location of brake proportioning valve on 1983 930

[mickster8888]

i'm installing an adjustable proportioning valve and was wondering where the stock one is so i can intercept brake lines and run to location of new valve. thanks in advance, mick

[proffighter]

There is no valve at a 930 brake system (at least never saw one)... If then it would be beside the brake booster before line goes down at the smugglers box

[totle]

Mine is installed as Roland describes, down in the smugglers box by the steering shaft

[JFairman]

Most cars have them to reduce the hydraulic pressure going to the rear brakes. It's usually set conservative by default so the rear brakes don't lock up easily on wet roads resulting in loss of control.

[mickster8888]

thanks for the info guys. i don't have one on my grey market 930. the brake line that goes to the rear brake circuit is the port to rear on the master cylinder? just want to be sure i install the adj. p/v in the rear circuit.

[proffighter]

A pic says more than bla bla bla...

[mickster8888]

my car definately does not have that. at least now i know the identity of the rear line.

[fredmeister]

Since you asked for placement of an adjusatble valve....I assume you intend to play with it for some reason. Racing or track days in the rain?

Anyway, I had one from Tilton installed in the passenger side front compartment in my 911SC that I used to own, down by the shift linkage going thru the side of the center tunnel.

It tied into the rear brake line that runs thru the tunnel. It was used to reduce the rear line pressure and had no effect on the front pressure or overall brake pressure coming out of the MC.

I never messed with it much to be honest, as the brake caliper pistons are sized accordingly from the factory to provide enuff front bias so that rear almost never lock before the fronts.....unless things were really out of balance like driving in the rain on track tires.

Be sure you need to do this before dumping money in this device is all I am suggesting.

Fred

[mickster8888]

fredmeister, thanks for the comment. i installed mine in basiacally the same location and ran lines forward to where master cylinder is. i left the lines disconnected as i was going to have shop flush fluid for track event. i use the castrol srf and just figure while they were at it they could just disconnect the rear circuit at master cylinder and connct one line to master cylinder and other to line which was removed from mc. i even had the correct adapters so all they had to do was connect everything. my mechanic told me that the proportioning valve would need to be relocated to somewhere near mc for bleeding purposes. does this sound right? could he just crak the fitting at the pv to bleed? anyone please chime in.

[fredmeister]

Its hard to say without seeing which valve you are installing but my experience is that once the valve is installed there is no bleeder screw or anything on it. Its just another "fitting" in the line so the intial bleed after you install it might be more difficult but once the air is out of the valve subsequent brake bleeds are not effected.
I hope that makes sense....the short answer is NO--- install it where you can reach it in the passenger footwell easily. the whole idea is you want to be able to reach over and make adjustments on the track or if thats not safe to do at least in the pit lane and then run back on track.


Fred

[mickster8888]

fredmeister, thanks. i had the mechanic install it with no bleeding problems. did a de the next day and fine tuned it. it worked beautifully.