Hydroboost retrofits?

[gsxrken]

Some searching has taught me that older continentals and newer 4.6L powered mustangs used hydroboost assist for power brakes.
I am interested in going this route myself. I have a manual TCP rack setup, but I still have my original PS pump and brackets that I could use strictly for the hydroboost.
Will the stock pump be too much or too little for the hydroboost?
What else do I need to do besides buy a late-model mustang setup and run a return and pressure line from my pump?

 

[rbohm]

you need to have powering steering with the hydroboost. not just the pump.

 

[gsxrken]

RBHOM, can you elaborate on that? I'm wondering how it can matter to the hydroboost unit whether it is fed/teed from the pressure line or (in my case) is the only thing on the pressure line. I have an inquiry into hydratech as well.

 

[rbohm]

the hydroboost unit has two outlets, one to the power steering gear, and one to the pump(return line). the unit is balanced for use with power steering.

 

[reenmachine]

Why do you want to run hydroboost? Unless you have little vacuum or don't have the space for a vac booster for some reason, it's just more complexity, more fluid lines to leak, more expense, and a horsepower-robbing pump.

 

[mdjay]

Pete gives a good point.

Howver, you could still run it without the ps pump. Although you may have to run the Heidt's flow limiter so it doesn't get too much flow/pressure.

 

[gsxrken]

Why do you want to run hydroboost? Unless you have little vacuum or don't have the space for a vac booster for some reason, it's just more complexity, more fluid lines to leak, more expense, and a horsepower-robbing pump.

I agree with you. But with my 10" vacuum, even with a comp cams vac cannister, my rock hard pedal will not lock my brakes up. After I have been underway and generated a little vacuum, I get a halfway decent power- assisted application of the brakes, but if I really want to stand on it from there, it is not linear to the effort applied, and again no chance I could lock them. (Not that I want to lock them, but it would demonstrate that I can generate at least that much PSI in the system to at least one wheel.)

I would love to suspect my original undisturbed distribution block and prop valve. In fact, the brake light is on due to the shuttle valve switch on the block. But searches here and elsewhere seem to rule them out, and that that shuttle is for the warning light on the dash only and would not affect the brakes themselves. Contrary opinions welcome!

 

[rbohm]

Pete gives a good point.

Howver, you could still run it without the ps pump. Although you may have to run the Heidt's flow limiter so it doesn't get too much flow/pressure.

thats interesting, run hydroboost(requires pressure from the power steering pump) without the power steering pump. makes for a very hard pedal.

if you dont want to run powersteering, then you can always use an electric vacuum pump. gm put them on a number of oldsmobiles and cadillacs starting in the mid 80's. look for olds with the diesel engine as they will have the electric vacuum pump.

 

[Hack]

I agree with you. But with my 10" vacuum, even with a comp cams vac cannister, my rock hard pedal will not lock my brakes up. After I have been underway and generated a little vacuum, I get a halfway decent power- assisted application of the brakes, but if I really want to stand on it from there, it is not linear to the effort applied, and again no chance I could lock them. (Not that I want to lock them, but it would demonstrate that I can generate at least that much PSI in the system to at least one wheel.)

I would love to suspect my original undisturbed distribution block and prop valve. In fact, the brake light is on due to the shuttle valve switch on the block. But searches here and elsewhere seem to rule them out, and that that shuttle is for the warning light on the dash only and would not affect the brakes themselves. Contrary opinions welcome!

Don't drive the car with the brake light on! Generally that means either the front two or the rear two brakes aren't working at all. You have something seriously wrong with your brakes, probably a wheel cylinder is leaking or a line is broken.

How recently have you maintained the brakes? If it's been a while, you should have someone check them for you or get someone to help you go through them. Your stock system will most likely work pretty well once you fix it. You will certainly be able to lock up the brakes.

 

[mdjay]

rbohm Agreed on the elec vacuum booster. If you're running a ps pump and it doesn't have to supply the steering, that means everything would go to the hydro brakes. Depending on the pump, this could make very touchy brakes and could be moderated with a flow limiter!

 

[gsxrken]

Don't drive the car with the brake light on! Generally that means either the front two or the rear two brakes aren't working at all. You have something seriously wrong with your brakes, probably a wheel cylinder is leaking or a line is broken.

How recently have you maintained the brakes? If it's been a while, you should have someone check them for you or get someone to help you go through them. Your stock system will most likely work pretty well once you fix it. You will certainly be able to lock up the brakes.

My entire system is brand new (booster, M/C, lines, hoses, calipers, wheel cylinders, drums/discs, and hardware) WITH THE EXCEPTION of my distribution block and proportioning valve. I have bled the lines many times, and do get a stream of fluid out of each of corner. I have not, however, been able to get the warning light on the dash to go out, which indicates that the shuttle valve inside the distribution block is not centered. The manual says to crack one of the rear lines on the dist block and slowly press the pedal until the light goes out, then snug up the line, and then try the same thing on the front line if the light did not go out yet. This does not work for me, so I assume that my shuttle valve is seized in the dist block bore. I also ASSume, however, that since I get fluid from every corner, that nothing is “blocked”.

