Brake System/Pedal Help

[Jack92]

Hi Guys,

So, after loads of work on the rocco this lockdown I drove it out the garage today on our back road as a test and came across a problem I had forgotten about, the brakes.

Quick overview of the symptoms:
- If the engine is off and I pump the brake pedal it firms up ( still slightly soft but doesn't seem to drop at all while pushing the pedal)
- with the engine on the pedal drops to the floor as soon as any pressure is applied, the brakes work but require a lot of pressure to be applied to the pedal to have any affect. (the pedal does come back up when not on it)
- all pads have been replaced front and back (back are drums)
- handbrake works fine so I know there is no issue in the drums themselves.
- System has been bled twice and the rear lines replaced.

I firstly presumed master cylinder but thinking about it, wouldn't the pedal drop when its pumped with the engine off if this was the case?
My only other theory, which I really don't want it to be, is the servo?

What are peoples thoughts?
Thanks in advanced :)

[Jack92]

For anyone else who finds this on a forum search. The issue was indeed the master cylinder. Replaced it, bled the system up and jobs a goodern.

[mark1gls]

Good to hear it's sorted, I saw the post on facebook and mentioned I had a similar problem and a new brake master cylinder solved my problem.

[Jack92]

You did indeed you saying it made me decide to just buy it and see haha

Thanks buddy

[mark1gls]

Did you have problems bleeding the master cylinder?

Could not get the air out of the rear lines at the wheel cylinder bleed nipples, I had to bleed them from the master cylinder 1st then move to the rear.
I guess if you had a pressure type bleeder you wont have the same problem as pumping the brake pedal.

[Jack92]

Nah wasn’t to bad,
Pressure bled from the master cylinder through passenger front for the master. Then bled up as normal. Did have an issue with driver front but bleeding the old fashioned way on the pedal sorted it. Needed more pressure in the pipe lines than the kit would give me.