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Technical Brakes seized in while driving! Help.

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Technical Brakes seized in while driving! Help.

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typecastboy

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While driving to work tonight having been stop start in traffic, I pulled into a traffic free road accelerating normally and thought, "hmm, it seems to be holding back". As I got further down the road it became increasingly worse. I then realised that the front brakes were binding. It got worse and worse and I decided I was going to have to turn around. I ground to a halt with the clutch burning and eventually kept stalling as the brakes were on full and jammed!

I stopped, called the AA. Whilst waiting for recovery, I put my foot on the pedal and thought that it felt normal. I started the engine, put it in gear and it was back to normal. When recovery arrived, the I drive home with him following and it was fine all the way home.

He suggested it might have been air in the system!

It seems that the hydraulic pressure had built up pushing the pads into the discs and whilst stopped, the pressure released.

I'm now scared to drive it.

Anyone any ideas what might of caused this? Is it possible it could have been air?
 
typecastboy said:
Is it possible it could have been air?
Click to expand...

I doubt it (air in the system usually gives you a spongy pedal), but you could have a sticking master cylinder - unusual if that's the cause.

It's also possible that one of the pads was sticking in the reaction frames; this is common.

Read this thread, then strip down the front brakes, clean, lubricate and reassemble. Look carefully for signs of a sticking pad; check particularly that none of the pads have warped (run a straight edge across them if you are in any doubt) - take some pictures and post what you find. Also change the brake fluid; that will flush any contamination out of the system and get everything moving freely again.

There have also been a very small number of posts about similar, as yet unexplained incidents regarding uncommanded brake application. One of these is very recent; follow it here. It's possible this could be down to some kind of uncommanded input from the ABS modulator, but there's no proof yet that this has ever happened.

If the car has any prior accident history, then an electronic ABS fault due to a dislodged component or connection is certainly a possibility.

Finding a definitive reason why this happened would go a long way toward restoring your confidence in the car.
 
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As always JRkitching, thanks for your help. I had actually read your other thread which was most useful and I thought that was probably going to be the answer. I'll get some grease and give it a go.

However, there was no pulling to one side, so it seems that both brakes were applied evenly. I think I scared the bloke behind me more!!!

As for an ABS fault, would that show up as a fault on the ECU I wonder? I'll plug in my ECUMultiscan tomorrow, see what I can find.

This is on my Cat C car, so it has been in an accident obviously. I only picked it up from the bodyshop this morning and it's looking like a brand new car. Thought I would drive it work tonight, big mistake!!
 
I have seen one instance of a damaged master cylinder where, after a minor accident, something had locked up inside preventing the hydraulic fluid from being released. You should also check that the cross shaft that goes from the pedal side to the servo on the passenger side is free, as even a minor shunt may cause the structure to move.
 
David Bliss said:
I have seen one instance of a damaged master cylinder where, after a minor accident, something had locked up inside preventing the hydraulic fluid from being released. You should also check that the cross shaft that goes from the pedal side to the servo on the passenger side is free, as even a minor shunt may cause the structure to move.
Click to expand...


Would that be something that would just right itself though? I haven't driven it far since but yesterday I ran the engine and continually pressed the pedal for 5 minutes with the brake fluid cap off just in case that helps.

I'm going to buy some copper grease tomorrow and try the brake cleaning as recommended p. At the very least that will eliminate that.
 
Long shot maybe but do you think the return spring on the pedal is ok?

Even if it's just allowing the brakes to bind very slightly they could get that hot that they eventually seize.
 
David Bliss said:
I have seen one instance of a damaged master cylinder where, after a minor accident, something had locked up inside preventing the hydraulic fluid from being released. You should also check that the cross shaft that goes from the pedal side to the servo on the passenger side is free, as even a minor shunt may cause the structure to move.
Click to expand...

On a RHD car, there's so much mechanism between the master cylinder and the pedal box that I'd say a damaged master cylinder is unlikely, but damage to the pedal assembly, cross shaft and associated components is a definite possibility, especially as the driver is quite likely to have applied maximum force to the pedal at the time of the accident.
 
jrkitching said:
On a RHD car, there's so much mechanism between the master cylinder and the pedal box that I'd say a damaged master cylinder is unlikely, but damage to the pedal assembly, cross shaft and associated components is a definite possibility, especially as the driver is quite likely to have applied maximum force to the pedal at the time of the accident.
Click to expand...


