Vacuum Brake Servo

[Pembo]

Sounds good, I might have a go at this since I'm scrapping my B4 and have the parts available. I'll attempt to convert to an electric PAS pump as well and get rid of the mechanical pump up front. I like the idea of having an active speed controller on the pump so it doesn't run flat out continuously. I have some homework to do on this

I'd like to go down the electric power steering pump option next too. I would like to fit the VW SEAT SKODA AUDI pump XXX 423 156 X I have the schematics but need to know which would be the input for a speed sensitive pump. Quite happy for it to run in the 'slow' pump (high road speed mode) all of the time. Has anyone got info on this modification?

[Pat D]

Just enough room, as always under the bonnet of these cars. Be prepared for some very neat and tide brake pipe installation. Having a roll of copper brake pipe and a GOOD flaring tool makes life a lot easier. Rip all the old pipes out and put new in. Cover them with silicone tubing for a top job keeping them insulated for the heat of the engine. I've also fitted a heat shield below the master cylinder to protect it from the exhaust side of the engine.

Sounds good, I might have a go at this since I'm scrapping my B4 and have the parts available. I'll attempt to convert to an electric PAS pump as well and get rid of the mechanical pump up front. I like the idea of having an active speed controller on the pump so it doesn't run flat out continuously. I have some homework to do on this

[AndyP]

Any pics of your engine bay?

[Pembo]

Just enough room, as always under the bonnet of these cars. Be prepared for some very neat and tide brake pipe installation. Having a roll of copper brake pipe and a GOOD flaring tool makes life a lot easier. Rip all the old pipes out and put new in. Cover them with silicone tubing for a top job keeping them insulated for the heat of the engine. I've also fitted a heat shield below the master cylinder to protect it from the exhaust side of the engine.

[Error404]

Not fitted mine yet but James (RE2500) has the same unit in his 10v coupe with an ABY fitted and no problems AFAIK

[AndyP]

I have a 10v / 2.0 16v unit waiting to go on my car.

The p/n is 8A2 612 105 A

Have you tried fitting this yet? Are you sure there's room for it?

[Kieron20V]

I used 7A master cylinder on mine, with servo off a 10v. straight fit.

[Error404]

I have a 10v / 2.0 16v unit waiting to go on my car.
My 20v MC which is the same as an S2 one is a straight fit as Pembo says.

The p/n is 8A2 612 105 A

[Pembo]

Currently using a 7A master cylinder which 'looks' physically larger but not too sure of piston/seal sizes. I run RS2 big reds calipers on the front and Cayman S 4 pot calipers on the rear. Hydraulic handbrake too and all is sweet. No ABS, No bomb just servo which came off a 10v n/a quattro but load available to chose from. Great pedal no fade and I use Castrol SRF Racing fluid.

http://www.facebook.com/alan.pemberton.127/photos_albums

[AndyP]

I run vacuum servo on the rally car. Just run the vacuum pipe , with a one way valve which is usually fitted in the 'hard' tube, to a 'T' on the intake. I did have a 12v electric vacuum pump but did away with that. To be sure you can fit a vacuum gauge too! No 'bomb' either to great brakes. Master cylinder fits to the servo perfectly. PM me if you want further details.

Which master cylinder did you use?

[Pembo]

I run vacuum servo on the rally car. Just run the vacuum pipe , with a one way valve which is usually fitted in the 'hard' tube, to a 'T' on the intake. I did have a 12v electric vacuum pump but did away with that. To be sure you can fit a vacuum gauge too! No 'bomb' either to great brakes. Master cylinder fits to the servo perfectly. PM me if you want further details.

[Error404]

I don't think there will be any issues Pat. RE2500 on the forum has done this on his RHD car with an ABY fitted and don't think he has any problems.
With what you're going to be running I would just make sure you have a good heat shield for the master cylinder

[Pat D]

Has anyone gone and fit a vacuum brake set up? I'm wondering if the master cylinder sticking out further would cause any dramas or make a tight fit for other items?

[Error404]

thats how I'd seen it done before

I promised myself I'd go to vacuum brake assist and electric PAS pump the next time my servo went bad since new servos are not affordable and there is a limit to the life span of used ones.. I've done a quite a bit of research into the PAS side of things so good to hear that the vacuum end isn't too much of a PITA

[siV6Qcoupe]

You remove the pistons and springs under the large cross-head screws on the front of the PS pump so that it does not generate pressure to the brake system. Remove the bomb and hydraulic lines and close off the return at the steering rack and bung the feed to the bomb. Replace the brake actuator with one from an Audi 80 B3/B4 with a matching MS - all a direct fit onto the bulkhead and run a large vacuum line with one-way valve from the inlet manifold to the vacuum actuator.