So your system has an accumulator? Not trying to bash your mod, I know my truck could usesome help inn the brake department. Thes old fords never were much with their brakes IMO

 

The hydroboost is a big advantage in a pickup with a diesel. The 250's and 350's with the diesel engine had the vacuum booster, with the little belt driven vacuum pump on the engine. Pulling a heavy load this system is easy to overwhelm and it runs out of vacuum. I have experienced is my 89 while slowly pumping the brakes while pulling my trailer. I try to modulate the electric brakes on my trailer by letting up and applying the truck's brakes, but if I am not careful I run out of vacuum and my pedal will start getting hard.

The hydroboost was original in the heavier duty trucks and chassis for motorhomes and other heavy duty applications. It probably would be overkill on a smaller truck with a gas engine that has plenty of vacuum, but it certainly wouldn't hurt anything. I believe some of the newer mustangs also had a hydroboost system, I am not sure why, maybe a real estate problem under the hood? But I do remember a guy I worked with a 99 Cobra, and he had to take it back to the dealer because when he hit the brakes, the steering wheel would jerk a little bit.

 

No problem, yeah they do have an accumulator of some kind. I am not exactly sure how it works, but I was taught that all power assist systems are supposed to have reserve per federal law.

As for the late model mustangs, it is a real estate problem under the hood.

 

I share that concern but even more for the 29 year old brake hoses on my truck.
Back before front wheel discs and proportioning valves I had to make a hard stop in my '65 Falcon station wagon. I pushed hard on the pedal and boom- it went all the way to the floor. Since I still needed to stop I grabbed the emergency brake and pulled as hard as I could. It didn't do much so I made a quick right in a parking lot that just happened to be there.
When I tore it down I found I had blown out a rear cylinder. Cars just don't stop too well on rear drums when one of them is full of brake fluid. I just had to share, but the point is I blew that cylinder out without power anything except size 12.

Great job on the write-up bghnkin250.

 

WHen you get enough hydralic pressure to lock the wheels I'd think most people wouldnt press much harder unless somethig big and scary is comin at you. A mechanic I used to work with taught me to try to push the brake pedal through the floorboard (engine running) so if something's gonna blow it will be in the shop and not on the road. Usually wheel cyl's just leak and dont blow out, same with calipers. Usually a line or hose is the cause for total brake loss. Iguess what I'm getting at is I should replace those rusty brake lines. Pardon my drunken rambling

 

A thorough brake inspection should be in order since you will be running more pressure through. I will be upgrading to braided lines as cash allows.

 

Back to the accumlator, can anyone confirm that hydroboost uses one, I have worked on several and never saw an accumulator except on some abs vehicles and they are not to provide boost

 

I think that is the piston on the side. Here is a break down: http://littlekeylime.com/MrN/img/hyd...lodedview1.jpg

 

I stand corrected

 

Well, a little update - my pump was making a growling noise, like there was air in the system. I have tried bleeding it, and it was still there. I read on line of a few people that floored the pedal, and turned on the truck to get rid of the air in the system. I tried this a couple of times, and it seemed to be working...that is until the pedal dropped and the brake light came on. I saw no leaks under the truck. I took the top off of the reservoir, and the rear reservoir was very low. The calipers look dry and I see no wet lines. Looks like it is time to replace the master. It looked to be leaking a little out the back when I replaced the booster, so it was on its last leg.

Lesson learned. I should have taken my own advice and made sure the rest was up to the task of the higher pressures. I replaced the wheel cylinders when I bought the truck, so there is a little peace of mind.

 

Excellent "how to" complete with pictures! Thanks for your excellent contribution. Added to the Tech Tips sticky at the top of the forum!

 

Thank you very much Scott, I appreciate the feedback.

 

I just grabbed everything out of a 1975 lincoln continental for fifty bucks yesterday. My uncle is going to install it in his 65 F-100. I am getting another for their first series bronco also.

I just found a video that says you do not have to change your existing power steering pump. That makes the swap even easier.
www.V8TVshow.com - Hydroboost Brake Booster Cures Bad Brakes

 

That's true, the factory pump is decent enough for the hydroboost to work good. However, something got me thinking - Lincoln Mark VII cars have steering racks, and early-'80s models also had hydroboost (later switched out for a rather odd 4-wheel ABS setup), steering racks generally run higher line pressures than steering boxes do, so I was wondering how would the hydroboost in my truck take to a higher input pressure... Took a Mark VII pump apart, pulled the relief valve and spring, installed it in my truck - yeps, there's a difference alright, lighter brakes (pedal feel) in particular, which suggest better assist from the booster. Then the fitting that holds the relief valve in the PS pump can also be drilled out for more flow, which results in a lighter steering (more assist from the steering box). It's been several thousand miles like that already, no adverse effects noticed at either the box or the booster - I'd imagine the booster was designed to be able to handle the higher input pressure to begin with (I actually use a Chevy booster, their Saginaw pump does put out higher pressure than the Ford truck pump), and the box likely survives at the higher pump pressure because the pressure drop across the hydroboost brings it back down some...

 

Awesome, I'm gonna have to do this...

Thanks!