jss

I was just about to install the 5/33 valve on my s2 body car and there is no valve on mc or abs unit which I don't understand why

zerMATT951

My '86 951 doesn't have one either. I do know that the drivetrain and suspension were swapped from an '88 Turbo S w/ABS, but the ABS unit was not installed. I suppose it's possible that the bias valve was on that and they didn't think to move it over when the swap was done (previous owner). I've since bought a 5/33 and plan on installing it, but I haven't noticed any bias issues, even when making hot-laps at the track.

Do we know if these things are really necessary? Is it possible that with certain brake master and caliper combinations that it's not needed? I've got Turbo S "big blacks" on the front if that makes any difference.

Oddjob

5/18 bar units were stock on all Turbos and S2s, either on the MC for non-ABS cars or on the ABS pump. If you have something else on your car, it has been removed or changed by a previous owner.

jss

mine was removed and hardline swapped too. I was able to get correct hardline and installed the 5/33 so problem solved.

reno808

Was the car not braking properly?

jss

the missing bias valve was there when I bought car. I never drove it like that.
once I went to big brakes thats when I added the new valve and correct hardline.

zerMATT951

My car brakes fine, so I'm debating whether or not I need to install it. My suspension is stock Turbo S stuff (with 26.8mm & 18mm sway bars), which seems soft compared to my 924S, and I haven't noticed any late-brake oversteer on turn-in. Maybe it will show up more when I swap to rear coil-overs with stiffer springs all the way around.

I'm really wondering if I need it, or if my caliper combination doesn't require it?

reno808

I wouldnt add it if i were you. I would touch it if you fee like you need it.

jss

if you have turbo S brakes then you do not have big blacks. most call those med blacks from a turbo s.
if it was my car I would run a stock valve forsure. if you have no abs then mount it on the master cylinder area like oem.

helpful picture
http://www.968cs.de/Fahrwerk_Umbau/Bilder/M030(17).jpg

zerMATT951

Thanks for the clarification. You're correct, mine are the Turbo S or 928 "S4" brakes, and they are the medium sized caliper in the photo that uses 304mm rotors.

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