Dual Circuit Brake Engineering Thread

[hndrsonj]

It doesn't matter what you want to call it. If one is recreating the GOVT approved split system for the late A2's you need that part.

When you are figuring how to install it the Manual calls it the pressure differential switch.

When you go to order the part by NSN the GOVT calls it a proportioning valve.

If we can verify the HMMWV switch is the same, the only part left to find is the master cylinder mount and that could be made if absolutely had to be.

 

[oddshot]

I don't know about most of you out there but my 2000 E350 4X4 van has 4 wheel disks and I wish it had more pressure to the rear brakes. My front brakes are always taking a beating. I understand the locking up first, but all I have ever know is front lock and rear seems to be along for the ride...lol. Jim

All true ...

Most vehicles with 4 wheel discs wear out pads at a rate of 2 sets of fronts to one sets of rears. To balance out the REPLACEMENT rate, some manufacturers designed the rear brakes with pads that are 1/2 as thick as those at the front.

FWIW ... I seem to remember that FIAT was the manufacturer.

Vans and pickup trucks are especially light in the rear end ... hence more brake bias towards the front.

oddshot

 

[Recovry4x4]

A 4 wheel drum vehicle should only have a pressure differential switch. Then again, proportioning might be required since one circuit is operating 4 brakes and the other 2 brakes.

 

[oddshot]

Quote:
Originally Posted by oddshot
BTW ...

I think we might be talking about TWO different things here:

A) replicating the dual circuit system found on the A3 ...

and

B) trying to come up with a (safe, reliable, cheap) dual circuit master cylinder as a basis to REPLACE the existing system. YES, I know that a booster (or a way to use mechanical advantage) will be required to reduce pedal effort.

oddshot


I hope we are talking about both. Hopefully we can sort it out though

You're a bit more optimistic than I am.

Its looking like the two conversations are getting confused ... and I'm not certain that there is a willingness to accept that there may be more than one way to address this.

Maybe two threads for the hydraulics is needed.

One for replicating the government system
and the other for gettin' creative.

If only for clarity.

oddshot

 

[Trango]

hndrsonj, you may be interested in some parts I have..... long ago, before I realized that the M35a2 platform had more limitations than I wanted to deal with, I purchased air over hydraulic parts from a Hino cab over truck - air treadle, master cylinders with bracket, and a few assorted air lines. I paid $150 and 4 hours removing those parts! I was dead set on installing them, so I got everything I thought would be useful.

I got this system after a good convo with Tom Bauer about his truck, and the value of split circuit brakes. Yes, you absolutely need air pressure with these brakes, but they're going to be light years ahead of military parts.

I now have 2 problems - I have a garage fridge with nothing in it, and a shelf in my storage shed with parts that don't have a home. Maybe you could help with both? PM or email me if you're interested. You're close enough to make this feasible - shipping would be more than I want for the whole system - a couple cases of beer?

Best,
Bob

 

[Welder Sam]

 

[G-Force]

I beleive if you look at the parts list in the SMARPI TM for dual circuit brakes the part number called out for the front wheel cylinders is 1 1/2" bore as compared to the stock single circuit which is 1 3/8".
Also, Gimpy, if you get the mounting bracket for the master cylinder that is listed in this Tm it has a mounting position on it for the winch pto engagement handle.
I also did some checking a while back and the master cylinder in the SMARPI Tm is obsolete from Bendix. The master used on the A3 was still a valid part number from Bendix but the reservoir (which is remotely mounted on the firewall) was obsolete......go figure......

 

[mikew]

G-Force,

Interesting on the wheel cylinders. Which SMARPI TM are you looking at?

The retrofitted A2's in SMARPI "SMI 209-2320-209-14&P" for modified M44A2 trucks does not show any changes in the wheel cylinders and the master cylinder's reservoir is not remote mounted.

I assume this SMI is for the Air Force split brake trucks. Remote reservoir and larger front wheel cylinders must be an A3 thing.

It also shows how to mount the PTO controls and details on building the various lines.

This is the retro fit I will do on my truck.

 

[frodobaggins]

You're a bit more optimistic than I am.

Its looking like the two conversations are getting confused ... and I'm not certain that there is a willingness to accept that there may be more than one way to address this.

Maybe two threads for the hydraulics is needed.

One for replicating the government system
and the other for gettin' creative.

If only for clarity.

oddshot

Well it seems we are hammering out one system right now. When we get that one done we can start talking about the others. I reserved some posts to consolidate, so even if it doesn't happen in this thread, we should put links here so we can catch them.

 

[hndrsonj]

Well it seems we are hammering out one system right now. When we get that one done we can start talking about the others. I reserved some posts to consolidate, so even if it doesn't happen in this thread, we should put links here so we can catch them.

The systems are basically the same. You just have to find equitable parts and not something off a pinto, remember there's 13K of weight here.

 

[frodobaggins]

The systems are basically the same. You just have to find equitable parts and not something off a pinto, remember there's 13K of weight here.

See, now you are confused. I know what you are talking about, but we are also talking about alternatives, like hydroboost etc. But I'm certainly ok with talking about one at a time. So let's keep going on the A3 /late deuce dual system.

 

[Trango]

Well, should there end up being a thread for creative solutions, that would be the place for this explanatory post:

I have all the parts to a 2 circuit, air-over-hydraulic foot treadle and master cylinder system. I painstakingly pulled this system from a commercial truck, with the intent of installing it into the M35a2 platform. Moreover, I don't really expect to recoup the cost of these parts - to see them used would be enough (although, some beer would be nice).

Yes, I did just spend a few weeks recently adapting S-cam airbrakes to my 5-ton-axled 4x4 project, and a few years ago I also pioneered the retrofit of 6 piston Porsche Cayenne calipers onto the Audi allroad, so I'm fairly comfortable with odd brake projects; however, the project represented by the air over hydraulic parts I have seems quite straightforward to me. I don't really have time or interest in shipping them, so I'm suggesting that anyone with interest in checking them out and picking them up in person, contact me.

Best,
Bob

 

[apm80814]

These guys claim to have worked out the solution:

M35A2 Dual Circuit Brake System Upgrade

 

[paulfarber]

Link works.. its a flash album of about 6 pics.

Turn off ad-blocker etc if you have them.

 

[apm80814]

I talked with the guys from m-series rebuild and he quoted me in excess of 2000 for the master cylinder and mount that will work with a winch truck.... plus more than 400 for a remote reservoir ???

If the link isn't working try M-Series Rebuild LLC, CUMMINS DIESEL engine for DODGE M37, M37B1, M43,V41, M56 military trucks, civilian power wagon, B1pw, B3pw, C3series, B3 series. then go to services and scroll down to m35a2 brake upgrade

 

[cbvet]

From a 2007 post I started, asking what I had,

Emaddo22 said - NSN is 5340-01-259-0257
It's a bracket for the dual brake system deuces.

 

[frodobaggins]

These guys claim to have worked out the solution:

M35A2 Dual Circuit Brake System Upgrade

From a 2007 post I started, asking what I had,

Emaddo22 said - NSN is 5340-01-259-0257
It's a bracket for the dual brake system deuces.

Looks pretty simple to fab.

 

[cjtroutt]

Nice Thread.
More info keep it coming.

 

[markaroe]

i thought this might be of interest to those with or wanting split brake systems.

It is the Supplemental Maintenance and repair Parts for the Split brake system.

I describes the system in good detail.

I don't remember where I got it but I believe it was the instruction used to convert Deuces to split circuit.

SMARPI 9-2320-209-14&P

 

[Welder Sam]

Thanks. Looks like ill need it for my 2 A2's w/w