Brake fade Help

[WeekendMechanic]

My brakes do not feel assisted when braking I replaced the master cylinder but it remained the same also checked all vacuum lines for leaks but nothing,it is either the booster or the vacuum pump I tried disconnecting other vacuum pipes in order to feed the booster directly and there was some improvement but mind you nothing dramatic.
My question is how much suction is the vacuum pump supposed to have I can put my finger on the outlet and it will suck it but i can take my finger off fairly easy,is it the pump or should i replace that or the booster?

[VW BUSH]

Which vac pump?

[tweed]

Hold up. Whats the problem?

You getting brake fade so brakes work.

If its not assisted then the pedal would be hard!

When I got my abf the brakes didnt feel too great. I bleed them twice. I could stamp on the pedal but wouldn't get a bite. So we got a new master cylinder and it was the same. So I decided to get new pads and after wearing them in I jumped on the pedal and almost went through the screen!!

So describe your problem and it will be easier to help.

[tweed]

And if you have a air leak to the brake servo the car will idle over 1200rpm

[VW BUSH]

And if you have a air leak to the brake servo the car will idle over 1200rpm

Good point

[Bellend]

Guys, remember this is a diesel, give it all the air in the world and it won't rev up.

Explain what you are thinking is brake fade?

[WeekendMechanic]

The brakes work but pedal is hard, there is no bite in the brakes,I tried replacing the brake pads also with original vw ones but it had no effect either, check valves are all ok no leaks anywhere, i connected the vacuum line directly to the servo and there was improvement with assistance but how do you tell where the problem is?

[gasketface]

if you run the car for 30 secs and then disconnect vacuum pipe from servo do you get a whoosh sound ?.If not your servo is leaking.

[WeekendMechanic]

if you run the car for 30 secs and then disconnect vacuum pipe from servo do you get a whoosh sound ?.If not your servo is leaking.

Yes there is a vacuum in the servo and its being held

[WeekendMechanic]

Ok a wierd thing just happened yesterday,while I was waiting for a mate,I started applying pressure to the pedal and pushed it all the way down from frustration of my brakes,and as my mate came in and I left, the brakes were ok there not 100% but id say that from from 30 % they jumped to 70% just buy pushing the pedal down 5 times slow and hard.
This got me thinking did my proportioning valve open up was it blocked?