dual circuit brakes

[roady]

Hey Guys,

Is there a quick way to tell if I have dual circuit brakes on my new Deuce. I just got it last weekend and got it in the garage and getting ready to check everything out real good. I am pretty sure I have a late model M35a2C Deuce but am waiting for CARNAC to get back with me in the 2010 VIN thread. I did do a search and only found a few threads on it and the TM manuals didnt seem to cover it that I seen.

Thanks for any help in advance. I will try to get some pics of it on here soon.

 

[FMJ]

Here you go.

 

[srodocker]

if its a m25a2c then its a USAF truck which has dual brake system

 

[roady]

Hey guys thanks a bunch. I am reading that TM manual now. I missed that one somehow. I guess that means that CARNAC may not be able to get me any VIN info on the truck since it is an Air Force truck.

 

[OD_Coyote]

FWIW - I have an ex USAF M35A2C and it does not have dual circuit brakes.
My truck is a 1986 model...My oldest son has a ex-USAF M35A2C which is 1988 model and it has the dual circuit brake system.
The easiest way I found to tell without looking under the truck is to look for the red brake system warnng indicator centered below the speedo and the tach.

 

[roady]

I do have the brake light but thought I shouldnt go by that alone. I was looking under the truck today and noticed the master cylinder looked like a dual circuit system but wanted to check with the pros. I think mine is an 1987. Is the brake system any better then the older system other then being dual circuit?

 

[roady]

Here is one picture of it. I am pretty happy with it so far. Cant wait to get the title though.

 

[OD_Coyote]

I do have the brake light but thought I shouldnt go by that alone. I was looking under the truck today and noticed the master cylinder looked like a dual circuit system but wanted to check with the pros. I think mine is an 1987. Is the brake system any better then the older system other then being dual circuit?

Look on the passenger side of the truck behind the battey box... If see an airpack there then you have a dual circuit brake system.

 

[mdmorgan]

you should have 2 airpacks, 1 on each frame rail pointing in opposite directions. And yes they are better because if you loose brakes in one system the other will still stop you. mine has dual circuit brakes.

 

[roady]

So other then being dual circuit is everything else the same? So I could buy brake linings or wheel cylinders for any Deuce and they would fit.

Thanks again.

 

[mdmorgan]

i would think so but not 100% sure

 

[powerhouseduece]

So other then being dual circuit is everything else the same? So I could buy brake linings or wheel cylinders for any Deuce and they would fit.

Thanks again.

Just bring it by the shop and ill tell you!

The wheel cylinders, liners, and every thing would be the same. The only thing diffrent is you you have to buy a air pack rebuild, you have to order 2 kits!

 

[G-Force]

According to the research that i've done on this, the front wheel cylinders are 1 1/2" bore. The wheel cylinders on the rears (both) should be 1 3/8" bore. If you happen to pull the wheels and drums off I would appreciate it if you would measure the bores on the front and rear wheel clyinders to confirm. Also, the master cylinder is no longer available from Bendix. There isn't even a rebuild kit available. BUT the bore is 1 3/4" according to Bendix AND the master for the M35A3 is still available. As far as I could find out the only difference is that the reservoir is remotely mounted in the engine compartment on the passenger side. Also, if you could measure the bore on the master cylinder and confirm that it is 1 3/4" and let me know I would appreciate it also.

 

[roady]

G-Force,

It may be awhile before I get to pulling it all apart to get the measurements for you. When I do get to it I will let you know. The brakes feel real good but I dont want to go by feel. I dont mind putting in some well earned sweat equity to make sure everything is good to go and flushed out.

Matt,
I do got to get to your shop to see what you have going on there. As soon as I get my title I will bring it buy. You are always welcome to come by my shop also. I always have some of your favorite stuff in the fridge......

Mike

 

[wsucougarx]

Ok, if it's an 87 and later then it more than likely has a dual circuit braking system. The only way to really verify is checking for the presence of two airpacks.

You cannot go off the presence of the red parking brake light in the middle of the dash cluster. As I have seen that on some early '70's trucks as an add on. All that light does is show you have your parking brake on. The later USAF trucks had a blue warranty dataplate on the dash. Check it for 87 or 88. Also the serial number also will help tell you the year of the truck with these later years truck ie a 1988 truck starts with 88k...... and 1987 starts with 87k...... Hope that helps

 

[G-Force]

Roady,
i would GREATLY appreciate it if you did let me know.

 

[roady]

SN starts out with 87K. Thanks that helps me at least confirm the year.

 

[powerhouseduece]

Matt,
I always have some of your favorite stuff in the fridge.....

SOLD!!!!!! Ill have to bring the M818 out as soon as I fix all my rear axle seals. (might be a while!)

 

[hogtruck]

Pics of airpacks and master cylinder and linkage.

 

[Keith_J]

Just take the master cylinder hatch cover off and look. Dual circuit have plastic fluid reservoir with a cap that is removed by hand. It also is a PITA to add fluid since the hole in the cross member doesn't line up with the master cylinder opening.

Yes, shoes, wheel cylinders and all other parts, save hard brake lines, are the same.