Need help installing a new brake master cylinder

AmbroseM · Jun 5, 2023

Hi, this is one of my first posts so tell me if I'm in the wrong spot.

I have a 1989 Perentie 4x4 and I need to replace the brake master cylinder.
I've purchased a brand new one and now need to swap it over, my only questions are with the bleeding process.

When I'm installing the new master cylinder should I bench bleed it with a kit or is it possible to bolt it on and just bleed the brakes as usual (from furthest wheel to closest)?
and if bench bleeding is necessary could you please link a kit that would fit all three brake lines.

Thank you in advance

tottot · Jun 5, 2023

It is a good idea to get some fluid into the master before fitting, not so much bleeding it but just a slow pour of fluid into where the reservoir fits. What can happen if fitted dry is on first press of pedal piston sticks at the bottom of the bore and nothing will bleed.
Once fitted I gravity bleed, fill reservoir open furthest brake bleed and wait for fluid to run clear of bubbles. Keep topping up res and go around others in turn. [ do not re use catch fluid ] May take a couple of half presses of pedal to start flow. Repeat to eliminate any further air.
The Perentie 6x6 is an impressive truck. Is your 4x4 version ex military?

AmbroseM · Jun 5, 2023

tottot said:
It is a good idea to get some fluid into the master before fitting, not so much bleeding it but just a slow pour of fluid into where the reservoir fits. What can happen if fitted dry is on first press of pedal piston sticks at the bottom of the bore and nothing will bleed.
Once fitted I gravity bleed, fill reservoir open furthest brake bleed and wait for fluid to run clear of bubbles. Keep topping up res and go around others in turn. [ do not re use catch fluid ] May take a couple of half presses of pedal to start flow. Repeat to eliminate any further air.
The Perentie 6x6 is an impressive truck. Is your 4x4 version ex military?

Thanks for the tip.
And yes, Its an ex Australian Army FFR

KISSMYAURA · Sep 11, 2023

i never bothered bench bleeding myne, popped it on filled it up and bleed away as normal...

lynall · Sep 12, 2023

It is easier to remove the pedal box, as m/cyl bottom nut is a sod to get to.

dag019 · Sep 12, 2023

KISSMYAURA said:
i never bothered bench bleeding myne, popped it on filled it up and bleed away as normal...

That was my method as well, just fit it, fill it and bleed as normal.

Need help installing a new brake master cylinder

AmbroseM

New Member

tottot

Well-Known Member

AmbroseM

New Member

KISSMYAURA

Well-Known Member

lynall

Well-Known Member

dag019

Well-Known Member

Similar threads