using brakes = engine almost cutting out?

Ok so i have a 16v servo and mastercylinder conversion in the car, took the lot out of a mk2 and fitted straight into mk1 the bar the lot,
plumbed up ok no leaks.  Second, i have bogg bro manifold with r1 carbs, now the issue is when i press the brake pedal it almost hits the floor if i pump it it hardens up (need bleeding?) but worst is the enging almost cuts out whats happening?

Bleed it first, then see what happens. Could be many things, eg fuel system or a vacuum plumbing error.

Ok have bled the brakes, still the same when I push on the pedal it slowly sinks to the floor, if I pump it it goes hard but can here a sort of hiss then brakes go soft again, I assume servo is the issue, can this be fixed if it is

Here is the test for a servo:

Run engine, then turn engine off
Pump the brakes a number of times then hold your foot on the pedal
With your foot still on the brake pedal, start the engine

If the servo is working, the pedal should go down a little bit more.

Right I've done test as mentioned and my pedal does sink but it goes right down, like I say when I pump the brakes the idle almost dies, have bled brakes again just to make sure, any idea's suggestions?

whats the name of the box that attaches from the vacuum pump? the one with the diaphragm?

baggie said

whats the name of the box that attaches from the vacuum pump? the one with the diaphragm?

What engine? No petrol Mk1s have a vacuum pump except some USA and other ones but that's for emissions reasons not braking. Not sure on diesels though.

Really? ok what contains the Diaphragm for the fuel

paul_c said

baggie said

whats the name of the box that attaches from the vacuum pump? the one with the diaphragm?

What engine? No petrol Mk1s have a vacuum pump except some USA and other ones but that's for emissions reasons not braking. Not sure on diesels though.

I have a German one, but it should be the same as the UK one

just thought id point out, there a bleed nipple on the master cylinder (bit below where u put the fluid in) there can often be air trapped in here.

VW mechanic showed me a vacuum that was working but said the diaphragm housing was probably gone, will post a pic om Monday

baggie said

Really? ok what contains the Diaphragm for the fuel

What engine?

1.8 carb

If its similar to my old 1.6 carb Mk1 Golf, then there are no vacuum connections to the fuel system, the fuel lines are quite simple in that it went from fuel tank to fuel pump, to fuel vapour separator. From here, the fuel goes to the carb but also there's a return line (ie the vapour separator has 3 connections); and this return line tees into the carb's return line too.