brake system questions

[Cav Trooper]

First of all, I don't want to start any flame wars. What I am looking for is a thread or some other info that is a consise review of the pro's and con's of replacing a stock mc and drum brake system with a dual mc with or without changing the drums to discs. I don't intend to drive this daily, it's taged as a Historical vehicle. I'm torn between originallity and practicality and cost. I understand the safety concerns but really lean toward original. I just purchased the truck and still have to resolve brake issues such as pulsing pedal and as the brake system is used over a few miles, the pedal gets stiffer and stiffer, already had the left front drum lock up. Lots to do, fun to tinker with. My thoughts always been, if you build a street rod, the sky is the limit, do whatever you want with the whole package, fuel injection, blowers, pw disc brakes, electronic everything. If you are building a restored 1957 Chevy you go with what was factory then and live with it. I'm looking for facts and I'll draw my own conclusions.

Again, please no P---ing matches or flames. A lot of you here from what I've read so far have great experience and I want to draw from that, not just opinions.

BTW, I only had this truck since last Saturday, bought it "restored" more like a cross of a great start and a work in progress.
Thanks,
Cav Trooper

[Rick C]

I'm by no means an expert but have had my M37 for about 14 years. I run stock brakes with the dual master cylinder set-up. I replaced all the rubber lines and wheel cylinders when I started driving my truck as well as most of the steel lines. I chose the dual cylinder strictly for safety in case a line blows out. My M43 is still the original master cylinder. Both trucks stop pretty well as long as the brakes and pedal are adjusted like the manual says.
Rick

[Lifer]

Okay...first off, the stock single-mc system is perfectly adequate for the truck when it is used as intended. It is also the cheapest to maintain (until parts become unavailable, anyway).

The stock system with a dual mc is an improvement in that it will allow you to have brakes on two wheels if you lose the other two. Under normal operating condsitions, though, there is no difference in stopping ability.

Disc brakes are an expensive improvement, but WHAT an improvement they are! They are much more efficient than the stock drum brakes, much easier to maintain, and require no complicated adjustment procedures.

If you are a restoration "purist" who wants to show your truck, restore the original system. If you plan to drive it regularly, the stock system is "okay" but the dual mc may offer you some peace of mind.

If you want to make it a daily driver, a dual mc with front disc brakes will help make sure you don't rear-end the idiot who slams on his brakes in front of you.

Good street tires will also be of great value when making unexpected stops. The military NDTs are good in dirt, but can have you going "surfing" if the pavement is wet.

If you plan to do a lot of daily driving or if you plan to swap the stock engine for something with more beans, I would consider the dual mc, 4-wheel discs, and good street tires to be necessities.

That pretty much outlines your choices, I think.

Personally, I'm one of the "purist" type guys, but once I restored one, I'd still drive it.

[Cav Trooper]

Well, there's the rub, I want my cake and eat it too. The last time I drove one of these was in Nam, speed wasn't much of an issue, however, in Germany from Nuremberg to Stuttgart on the Autobahn, in the winter, no heater, 45mph sucked big time. I have just purchased the heater from Mr. Bizal along with lockout hubs and seat belts. Sure would like to get a little more speed, at least enough power to pull hills without downshifting to 3rd and 25mph. The truck has been restored but has a problem with the brakes at the moment, warped drum and just needing to be bled. That's the easy fix. The dual mc sounds good but I would assume that along with the dual mc one would need a proportioning valve? Which one, is there a difference, adjustments? The truck also has brand new military NDT's and I would like to keep them. I've been considering having them siped but have to find a local shop to do it and I don't know if that procedure helps all that much. It's going to be a fun winter, tinkering.

Thanks for the input,

Cav Trooper

[Paul in Kempner, TX]

Welcome, Cav Trooper. Here's an interesting coincidence. I just happen to be wearing one of my "Brave Rifles" shirts that I have to honor my son who recently returned from a tour in Iraq. He would have been known to other Cav Troopers as "Muleskinner Six". What is your Regiment and Squadron?

