brake fluid in footwell

[falcoron]

i have been trying to see where a brake fluid leak is and have had no luck in all the places ive looked, just noticed today when cleaning the interior taht my drivers side carpet is damp with brake fluid i cant see up enough to see where this is coming from, any ideas please 2001 W203 cdi220

 

[horgantrevor]

its not brake fluid its gearbox oil from a seal gone on gearbox called pilot bush

 

[falcoron]

No its brake fluid, i have a brake fluid leak and need to top up every 10 days or so i cant see any leaks at wheels and lines but this is brake fluid ok not oil

 

[moonloops]

It will be a leak on the back of the master cylinder

 

[horgantrevor]

remove the carpet section and have a good look easy job

its a strange one brake fluid in foot well

but the pipes dont run any were near that area im sure of it ahhhh you may have a leaky master cylinder the diaphragm may be going pop the bonnet and look under master cylinder for a leak then remove cover under steering wheel and look up follow the brake pedal up you will see a leaver going into diaphragm i bet the seal is gone their

so a bit asleep tonight

 

[horgantrevor]

remove the carpet section and have a good look easy job

its a strange one brake fluid in foot well

but the pipes dont run any were near that area im sure of it ahhhh you may have a leaky master cylinder the diaphragm may be going pop the bonnet and look under master cylinder for a leak then remove cover under steering wheel and look up follow the brake pedal up you will see a leaver going into diaphragm i bet the seal is gone their

so a bit asleep tonight

 

[falcoron]

Is this an easy DIY fix im pretty handy but never done this before does the master cylinder have to be completly removed, how easy is that to do
Thanks

 

[renault12ts]

Bleed the fluid from the MC. Then unbolt all pipes and then the MC. Be clean.

 

[horgantrevor]

its a bolt on bolt off job but you will need to be good with the hands also you will have to bleed the brake system after words all four wheels best bet is get a manual

and have a read

not a big job but will need to take your time

 

[momomo]

Its the master cylinder. The seal in the master cylinder has gone and it is allowing fluid to leak backwards into the servo. This is 100% the problem. This is why you are not seeing any fluid leaks anywhere but are loosing brake fluid in such amounts. The fluid is leaking from the servo into the footwell. The back of the servo connects inside the car directly to the brake pedal.

To 100% confirm this, pull off the large vacuum pipe from the front of the servo and see if any fluid is in there. There should be no fluid in there. If there is, its the master cylinder.

 

[horgantrevor]

Its the master cylinder. The seal in the master cylinder has gone and it is allowing fluid to leak backwards into the servo. This is 100% the problem. This is why you are not seeing any fluid leaks anywhere but are loosing brake fluid in such amounts. The fluid is leaking from the servo into the footwell. The back of the servo connects inside the car directly to the brake pedal.

To 100% confirm this, pull off the large vacuum pipe from the front of the servo and see if any fluid is in there. There should be no fluid in there. If there is, its the master cylinder.

great advice

 

[219]

I would recommend not driving the car any further until this is fully diagnosed and sorted .

A minor leak in a seal could , without warning , turn into a catastrophic failure with loss of all braking , depending on what exactly has gone wrong - I experienced this in a single circuit older car when a wheel cylinder seal failed ; in theory this should not happen on a modern car with dual circuits , but stranger things have happened and , even with one circuit gone , your car would lose 50% of its braking capacity .

Also , if you have brake fluid leaking around the place , you need to get this stopped and all residue cleaned up thoroughly since brake fluid is an effective paint stripper - once the paint is gone , your unprotected metalwork will rust away .

 

[Dieselman]

^ A leaky wheel cylinder won't cause catastrophic failure on it's own you must have let the fluid level drop too far so the master cylinder was sucking air.
My Brother had this happen and found that the back of a lorry made for effective deceleration from 30+mph.

 

[Mercsys]

I’ve put the pedal to the metal, (brake) it’s not an experience I would recommend. Get it fixed, work clean and dry.

 

[219]

^ A leaky wheel cylinder won't cause catastrophic failure on it's own you must have let the fluid level drop too far so the master cylinder was sucking air.
My Brother had this happen and found that the back of a lorry made for effective deceleration from 30+mph.

The brakes went from fine one second to pedal right to the floor : the car was slowing when all pressure disappeared . Surely a burst seal in any cylinder on a single circuit system , as on the Ponton , would result in an immediate loss of pressure throughout ?

The car had been recommissioned ( after being laid up for a number of years ) only a week or so before , and MOT'd at that point , with fluid having been changed , drums off and shoes inspected , all nice and dry , and everything bled at that point .

There was nothing left in the system afterwards , but several panic pumps at the pedal would probably have expelled anything there anyway . Fluid leaking out of the drum and running down the inside of the front tyre was a pretty good clue where to look for the leak .

On dismantling the offending cylinder , the rubber seal was cracked and split , the others were not much better . At the time MB told me new cylinders were not available , although 30 years on they now are

in the end , I got all six cylinders bored and sleeved back to original dimensions , as well as replacing flexible hoses ( then current W123 ones fitted straight on ) .

It was fun driving home from Edinburgh with only gears and a handbrake ( coupled with planning and anticipation ) to stop with

I didn't have a 30 ton lorry in front to stop me - only a Rolls-Royce Thankfully I almost managed to stop with the handbrake and only gave him a gentle nudge , with no damage to either car .

Ever since that incident , I have been paranoid about brakes .

 

[falcoron]

thanks guys,
Just out of interest is the bottle on this mater cylinder fuel the cluch as well or is there a seperate flud resevoir if so where is that located please

 

[BlackC55]

I bet you have a manual and the return pipe to the clutch cylinder is leaking or the cylinder itself is.

 

[falcoron]

it is a manual. dont want to buy a brake master cylinder and its the clutch. where do i check please and where is the top up reservoir?

 

[Mercsys]

The brake is reservoir is usually much larger than the clutch, so you will be wanting the one that you have been having to top up!

 

[falcoron]

Yeah, but the brake and clutch is feed from same top up. could the slave cylinder on the clutch pedal be the culprit? any way of checking this and how easy is this to replace if it is this part thats leaking