Hydro Boost Brakes.

[wrsainio]

I am interested in converting from vac assist to Hydro assist on and 86 250 6.9 and read some of the articles. Does Ford not use a little Heater/blower size motor to use as an assit pump motor in case the ps pump fails or motor stalls etc? We have an old F800 at work that has it and my neighbor who is the service Foreman at the Navistar dealership said all the school buses use them. He said you need all kinds of specail wiring and modulators to make it work. He said it would ne a real nightmare. Thanks Wilf.
Maybe easier to switch to the 10 3/4" booster.

 

[Mr_Roboto]

The bigger trucks use the electric backup pumps. I don't believe the F-Superduty / F450 uses them. I know when I drove F450 wreckers you were out of luck if you wanted to turn and apply the brakes at the same time (parking lots).

The factory hydroboost system is actually quite simple, the problem is finding the parts. I'm ashamed to say I took an old 78 or 79 Lincoln to the junkyard with a hydroboost system on it (years ago). I bet the parts from that system would be big enough for a truck, that old Lincoln probably weighed as much.

 

[GenLightening]

My '88 Chevy has it. I'd bet there are pleny of those and Suburbans at the wreckers. I'm not sure how much work it would take to adapt to the Ford. If I get a chance before the donor truck leaves, I'll see what it looks like.

Doug

 

[Full Monte]

See the article in the tech articles section. It's a straightforward conversion.
I don't know if a backup hydropump has been done on a F series truck. Hydroboost braking is very improved over vacuum assist. You are right...if you lose the power steering pump, you lose power braking and steering. If that happens, you can count on a big boost of adrenalin and the parking brake to get you stopped. But if you lose vacuum on the standard setup, you also lose braking. And those vacuum pumps are a common replacement item. I like hydroboost a LOT.

 

[jauguston]

I'm the guy that did the 10 3/4" booster swap and I am very happy with the improvement in stopping ability. I have no way of knowing how it compares to the Hydraboost but I bet it is a heck of a lot easier and cheaper to do.

The only thing that has to be done other than a normal booster replacement is slot out the bolt holes in the master cylinder about 1/8" on each side and shorten the pedal pushrod 3/4 - 7/8". I shortened mine 3/4" and if I had it to do over I would have done 7/8". My pedal sits a little higher than I would like. Just carefully measure how far the pushrod sticks out from the face of your stock booster and make the new one the same. Make your cut in the flat part of the pushrod right behind the hole for the pedal pin. I vee'd both pieces on both sides and TIG welded the pieces back together. Just as strong as the original.

My rig is a '86 E-350 and I used a booster from a '93 E-350.

Jim