Final RS Conversion Issue: Brakes!

[A1337STI]

Well after making many misteps (mostly all lack of research) My car is finally on the road and driving around. We need to install the phase 1 shift linkage so that 2nd is easier to get into , but that's pretty minor at this point.

my big issue is my pedal feel. its really bad compared to what it was, way harder pedal effort. but i can still lock the brakes. its not so much the increased effort that's bugging me, but its way way harder to modulate the brakes like i used to be able to .. maybe that's related to the increase in effort?


on my first attempt to assemble the brakes i put in one of the slider bolts (backwards?) and some how that was bowing the brake pads away from the rotor so it had almost no braking, now the rotors feel warped .. (not sure if that's playing into the above issue)



So my current master has .... 3 lines ?
This is my Current One

CENTRIC Part # 13047018 Base; Sedan; FWD; Standard trans.; Rear Drum brakes; Non-ABS; Fr 11/92 - To 8/93

http://www.rockauto.com/catalog/moreinfo.php?pk=1610934

So 3 Lines =\ seems like all the ones listed for a 99 have 2 or 4 ports. (i got the brakes off someone's 98 RS)

Uhm.... lil help ... hehehe

What should i do? what are my options now? to stay class legal i can Only use parts for an impreza 93-01 could be off a fwd or an awd...

hmm.. i'm so confused. i don't want ABS on my rally car but would an abs unit fix up my problem?

does a 93 base ( non abs, rear drum) have a different hard line setup compared to other imprezas (rs 2.5) ??

Confused and collecting no rally series points. boo

[Kevin M]

If you bypass the hill holder dealie underneath the fuel filter on top of the framerail, you really only have a two port MC, but you may have to get replacement lines to re-plumb for the part you bypass. I forget exactly what I did on my wagon to bypass it but if you stop by this week we can look at it and maybe figure it out.

You may need to fab up your own brake line system at this point. If that's not legal, you're just going to have to find out if you can get a big enough non-ABS MC to push your new, ABS-intended RS brakes around. Or go back to the single piston sliders and upgrade your pads.

[Kevin M]

Oh, and the drum vs. non-ABS rear discs will have the same plumbing in the back, but the proportioning valve under the hood may be different. Take a volunteer out somewhere you can do some lock-up testing to see which end locks first. Hopefully the front for what I would think are obvious reasons.

[A1337STI]

Brake lines may be rerouted, and Any Part may be updated / backdated with in the body style (restrictions on engines) so that's what I'm left with. I already bought brand new porterfield R4 pads for these brakes ... and you can lock up the brakes with the pedal now , its just a modulation / pedal effort (feel) issue ..

hmmf

would a bigger booster do anything ?

is the brake proportioning (thingy) built into the MC ?


Is it possible to also convert (or add in ) the missing ABS unit the biggest MC i've seen is 1 1/16 " but i believe it had 4 lines, where as my MC has 3 lines..

anyone know the number of lines out of the ABS unit?

[Kevin M]

Don't try to add ABS. It would be a ginormous pain in your ass. As for lockup, I was asking how your bias was affected. You should be able to lock up one end of the car before the other on pavement with average all season tires.

Luckily, since you can run your own brake lines, you don't need to add ABS. Just get the MC that matches your caliper setup (so stock RS) and run directly from A to B with an RS prop valve in the correct position. It's not part of the MC, it's the thing that appears to have no purpose on the passenger side shock tower, but has brake lines running to it.

Changing the booster will affect pedal feel but not anything about how they actually work. Basically the RS guys like to swap in an older, single stage booster over the newer 2 stage booster, but I would hold off on that until you have corrected your MC.

[A1337STI]

Is this what i need (basically) ? http://cgi.ebay.com/ebaymotors/ws/eB...em=#vi-content

where in the picture does the ABS control unit normally come into play? after the proportioning valve or before it ?
so is it normally MC >> proportioning valve >> ABS >> brakes ? so i can hopefully just run mc >. Valve >> brakes ?

[Kevin M]

Yeah, that's the prop valve. I'm not certain where it's plumbed in relative to the ABS unit, but probably after. Doesn't really matter though, since you won't be using one.

[A1337STI]

so i can just run 1 brake per line off that 4 line MC and everything will be good
(I'm guessing i have to match up the correct ones front and rears)

Sounds simple enough .. thanks I think that's what Tom was getting at. he just said "i can make that other MC work " referring to my 4 line unit..

[Kevin M]

I would just mimic the RS setup as closely as possible. IIRC, it's two lines from the MC to the ABS pump (FR/LR and FL/RR) which split into individual lines in the pump, with both rear lines running through the prop valve. But that's a guess going from memory.

[Kevin M]

I just remembered, I have an RS ABS unit in the garage. You can have it for $25 if you want, since I decided not to try to put ABS back in the wagon. Or if you want to just take a look at it to see how the lines route in and out of it, that's cool too. I'll bring it with me to the shop today.

[A1337STI]

sweet! ya i'll take a look at it and see what i need to do to get my brake feel back. probably won't make it into the shop until tomorrow @ lunch.

if i ran the ABS unit plumbing only, but no electrical would my brakes work normally with out abs? or would the brakes not work .. lol

[Kevin M]

It would work fine, but pulling and installing the OE lines from another car and putting them into yours is probably harder than fabbing some new ones yourself.

[A1337STI]

I think I'm class legal if i make new lines. i know there's some verbiage in there for going to steel braided lines, and rerouting lines.

[Kevin M]

Yeah, it's the "rerouting" phrasing that makes it legal. You can't "reroute" pre-bent lines...

[A1337STI]

so, AWESOME AWESOME Update.. I figured out the problem.

I went to the top of talus way (down hill) and rolled down at 15-25 braking down to 15 every time i hit 25, then coasting again. did that a few times, then i shut the motor off, no change in pedal feel.

something is up the booster! Tom.B helped me check it out and it was a collapsed hose..
So i've gone from unboosted and a lil spongy , to just a little spongy. feels like my brakes need to be bled at this point (though maybe a .9375 bore versus the 1.00 bore issue) either way i'm super happy with my car now.

amazing how brake pedal feel makes a huge difference in my overall impression of a car.

[cody]

Sweet!