M35A2 BRAKE MASTER CYLINDER TECHNICAL CHALLENGE

[saddamsnightmare]

February 2nd, 2008.

I will report back whatever I can find out from Memphis Equipment (and/or Boyce and/or Eastern Surplus)on the components, and prices if available as kits, also what they would charge to convert the vehicle on site (theirs) as no doubt their mechanics have done it before. I'm leaning to all new brake lines and hoses, and possibly wheel cylinders, even though this truck is only 22,000 out from the MWO rebuild, its still 18 or 19 years out of its last major shopping and starting to show it. I'm only 362 miles from Memphis, and if the Deuce feels up to it, I should be able to make it in just under 10 hours (no failures or screwups enroute), should they come up with an installed price that I can live with. Restoration is one thing, but when you think about it, sooner or later almost everything on these trucks is going to be repaired or replaced, and at some point they will no longer be the 1971 M35A2 or whatever, just a facsimile of it.
I'm seeing this at one trolley museum I work at, where so far about 50-75% of the structure below the belt rails under the windows, about 80% of the woodwork, and about 90% of the wiring has been replaced due to wear, rust, salt damage and poor maintenance over the last operational years (1941-1957) by Pittsburgh Railways Co., so sooner or later 4398
isn't going to be the 1917 car it started out to be. But, for the car to survive and be a viable running car, these repairs must be made, so it will be with our trucks.

Thanks again,

Sincerely,

Kyle F. McGrogan
1963 Mercedes Benz S404.114 Unimog (Swiss)
1971 Kaiser Jeep M35A2 Wo/W "Saddam's Nightmare" Vietnam and Desert Storm Veteran Deuce and a Half.

 

[saddamsnightmare]

February 3rd, 2008.

WOW! Wish I didn't need a CDL for one of those 900's, but that is a great way to arrange the brake system components, but on the Deuce the spare tire would sure get in the way of the master cylinder/proportioning valve/reservoir assembly!! Man, that setup is pure genius compared to the M35A series as built, just shows you what thiry or forty years can do for engineering. I figure I'd better stop at one duece and/or one M104/4/332 trailer, or the wife's going throw me out on my BURRO (and I don't even have a BURRO (crane)! Place Drool pans here!

Sincerely,

Kyle F. McGrogan
1963 Mercedes Benz Unimog S404.114 (Swiss)
1971 Kaiser Jeep M35A2Wo/W "Saddams Nightmare" Vietnam and Desert Storm Veteran Deuce and a Half.

 

[m-35tom]

the pics are of my duece, 900 series valve and pedal is what i used. air packs and dryer are from nissan UD truck.

 

[devilman96]

Following that argument, every part of the truck needs to be replaced...And installed by an "OD Iron authorized technician".

Come on now BW, you know me better than that... There are some things I cant comfortably advise people on doing is all, no more no less. If I sold half a kit to someone for a braking system and something failed it would carry a lot of liability on my behalf.

If you want an A3 cylinder and a valve, not a big deal I will go chase them down and stock them... But I cant in good conscience call it a kit like that…

Im on your side brother… The day im not I hope someone shoots me for it!

 

[Capt.Marion]

I don't know what y'all are willing to go through, but I made a post a week ago or so in the deuce hotrodding section about exhaust brakes. You can already get ones the right size for Deuces as take offs from like Isuzus and stuff. Perhaps that would be easier than digging all around for these dual brake systems. I remember Cranetruck did that, and he doesn't hardly use his service brakes while going down the mountains he works in. FYI.

 

[saddamsnightmare]

February 7th, 2008.

