elliot0850

Active Member
I've replace my brake servo and master cylinder with a secondhand one after brake fluid was leaking from the master cylinder into the servo now all the brakes are seizing on and the only way to push the piston back is to release pressure by opening the bleed nipple.
I'm convinced it's either the servo or master cylinder but which one do you think it is and why.
Thanks.
 
I've replace my brake servo and master cylinder with a secondhand one after brake fluid was leaking from the master cylinder into the servo now all the brakes are seizing on and the only way to push the piston back is to release pressure by opening the bleed nipple.
I'm convinced it's either the servo or master cylinder but which one do you think it is and why.
Thanks.
you need to shorten the servo rod ,once master cylinder is pulled carefully out of the way get someone to press brake pedal fully ,hold rod with thin nose pliers or similar as is only loosely clipped in and wind adjusting tip clockwise a couple of turns then retry
 
Make sure that the brake pedal is able to fully return to its metal stop - as if it doesn't, that's the main symptom.

BTW What vehicle is it & has it got ABS.
If it's a D2, there should be absolutely no need to adjust the servo outputrod. If it helps cure the problem, there's still a problem somewhere else !
 
Make sure that the brake pedal is able to fully return to its metal stop - as if it doesn't, that's the main symptom.

BTW What vehicle is it & has it got ABS.
If it's a D2, there should be absolutely no need to adjust the servo outputrod. If it helps cure the problem, there's still a problem somewhere else !
d2 is a common one with the issue of needing to adjust rod for new master cylinder
 
James, I think you've probably got a lot more practical experience of these vehicles than I have, but the way the D2 boosters & mastercylinders are designed & made, there should be no reason the booster needs to be adjusted to avoid jammed on brakes.
The booster outputrods were set in the factory to be compatible with any mastercylinder without additional adjustment - with a bit of extra leeway for component tolerances (I was part of the TRW engineering team).
The only reason I can think it would help is if something is physically holding the booster inputrod forward of where it should be (perhsps sticky or distorted pedalbox ?,)
 
James, I think you've probably got a lot more practical experience of these vehicles than I have, but the way the D2 boosters & mastercylinders are designed & made, there should be no reason the booster needs to be adjusted to avoid jammed on brakes.
The booster outputrods were set in the factory to be compatible with any mastercylinder without additional adjustment - with a bit of extra leeway for component tolerances (I was part of the TRW engineering team).
The only reason I can think it would help is if something is physically holding the booster inputrod forward of where it should be (perhsps sticky or distorted pedalbox ?,)
it never used to be an issue, it it something i find a good few times now when new master cylinders are fitted, tried new servos too still adjustments been necessary
 

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