Split brake system

[jatonka]

Anyone who wants to can come to my place and check out a military prototype split brake system for the deuce. It uses a suspended pedal from a 900 series truck and two pacs that look like M105 Trailer brake pacs. It was built at Romulus Army Depot, there were two trucks, now there is just the one I have. It stops on a dime and gives 6 cents change. JT out

 

[Rattlewagon]

The braking system on the M35 is the sole reason I haven't gotten one. I would love to have one but without some sort of brake redundancy, I just can't do it.

maybe I am making a mountain out of a molehill but, if there is a better system to either build or buy, I am all ears!

Please keep the ideas coming!

dan

 

[hndrsonj]

Just buy one of the late 80's Air Force trucks if that's the only reason you have not bought one!

 

[M813A1]

Hey Guys !! I am wondering if you could mod a brake system using a Dual chamber MC ?? and still use one air pak ?? And just split the line to the front chamber for the front and Back lines to the back chamber ?? Instead of having to reengineer the system ?? And I wonder if that mod could be used on a 5 Ton as well !!

 

[Ironclad]

Brake upgrade? Count me in!

I'd definitely be interested in any kit, parts, etc to improve the safety of my truck. Thanks for the info, thoughts and ideas!

 

[Rattlewagon]

Just buy one of the late 80's Air Force trucks if that's the only reason you have not bought one!

Please bear with me, this will probably be long...

I should elaborate as to why I haven't bought a late model truck already. The First is that every one that I have found that is even remotely close to me has gone for way more than I have to spend (I only have so much to work with).

The other is that if I did get one of those trucks the possibility of having to source replacement parts on a truck that has unique system that is kind of rare is also enough to worry me. Meaning, what if something breaks that is specific to a dual system truck and I can’t find a replacement? I’ll be stuck. Know what I mean? If there is a system that exists in the world that can be adapted then in my opinion, any truck would do and we all would benefit.

The other fact is that I am by no means made of money. My plans are to bob it and use it as an over-sized pickup truck. And while I probably wouldn’t drive it daily, I certainly would like to drive it frequently! I am also a Volunteer fireman and it would have been really nice to have on some of the brush fire calls we had this year. If only to get brush trucks out of the silly places rookie's put them! (if your a fireman, you understand!)

I'll be the first to admit that I'm paranoid and I'm over-thinking this but, it hasn't let me down yet...

with all of that said, if anyone has a truck in the SW PA area that is for sale, I would certainly entertain the idea!

Thanks all,
dan

 

[Jake0147]

The other is that if I did get one of those trucks the possibility of having to source replacement parts on a truck that has unique system that is kind of rare is also enough to worry me. Meaning, what if something breaks that is specific to a dual system truck and I can’t find a replacement? I’ll be stuck. Know what I mean? If there is a system that exists in the world that can be adapted then in my opinion, any truck would do and we all would benefit.[/color]

Someone on this site has adapted a "Hydro-Max" brake master cylinder (search for that, "hydromax" and "hydroboost", they have been used interchangably in discussion but the first one is the brand name). Very common on medium duty trucks with hydraulic brakes. This is a dual outlet, hydraulically boosted system (search for that as well, bone yard retrofits and 5 ton pumps have been used). This is boosted in a way more familiar on modern stuff. That is, the boost is a mechanical amplification of your pedal linkage prior to the master cylinder, versus the air assist in a deuce where the fluid output pressure is boosted "in line" but after the master cylinder. They are most common with the same bore for the front and rear outlets, which means you could plumb one outlet to any axle (most likely the front I would think) and the rears from the other outlet. Then all braking pressure would remain balanced, as it is in the existing system, eliminating the need for any proportioning valves. The installation here was on the firewall with a swinging pedal, however I'm sure with a little bit of creativity the assembly could be placed under the cab to use the existing pedal as well.

Hey Guys !! I am wondering if you could mod a brake system using a Dual chamber MC ?? and still use one air pak ?? And just split the line to the front chamber for the front and Back lines to the back chamber ?? Instead of having to reengineer the system ?? And I wonder if that mod could be used on a 5 Ton as well !!

I think I understand what you're saying here... But as soon as you "T" anything, you've lost all of the redundancy of a dual master cylinder. Same issue. Any one failure will vent pressure from BOTH outlets of the master cylinder. By combining the outlets, you've only added an additional failure point.

 

[wdbtchr]

It occurs to me that you would need to find the total operating volume of the front wheel cylinders and the same for the four rear cylinders and find a master cylinder with the proper volumes. It seems to me that most dual cylinders would have about the same volumes front and rear as they would come from two axle vehicles.

I know there are brake boosters out there that use pressure rather than vaccuum to operate, I have a trailer that is air over hydraulic so I know they're out there. Unfortunately the booster I have has no part numbers. It's a Totum trailer titled as a 1967, but the data plate is long gone.

All we need is someone who can find out the information we need.