Gentlemen:

So far Memphis Equipment said that they have done the conversions on their trucks, when the Master Cylinders show up, but apparently AM General controlled the supply of the conversion sets for the ESP, and they are not commonly found. They can work trucks into their shop when their production shedule is slack. I will check with Eastern and Boyce Monday, Feb. 11th or Tuesday the 12th, if my repair work on the M35A2 permit (batteries to be changed out & replaced with DEKA 6tl's ordnance type, and an exhaust gasket fitted). Memphis did indicate the parts for conversion to a Turbo would run about $200-$250.00 without the turbo, "D" turbos were about $800.00 there, I believe.
So far, I should ask M35tom above for a diagram and list of what it took to do the conversion with the M900 Treadle brake and master cylinder system, or maybe he could do a photo article, as that does seem to be the best method so far. Does the M900 treadle brake system require the two Airpacks? I was told that the M35A2 could be modified with two master cylinders and two airpacks to get the same effect as the Modified M44A2 Split system used in the ESP trucks as noted above on Page 1 (I believe).
Personally, I feel that the added redundancy in the brake systems does justify the modification, given that my truck does move frequently in city traffic and on slightly hilly streets, and will vbe used for longer road trips once the bugs are shot out of her systems (1200 miles from Feb 2002 to October 2007, 250+ miles since January 2008 to date). Just my thoughts, but I do see others above thinking similarly.

I remain, Sirs and Madames,
Most Sincerely,

Kyle F. McGrogan
1963 Mercedes Benz Unimog, S404.114 (Swiss)
1971 Kaiser Jeep M35A2 Wo/W "Saddam's Nightmare" Desert Storm and Vietnam Veteran Deuce Truck.

 

[kochevnik]

I know this is an old thread ...

So based on my googling skills it looks like the dual brake master cylinders for the '87-'89 USAF trucks / M35A3's are impossible to find ???

Is there a rebuild kit available anywhere ?

If not, then what do people who own a USAF or M35A3 do if they have MC problems ?

Are there any civilian MC's that would do the trick ?

And a dumb question - what if you modified the brake assembly so that it pushed on two individual M35A2 MC's - is this going to double the amount of force that the driver would have to exert to stop the truck, or is that force dependent on some other system component ? If this doesnt double the force, it seems you could just set up two completely seperate brake systems working off one brake pedal assembly - I'm sure a decent machinist could modify the pedal assembly to work.

Seems hard to believe that M35A3 folks can never find another brake MC if the one they have gives up the ghost.

 

[paramedic7831]

I know this is an old thread ...

So based on my googling skills it looks like the dual brake master cylinders for the '87-'89 USAF trucks / M35A3's are impossible to find ???

Is there a rebuild kit available anywhere ?

If not, then what do people who own a USAF or M35A3 do if they have MC problems ?

Are there any civilian MC's that would do the trick ?

And a dumb question - what if you modified the brake assembly so that it pushed on two individual M35A2 MC's - is this going to double the amount of force that the driver would have to exert to stop the truck, or is that force dependent on some other system component ? If this doesnt double the force, it seems you could just set up two completely seperate brake systems working off one brake pedal assembly - I'm sure a decent machinist could modify the pedal assembly to work.

Seems hard to believe that M35A3 folks can never find another brake MC if the one they have gives up the ghost.

bump. Would 2 linkages from same brake work using one MC for the rear and one for the front?

 

[Keith_J]

Primary pressure is pedal force divided by the net piston area. Running two cylinders in tandem so one pedal movement actuates both will result in half the primary pressure. Furthermore, if one master cylinder is used for the front while the other actuates the rear, the pressure differential will be far greater because the rear would have 4 wheel cylinders to actuate, meaning double the volume which is master cylinder stroke length

The booster amplifies pressure on a constant ratio.

The best return on investment is to make sure all six wheel cylinders are upgraded from the crappy plain-ended wheel cylinder springs to ones with cup exppanders. I've harped on this before, the contractor that supplied the wheel cylinders used plain-ended springs which allow the cups to leak. If the leakage isn't trapped by the boots, you have a leaking wheel cylinder. If the boots trap the brake fluid, the brake pedal drops to the floor.

Also, make sure all brake lines are in excellent shape.

 

[Clay James]

The best return on investment is to make sure all six wheel cylinders are upgraded from the crappy plain-ended wheel cylinder springs to ones with cup exppanders. I've harped on this before, the contractor that supplied the wheel cylinders used plain-ended springs which allow the cups to leak. If the leakage isn't trapped by the boots, you have a leaking wheel cylinder. If the boots trap the brake fluid, the brake pedal drops to the floor.