When properly maintained and adjusted, the stock brakes do a remarkable job. The pressure buildup you describe is usually the result of failure by the former owner to do a MAJOR brake adjustment following the factory/military service manual. These instructions are the same for the WC 3/4 and 1 1/2 tons, the "flat fender" Power Wagons, and the Dodge "M" series 3/4 tons. I have placed them on my Kempner Power Wagon Museum web site in a form that can be down loaded and printed out to give you a brake manual. Scroll down the main page to “BRAKES” under Frequently Asked Questions. If you follow the manual and the supplemental notes, you will have good brakes.

Don’t worry about “flaming” on this Forum. It only occurs when someone is presenting opinion instead of knowledge. I have about $3,000.00 worth of factory service manuals, Army Technical Manuals, and other Dodge references upon which I base my information. I do present opinions based on lessons learned from driving M37’s since 1963 and usually identify this content as being an opinion.

A common example of bad information about brakes is when someone tells you to adjust the rod that pushes the master cylinder piston. The manual says, unless you are replacing the master cylinder, do not adjust it. It affects the alignment of the piston in relation to the relief port - as explained and pictured in the manual.

History has shown it to be one of the best all-around on and off road trucks exactly as built. (My opinion) If you make only one change to enhance its off-road performance, the greatest single modification is equipping it with the 11.00 x 16 Michelins (My opinion, again).

Good luck. Enjoy your M37.

[MSeriesRebuild]

You already received a wealth of good brake knowledge. Many would disagree, but after doing both the disc system and the original system rebuilds many times, my honest opinion is this. The original system with all good components in place and correctly adjusted for optimum shoe lining drum contact surface is a good system. It will stop the truck just as good as the disc system. The plus side to the disc is getting rid of the drums which is the hard component to find in usable condition. Once the disc system is in place, all the normal wear items are simple over the counter stuff at the local auto parts store. There are no new drums and turning them does not solve issues long term. Neither system will compare to a current production vehicle system when you consider pedal effort and stopping distance. The disc system and the original drum system is VASTLY improved by adding a booster to the system. The most economical way to do this is to simply install a vacuum booster; it's a relatively easy install and well worth the cost and effort to put it in place. A dual M/C is a plus on the safety side of things, also an easy relatively inexpensive install. I've dealt with many customers concerning brakes; long story short, very few will be happy with the performance of either system unless a booster of some sort is added. It's just the world today's driver's have gotten used too. Nobody wants to stand up on the brake pedal when the need for a quick stop arises. You'll have to make that call in your situation. You have several options to building a very good system either way you go.

[Cav Trooper]

Thanks to all for your replies. I don't mind manual brakes as long as they work. My first several cars were manual brake systems. I think my first power brakes were on a 1966 Plymouth Fury III. I drove the M37's in the US, Germany and Nam. I like the nostalgia and the inherent eye contact factor I get with the truck. As long as I can maintain the original equipment without too much expense, I think I'll keep it. I agree that some parts will probably soon be too hard to acquire in any servicable condition and I am contemplating the disc swap, maybe next year. After the initial cash outlay and making an asessment as to what are the most critical issues to address first, I'll start down the keep it/toss it list. I gather the brake system swap would be in the $1200 range? I have noticed that every seal leaks also, looks like they may be a late winter project. The previous owner replaced all of the seals, did an engine rebuild. I am assuming that there is just too much wear on the seal surfaces of the shafts to allow the new seals to do their job. I see that there may be a seal kit offered of better quality? What can I expect to pay for that and does it include seal sleaves (not sure that's the correct terminology) they slip over and locktited onto the shafts to restore the seal surfaces. Again, a presumption, from working on older cars and machines, that is the way we dealt with worn seal areas. Lots of things to do, now just where to start throwing the $$$$.