 

[FM5332FF]

ive seen the split setup in person. Matt (greengem) has the setup on a deuce that he is parting out. it looks like all of the parts are there

 

[vinny-socom1]

Yep I bought the frame less the brakes, so its all there and has not been removed yet. But it won't be on it much longer... Vinny

 

[jesusgatos]

I'm really interested in this too. Today I took out the air tanks on my M109 so I can put a water tank where they were (air tanks are going up on top of the roof). So this has got me thinking about what I would have to do to upgrade to a dual-circuit braking system.

 

[Rattlewagon]

I thought of something else that might be an option. It could be complicated and potentially expensive though.

Has anyone given thought to changing over to all air brakes? Are there even parts that would remotely come close to fitting?

I’ve had a CDL for years so it wouldn’t bother me... however, sourcing all of the parts does give me some concerns... and of course, realizing that whatever I do could have a direct impact on the safety of not only myself but others as well concerns me as well… then again, so does having no redundancy in the current brakes does too…

It would be nice to have rear service brakes as parking brakes though! That would be cool!

Just another thought. Shoot holes in it all you want, please!

Thanks,
dan

 

[wdbtchr]

I believe there was a thread on this some time back, I don't remember the details though.

 

[outcast]

hydraulic fuse

Just throwing this out there, would placing three hydraulic fuses in the brake system work?
I was thinking one for each axle. That way in the case of a blown brake cylinder or broken line you would loose just the brakes on that axle.
When a hydraulic system is damaged, there is generally a rapid flow of hydraulic fluid towards the breach. Most hydraulic fuses detect this flow and seal themselves if the flow exceeds a predetermined limit. There are many different fuse designs but most involve a passive spring-controlled mechanism which closes when the pressure differential across the fuse becomes excessive.
As an aircraft mechanic I’ve seen these used quite often on large aircraft.
LaMont

 

[Speddmon]

outcast, I was tyring to think of a way to do something similar with some sort of flow metering device or restricting device. That idea sounds like it has potential.

I was also thinking of something else...please someone who has a lot more experience with MV's and MV trailers tell my if I've lost my marbles or if it could conceivably work?

Most of the trailers I've seen have an air braking system used through the glad hand couplers at the rear of the truck. I will not admit to understanding the operation of this system that's why I'm asking for people with more experience with these to chime in. But, would it be possible to use the service brake master cylinder from a trailer, along with it's air/pressure regulator (whatever it uses) and tap into the service air line going to the rear glad hand coupler. That way when you apply the brakes, it applies air to the new MC/regulator set-up and applies brakes to whatever axle you have that MC hooked into???

 

[army70deuce]

First question, I have a 1970 Air Force M35A2 (the army in army70deuce is because I'm ARMY). Is there a really easy way to tell if I've got an upgraded dual circuit system?

Second Question, Do I really need a dual circuit system, the military didn't see it as an issue for decades, and my understanding and please correct me if I'm wrong but brake failures should have a warning sign its not "wow these are perfect and half a second later turns into oh god no brakes." Since I won't be driving down mountain passes at 70mph with a full load in the back, shouldn't I have time to go "hey something's wrong" and start downshifting and then apply the E-brake to get to a stop?

I apologize for the run on sentence.

 

[AceHigh]

First question, I have a 1970 Air Force M35A2 (the army in army70deuce is because I'm ARMY). Is there a really easy way to tell if I've got an upgraded dual circuit system?

Second Question, Do I really need a dual circuit system, the military didn't see it as an issue for decades, and my understanding and please correct me if I'm wrong but brake failures should have a warning sign its not "wow these are perfect and half a second later turns into oh god no brakes." Since I won't be driving down mountain passes at 70mph with a full load in the back, shouldn't I have time to go "hey something's wrong" and start downshifting and then apply the E-brake to get to a stop?

I apologize for the run on sentence.

I have a dual circuit truck, it has two separate air packs and lots of plumbing underneath. I do not know if there was a simpler system in 1970, but it is real easy to see compared to a single circuit system.

The military upgraded engines, seatbelts, and any other items from time to time but never bothered with the brakes and that tells me they thought a properly maintained system as built was safe.

 

[army70deuce]

Another question I forgot to ask. When the brakes do fail on a M35 do they fail open or closed (locked)? I know on a lot of military trailers with airbrakes the air supplied keeps the brakes open so you can tow it and they fail in the closed (brakes on) position, so no air and you're just dragging the trailer and smoking the wheels.

Thanks

 

[gimpyrobb]

If the system fails, it fails to "no brakes".

 

[FireFighterHill]

And yes it can go from just fine to no brakes in a hurry. I was driving my father in laws deuce to go get some lumber, Im glad he lives down a long dirt road or I would have been at highway speeds before the brakes gave out. I was coming to the stop sign before the highway and the brakes went from fine to the floor. Fortunately I was coasting and was slow enough that down shifting and turning into the grass stopped me. I got out and sure enough there was brake fluid all over the drive inside front tire. The rubber brake hose had burst. I drove it back to his house in low gear using the tranny to brake when I needed.

On a side note I replace the front brake lines with braided stainless lines. The hard lines were pretty bad if it was my truck it would have gotten all new brake lines and cylinders, but being that its not my Deuce I dont have the money to throw at it.

The point of the whole fiasco is if I had dual circuit I still would have had rear brakes and would have had less a chance of hitting something or someone.