Multiple brake problems - 300TDi

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davesnapeuk

New Member
Posts
18
Location
Llanelidan
I have a number of problems that have started to develop with the brakes on my Disco over the last few weeks and hope the wealth of knowledge here can point me in the right direction. I'm short on time due to needing the car for a 400 mile journey on Friday so may end up taking it to a local garage if it's not a small job but I'd value your thoughts to help me gauge that.

Pads checked all round and all have 3/4 wear left on them.

Brake fluid reservoir is full and fluid use isn't an issue.

First thing in the morning the brake pedal pretty much descends to the floor on the fiirst couple of presses. Braking is not affected except for elongated pedal travel. Brakes bled but still the same.

Occasionally the pedal goes really hard even though it's right at the top and I can't press it any further than 1/4 down. Braking pressure when pressed as far as the pedal will go is approx 1/4 of what it should be as I would expect for a pedal that's only going 1/4 down.

Brake pedal sometimes feels spongy meaning that sometimes I press the pedal and get lots of brakes, sometimes very little. Next time I press them (even after a few minutes) they are back to normal or feel different again.

As I live in a rural village the roads are single track and meet many tractors coming towards me with big loads and cannot stop. Frequently I have to use an emergency stop and reverse to avoid them hitting me. Usually the wheels lock up and the vehicle skids - yesterday it was like I was tickling the pedal and could do nothing - not even pumping the brakes - to get any more braking power. It was down to about 1/4 brake strength again even though the pedal felt normal and went quite a way down.

If I can't fix it quickly I'm gonna have to hire a car for the weekend journey because I'm not convinced it's safe to drive at the moment so any suggestions are much appreciated.

cheers everyone, Dave
 
Sounds like you've got a vacuum problem !
The servo uses vacuum generated by the engine driven vacuum pump to assist the force you apply.
have you tried disconnecting the vacuum pump from the servo & checking whether it sucks air in - ie the pump is working ?

Paul
 
Sounds like you've got a vacuum problem !
The servo uses vacuum generated by the engine driven vacuum pump to assist the force you apply.
have you tried disconnecting the vacuum pump from the servo & checking whether it sucks air in - ie the pump is working ?

Paul

Unfortunately yes and it is sucking. But then the 'feel' of the brakes is different every time I press them so it cold be intermittant failure which I'm not sure a vacuum pump would get. I'd expect it to either be working or not especially as the amount of braking isn't related to the speed of teh car. In fact, yesterday when the pedal went hard and wouldn't press down I was doing 40mph and yet back down at 20mph sometimes it was OK, sometimes little brakes at all.

My gut feel is on master cylinder which I've not got time to strip down before weekend so it's looking like a trip to my local mechanic - who thankfully is quite reasonable and quick!
 
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