BTW I was in the 2nd ACR Regimental HQ in Nuremberg, Germany in 67/68. HHT, Signal Corp. wireman, classified courier, classified document printer, etc. Worked in Commo message center, then in S1 and with S2. Spent few months in Nam 71st Assault Helicopter Co. Chu Lai, S. Vietnam. This truck was a toss up between an M151 Mutt and this, would like to have gotten a little newer but this was mostly restored and only driven in parades etc. Always like these, maybe a Mutt as a little brother later. The M37 seems to me a better choice for cruising around and out to the range as far as traffic safety.


Cav Trooper

[SOTVEN]

WELCOME ON BOARD CAV TROOPER. AS FOREMENTIONED, THE M37 BRAKES IF PROPERLY MAINTAINED AND ADJUSTED WILL STOP THE TRUCK MUCH BETTER THAN ITS NDCC NYLON TIRES CAN TOLERATE. THIS AT LEAST I FOUND IN MY EXPERIENCE. I HAVE HAD MY M LOADED WITH STUFF WAY ABOVE ITS CAPACITY AND THE BRAKES DID WHAT THEY WERE SUPPOSED TO. YET, SINCE I INTENT TO KEEP THIS VEHICLE FOR AS LONG AS I DRAW BREATH AND I INTENT TO DRIVE IT AND ENJOY IT TOO, I HAVE DECIDED TO SWAP TO DISCS. THE MAIN REASON IS THAT AS YEARS GO BY, LESS AND LESS I FEEL THE URGE TO CRAWL UNDERNEETH AND ADJUST/REPLACE THINGS. SO I WANT TO MAKE EVERYTHING AS EASY AS POSSIBLE MAINTENANCE WISE, SO I CAN ENJOY MY TIME OPERATING IT. AS FOR THE DUAL LINE MC, NO DOUBT THAT IT IS AN ADDED MEASURE OF SAFETY. YET, WHEN I FIRST GOT MY TRUCK ITS BRAKES WERE FAR FROM OK, AND WHEN I REALISED THAT, I WAS ALREADY DOING 35 MPH, SO CALMLY I USED THE EMERGENCY BRAKE TO SLOW DOWN AND EVENTUALLY STOP MY TRUCK. AND IT ENGAGES THE TRANSFER CASE REVOLUTION AS OPPOSED TO ENGAGE THE BRAKES THAT PERHAPS COULD HAVE BEEN TRASHED. I GUESS THAT IS WHY THEY CALL IT EMERGENCY BRAKE. REGARDING THE SWAP COST I AM NOT SURE, BUT CHARLES AT MSERIESREBUILD.COM MIGHT BE THE PERSON YOU SHOULD CONTACT. AND YES, I THINK SWITCHING TO COMPOUND TIRES AS OPPOSED TO NYLON WILL GREATLY IMPROVE YOUR STOPPING ABILITY. UNLESS YOU NEVER DRIVE ON WET PAVEMENT. THEN YOU ARE FINE WITH THE NDCC. JUST MY TWO CENTS

[Cav Trooper]

Thanks. Here's another question, I don't recall what tools were issued with the M37 such as jack, lug wrench etc. Were they in a bag in the side box compartment? I have the lug wrench but nothing else. Where's the best place to look for a set? I'm planning on going to the MVPA show in Crawfordsville, In. next weekend.

Cav Trooper

[52m37Hal]

Charles:
Can you please provide some details on adding a vacuum booster to the standard brake system? What booster works best and how is it installed.
Thanks
Hal

[billy]

Charles:
Can you please provide some details on adding a vacuum booster to the standard brake system? What booster works best and how is it installed.
Thanks
Hal

me too

[MSeriesRebuild]

If you are wanting to install with the original single circuit system, it's easy. You will need only 1 remote mount booster, not a lot of choices anymore, just pick one that is easiest for you to work with; will have to fabricate a good, steady bracket for it. We usually mount it on the inner frame rail. You will need a vacuum reservoir for best operation and a check valve. Once you have the reservoir and booster mounted, all that is left is vacuum plumbing and brake fluid plumbing. This should be clearly marked on the booster, or in instructions included with it. I'm sure you likely have further questions; if so just ask, I'll respond when I have more time.