Hi, After having to do an emergency stop the other day something has 'happened'  to my brakes! The pedal just keeps depressing as on brakes as if system had a huge leak. Have just checked the (new) front discs & pads-all in order. Hoses look fine. Master cylinder was a touch low-now topped up. The car is a 1999 Octavia 1 with rear drums and has only done 75000 miles.(haven't been inside the rear drums yet but no sign of brake fluid anywhere!)

Could it be the servo seals that have suddenly given up, or the master cylinder?? Never had anything like this in 40 years!

Vacuum leak?

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I'm guessing it either a rear wheel cylinder that's blown or the master cylinder seals. I'd get under the car and have a look at the rear back plates or get the wheels and drums off. I doubt it a vacuum leak as the pedal would be hard as if no servo assistance.

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Scary.  I generally try the odd emergency stop on all my cars every now and then to be sure the hydraulics and the mechanicals are in good order.  Might start doing that more often, as you really don't want it to fail when you are using in an emergency!  Does sound like you've lost fluid somewhere.  I'm tempted to suggest that if your pedal is still long, it's more likely to be a master cylinder issue, but I'm not an expert.  If the reservoir only dropped a bit, it's unlikely you got air in the system - other than if you had a seal failure perhaps.

Reckon the servo's okay-tested it as per manual. Will check drums tomorrow.

Hi,

this reminded me of a similar event I had a few years ago on a R/Rover.

 

Driving home one a/noon I had total foot brake failure, the pedal went to the floor with no resistance. I managed to slow down and got home using the handbrake ( mechanical linkage to massive internal pads/ drum on the rear output shaft). I checked for leaks, no fluid loss, all pipework was intact including servo line. Anyway, I bought a new master cylinder, fitted it all ok.

I think it could have been in my case:-

1/ Both sets of master cylinder seals had failed at the same time or

2/ Because of pumping brakes when bleeding them maybe the seals turned inside out and / or were damaged.

 

NB: The stink from the transmission brake when i got home was something else, now i use "ezee- bleed kit" for the vrs.

Well, removed rear drums-both cylinders 'burst', fluid drenched shoes etc.............ho hum! Least it's just a couple of cheap bits & easy to get at!

Hi,

this reminded me of a similar event I had a few years ago on a R/Rover.

 

Driving home one a/noon I had total foot brake failure, the pedal went to the floor with no resistance. I managed to slow down and got home using the handbrake ( mechanical linkage to massive internal pads/ drum on the rear output shaft). I checked for leaks, no fluid loss, all pipework was intact including servo line. Anyway, I bought a new master cylinder, fitted it all ok.

I think it could have been in my case:-

1/ Both sets of master cylinder seals had failed at the same time or

2/ Because of pumping brakes when bleeding them maybe the seals turned inside out and / or were damaged.

 

NB: The stink from the transmission brake when i got home was something else, now i use "ezee- bleed kit" for the vrs.

It wouldn't be the first time I've heard of that happening, normally it's (1) as a result of (2) taking the MC seals to parts of the cylinder bore they don't normally visit.

 

Although I note that in this case it seems to be rear wheel cylinders.