Plumbing hydroboost w/ manual steering

Has anyone installed the ford hydroboost with manual steering? I'm trying to figure out how to plumb the high pressure output from the HB that normally goes to the rack.

I'm not an expert but having installed a HB with PS I would imagine that you will have to install some kind of unit that mimic's the pressure drop in the PS rack, some kind of regulator.

The third low pressure line on the HB unit should T into the low pressure side of the above regulator device and then go to the PS pump reservoir low pressure return line.

My 2 cents worth.

That is what I was thinking Mike, I read someone mention a restrictor fitting but was hoping to get more details on that or a part number.

Also, for the front brake lines I was going to run them to a tee and then use a M10 -> M12 adapter to mate to the mustang prop. valve. Were you able to find a tee with the 10mm ports or did you just convert the lines to 3/16"? I haven't had much luck finding a metric tee.

I used a brass metric Tee, I think I got it from Autozone. If not search on line.

Tee can be seen in this pic.

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Any advantage to using the Mustang HB versus BMW HB? It looks shorter than the BMW unit.

Great.. thanks for the link. Anyone have a suggestion for the restrictor / regulator needed on the high pressure line?

I believe the BMW has a separate backup reservoir, Mustang is built in.
Perhaps a BMW user can chime in.

BMW HB lets you reuse the stock 951 master cylinder so your brake bias stays normal. With the Mustang one you have to use the Mustang master cylinder and run an adjustable rear brake proportioning valve if you track the car...

OK, found some more info on the web. Some have stated that the High Pressure out line from the hydroboost to steering rack (port 2 -> port 5) is under no/minimal pressure when the wheels are straight. In other words, it is basically a low pressure line until the steering rack is turned, at which point the rack creates a restriction and pressurizes the line. If you cut the rack out of the system, there is nothing to pressurize that line. Based on this, I can't see why you would need a restrictor or regulator between the high pressure out and the reservoir. I should be able to just tee this line into the low pressure return to the reservoir.

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Is it possible to block off the "high pressure" out port on the HB? Fluid return to the pump/reservoir would be via the low pressure line.
Must be a HB expert somewhere.

Hi,
After searching and searching I can't find any conclusive information about running of lines for a manual steering rack / hydroboost setup. I'll be the first to admit brakes aren't my strong suit... but the last thing I want to do is get it wrong...
I have a 1981 924 turbo with LS1 engine conversion;
GM P.S pump/res
GM PAS ,electronic power assist variable setup , stock manual rack
upgraded 4 pot brakes front / stock single pot rears.
stock 23mm brake master cylinder

I have these questions please if some one can help,
if I route the high pressure line design to go to rack through a cooler would this be enough of a drop or would a restrictor be required ? would it be better to run the restrictor pre cooler and any suggestions on size of the restrictor.
Or can I just block the rack outlet port and run the cooler pre hydroboost? Would a cooler even required? The car is going to be street driven but amongst some knarly hills, So overkill is ok too...
When people mention the mustang unit has more bias to the rears, is this because the mustangs ran bigger brakes in the back?
Can I used the stock M.C from a 931 on the BMW unit? or is there difference to the 944 unit?

I know, alot of questions, thanks if you can enlighten me,
regards
Stu

I've been running with this setup for over a year now.. no issues at all and lots of stopping power. Manual rack with Mustang hydroboost master cylinder and proportioning valve, GTO PS pump. I'm not using a restrictor or a PS cooler, and just street driving. Take the above diagram from the 04 mustang and just bypass the steering rack, that's how I routed it.

Legend,
Thx mate, was hoping it was that easy,
Stu