Early and late brake differences

[EnthusiastOwned 7]

Hey all,

I'm trying to get my head around the early and late VR6 brake differences. I'm specifically looking at the ABS set up and the servo/MC.

I believe in 1995 VW ditched the rear brake compensator, ABS position sensor from the servo and changed the MC to a larger alloy type which is flat facing compared to the earlier which had the 45degree face.

Am I correct in saying the the early MC is 23mm and the late 24mm? What about the servos did they change in size?

Also, are the late servos and MC's the same as Mk4's?

Apologies for the 20 questions, in short I have all the late brake gubbins from a 1997 VR I'm breaking and I have the early set up on my current car. Knowing that the early stuff isn't as good a feel as the late brakes and that the early MC is now obsolete from VW; changing to the later brake types would be worth while in my opinion.

I understand it's probably more hassle than it's worth but my dash and engine will be coming out for a new head, gearbox and OBDII parts so whilst everything is all accessible It won't be as hard as it could be.

Thanks

[legvw 0]

Yes the abs systems are slightly different, the load compensator was removed, the front brakes were upgraded to larger 288mm discs and diff calipers to suit, not sure on the master cylinder size.

The only real difference I've noticed is the front brakes.

[Lukey. 381]

The abs system went from teves 4 to teves 20. The newer one is much better system

[EnthusiastOwned 7]

The abs system went from teves 4 to teves 20. The newer one is much better system

Interesting. So what's the main differences?

[Lukey. 381]

well theres the electronic brake proportioning system, negating the need for a rear beam valve, it has (a form, and capability) of traction control component, though on the VR6 it is only really ice traction via its acceleration switch, it weighs half as much, it has an electronic switch on the brake pedal in addition to the other components in order to react in the fastest time possible.

It is probably the most commonly used ABS system still

[EnthusiastOwned 7]

Brilliant!

The brake switch, is that literally the switch which the brake pedal pushes, similar to those in earlier VW's which controls the brake lights?

Accelerator switch.. Part of the TB? Or..?

And, you know it was coming... What would be required to upgrade to the later ABS. Off the top of my head, ABS unit (ECU is part of this if I'm right?) full wiring loom, all four ABS sensors, going from the above the brake pedal switch. Anything else?

[Lukey. 381]

Acceleration switch is 3 mercury switch G meters in each dimension of travel, I don't know what would be required to convert from 4 to 20 but I would hazard a guess you'd need the OBD2 loom. This information I gave is what I came across when trouble shooting my own ABS issues, but mine is a late OBD2 so i don't know what would be different to the early system, whether it's just the newer pump and ecu with a couple of sensors or much more elaborate

[EnthusiastOwned 7]

Thanks for the reply.

Well I've stripper the ABS loom from the car, well most if it and it doesn't fasten to the fuse box directly, but has a few wires going to a contact board instead.

You've been a hero already, but you wouldn't happen to know where these acceleration g-switches switches are?

[Lukey. 381]

They are within the unit

[EnthusiastOwned 7]

They are within the unit

ABS unit?

that makes sense!

Just been going over the loom and the ABS loom literally goes from the ABS unit, to all for ABS sensors on the wheels, to x2 separate fuses which clip on top of the fuse box, an earth, x2 battery live feeds and then there are a few wires which go to a crossover style board. From what I can see there is one which goes to an earth crossover, one for the brake pedal switch crossover and one for ignition on.

And that's the loom really.

So I'd presume that the earth and ignition crossover's get activated on a turn key and the brake pedal crossover which will activate the ABS when the brake switch is pressed. Or something along those lines.

thanks a lot for your help Lukey. much appreciated

[Lukey. 381]

Sounds like it should all be there, you have to make sure that the abs unit is installed perfectly square level because of these 3 mercury switches and you'll have to re pipe at the rear to bypass the proportioning valve, don't know how it incorporates into the OBD2 port for scanning/fault finding though, also for self testing on startup with the orange abs light

[EnthusiastOwned 7]

Good point about the ABS light. I'll have another look at the loom before it all gets stripped.

If I manage to get round to fitting it all and getting it working I'll be doing a how to anyway.

Thanks for all your help

[VR6Pete 1,455]

I think FishWick has done a complete transplant in his corrado with the later setup and ditched the compensator valve etc...

[EnthusiastOwned 7]

Fishwick!?

What hasn't he done!

I want to be his prodigy.