Dual Circuit Brake Engineering Thread

[cbforme]

I just inquired my 88 Air Force truck. I have split brakes as well. Having a hard time finding any parts whatsoever for the split brake system. Do you have any idea where I could find a master cylinder rebuild kit for a post that has some info listed?

Check sweeting performance look at bosh / bendix hydro-max they sell air force style with the reserve and the a3 version with the remote reserve. not cheap but give it a look.

 

[DUUANE]

Has anyone plumbed in a gauge at the outlet of the stock airpak and measured the line pressure with a max application? Inquiring minds want to know!

 

[Jbulach]

@rustystud ?

 

[biscuitwhistler37]

Has anyone plumbed in a gauge at the outlet of the stock airpak and measured the line pressure with a max application? Inquiring minds want to know!

Page 15 of this thread has a reply from rusty that says around 800psi, checked by gauge. Glad you asked, I was curious too.

 

[DUUANE]

Page 15 of this thread has a reply from rusty that says around 800psi, checked by gauge. Glad you asked, I was curious too.

Thank you very much for pointing me to that. There is so much info on these forums, but alas...for some reason i totally suck at the search.

800psi..is both good and surprising. I woulve thought it to be in the 12-1500psi range for sure. This is good news though and greatly simplifies things for what i want to try in another thread. Will make packaging much simpler.

 

[Sumner]

So I thought I’d jump in here to share what I did on my bobber.

I had read a post previously by one fellow that mounted the Hydromax unit under the cab, rearward from the factory master cylinder, but I can’t seem to find it now. His installation is the route I decided to go, for a few reasons.

So a little more info on my truck. I installed power steering using a steering box and components from a Canadian MLVW, and used a 5ton power steering pump to run it. Works excellent.

I also wanted dual circuit brakes though. I used Hydromax setup out of a ford b-series school bus, and mounted it underneath, with a remote reservoir. I also used stock brake pedal too, with my own made adjustable link to the hydromax unit. Part of the reason I didn’t mount it on the firewall is that I didn’t want to have a hanging pedal for the brakes and a through the floor pedal for the clutch.

Using the factory pedal gives me a lighter than stock pedal feel, but not too light. And man does it work well. Will easily lock up all four tires on pavement if needed. Brakes better than it ever did with the stock setup.

One advantage with using the stock pedal geometry is that I don’t need to have the auxiliary electric pressure pump hooked up, could prob remove it altogether, especially considering the expensive “cross” part required to rotate 90 degrees from stock configuration. Did a test, and with the engine off, I can still stop the truck, just requires a bit more effort.

Only things left to do now is fabricate a mount for the winch pto shifter, and mount a switch for the brake lights.

Here’s a few pics of the installed Hydromax.

 

[Another Ahab]

So a little more info on my truck. I installed power steering using a steering box and components from a Canadian MLVW, and used a 5ton power steering pump to run it. Works excellent.

I also wanted dual circuit brakes though. I used Hydromax setup out of a ford b-series school bus, and mounted it underneath, with a remote reservoir. I also used stock brake pedal too, with my own made adjustable link to the hydromax unit. Part of the reason I didn’t mount it on the firewall is that I didn’t want to have a hanging pedal for the brakes and a through the floor pedal for the clutch.

Here’s a few pics of the installed Hydromax.

View attachment 943927View attachment 943928View attachment 943929View attachment 943930

Brilliant!

Hey, Sumner, you could maybe document how you made the conversion, and sell the instructions for a popular (and nominal well-deserved fee)!

Oh, wait: Public Safety. Tort Attorneys. Liability.

Well. Then again. Maybe Not!

 

[Sumner]

Brilliant!

Hey, Sumner, you could maybe document how you made the conversion, and sell the instructions for a popular (and nominal well-deserved fee)!

Oh, wait: Public Safety. Tort Attorneys. Liability.

Well. Then again. Maybe Not!

I’m not sure how to take this? Are you saying I should not have posted? I can remove it

 

[Another Ahab]

I’m not sure how to take this? Are you saying I should not have posted? I can remove it

No, no, no; not at all what I am saying!

My abject apology to you for making you uncertain:

- I am saying that your skiil and expertise (in making the retrofits), is SUPERB!!

And I am only realizing (in the middle of recommending that you capitalize on your talent), that the world is a complex (sometimes messy), place...

You are particulalry talented, Sumner, and that is especially commendable!

 

[Sumner]

No, no, no; not at all what I am saying!

My abject apology to you for making you uncertain:

- I am saying that your skiil and expertise (in making the retrofits), is SUPERB!!

And I am only realizing (in the middle of recommending that you capitalize on your talent), that the world is a complex (sometimes messy), place...

You are particulalry talented, Sumner, and that is especially commendable!

Thank you, much appreciated.

 

[DUUANE]

So I thought I’d jump in here to share what I did on my bobber.

I had read a post previously by one fellow that mounted the Hydromax unit under the cab, rearward from the factory master cylinder, but I can’t seem to find it now. His installation is the route I decided to go, for a few reasons.

So a little more info on my truck. I installed power steering using a steering box and components from a Canadian MLVW, and used a 5ton power steering pump to run it. Works excellent.

I also wanted dual circuit brakes though. I used Hydromax setup out of a ford b-series school bus, and mounted it underneath, with a remote reservoir. I also used stock brake pedal too, with my own made adjustable link to the hydromax unit. Part of the reason I didn’t mount it on the firewall is that I didn’t want to have a hanging pedal for the brakes and a through the floor pedal for the clutch.

Using the factory pedal gives me a lighter than stock pedal feel, but not too light. And man does it work well. Will easily lock up all four tires on pavement if needed. Brakes better than it ever did with the stock setup.

One advantage with using the stock pedal geometry is that I don’t need to have the auxiliary electric pressure pump hooked up, could prob remove it altogether, especially considering the expensive “cross” part required to rotate 90 degrees from stock configuration. Did a test, and with the engine off, I can still stop the truck, just requires a bit more effort.

Only things left to do now is fabricate a mount for the winch pto shifter, and mount a switch for the brake lights.

Here’s a few pics of the installed Hydromax.

View attachment 943927View attachment 943928View attachment 943929View attachment 943930

That looks really good, and is perfect for a 2 axle truck. I'm a bug and i like my air brakes. If i could make an air brake spider work on our axles without reinventing the wheel i would hahah. I just did the same conversion (hydromax) on a 1980 C60 that had that horrible hydrovac single system. Should smarten it right up. I plan on using the stock pedal and mounting the foot valve under the floor as well.

 

[SteelNinja]

Sumner Sumner Sumner!!!!!!!!! Nice Job! Ditto Another Ahab