Vacuum Brake Servo

[Pat D]

I have few questions in regards to the brake bomb and high pressure lines, hopefully someone might know the answers.

1. Is the high pressure line from the PAS pump to the steering rack a different pressure to the one going to the bomb? Hence two separate pump outputs?

2. Can the bomb be deleted all together if there is no need for assist in the event of the engine not running and just run the high pressure line direct to the master cylinder?

Reason I ask is that I would like to use an electric PAS pump without Vacuum servo brake assist, since the electric pump can run with the engine off there is no need for accumulated assist.

[AndyP]

Is this an earlier S2? I just had a look at the size of my vacuum servo on the B4 and it looks like it won't fit as my S2 has braces welded from the strut tower to the firewall on my S2 which are right in the way of where the servo will sit

This car wasn't an S2, it was a coupe quattro with an ABY engine conversion, so the S2 strut brace will need modification.

[Pat D]

Just found this pic in his build thread, looks tight!

Is this an earlier S2? I just had a look at the size of my vacuum servo on the B4 and it looks like it won't fit as my S2 has braces welded from the strut tower to the firewall on my S2 which are right in the way of where the servo will sit

[Pat D]

Just use the AC pipe off the car where the servo came from?

[Error404]

yup we had a chat about that at ADI, I think that's the only bit that will need to be majorly modified i think

[rj scotty]

There is an A/C pipe runs in that area to the drier in the right hand wheel arch. If the servo is going to foul anything it WILL be that.

[Error404]

Just found this pic in his build thread, looks tight!

Thats loads of room by Audi standards

[A80Avant]

Easier with a reverse manifold

sent with Nokia 5110

[AndyP]

Just found this pic in his build thread, looks tight!

[AndyP]

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

Right, it'd better fit, I've just bought one

[Pat D]

It would'nt be too hard to control a pump without a speed input. A 12v high current PWM can be controlled by most after market ECU's that have spare PWM outputs, and you could have full control over the pump according to road speed and any other variables.

[Pembo]

Tonks has done it on his 80 two door but I dont think this has been tested on the road yet.

I think I need a 100% tried and tested solution. Can't afford a failure at pace on a stage. Neither can any one us for that matter! I know an MR2 has a speed input but have not seen a pump in the flesh. I'm there must be a solution.
This post seem to have changed subject! Can we start another thread to keep track of solutions please?

[Pat D]

I can get a Mazda 3 or Holdan Astra pump fairly cheap here, so I'll try one of these out. Looks like it would sit nicely where the original reservoir is. Pembo keep us updated on how you go with yours. I'd rather wait till I sit my engine in the bay before routing new lines, but I might have a go if I find a suitable pump in the meantime.

[URquattroGus]

Why did they bother with this system inthe first place FFS? Lots of extra engineering and extra cost for no gain.

[robo]

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?

Tonks has done it on his 80 two door but I dont think this has been tested on the road yet.