Classic cars forum & vehicle restoration.

[Southernscouse]

Hi people I need help with my 1954 Devon van tried the vacuum method to bleed the brakes with no success so purchased a pressure system
While the air is connected I have a firm pedal but this fails when the air is off
I have run over a litre of fluid through the system and have no leaks
Is it pointing to a new master cylinder Cheers Tom

[ukdave2002]

Will it pump up (with the pedal)?

[Southernscouse]

It will pump up pressure but only if I do it fast enough will hold pressure if I keep pressing the pedal but if I release pressure is lost

[Ray White]

Hello SC. I don't think you need a fancy bleeder set up. All I have ever used is a simple rubber tube with the end blanked off and a slit near the end and a clean glass jar half filled with brake fluid. Make sure the master cylinder is full.

Starting with the wheel furthest from the master cylinder, fit the tube on the bleed nipple and the other end in the brake fluid. Crack open the bleed nipple and depress the brake pedal a few of times. When bubbles stop appearing in the jar tighten up the bleed nipple and go onto the next one. Make sure the master cylinder is kept topped up.

You can speed things up with a helper depressing the brake pedal but I usually do it by myself.

Hope this helps.

[ukdave2002]

[Southernscouse]

Now looking at my own replies I have bad feelings it?s pointing to a new master cylinder anyone have a good one laying around

[Southernscouse]

Now looking at my own replies I have bad feelings it?s pointing to a new master cylinder anyone have a good one laying around

[Southernscouse]

I am thinking I need a new master cylinder

[ukdave2002]

[Southernscouse]

Yes it holds pressure while it is under pressure but fails once released

[Southernscouse]

I have also tried using an assistant and also used a tube with a one way valve

[Southernscouse]

Reply for uk Dave
Can tell what a slow return valve looks like
It?s a1954 Devon van

[Southernscouse]

Reply for uk Dave
This slow return valve is it also called the recuperating seal
Before I spend big money I will get a seal kit and see what happens

[Rusty]

To diagnose it ,one would really have to feel it oneself, but if the fluid coming out is "air free" on all bleed points that could be a primary bucket worn. Sometimes they will hold pressure when pumping but let it off when pedal pressure decreases such as you are describing, and won't leak fluid through the secondary bucket out to atmosphere. Would need a new kit through the cylinder to fix it, but before you do that check for any other culprit, like ,maybe a brake light switch in a high position trapping air (I have seen it), or does it have a non standard fitting such as a booster that could need bleeding.

[Southernscouse]

The master cylinder is mounted on the chassis with the brake light switch on the end the reservoir is high on the bulkhead all standard no brake boost