sinking brake pedal

[dave_Sw1]

Hi, I have a gs4 Lancer diesel sporthatch on a 58 plate, when you press the brake pedal the first 30-40% of the total pedal travel can on some occasions happen with basically no resistance under foot, meaning the pedal only comes in after that point, then if you are stationary, and apply a reasonable amount of pressure, you can push the pedal till it goes to the floor. I've driven this car for 15000 miles and it never did this until one day when it started doing it, I took it to mitsubishi and under warranty they have changed the servo, the master cylinder and the abs pump, and now say they have fixed it, but its exactly the same, They have sent the car to the uk head office technical department and they say its fine- I sat in a 4 door lancer diesel in the show room, and it had a normal hard brake pedal that would not sink to the floor, but mine does, and yet they are telling me its fine! could anyone please tell me if under any circumstances it should possible to press a brake pedal to the floor when stationary, I don't think its right or safe but am being told otherwise!

also anyone know what my options are as they now claim its fine and want to return the vehicle?

Cheers

David

[tr7v8]

Lots of diesels do it. It has been discussed on here & it is even mentioned in the MOT test manual.

[dave_Sw1]

it never used to do it though, and letting it sink till you feel it hit the hard stop, really doesn't inspire me that its safe

[dave_Sw1]

also the fact that they had another one in the showroom that didn't do it, suggest there is something not right about it

[taylormj4]

A brake pedal to the floor cannot be normal on any car surely. What happens if you are stationary on a hill and this happens. The brakes come off ?!

Matt

[Jellinek]

I did some work on a Jag a while back and if you pressed the brake pedal as though you were on a steep hill, before keying on, when the vacuum built up in the booster the brake pedal would go to the floor. You had to maintain a constant pressure on the pedal, but it went all the way down and you could tap the pedal on its stop, so there was no pressure in the line. I too was shocked to hear people telling me it was normal and that "they all did that".

I think the "problem" was with the Master Cylinder seal, which was actually designed to let some fluid past it in certain circumstances and back into the reservoir. Something to do with ABS operation I was told, but it sounded like a load of BS to me. Might be worth checking yours out?

[tr7v8]

Oh FFS! Read what I wrote above, google sinking brake pedal if you don't believe me. It is even in the MOT testers manual as a specific characteristic of diesels.