Drove the car home last night everything fine.

Jumped in it earlier to go to work and ended up in the hedge next to my house. Foot pedal went straight to the floor. No resistance at all and no pressure build up when pumped.

I've checked for leaks from my brake lines, there wasn't a puddle where the car was parked last night and the brake reservoir looked fine.

Possible Master cylinder failure? Hope not as its only been on the car a month or so.

Fuck! Could have been a lot worse!

Sure you didn't press the clutch instead of the brakes?

fucks sake dude.... pics or it never happened

You and the car ok? strange that one like

Wasn't going fast enough to justify left foot braking. Lol. Ye could have been. Was only doing about 15mph as I had just pulled out of my drive, worse thing is sometimes I can just pull out and go at the main road, the next point I normally need my brakes on that road is a hair pin at the end of a long straight. So I'm glad that I found out they wernt there at that point.

If reservoir is still full and u have absolutely zero seeping of brake fluid around you are hoses or pipes then your brake cylinder is goosed. Was it a brand new master cylinder that was fitted a month ago?

Wasn't going fast enough to justify left foot braking. Lol. Ye could have been. Was only doing about 15mph as I had just pulled out of my drive, worse thing is sometimes I can just pull out and go at the main road, the next point I normally need my brakes on that road is a hair pin at the end of a long straight. So I'm glad that I found out they wernt there at that point.

The level has dropped about 1cm in a month but there isn't a leak in the hoses or anything. I checked the whole lot on Sunday again and there was nothing leaking from any joint or connection.

Cylinder was brand new, rear brake cylinders were also brand new (no fluid leaking from the rear drums)

Try bleeding the brakes manually then u can come to the conclusion its you are master brake cylinder. If nothing is coming out bleed nipple then your master cylinder is definetely knackered. But if you are lucky its one big fat air bubble in the system thats preventing any kind of proper vacuam/compression in the system. 1 very un likely possibility is contaminated brake fluid .But if fluid gets contaminated it turns acidic and burns the seals. I assume it was a full brake fluid change with new fluid aswell. Right now i would say the master cylinder has just popped :(

The level has dropped about 1cm in a month but there isn't a leak in the hoses or anything. I checked the whole lot on Sunday again and there was nothing leaking from any joint or connection.

Cylinder was brand new, rear brake cylinders were also brand new (no fluid leaking from the rear drums)

The MC was primed before fitting, then used a pressurized bleeder to get the fluid to the brakes, then a manual bleed to make sure there was no air in it.

Fluid was new (sealed) 5.1 racing blue same as I was using in the original system.

It wouldn't build up pressure with the engine off either and pumping the pedal when I tried it at home earlier.

I wouldnt use them pressurized bleeders. Yeah once the MC is primed n u got it coming out with no air bubbles u as good as got the MC done and more often than not the pipes are ok. I would advise if u have to replace your MC not to use a pressure bleeder. Only reason am saying this is coz i got a guy to replace a pipe on me on my 4x4 coz a didnt have the time to do it myself. But turned out he used a pressure bleeder and it bust the MC. Just telling u my own experience. I would only manually bleed the brakes with a new MC. Its very time consuming but well worth it when u got a nice hard pressurized pedal and full braking back. test the MC when u take it off and see if it squirts out anything when u push it in by hand. it should. They have a habit of the seals going when pressurixed or vacuamed too much and of of the seals warps and it no longer holds vacuam letting air in. If its not fitted flush aswell and the cylinder sits at even a slight angle then every time pedal is pressed and the cylinder goes in and out its tearing at the seal/s until it is just drawing air all the time. Check it and change it if you have to and bleed it all manually. If your really lucky the MC has air locked but very doubtful m8. Just wishful thinking!

The MC was primed before fitting, then used a pressurized bleeder to get the fluid to the brakes, then a manual bleed to make sure there was no air in it.

Fluid was new (sealed) 5.1 racing blue same as I was using in the original system.

It wouldn't build up pressure with the engine off either and pumping the pedal when I tried it at home earlier.

This is absolute failure then, there's nothing. Well there are two seperate circuits, so if the fluid had leaked out a line then you should still have brakes. So your lines are both still full and fine, as indicated by there being fluid in the reserveoir.

The servo is merely an assistance, failure does not leave you with no brakes.

That takes you back to the piston in the MC, and from there back to the pedal. Damaged seals is good, but such a sudden and absolute failure..? Another likely the linkage of the two, is there anything mechanical on the carpet? If you get your head under the dash and push the pedal, is it pushing the piston through the bulkhead panel?

