• Steel Soldiers now has a few new forums, read more about it at: New Munitions Forums!

  • Microsoft MSN, Live, Hotmail, Outlook email users may not be receiving emails. We are working to resolve this issue. Please add support@steelsoldiers.com to your trusted contacts.

 

modern dual circuit air over hydraulic brakes

Mullaney

Well-known member
Steel Soldiers Supporter
Supporting Vendor
7,157
18,515
113
Location
Charlotte NC
.
So, I have to ask... Will we eventually see a replacement (bolt-on) Air Disc Brake kit for heavy truck axles? OR is it never going to happen with older military trucks mostly because the old axle technology has just "moved along"?

There is a Meritor KIT225222 for example. They are darn EXPENSIVE, but then again too we would have a spring brake chamber and air powered braking system. The spring brake automatically gets applied when the air gets too low. Better than a mechanical dual brake system...
 

rustystud

Well-known member
9,070
2,384
113
Location
Woodinville, Washington
.
So, I have to ask... Will we eventually see a replacement (bolt-on) Air Disc Brake kit for heavy truck axles? OR is it never going to happen with older military trucks mostly because the old axle technology has just "moved along"?

There is a Meritor KIT225222 for example. They are darn EXPENSIVE, but then again too we would have a spring brake chamber and air powered braking system. The spring brake automatically gets applied when the air gets too low. Better than a mechanical dual brake system...
I've looked at that kit from Meritor and yes they are extremely expensive ! It would cost more then my truck is worth and then some ! Plus all the fabrication for our older axles.
I would go with one of the kits from Boyce or try what several members here have done first.
The transit agency had toyed with that idea before I retired, but in the end the cost was too much since the drum brakes meet all federal standards of stopping.
I'm sure in the future the newer buses and heavy trucks will come factory with air disc brakes, but that is the future.
 

Superthermal

Well-known member
261
760
93
Location
Utah, Murray, United States
Info on Hydro-max units. Info on electric motors relay/peddle control to be interesting(Figure 6) and the info on the power steering hydraulic pressure and GPM to be important to reference. There was no spec sheet to give a max PSI input. The general info in the screen shot below was on page 15.


I did not see a brake fluid volume Min/max and output pressure comparison for a 1.75 or 2" master which would be helpful to determine if one or the other would be preferred/required if keeping drums on a 5 ton or using dual piston or 4 piston brake calipers on rotors. There is a graph giving a general pressure output PSI for the larger 2" piston which tops out about 2000 psi.

This last link has a graph on the 1.75 piston "typical" PSI

1668473458967.png1668474284253.png1668474317597.png
 

Bigsbetter

New member
4
6
3
Location
Missouri USA
Those valves still need two inputs for the two outputs.
Could it work if you split the single line with a T fitting to have 2 inputs into the proportioning valve and then 2 outputs? I understand the system would be ‘single circuit’ before the Tand proportioning valve, it then dual after that which would provide more safety.
 

banditt1979

Well-known member
272
728
93
Location
Cincinnati, OH
Curious to see if there has been any forward movement on this. Also found a thread where a guy mounted his hydra max behind the crossmember to keep the original pedal assembly, thought I would share

 

fleetmech

Well-known member
197
374
63
Location
Connecticut
Returning to the site after a break from much internet use......

The short answer is no, i haven't made much progress other than amassing a few parts. The long answer is that now I need to take some action. What was to be one of my last drives before putting the deuce away for the road salt season turned into the last drive for the season when my airpack seal let go and sent all my brake fluid into the air side. I went from full brakes, to half pedal, to no brakes in three applications while going down a long hill. Thankfully there was nothing at the bottom of said hill and i got it turned around and home safely.

That experience pretty well convinced me (if I wasn't before) that the stock system has to go. I haven't decided if im going to try to buy or build.
 

banditt1979

Well-known member
272
728
93
Location
Cincinnati, OH
Returning to the site after a break from much internet use......

The short answer is no, i haven't made much progress other than amassing a few parts. The long answer is that now I need to take some action. What was to be one of my last drives before putting the deuce away for the road salt season turned into the last drive for the season when my airpack seal let go and sent all my brake fluid into the air side. I went from full brakes, to half pedal, to no brakes in three applications while going down a long hill. Thankfully there was nothing at the bottom of said hill and i got it turned around and home safely.

That experience pretty well convinced me (if I wasn't before) that the stock system has to go. I haven't decided if im going to try to buy or build.
Glad you didn't get hurt or hurt anyone else! I hope to see your project get moving again soon.
 
  • Like
Reactions: HDN

HDN

Well-known member
1,902
4,573
113
Location
Finger Lakes Region, NY
Returning to the site after a break from much internet use......

The short answer is no, i haven't made much progress other than amassing a few parts. The long answer is that now I need to take some action. What was to be one of my last drives before putting the deuce away for the road salt season turned into the last drive for the season when my airpack seal let go and sent all my brake fluid into the air side. I went from full brakes, to half pedal, to no brakes in three applications while going down a long hill. Thankfully there was nothing at the bottom of said hill and i got it turned around and home safely.

That experience pretty well convinced me (if I wasn't before) that the stock system has to go. I haven't decided if im going to try to buy or build.
That's absolutely wild! I'm thankful my truck came with dual-circuit brakes for situations like this. I'm glad everyone is safe (y)
 

Superthermal

Well-known member
261
760
93
Location
Utah, Murray, United States
Returning to the site after a break from much internet use......

The short answer is no, i haven't made much progress other than amassing a few parts. The long answer is that now I need to take some action. What was to be one of my last drives before putting the deuce away for the road salt season turned into the last drive for the season when my airpack seal let go and sent all my brake fluid into the air side. I went from full brakes, to half pedal, to no brakes in three applications while going down a long hill. Thankfully there was nothing at the bottom of said hill and i got it turned around and home safely.

That experience pretty well convinced me (if I wasn't before) that the stock system has to go. I haven't decided if im going to try to buy or build.
Even with my rig working very well, I am always leery of the breaks. I am always looking for a way off the road etc.. just to make sure if there was a problem that I wouldn't hurt anyone. Dual circuit is a very important mod for these trucks. I am still interested as well.
 

fleetmech

Well-known member
197
374
63
Location
Connecticut
Even with my rig working very well, I am always leery of the breaks. I am always looking for a way off the road etc.. just to make sure if there was a problem that I wouldn't hurt anyone. Dual circuit is a very important mod for these trucks. I am still interested as well.
Same here, and that leery-ness is one reason I dont use this truck as much as I otherwise would.

I intend to jump back into it once the weather warms up a bit, and I'll post up what i end up installing.

FWIW, I chatted with a guy at a show last year who had installed a rock crawler style pinion brake on his deuce, with a 4th pedal and independent master under the dash. According to him, it stopped the truck just fine. I know its something weve discussed on here before; that was the first time ive seen it actually done on a full size m35.
 
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website like our supporting vendors. Their ads help keep Steel Soldiers going. Please consider disabling your ad blockers for the site. Thanks!

I've Disabled AdBlock
No Thanks