Hey guys,


I am collecting brake stuff for my F-600 and I'm going with all hydraulic boosted brakes.

None of the after aftermarket companies can tell me if their boosted brake systems will work with F-600 (dual wheel-cyl BACK and single piston FRONT) brakes. (they have fairly SMALL bore master-cyls.)


I did a little research and discovered that Ford used double wheel-cyl BACK and single-piston front (DRUM-TYPE) brakes on medium trucks up into the 80's! AND used the HYDROMAX brake booster (like below) in many of those years (actually up into the 90's)






SO I am considering a Bosch type HYDRO-MAX unit with a 2" bore MC, and putting it all on the firewall, and powering it with the wonderful EATON power steering pump I have.


Anyone have any thoughts on using one of these? While I might be able to put it under the cab, I'll probably do a hanging pedal and put it on the firewall!!

 

I know absolutely nothing about that system (among other things) you are referring to.What else is it used on?And do you really "power" a master cylinder with a power steering pump?

 

A normal power brake system is powered by engine vacuum, you have a vacuum line going from your intake to the big drum on your brake booster.

With a hydroboost setup instead of using vacuum to power the brake it uses hydraulic pressure, usually tapped into the power steering pump. I've been thinking of getting one for my truck. Never actually driven a vehicle with them but they're supposed to be a lot better than vacuum.

I'd definitely like to hear how this works out.

 

It all depends on what "normal" is.


Look under the hood of ALL the recent diesel Ford, GM, or Dodge trucks and a "normal" brake booster will be powered by the power steering pump (same as the one under the hood of my 94 GMC Suburban)

Back in the "old days" vacuum boosters were "normal".


Not any more.



All the diesel trucks nowadays have hydro-boosted brakes. (no good source of vacuum........Even the vacuum pumps don't really cut it.)

I bought a 94 6.5L diesel Suburban new in 1994. It's got 190,000 miles on it and of course hydroboosted brakes. (GM has been using the system for years (made by Bendix I think)

The medium truck model in the above picture is Bosch I believe but Bendix also makes a similar model.

The ones for light trucks use a hydraulic pressure accumulator for a couple of brake applications if the power steering belt breaks (or the engine quits) After that, you have to push harder to stop.


With the one in my picture above, if hydraulic pressure drops below a certain pressure, the electric motor driven pump then provides the pressure for a boosted stop.



They're ABSOLUTELY better than vacuum!


It appears that it's my only real choice since I want to go to a dual circuit brake system. The way it is now if ANY ONE of the 6 wheel cylinders I have in my F-600 develops a leak, I lose ALL the brakes.

The thing will weigh around 9000lbs empty. I want to be able to stop it!



Cheers,



Rick

 

electric hydraulic is the absolute best !!! if the booster fails you still even have brakes , harder than hades to use , but they'll be there . looks just like the stuff on some of the 8 , 9 and 10 ton straight trucks with 4 wheel discs . maybe you should go find a parked ih and relieve it of the discs too huh ???????????? you'd be able to stop the queen mary with 'em !!!!!!!!!!!!!! for all intents and purposes the only better on our work truck is good old fashioned air brakes at bringing the heavy loads to a stop . let us know how it works with the drums . i was wondering if they'd put out so much pressure they'd pop the wheel cylinders and spit the wheel links out the side of the drums LOL !!!!!!!!!!!!!!!!!

 

Great discovery. That 2" MC bore will require more effort at the pedal when boost is not available, but with the boost you should have really good brake action.

 

I think a more productive place for your question might be:
Large Truck - Ford Truck Enthusiasts Forums
JML

 

I have converted a 60 series Chevy from vacuum booster to the Hydraboost style brakes . This worked out very well better brakes than the truck had new. The only problem was the master cylinder was for disc brakes and we had drum brakes , so I got some residual pressure valves from Summit and it works perfectly. I also converted my 57F600 to Hydraboost it also has great brakes. School busses are a great source of Hydraboost parts, most of the later ones have dual systems and are eaisly adaptable. Some of the mid size gas engine busses have a combination vacuum/ hydraulic boosters.


Have A Great Day------------Hotwrench

 

Yeah....I think you may be right!!








Thanks for that!! My original concern was that the double wheel-cyl back along with the single piston front brakes would be a problem.


Evidently, the above system has been used with hydroboost for many years.

The larger bore M/C is needed since the back wheel cyls are pretty BIG and there's 2 of them per wheel. They require a LOT of fluid!

So small master cyls might require a LOT of pedal travel to get shoe-to-drum contact on the back, while locking the front etc.....If you use some sort of proportioning valve (which I'll probably need to do to fix that) I may still have too much pedal travel.


SO a BIG M/C is definitely required!

 

Rick,I found this over on the Y-Blocks forever site,maybe you've already seen it or it could be of use to you.

Steve

Hydroboost

 

Hey thanks Steve! That's the same unit that came OEM on my 94 Suburban! (less the fancy shiny master cyl!!)



I could probably use one of those if I could find a 1-3/4"-2" master cyl to bolt to it!


So far I haven't. Most of them are for disc brakes AND are of smaller diameter .......1" or so and LESS.


The medium trucks that used ALL drum brakes up into the 80's used much larger master cylinders because of the additional fluid requirements.


I think I like the HydroMAX booster too because it has an electrical motor driven pump backup!


There's always GOOD STUFF on the Y-Blocks Forever site!!


Cheers,


Rick