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I'm looking for someone who may know something about the Hydro-Boost brake system. I have a 1964 F250 cab and chassis with a camper built on the back. Currently I have a single 7" booster with the master cylinder. About 10 years ago I swapped out the old 292 Y block and granny 4-speed for a 460 EFI and ZF5 manual transmission with overdrive from a 1989 F250. I have replaced the rear axle with a dually Sterling 10.25 from a 1985 F350. I replaced the front drum brakes with an eight-bolt disk brake setup. My trouble is that my braking still sucks. The rig I have weighs 9200 lbs.
I was originally going to convert the rear axle from drum to disk brakes. After talking to several people, they said I would be better off if I could find a way to use a Hydro-Boost brake system instead of going with the rear disks. They thought that with the weight of the camper and the size of the booster I just didn't have enough pressure to ever get good brakes. Most of the larger trucks and diesels use the hydro-boost brakes for better pressure and lack of vacuum.
I picked up a Hydro-boost setup from a 1999 F350 with a 7.3 including power steering pump and all the hoses. The Hydro-boost has a high-pressure inlet port from the power steering pump. A high-pressure outlet port to the steering gear box and a return line. My question is can I plug the high-pressure outlet port, and will the brakes work with just the High-pressure inlet and the return line, or do I have the run a line to a power steering gear box? I do not have power steering on the truck. I am using the foot pedal assembly from the 1989 because I needed to use a hydraulic clutch. My 1964 F250 straight axle camper. 460 EFI -- ZF5 five speed with overdrive manual transmission -- Power front disk brakes -- 10.25" Sterling rear end with 4.10 gear ratio, dual tires from a 1985 F350.
You can’t really run a Hydro‑Boost as a stand‑alone unit with the outlet capped. The booster isn’t just a pressure‑in/pressure‑out can; it’s a flow‑through hydraulic device that expects a full circuit from the pump, through the booster, through a steering gear, and back to the reservoir. That constant flow path is what keeps the pump from dead‑heading and what lets the internal spool valve in the Hydro‑Boost cycle the way it’s supposed to. If you plug the outlet, the pump has nowhere to send flow, and that’s when you get heat, pressure spikes, and a booster that doesn’t behave the way it should.
If the truck doesn’t have power steering, you either add a steering gear to complete the loop or you engineer some kind of bypass block that mimics the restriction of a steering gear. That’s been done in industrial setups, but it’s not something you just bolt on from a parts store. The only other alternative is going back to a vacuum booster, but on a 9,000‑plus‑pound camper rig, that’s asking a lot from a single 7‑inch diaphragm. Hydro‑Boost is the right direction for that weight, it just needs the full hydraulic circuit to work the way it was designed.
A big thanks to you for answering my question to TA455HO and KULTULZ. Thanks for all the knowledge that you are spreading around. I was hoping that I could run the Hydro-boost as a stand-alone unit, but I had my doubts about it. No harm in asking. I guess that it's another trip to the junkyard to get the steering gear off the other truck. It also had a power steering cooler. I might just as well grab that at the same time.
Last edited by gcooter; Apr 1, 2026 at 09:26 AM.
Reason: more info
If you do go with take-off, be aware of the donor brake style/sizing as the take-off unit may over power (overly sensitive pedal) what front brakes you have now.
Also the same with chosen pump style output pressure.
First off, love the rig. Your upgrades encompass many of the reasons we decided to get a mid 70's class C. We would've preferred a slick for sure.
Since I know nothing about the Hydro Boost setup my take may just raise more questions than answers. To compare, I am currently building a 1975 class C F350, dual rear wheels, Dana 70 (10-1/2") w/ 12"x3" brakes, stock dual piston discs at the front, stock 9" brake booster. At 9800lbs (under 9500 empty) I have not noticed a need for any changes/improvements to the braking system. Further, as we are currently in process of stretching the mh by nearly 3ft and likely increasing weight by a few hundred pounds conservatively (lots of extra steel plus added generator and generator framing/supports etc) I am confident the stock braking system will be sufficient. I may be proven wrong eventually but for now that's where I stand. My question is where was the front disc set up sourced from and did you include the booster/mc in your swap? Perhaps a setup from a truck that matches your rig more closely is all that's needed. With so much being similar to my rig (even with the weight difference) could that be all that is needed for yours?
As purchased original 26' bumper to bumper 175" wheelbase
Hi @AZSCAWPION. I sure like the looks of your rig. I see a lot of similarities in the two trucks. I still have the old straight axle in the front of the old 64. I found the brake setup for an eight bolt disk brake setup at TSM Mfg in Colorado. They are now called Rustic Brakes. RUSTIC DISC BRAKES - TSM Mfg now Rustic Disc Brakes. I bought the 7" booster and master cylinder from CJ Pony or Classic Industries. When I switched to disk front brakes I bought the Master cylinder at NAPA. I'm glad that your brakes work better than mine. Even with the rear brakes setup nice and tight it still has a hard time coming to a stop. Good luck with your rig and getting your generator on it. What size generator? Generator or Inverter?
I'll add one more thing. A while back I upgraded the front drum brakes (with 7" booster) on my '65 3/4 ton to discs from a mid 70s 3/4 ton. Swapped everything including m/c and booster from the later truck into my '65. There have been many discussions here in these forums about how so many factors come in to play when modifying braking systems. Everything from pedal arm length to m/c bore size are things that are engineered from the manufacturer that make cobbling a system together that works properly difficult at best. Case in point my '65. The 9" booster that I swapped over is way too powerful. So much so that I added a spring to the pedal to offer some resistance. Ironically, it's the same booster that's on the mh but since didn't have the mh at the time never made the comparison. Now on the contrary, currently since mh is just a cab/chassis and probably hovers around the same weight as the '65, I could lock up the brakes with my pinkie toe. Reinforces my thought that with a proper sized booster your brakes will function as they should. And I should probably go back to the 7" on the '65.
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