stluciascooby

I am removing the ABS system on my car and replacing it with a non abs master cylinder.
Can anyone tell me which ports go to which lines on the non abs master cylinder?
Should I keep the rear proportioning valve?
and any other tips.
Jon

911

Try this:
22B Bulletin Board: Removing ABS system
Graham.

stluciascooby

thanks
I read through sll the links but I can't find where the four outlets from the master cylinder go, I hope wallis will chime in here.
Jon

harvey

iTrader: (48)

Against my better judgement and because of space considerations, I removed the ABS and servo on my STi 6 Wagon and used a Pajero master cylinder.
A very bad move. With the bias valve removed the rear axle locked first and the pressure required to make the brakes effective meant I was standing out of the seat. The set up as I had it was dangerous IMHO. It may have been different if I had experimented with other master cylinders but the delay in the brakes becoming effective without the servo assistance and the effort required was unacceptable.

stluciascooby

I am using a type R non abs servo and master cylinder so hopefull it will work well. I just need to know what pipes go where.

There are four outlets the front one has a side port and a lower port that appears to be driven by the same portion of the actuator the same goes for the rear ports.

Jon

Kenny.S

There's a few pictures in my project thread 22B Bulletin Board: Project RA that might help.
I'm not 100% sure where the pipes go but i think the two on the side are for the front and the two on the bottom are the back, via the proportioning valve on the strut tower.
I'd be happy to do you a sketch but i'm not home till later this week, if you've not sussed it out by then let me know.


Kenny

911

I am going through the very same exercise on my ABS equiped Sti V3.

I want to got to basic brakes with the stock cylinder/servo (I know someone who did the same as Harvey and the car was a death trap..all because he had anti-lag)

you can remove the ABS/proportioning valve and re-pipe so the one half of the master goes to both fronts, rear master to both rears, but with a pressure proportioning valve in the rear line mannually adjusted (made by Tilton, about £80).

Job is done. I will try pulling the ABS fuse first to see what happens.
Graham

stluciascooby

A sketch would be great when you have time since the master cylinder has two rear outputs I guess I need the subaru prop valve since the tilton one is only one port?



Jon

911

The Tilton will tune the backs to the front, the fronts getting 100%, the rears need a lot less.

Kenny.S

I cant remember ever seeing a two port adjustable brake bias valve so i'm not sure what you would do with the other rear port if you used a single port bias valve, not sure if you could blank it off?
I imagine you'll be able to get hold of a Type-R or an RA prop valve without too much trouble, just need to phone round all the usual breakers.

ZEN Performance

The original setup uses a dual circuit master cylinder, with each circuit feeding one front and one rear wheel with a diagonal split. The non abs bias valve is a dual circuit one also.

A good way to plumb it, will be to swap the circuits so that the front is fed by one, and the rear from the second. Use the two outlets from the master cylinder on circuit "one" for the front brakes, then on the second circuit, block one port and take the remaining port to the rear via a bias valve, and T the line afterwards to go to the 2 rear calipers.

This keeps the 2 circuits independant, unlike just teeing the exiting rear brake lines.

Using the ABS master cylinder is sightly different as that only has one port on each circuit, so you need to tee out from it to the front calipers, and run the rear to the bias valve and so on. In my opinion the non ABS cylinder with the large round resevoir is better as it's a sealed unit with a diaphragm which doesn't vent to atmosphere, and should allow less water absorbtion, but how much less I really don't know.

Paul

911

I have the ABS system and my game plan is 2 fold:
1
Remove the abs block.
T the primary on the master to BOTH fronts
T the secondary on the master to BOTH rears

In the single line from the master to the rear T install a Tilton manually adjustable pressure valve to get the balance right by trial and error (sounds risky?). Rally cars are done this way.
Cost £100 plus a good morning of work/messing.

2
Get an RA master and bias valve and substitute it for the ABS master/bias/block currently on the car.
This way you get factory brakes as used on a fast dccd equiped car.

Cost? Possibly the same as above.

Graham.

(god I hope this dccd is worth it!)

ZEN Performance

I would go with the initial plan Graham.

911

Does that mean Option 1 above?
I've had so many initial plans this winter I've lost track!

MEF has said the same and cars I've scratch built in the past were exactly the same too.

Who sells the Tilton part cheapest?

2 months to go before it HAS to be ready.

Thanks Paul.

When is your Open Day. Would like to spend some time with your racer.

911

Bought a new Tilton off ebay last night for £37 delivered.
Just need to do it now, and no ABS/dccd worries.

Graham.