If there's no break there and it looks normal, gonna have to take the MC off and have a look, i'm thinking.

When a seal completely goes in a MC it is instant failure as all the pressure escapes back out of it then u press the pedal all the way to the floor continuously with no pressure in the system happening. It will not be anything mechanical with the pedal because if it was then the pedal would be hanging low to the floor without returning by the spring and clips that hold it to the MC. As i said before i reckon your MC is shot unfortunately.

This is absolute failure then, there's nothing. Well there are two seperate circuits, so if the fluid had leaked out a line then you should still have brakes. So your lines are both still full and fine, as indicated by there being fluid in the reserveoir.

The servo is merely an assistance, failure does not leave you with no brakes.

That takes you back to the piston in the MC, and from there back to the pedal. Damaged seals is good, but such a sudden and absolute failure..? Another likely the linkage of the two, is there anything mechanical on the carpet? If you get your head under the dash and push the pedal, is it pushing the piston through the bulkhead panel?

If there's no break there and it looks normal, gonna have to take the MC off and have a look, i'm thinking.

I've never had a seal pop, so i'm trying to imagine how it can happen with such instant absolution. Scary stuff!

i personally love pressure bleeders - but be careful to use recommended pressure in them, which is quite low. I've heard stories of manual bleeding causing excessive wear to the seals in the m/c - going past their normal sweep (i.e. straight to the floor with the pedal).

tbh if your foot has gone straight down and there's no brake at all, i'd agree with mikey and be looking at the linkage and the push rod that goes into the m/c

I have had a seal pop travelling on a single track road going round a blind bend when it happened. All I can say is I'm lucky there was nothing coming towards me because my pedal DID go to the floor and 1 seal gave up the ghost so yeh m8 you are damn right it is scarey and not something to joke about.

I've never had a seal pop, so i'm trying to imagine how it can happen with such instant absolution. Scary stuff!

Was it from Euro Car Parts????????

If reservoir is still full and u have absolutely zero seeping of brake fluid around you are hoses or pipes then your brake cylinder is goosed. Was it a brand new master cylinder that was fitted a month ago?

Wasn't going fast enough to justify left foot braking. Lol. Ye could have been. Was only doing about 15mph as I had just pulled out of my drive, worse thing is sometimes I can just pull out and go at the main road, the next point I normally need my brakes on that road is a hair pin at the end of a long straight. So I'm glad that I found out they wernt there at that point.

Yep ECP one.

Right I have brakes again.

Checked every join, banjo and fitting, every cm of hose, front callipers and rear cylinders. Except for one hose fitting that I gave a few extra turns as it didn't look tight enough everything was fine.

So checked the servo even with the engine off for a while there was still a strong vacuum.

Master Cylinder, reservoir in place fine, mounted to the servo properly. Squirted fluid across the garage nicely.

Manually bled the system got small bubbles from front passenger and both rear wheels from the banjo being disconnected, then a huge bubble from drivers front.

Tested the brakes again and they were like they should be, no leaks and very sharp.

So I'm at a loss to say the least, only thing I can think of is that the reservoir cap I'm using isn't breathing creating a vacuum in the reservoir but I very much doubt that.

Any suggestions of what else it could be would be useful.

Thanks

Hmmm .. The resivour got a nice seal on it ? eg to master cylinder ?

Yep. Pushed entirely flush.

Id like to get separate reservoirs for both circuits as I can see if there is a problem with one circuit in particular.

Really baffled by this haha ...

I had same when my seals went in M/C..

pump it up so there's a vacume and hold your foot on brake with a bit of force .. Does it drop ?

Nope. Not even an inch and i had my foot planted for a while

Sounds good if all it was was a load of air bubbles. If it happens continuously then will be the MC. I would be a bit warey for a while driving and prepare to use you are handbrake and chipping down to low gear as quick as possible in case it happens again. Just suggesting precaution measures since your not entirely sure exactly what the problem was/is..........

Nope. Not even an inch and i had my foot planted for a while

Ye. Cars not going to edition this year. Lol just incase.

I hope the sealed res. cap has no effect, I've just bought one

Did you ever sort this Ceri?

Ill find out on the way to work. lol.

Had it back in the garage for 10 mins (after dealing with the insurance) and brakes were sharp and everything seems fine going up and down the drive.

No leaks or puddles under the car, all hose joins were devoid of blue liquid around them, so wish me luck.