes you get lucky and there's no-one around...
Exciting! Not half.
I'd decided to do a small B road route after some hours of motorway travel. So I came off the M4 at junction 14, for Hungerford if you head south, but headed north to where I intended to take the B4000 over to the A34. Its a lovely little road. Camera free. Lovely to drive and with pretty villages and pubs along the way. No need to hoon (but fun if you do).
I headed up the road. Looked around and saw no traffic. There's the junction I need on my right. Okey dokey time to brake.
BANG! Brake pedal drops another couple of inches. Braking effect reduced massively.
I think to meself. Oh ho. Not going to make the junction. Keep foot on brake, keep steering wheel straight, try and make the corner following. Phew! Did it.
Apalling grinding sound from the rear driver's side of the car. Yup - the brake pad has pretty much disintegrated. I'm in a very windy twisty road - bit of a dangerous spot so instead of call from where I was I limp a mile or so at less than 20mph to a nearby pub and call the RAC to get it recovered.
Interestingly I did have "some" brakes - after all, the fronts do most of the work, but I didn't want to ruin the caliper or try any emergency braking by trying to get home.
Got home very late and not just a little disturbed.
I have to tell you: spinning on track, spinning on the road (as a passenger), coming off in a kart and breaking a rib - all these things are significantly less scary than pressing the brake pedal and it NOT doing what its supposed to.
Damnit. I service the car regularly and change the discs and pads whenever required.
Moral of the story? Sometimes shit happens. And sometimes you get lucky and there's no-one around...
Fortunately no real harm done, but alarming all the same, Don.
I expect most, if not all, cars have dual circuit braking systems these days, but by the sound of it yours wasn't simply a hydraulics failure, unless the right rear piston(s) came out so far that fluid escaped from that circuit. Even then it should have left you with RH front and LH rear working.
No joke, in any case.
Best wishes all,
Dave.
I expect most, if not all, cars have dual circuit braking systems these days, but by the sound of it yours wasn't simply a hydraulics failure, unless the right rear piston(s) came out so far that fluid escaped from that circuit. Even then it should have left you with RH front and LH rear working.
No joke, in any case.
Best wishes all,
Dave.
bertbert said:
unusual occurence I think (although don't know). What car/age was it? Interesting to find out the cause.
Bert
Bert
I shall be asking at the garage. They are replacing the rear discs and pads.
Oh...sorry: It was a 51 plate Vauxhall Vectra. Kept services on the nose and pads/discs always replaced when the main dealer advised.
Edited by Don on Wednesday 7th March 13:08
I had exactly the same thing happen last November. I was braking moderately for a roundabout when one of the rear left brake pads disintegrated leaving a rather nice metal on metal graunching sound and reduced braking ability (although not by much I was surprised to find).
I had to drive the car in this state about 100 miles home as it was a Sunday - no chance of a fix and I had to pick my dog up on route. It's amazing how not using your brakes over a 100 mile drive lifts your vision!
The scarred left rear alloy burnt by the hot shards of metal off of the discs and pad backing bears testament to the folly of this. I think next time I'll call the AA.
I had to drive the car in this state about 100 miles home as it was a Sunday - no chance of a fix and I had to pick my dog up on route. It's amazing how not using your brakes over a 100 mile drive lifts your vision!
The scarred left rear alloy burnt by the hot shards of metal off of the discs and pad backing bears testament to the folly of this. I think next time I'll call the AA.
WeirdNeville said:
The scarred left rear alloy burnt by the hot shards of metal off of the discs and pad backing bears testament to the folly of this. I think next time I'll call the AA.
I didn't want to cause any further damage. I had *some* braking - which was what averted a rather nasty trip to the hedge - but I wasn't driving it 40 miles home.
I had a pipe split as I was driving, only found out as I was braking for the motorway junction exit! Car swerved as the braking system is split diagonally but it did slow gradually though there was no pressure on the pedal.
Just kept foot to the floor then slowed the car on its gears. Then felt I could drive the car the rest of the way home as I knew its failings
Only had to go another mile. Probably not a good idea but I made it.
Just kept foot to the floor then slowed the car on its gears. Then felt I could drive the car the rest of the way home as I knew its failings
Only had to go another mile. Probably not a good idea but I made it.
bertbert said:
unusual occurence I think (although don't know). What car/age was it? Interesting to find out the cause.
Bert
Bert
The rear discs and pads were last changed at 40k miles about 4 years ago. The car had done 80k when they failed. The pads were worn but still had life in them with about 5mm of material left. The discs were also worn but servicable until the pad backing hit them. Ironically I had booked the car in to the garage already to have the discs and pads changed.
The pad material sheered wholesale off of the backing plate with only the two little 'holes' in the plate where the material come through showing any sign of material. I have no idea of the brand, but they would have been cheap OEM spec kit I suspect.