 

[gsxrken]

rbohm Agreed on the elec vacuum booster. If you're running a ps pump and it doesn't have to supply the steering, that means everything would go to the hydro brakes. Depending on the pump, this could make very touchy brakes and could be moderated with a flow limiter!

Reply from Hydrotech:
Hi Ken,
" QUOTE: "Can I run your hydroboost from my original PS pump even though I now have a manual rack? In other words, the only thing the pump will be for is the brakes?"
Yes - no problem... How? Simple: The second high pressure line that normally would run from the brake assist unit to the steering will instead be diverted back to the ps pump reservoir unused. Note that this would require that you install a dedicated AN-6 male nipple / fitting / bung to the existing ps reservoir, as this will be a higher flowing line that must be securely dumped back unused to the reservoir..."

http://www.hydratechbraking.com/forums/viewtopic.php?t=51

Paul M. Clark
Hydratech Braking Systems
www.hydroboost.com
[email protected]
(586) 531-2115
(586) 427-6970

 

[reenmachine]

Paul at Hydratech really knows his stuff. I have dealt with him a lot in the past and I trust his reply.

The downside of the Heidt's flow-limiter valve is that by its very nature (a restriction) it heats the fluid.

Here's a wild idea -- consider manual brakes. With modern 4-wheel discs, the right pedal, and the right master cylinder (bore size appropriate for whatever calipers you're using) you can far exceed the performance of stock power brakes. For what you'd spend on the hydroboost, pump, etc. you could have killer 4-wheel manual discs and the very minimum of complexity.

 

[Hack]

My entire system is brand new (booster, M/C, lines, hoses, calipers, wheel cylinders, drums/discs, and hardware) WITH THE EXCEPTION of my distribution block and proportioning valve. I have bled the lines many times, and do get a stream of fluid out of each of corner. I have not, however, been able to get the warning light on the dash to go out, which indicates that the shuttle valve inside the distribution block is not centered. The manual says to crack one of the rear lines on the dist block and slowly press the pedal until the light goes out, then snug up the line, and then try the same thing on the front line if the light did not go out yet. This does not work for me, so I assume that my shuttle valve is seized in the dist block bore. I also ASSume, however, that since I get fluid from every corner, that nothing is “blocked”.

If you have a high, hard pedal and all four brakes work when you press the pedal everything should be ok. If it were me I would replace the distribution block if that is the source of the dash light, though.

 

[Hack]

snip

Here's a wild idea -- consider manual brakes. With modern 4-wheel discs, the right pedal, and the right master cylinder (bore size appropriate for whatever calipers you're using) you can far exceed the performance of stock power brakes. For what you'd spend on the hydroboost, pump, etc. you could have killer 4-wheel manual discs and the very minimum of complexity.

I love my manual brakes and they are just Granada front disc brakes. I bet the modern ones rock, especially with 4 wheels!

 

[Rusty67]

Take the distrobution block OUT. Just put a T section to the front and a coupler to the rear lines. I can't tell you how much pain and hurt that stupid stock distro block has caused me in the past. It doesn't have any valves in it so all it does is trip the warning light and and direct fluid flow.

My problem was a stuck pin that had shut off all fluid flow to the rear brakes. I had so many experts telling me the problem was with everything else and when I brought up the block they all laughed it off. Shoulda went with my gut instincts. That dumb block causes more harm then good IMHO. Toss it.

 

[19stang68]

Brake Light on

Hi gsxrken,

Finally something I can answer... I just went through this same thing a few weeks ago where the BRAKE light would not go out. I followed the same instructions that you did with the same results that you had. Then my mechanic across the street helped me get it squared away. First, when they say 'cracked' they mean just barely cracked. Fluid will barely seep out when you put you foot on the brake. Second. you need two people. The person in the car needs to have the ignition in the "on" position and needs to keep an eagle eye on the BRAKE light - don't blink. Then he needs to VVVVEEEERRRYYY slowly press on the brake pedal. The instant the light goes out he needs to STOP pressing the brake and hold it there - do not move. Then the person under the hood needs to tighten the line up. If this doesn't work, crack the brake line on the other side of the dual cylinder and try again as the valve may have slid to the other side. It worked for me. And you should keep the distribution block / brake warning system as it will let you know if you ever do have a failure.

Craig

 

[Rusty67]

Honestly, it would be a nice saftey feature if I believed it would ever work properly but I think you can feel it in the pedal when there is a problem that would trip the shutoff slide pin all the way. I'm just gonna wire the brake light up as a parking brake warning light.

 

[mustangdave]

I would definitely keep the light: I had a line get a small cut in it on a four-lane highway. I barely touched the brake to lower my speed and the light came on. I proceeded to stop and by the time I got off the road, I had no brake pedal! I finally stopped with the e brake. If it weren't for the warning light, I wouldn't have known there was a problem until I needed to stop in a hurry.
If the above method doesn't work, you can take the line loose at the top of the block and center it with a screwdriver. It is common for them to go off center during a major brake job/bleeding process like you did.

 

[bnickel]

if the shuttle valve is stuck you can actually free it up by lightly tapping on the dist. block and then follow the procedure described by 19stang68. it does take 2 people to do this as he said. the procedure is actually very similar to bleeding the brakes.