Would that not be like it all the time though? As the weather was rubbish today I didn't do the brake cleaning job, but I've driven round the block a few times and it's been fine.

I'm beginning to wonder whether it's a simple matter of the months it spent sitting in a scrap yard somewhere up north and a couple of months sitting on my drive. Apart from the short journey to and from the body shop, the night they locked was its longest outing.

Got to do the brake cleaning first, then I'll take a chances and start driving again.

At least I have Blondie, that's up for sale that I can use. Much prefer driving the 500s to the cmax
 
First chance I've had to attack the brakes since my brake lock up evening.

I had trouble getting the caliper pivoted up. The split pin and the rod came out easily but then I couldn't budge the caliper. I turned the disc and it was really hard to turn.

I had to hit the caliper with a hammer to get it started then it would release and pivot. I couldn't figure where the bolt was to take the reaction frames out and I don't have a rotary tool, so I used some 80 grit paper and rubbed them all down.

When I eventually pivoted the caliper upwards, the pads stayed in the reaction frames. Is that right? The pads have plenty of life left in them so I cleaned up the frames, put some copper grease both sides, top and bottom and then placed the pads back in, used a G clamp to compress the piston and then put it all back together.

Half way through doing it, it absolutely peed it down with rain and I got soaked through to the skin doing it, so I've only done one side so far. It's still raining hard now so I'll have to leave the other side until Christmas eve when I'm off work. Still took it for a spin round the block and it all seems fine.

Thanks very much for the tip, even though I couldn't figure out how to get the frames out it was still easily enough to clean them properly. There was no grease in there at all, now there's a good smattering so hopefully, it'll do the job.
 
Got the second side done this morning. Only took about half an hour now I know what I'm doing. I would have liked to have taken out the reaction frames but just couldn't work out which bolt it was. Duh!

Took the car for a blast, lots of heavy and prolonged braking and fingers crossed its done the trick.

JRKitching, once again I'm forever in your debt.
 
typecastboy said:
First chance I've had to attack the brakes since my brake lock up evening.

I had trouble getting the caliper pivoted up. The split pin and the rod came out easily but then I couldn't budge the caliper. I turned the disc and it was really hard to turn.

I had to hit the caliper with a hammer to get it started then it would release and pivot. I couldn't figure where the bolt was to take the reaction frames out and I don't have a rotary tool, so I used some 80 grit paper and rubbed them all down.

When I eventually pivoted the caliper upwards, the pads stayed in the reaction frames. Is that right? The pads have plenty of life left in them so I cleaned up the frames, put some copper grease both sides, top and bottom and then placed the pads back in, used a G clamp to compress the piston and then put it all back together.

Half way through doing it, it absolutely peed it down with rain and I got soaked through to the skin doing it, so I've only done one side so far. It's still raining hard now so I'll have to leave the other side until Christmas eve when I'm off work. Still took it for a spin round the block and it all seems fine.

Thanks very much for the tip, even though I couldn't figure out how to get the frames out it was still easily enough to clean them properly. There was no grease in there at all, now there's a good smattering so hopefully, it'll do the job.
Click to expand...
i did it as jrkitching said and all the noises disappeared until i change the pads again! so it really does the trick!
 
Couple of pictures of one side. What it looked like before cleaning and then after putting in the copper grease and putting it all back together.
 

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Took the car to work today for the first time and got there without the brakes locking up. I did feel at one point that the brakes were binding slightly, nowhere near last time so the copper grease and cleaning the reaction frames has obviously done the job.

I don't think it's 100% though. I hooked my foot under the brake pedal and pulled it upwards and then the brakes seemed to be better, they weren't binding at all. Is there a return spring on the pedal? It's as if it's not releasing properly on the pedal.

When I drove home, it seemed completely fine. Is it something you can lubricate in some way? I know there's the metal bar that joins the pedal to the slave cylinder, but is there something else that could be causing the pedal to not release properly?

Tried googling it, but couldn't find anything.

I've just re-read some of your replies above again, so it seems it could be the rod or a spring. Might try have a look at that if I can get to it.

Question remains though, can you lubricate the spring? I guess it's a bit tricky to get at!
 
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