belly257

Member
After fitting all 5 stainless hoses to the disco it seems the brake pedal is very poor now, was fine up until doing the last 2 front flexis. The brakes were working well beforehand no issues at all. There is no leaks in the system and I have had the pressure bleeder on it the whole works so there is no air in the system either, the pedal pumps up fairly well when engine is off and then start the engine up and the pedal almost goes to the floor and the brakes hardly work. I have done a search and it's looking like master cylinder but I don't understand how it can just destroy itself. I have a scrap discovery so may try the master cylinder off that as the brakes are fine has anyone else got any ideas?
 
yes mate I even tryed bleeding it from the master cylinder itself. No signs of air anywhere in the system but aftwr doing that the brakes did improve ever so slightly. So maybe it is a master cylinder fault....

Nowt as simple as you've not pumped brakes to get pedal to where it should be?
 
Could be the pressure from easy bleed has flipped the seals in the master cylinder....or something like that:)
 
I've heard a theory before where if you bleed manually, you push the pedal beyond it's normal travel, and therefore push the piston inside the master cylinder further than it would usually go into the unused area of the bore and the seal can become damaged or flip. I've never really been convinced though, as a master cylinder should be bored to allow for the seal to work across it's full range of travel, I can't imagine the bore would wear down or become rough enough to cause such damage.
 
I've heard a theory before where if you bleed manually, you push the pedal beyond it's normal travel, and therefore push the piston inside the master cylinder further than it would usually go into the unused area of the bore and the seal can become damaged or flip. I've never really been convinced though, as a master cylinder should be bored to allow for the seal to work across it's full range of travel, I can't imagine the bore would wear down or become rough enough to cause such damage.

it gets rusty and pitted from water in fluid ,its quite common
 
I've heard a theory before where if you bleed manually, you push the pedal beyond it's normal travel, and therefore push the piston inside the master cylinder further than it would usually go into the unused area of the bore and the seal can become damaged or flip. I've never really been convinced though, as a master cylinder should be bored to allow for the seal to work across it's full range of travel, I can't imagine the bore would wear down or become rough enough to cause such damage.

Been there years ago so it does happen, now I only press the pedal half way to the floor and not to the carpet.
 
Did you remove the calipers in the process of changing the hoses? I have seen calipers put back on the wrong side and upside down by a skilled (momentarily absent minded) mechanic. Bleed nipples at the bottom and couldn't work out why the brakes wouldn't bleed.
 
I've heard a theory before where if you bleed manually, you push the pedal beyond it's normal travel, and therefore push the piston inside the master cylinder further than it would usually go into the unused area of the bore and the seal can become damaged or flip. I've never really been convinced though, as a master cylinder should be bored to allow for the seal to work across it's full range of travel, I can't imagine the bore would wear down or become rough enough to cause such damage.

Maybe mate as there was abit of crap that came out of the bleed nipple so may have damaged the seals in the master cylinder
 
Did you remove the calipers in the process of changing the hoses? I have seen calipers put back on the wrong side and upside down by a skilled (momentarily absent minded) mechanic. Bleed nipples at the bottom and couldn't work out why the brakes wouldn't bleed.
No mate they stayed on as I have to seen this happen
 
Aaaaand final theory, the multi circuit front calipers on these are supposed to be bled in sequence, you have to bleed one nipple then link the other two together and bleed them at the same time.

the exact sequence is in haynes, me forgets which ones are which, but it could be your answer.
 
Aaaaand final theory, the multi circuit front calipers on these are supposed to be bled in sequence, you have to bleed one nipple then link the other two together and bleed them at the same time.

the exact sequence is in haynes, me forgets which ones are which, but it could be your answer.

Furthest, second furthest, third furthest, then closest to the master cylinder. :)
 
exact sequence doesnt really matter though bleeding a little at each to start with help to ensure both parts of master have fluid
 

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