master cylinder

[mwspit1500]

hi

i have fitted a Fiat Punto master cylinder, i've bled the brakes and is no air in the system, test drove and the brakes are rubbish,

 

do i have the pipes in the right place?

Mark 

 

Edited August 5, 2019 by mwspit1500

[richyb66]

Probably, what bore is it and what calipers / drums are your running? 

[theduck]

In what way are they rubbish? What is the rest of the brake setup? Does the punto master cylinder have a suitable bore size for the rest of the setup?

[mwspit1500]

bore size is  20.6 mm, all standard ford sierra brakes, discs front and drums on the rear, the peddle is solid, but when i brake its like they have brake fade, 

mark 

[theduck]

Slightly smaller than the sierra one then, so should be better, but possibly still a little on the large size.  If you are only used to driving cars with servo assisted brakes it will be quite a shock to the system to drive a servo-less setup - I am assuming you dont have a servo?  They will take a lot more leg effort to work, but should be able to lock the wheels.

[mwspit1500]

my old setup was servo-less, i've done some research  and i have probably got some air in the master cylinder, i didn't fit a bleed nipple to it just a pipe with some solider in the end, i'm just unsure if the pipes are in the right holes.

mark  

[Longboarder]

They are usually shown as the pic below. Split system, tandem pistons, pressure reducers? on rears. Intended connections are one front and one rear to each piston and thus equal displacement for each piston (near as makes no odds). You have one piston working two disc calipers for the fronts (lots of fluid) and one piston working two drum slaves for the rears (little fluid). When the piston currently feeding the rears has shifted its fluid and the rear brakes are hard on both pistons stop. Quickest check for this is swap the rear and one front connector on the master cylinder and bleed then try the brakes. Volumes each piston needs to shift would be closer but not equal so watch out for uneven braking, pull to one side etc, but I would hope more effective braking. Don't know if you need to use the reducers or not. First try without but be careful.

If so then I would re-plumb with the pressure reducers going to the rears as indicated so the MC works as intended. Yes you would need two lines to the rears. Benefit is the safety of a genuine split system.

Edited August 5, 2019 by Longboarder

[mwspit1500]

hi Longboarder

that's excellent, i've got them the  wrong  way, i'll will try the other way see how it goes.

cheers

mark