Brake residual valves?

[svr]

Laying out my new brake plumbing and want to make sure my mind is thinking right. C4 calipers on all 4 corners, Mustang hydroboost mounted under the floor stock location, planning on a remote reservoir up on the fire wall well above the master. Question is do i need 2# residual valves in both front and back with the reservoir mounted up high? I have a Wilwood adjustable prop valve that both front and rear lines go through. Thoughts from brake specialists please. Thanks

[_Ogre]

yes. the residual pressure valves keep the lines from bleeding back into the master cylinder. less pedal travel to refill the lines. mine close to the mc

water has .42 psi per foot of rise, oil is lighter than water ~.37 psi per foot of rise. you'd need the reservoir 6 ft above the callipers to maintain 2 psi. most mc have a combo proportioning/residual valve in the system. i use 2 psi residual valves and the stock mustang hydroboost combo proportioning valve on my 58 truk and have great brakes

for the remote reservoir to match the mustang hydroboost/mc look for the nissan quest/mercury villager reservoir. get the fittings out of the mc too. i spent more on the 9/16'' teflon tubing than i did for the reservoir/fittings. the mustang tank pulls out of the mc, the adapter fittings push in the rubber seals. assuming your using the same 02 style hydroboost/mc i used

[svr]

Just checking myself again, the hose closest to the camera comes from the pump to the hydroboost, the middle hose is the return to the tank, and the far hose is from the hydroboost to the R&P, do i have it correct? Only other choice is to swap the 2 high pressure hoses.

[mr48chev]

The line with the clamp on it is the return line that I am positive of. the fittings are usually two different sizes on most power steering units.

[svr]

Thanks Ogre and Mr48, the hose closest to the camera has a larger fitting than the one farthest away, makes sense that it would be the in put line.

[BAM55]

It looks correct to me but verify with this illustration.

[svr]

Thanks Bam, pretty sure i have it right

[Erics51chevy]

Quick question. Dont mean to hijack. My hydroboost is under the floor. Its out of a 01 chevy silverado. Does that have a valve built in? I have disk brakes all around. Would i need one for the back?

[svr]

From what Ive learned, not gospel by any means. Anytime your master is equal or lower than your calipers you need the residual valves where everyou have disk brakes. Dont know about your hydroboost but my mustang one had a brass priority valve plumbed into the mustang system and it very well could have the residual valves in it also. That priority valve was set up for the mustang weight balance and system to make it work on the mustang and is not adjustable as far as i could determine. So all disk brakes need to have 2# residual valves to operate properly and the rear needs an adjustable priority valve to account for the weight difference in your particular system. So on mine i did away with the mustang priority vavle and am using 2# residual valves both front and rear and also an adjustable priority valve on the rear even though my master cylinder remote reservor will be up on the firewall, would much rather install them now rather than wishing i would have later. From what i have learned you are better to have them in there and not really need them than not have them and wish you did. Others more expert than me may pipe in and disagree but thats what i am doing.

[_Ogre]

fyi... i used the 03 mustang hydroboost/mc and the proportional valve that came with it from the junkyard
works fine

i was worried about it until i had the first 10k miles on it

[Coupeguy2001]

My master cyl and hydroboost is out of a 96 chevy dually, and I am using the 2 PSI valve for the front because the rear is serviced by the internal check valve in the master cylinder.
I recently replaced the master cylinder, and the new one also had the internal rear check valve installed in it from the factory.