I can vouch for this activity turning your bowels inside out fairly quickly. Driving back home in my Cinquecento (many moons ago) having just collected it from the dealers after having a new master cylinder fitted, I had the brake servo fail at 70+mph at the instant I braked for what I know full well is a 40mph corner. The pedal thumped and dropped a half inch or so and I had bugger all braking. I levered myself out of the seat and pulled on the steering wheel to force the pedal down to scrub off some speed (anyone with a Cinq will know the handbrake is useless). Hit the corner still rattling on a bit. Chucked it in, understeered right over the other side of the road and just made it round. Would have been 
ed if there was anyone coming the othe way.
Got home and my mum said I looked very pale and asked was I OK.
Several years before that I had the brakes on my Metro cook and the fluid boil doing the Horseshoe pass near Llangollen. That shit me up properly. I won't harp on about it now, but will mention that the car was fully airborne at some point whilst I tried to stop it.
ed if there was anyone coming the othe way. Got home and my mum said I looked very pale and asked was I OK.
Several years before that I had the brakes on my Metro cook and the fluid boil doing the Horseshoe pass near Llangollen. That shit me up properly. I won't harp on about it now, but will mention that the car was fully airborne at some point whilst I tried to stop it.
Unfortunately an all too common experience, with the pad or shoe friction material parting company. This is no less common in the popular branded names than the cheap and cheerful ones, I personally would recommend changing pads well before they are worn to limits.
As for dealing with this scenario, you would be better pumping the brakes, as against holding pressure on and not releasing.
As for dealing with this scenario, you would be better pumping the brakes, as against holding pressure on and not releasing.
In the past I've found that metal-to-metal brakes work if anything rather better than the old fashioned sort with the linings attached - they just don't last as long. Didn't you find that the brakes came back after you pumped the pedal a few times to take up the extra travel?
On the other hand I've experienced total brake failure myself after boiling the brakes, and seen it once on another car that suffered a fractured brake line at the end of a 100mph straight, and the pedal went to the floor with negligible braking left despite the supposedly dual circuit brakes.
On the other hand I've experienced total brake failure myself after boiling the brakes, and seen it once on another car that suffered a fractured brake line at the end of a 100mph straight, and the pedal went to the floor with negligible braking left despite the supposedly dual circuit brakes.
GreenV8S said:
In the past I've found that metal-to-metal brakes work if anything rather better than the old fashioned sort with the linings attached - they just don't last as long. Didn't you find that the brakes came back after you pumped the pedal a few times to take up the extra travel?
I was very careful, but yes I found that the brakes were still effective. I only used them in moderation however. The things that worried me about metal to meatl brakes were mostly:
1) Horrible screetching noises.
2) Scarred alloys from shards of steel
3) Glowing red brake disc.
None of which I care to repeat in a hurry!
ipsg.glf said:
Don
Did you perform a slow speed and high speed brake test, prior to starting the drive?
Did you perform a slow speed and high speed brake test, prior to starting the drive?
Every morning I do a full drill (yes, really, I am a bit geeky about it). They seemed fine. I'd just done a hundred miles or so with no problems and full braking capability.
When younger (as a student) my car once ran all the way through its pads before I replaced them. You get some warning, usually, even without modern pad depth sensors - the start of a rough noise when braking and so on.
Nothing like that. Brakeity brake. Bang. Aaargh! As I said - I had *some* braking left. I wasn't going to drive any distance like that, though.
GreenV8S said:
In the past I've found that metal-to-metal brakes work if anything rather better than the old fashioned sort with the linings attached - they just don't last as long. Didn't you find that the brakes came back after you pumped the pedal a few times to take up the extra travel?
I did retain some braking, yes, and pumping up the pedal helped. Horrendous noise of course. Wasn't going to go far like that. In fact I did a mile or two to the nearest village with a pub and stopped in its car park.
freddytin said:
An effective simple repair of the failure you describe can be carried out by clamping the flexible rubber hose leading to the ineffective caliper. Cautious use of mole-grips as found in most tool kits will enable you to steadily and safely reach your intended destination.
I would think the vehicle is actually safe with all wheels brakes (although with one corner metal-on-metal) rather than have the brakes disabled on one corner.
I'd be concerned about the potential damage to the hose (itself safety critical) from being manked in the jaws of the mole grips - the damage may not be obvious.
It's possible that if the hose is not quite perfectly sealed off by the mole grips then they could act as a one-way valve, holding the brakes on.
GreenV8S said:
freddytin said:
An effective simple repair of the failure you describe can be carried out by clamping the flexible rubber hose leading to the ineffective caliper. Cautious use of mole-grips as found in most tool kits will enable you to steadily and safely reach your intended destination.
I would think the vehicle is actually safe with all wheels brakes (although with one corner metal-on-metal) rather than have the brakes disabled on one corner.
I'd be concerned about the potential damage to the hose (itself safety critical) from being manked in the jaws of the mole grips - the damage may not be obvious.
It's possible that if the hose is not quite perfectly sealed off by the mole grips then they could act as a one-way valve, holding the brakes on.
The cost of a replacement flexible hose, if indeed it suffered any damage,is negligible.
The cost and danger of allowing the caliper piston to extend beyond its intended range IMHO is far greater than any safety issues that might arise from clamping the flexi.
As for the clamp working as an NRV, well it would soon be very apparent , the noise would be a dead giveaway.
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