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Hi guys another fault my breaks are really bad, if I push hard while driving the peddle is hard but hardly does anything. Then the peddle slowly sinks and starts to slow the car a little. If stood still holding peddle it's sinks to the floor slowly. Iav changed discs and pads today no leaks hoses look fine. Can also hear air somewhere when let peddle rise from floor. Could this be the servo if so how hard to diy. Appreciate any help thanks regards Carl

check out the servo and change all the brake fluid, that always makes a big difference

Hi thanks for reply. Ial change the fluid what am I looking for on servo worn pipes etc. thanks Carl

Hi Carl,

Before jumping into a servo change......

If you can hear air then you have a vac leak somewhere but not neccesarily the servo, the potentially hard bit is tracking it down.
When I asked a garage about my brakes the guy said you can usually hear a hiss from the servo when the engine shuts off if there is a leak there, Jasper5 can probably confirm or deny that one.

The pipe from the pump to the servo is plastic tubing with push on rubber pipes spurred off it (at least it is on my car). Temporarily blank off all the rubber vac pipes just leaving the pipe from the vac pump to the servo and see if that improves anything. All you need for blanks are short lengths of rubber vac pipe with a tight fitting stopper of some kind, golf tee, screw that sort of thing.

If your brakes come back with everything blanked off then its probably a split pipe or leaky electrovalve, fit new vac pipe to each spur and test after you make each connection. I would imagine if it were a split pipe and you can hear the air leak it will be a big split and easy to spot

If the brakes don't improve I'd test the pump is putting out enough vac pressure, if you don't have a gauge and its safe to drive nip it round to a independent garage and they'll probably do it for a few quid as its a 2 minute job to test.

Be aware that with all the vac pipes blanked you will probably get warning lights as your EGR and turbo electrovalves are inoperative.

Hope that helps and it turns out to be a split vac pipe as thats the cheapest and simplest option to repair.

Hi thank you that gives me something else to try I was running out of ideas, great help thanks dude. Iav been told that a lot of diesel brake pedals sink to a degree don't know if that's true. Will certainly be trying this next tho. Thanks again regards Carl

annie10 wrote:check out the servo and change all the brake fluid, that always makes a big difference

+1 on the servo / vacuum leak, if your pushing hard on the pedal and yet the brakes bearly slow the car it all points to the servo
I've never heard of diesel brake pedals sinking anymore than petrol, I know mine doesn't

No vacume leaks checked all piping even cabled tied them to make sure. Brakes have improved with a bleed but still got to press hard. Must be servo then my next mission, how hard are these to diy? Thanks Carl

Hi guys still have brake problems doing my nut in now, they generally feel better but still not happy with them, if i slam on hard there's little braking force then 2 seconds after they start to work fine. Peddle still goes to floor if push down then if i pump them 5 a so times they feel good. Iam totally baffled thinking of getting a master cylinder just wondering if anyone else has an idea. Appreciate some helps thanks Carl.

Mate,
The fact that you state that the pedal sinks to the floor , but is ok after 5 or so pumps tell's me you have air in the system .
I would say that they need fully bleading, all four corners following the correct bleading procedure .
If your unsure then take the car to a pro, you can't mess around with brakes .
After all this is peoples lives were talking about here

Does the brake pedal sink to the floor if the engine is off and the servo is empty?
If this is so then you probably have a master cylinder problem.

It is not unusual with a diesel for the pedal to sink with the engine running if you just sit there and press the pedal, but if it sinks with the engine off and servo empty then master cylinder is faulty.

There could be a vacuum pump problem or the one way valve that fits into the servo could be faulty....or the servo itself could be faulty.

I agree with DDD, time to get it looked at properly, don't mess with brakes!!

How can air be in the system there's no spongy feeling, the peddle sinks all the way to the floor that's not normal for air in the system. I have bled the brakes around 3 times now to no avail and yes the right way. Iam fully aware what brakes are for that's why Iam not running the car at the mo.

Hi jasper peddle is rock hard with engine off, iav tried the test foot on peddle start engine the peddle drops to the floor not quickly tho. Then if pumped up get better but still sinks to the floor, iav checked all vac lines could the onway valve cause this? Thanks carl

Carl wrote:Hi jasper peddle is rock hard with engine off, iav tried the test foot on peddle start engine the peddle drops to the floor not quickly tho. Then if pumped up get better but still sinks to the floor, iav checked all vac lines could the onway valve cause this? Thanks carl

It's possible the one way valve is faulty, need to drive the car though or see what is happening....very difficult without the car.

My pedal also sinks slowly to the floor if pressed hard when stationary. Id be interested in finding the answer!

azazel wrote:My pedal also sinks slowly to the floor if pressed hard when stationary. Id be interested in finding the answer!

Have a search through the old posts in this section, someone on here has replaced there servo & it solved all their problems.
They even reported the car runing & boosting better .