Also, make sure all brake lines are in excellent shape.

My buddy are redoing our front axles and the entire brake system and the wheel cylinders and both trucks had the plain ended springs. My wheel cylinders did have a little fluid under the dust boots. The brakes did work great, especially after I adjusted all the brake pads, but I will feel much more confident with the brakes when I get the correct stuff on.

 

[FrankCopren]

In the Real world, has anyone had a total brake failure on their M35A2??
Or does anyone know anyone who had this failure? Not a friend of a friend of a friend

 

[doghead]

Yes


Sent from my iPhone using Tapatalk

 

[m715mike]

In the Real world, has anyone had a total brake failure on their M35A2??
Or does anyone know anyone who had this failure? Not a friend of a friend of a friend

Last year (if I recall correctly) someone had a total break failure on their recovery trip. Going on memory, they purchased the truck from a dealer and had already driven it 3 hours on their way home when the breaks failed. It resulted in a bad accident and their Deuce finally came to a stop inside a restaurant. It made the news and there is a thread on here discussing it.

 

[FrankCopren]

After turning wrenches for a few years (repairs, service and restorations) my gut tells me that if the owner of a M35A2 is on top of his (Her) repairs and service. That losing your brakes is really a remote subject. If the owner is not 100% comfortable with going through the brake (and air) system then they should hire a qualified mechanic. Soon I will drive my 1967 M35A2 across the country. Before I go I am going to replace all of the flexible brake hoses and any steel lines that look questionable.

 

[rustystud]

After turning wrenches for a few years (repairs, service and restorations) my gut tells me that if the owner of a M35A2 is on top of his (Her) repairs and service. That losing your brakes is really a remote subject. If the owner is not 100% comfortable with going through the brake (and air) system then they should hire a qualified mechanic. Soon I will drive my 1967 M35A2 across the country. Before I go I am going to replace all of the flexible brake hoses and any steel lines that look questionable.

That should be just the start of your repairs. You need to check/repair/replace your wheel cylinders, air-pac (or pacs), master cylinder and drums. Then properly adjust everything. While your in there also check your wheel bearings and repack them.

 

[FrankCopren]

Rusty, thank you for the sound advice
So far I have replaced the wheel bearings and races. Cleaned and inspected the drums, wheel cylinders and shoes. It looks like the good folks@ Fort Dix just replaced the shoes before I purchased the truck.
Dropped the fluid out of the three axles, the transfer case and the main box (through a VERY fine screen). Thank goodness NO metal came out, Refilled with the DELO gear lube.

 

[Valence]

In the Real world, has anyone had a total brake failure on their M35A2??
Or does anyone know anyone who had this failure? Not a friend of a friend of a friend

Last year (if I recall correctly) someone had a total break failure on their recovery trip. Going on memory, they purchased the truck from a dealer and had already driven it 3 hours on their way home when the breaks failed. It resulted in a bad accident and their Deuce finally came to a stop inside a restaurant. It made the news and there is a thread on here discussing it.

Of course doghead and m715mike are right. This is where the hilarious, but albeit serious subject, saying comes from when how to stop a run away deuce (or even about general maintenance) "Go to Subway. They know what to do."

http://www.steelsoldiers.com/showthread.php?138549-Deuce-Crash-Subway-drive-thru
Pictures are in post #21.

http://www.wgal.com/news/just-in-mi...gn=FBPAGE&utm_medium=FBPAGE&utm_source=Social

 

[FrankCopren]

Has anyone ever talked about an emergency system that would apply the rear brakes if the system fails?

 

[FrankCopren]

Call me Perry (paranoid) but I have inspected the inside of my air tanks with a small scope with a camera. I also did this on my 1948 Peterbilt Logging truck

 

[Valence]

Call me Perry (paranoid) but I have inspected the inside of my air tanks with a small scope with a camera. I also did this on my 1948 Peterbilt Logging truck

That's a good idea! Is this equipment you owned or did you have to find a shop that had one? (I assume for looking at pistons and inside the engine)