Hello,

Re: 1985 F-250HD, 460ci, XLT Lariat, 4x4, MT. End use: Pulling a travel trailer around for a few years when I retire shortly.

Can anyone comment on the Pro's and Cons of removing the vacuum boost and installing a Hydro boost system? Priority is sure braking and reliability

Thank you

Rgds

nonrev

 

First got to ask why if the vacuum system is working.

It has been 15 years since I drove a truck with hydro boost / diesel and it was bought to pull trailers. Don't remember anything bad about it other than if you run low on fluid, bad leak, you have vary little braking power to stop.

Now to do this swap it would be best to find a complete truck for all the necessary parts.
May need to swap pedals, pump & master to make this work.

If me and had bad vacuum booster I would just replace it with same thing and be done.
Dave - - - -

 

Going from vacuum to hydroboost is like upgrading from non power brakes to power brakes. The difference in braking power is huge. Nothing wrong with vacuum assist, but for heavier trucks and loads hydro is a very worthy upgrade. Some people complain about the pedal feel being too firm, but I have to wonder how many of these complaints may be from using the wrong brake pedal with the pin in the wrong place. You need the hydroboost pedal or move the pin. You also hear of complaints of jerky or stiff steering while braking, but these are on other makes of trucks... NOT Ford. I have never heard anything like that with Ford's HB system. That said, if you are running V belts another good and complimentary upgrade would be a Saginaw steering pump conversion with a small oil cooler. Not necessary though. F450's run the whiny Ford pumps and brake/steer just fine. If the PS pump fails you don't have brake, but PS pumps rarely fail catastrophically. The assist unit itself is just a hydraulic valve and rarely has any issues. Much less than vacuum diaphragms. The usual response from people converting to hydroboost is that they stepped on the pedal and about launched themselves through the windshield. A welcome change for heavy truck owners.

 

Thanks for the comment so far.

This is the first I have heard of needing a new Brake pedal. Can anyone advise of the appropriate brake pedal for use in an 85 F-250. I'd hate to decide to do this upgrade and find that one part is preventing proper operation.

One thing is that I have talked to several Brake specialist places here in town and no one wants to tackle the install. Don't know why? Maybe insurance liability?

Thanks

 

Isn't this strictly an aftermarket/mod style project?

I doubt you would get any traditional shop to take on a project of this complexity, and I would argue you wouldn't want to unless you found someone who specialized in old fords. These are the type of projects you need to research and do yourself to make sure it is done right because it can not be found in a manual or book, blazing new trails as they say.

I think if you do a search here or on the pre-powerstroke forum you will find some more information, I recall coming across it once.

Good luck,
Devin

 

Here's some info on the hydroboost.

Hydroboost Swap & Power Steering Pump replacement. What hangups can I expect?

Ditch The Weak Vacuum & Upgrade To F-450 Hydroboost Brakes!

Hydroboost Brake Pedal

 

Nice write-up here:

https://www.ford-trucks.com/forums/1...-write-up.html

 

I totally get why a shop would not touch this conversion. But there is absolutely no reason not to do it yourself or find a shade tree mechanic to do it for you. If you use 87-96 F450 parts it is 100% bolt on. Just a different boost unit (plus the corresponding pedal and a way to get fluid back into the PS reservoir). It is dirt simple and works ~so well. You're just not going to convince a shop to modify a safety system under any circumstances because of liability.

 

OK the OP has 1 85 F250 and you are saying to use 87-96 F450 parts.


I can see the pedal assy. boost unit, pump & hoses but I would check the masters if they have the same bore dia.
You also want to check front & rear brakes if the caliper/wheel cly are also the same size between the 2 trucks.


And when I said pedal assy. it was more for the placement of the push rod pin. If it is too high or low it throws off the ratio and why you go thru the window.


And yes it is because of liability why shops will not touch this.
Dave ----

 

Heres the HydroBoost I'm probably going to order.

Hydratech Braking Systems :: 1980-1996 Ford F Series / Bronco Hydraulic Brake Assist System Listing.

They say its a direct fit for the old Vacuum booster .

They are also capable of mating it up to this CPP MC and sending it as one unit.

CPP CP31501C MASTER CYLINDER. http://www.hydratechbraking.com/mastercylinders.html

The description of the HB is that it has an adjustable brake pedal rod for a range of brake pedal heights.

Sounds almost too good to be true reading about the hoops others have had to jump thru.

A local mechanic said to check the Custom Auto places as they would be most likely to take the job on. I will probably have to modify the brake lines somewhat as the old Proportional valve comes out because the CPP MC has them built in so they will need to come up a few inches. I'm probably also going to be removing the Truck bed load sensing proportional valve in the rear.

I would like to find out the part number for the 87-96 F-450 (not a F-350 also?) Brake pedal..... just in case. Manual transmission....as I understand the Clutch and brake pedals are an integral unit on some years in this range

Thanks

 

The unit you posted is strictly an aftermarket upgrade. I have no idea which pedal it uses. (If it is made to replace the vacuum booster it would make sense for it to be designed to use the vacuum pedal though). Not all vacuum pedals are the same either...



But if you end up using the F450 parts you need the 87-96 F450 manual transmission brake pedal. (F350's did not have hydroboost and do not have the special pedal). This is the engineering number stamped on the side:





The launching through the windshield comment just means the brakes worked unexpectedly well... not a leverage ratio or control problem.

 

Nice photo, thanks for taking the time to do this and supply info,

Rgds