Lets talk about brakes...please

[Djstorm100]

I'm in the market to get my first Deuce and my major concern is stopping. Is there a best bang for the buck brake upgrade other than going to disk and also to have a back up system in case air is lost? I know I would still have some brakes but not power. Would like to have back up power system, if that makes any sense.

Also how would one go about replacing the hardlines that run along the frame rails? From my searching those are 5/16 tubing and from axle to the cylinders are 1/4

 

[rebelqwes87]

All of the hard lines are a available at your local parts house and are simple to replace. I've always ordered my rubber lines from an online supplier. As far as upgrades go disk conversions are pricey. Install a remote reservoir and make it part of your pre trip inspection.

 

[Djstorm100]

All of the hard lines are a available at your local parts house and are simple to replace. I've always ordered my rubber lines from an online supplier. As far as upgrades go disk conversions are pricey. Install a remote reservoir and make it part of your pre trip inspection.

I would have to order a roll of it, even the napa and car quest just keeps the 6 foot sections in.

 

[rebelqwes87]

I've only replaced some sections, never needed more than 6' I guess.

 

[clinto]

I'm in the market to get my first Deuce and my major concern is stopping.

Good thinking. Stopping is important.

Is there a best bang for the buck brake upgrade other than going to disk

Before we go any further, I want to ask why you think it needs upgrading. My personal truck will lock all 10 tires at speed.................. and that's with a 100% stock system with old airpacks. If the stock braking system exceeds the capacity of the tires, what good will additional stopping power do? This sounds smart alecky, but it isn't.

A lot of people say the brakes on these vehicles needs upgrading, but I think they must have trucks with brake system problems because when the system works right, it is extremely effective.

and also to have a back up system in case air is lost? I know I would still have some brakes but not power. Would like to have back up power system, if that makes any sense.

I am sure there is some way to rig up a couple more air tanks and valve them in a way that mimics the safety brakes on an M105A2 but I think the complexity of creating such a backup would far exceed the statistical probability of such an event ever occurring.

Also how would one go about replacing the hardlines that run along the frame rails? From my searching those are 5/16 tubing and from axle to the cylinders are 1/4

Since no one offers prebent lines, you'll need to buy bulk brake lines and bend/flare them to match your factory units.

 

[Pugsley]

The thing you should be more worried about is that it is a single circuit system. Blow any line and you have no brakes.

 

[Flyingvan911]

Look for a late 80's Air Force deuce with the dual circuit brakes or do the dual circuit modification. Basicaly it is two brake systems operated by one brake pedal. Other than that, as said above, add a remote reservoir and keep on top of your preventive maintenance.

 

[rustystud]

If you have a single circuit brake system, upgrade to a dual circuit. Peashooter sells or did sell the brake lines . He has an excellent post about the brakes. As far as redundancy of systems goes. If you loose air pressure, you still will be able to stop before all the air is gone. As soon as that little buzzer goes off, pull off the road ! Our busses us air for everything. So we have on average 9 tanks with one way valves between them. Even with that, if you start to loose air pressure you pull off the road !

 

[Robo McDuff]

Good thinking. Stopping is important.

Before we go any further, I want to ask why you think it needs upgrading. My personal truck will lock all 10 tires at speed.................. and that's with a 100% stock system with old airpacks. If the stock braking system exceeds the capacity of the tires, what good will additional stopping power do? This sounds smart alecky, but it isn't.

A lot of people say the brakes on these vehicles needs upgrading, but I think they must have trucks with brake system problems because when the system works right, it is extremely effective.

Like the posts above, the main reason for me (M51A2) to want to upgrade before going on the road is the single circuit. The problem is not that in itself the brakes are not good enough to stop the truck when all is OK. The basic problem is that even a new system can blow a seal or break a flex hose. When that happen, you have a lot of dead weight on today's quick-moving unforgiving PUBLIC roads.

These trucks were designed for war-time situations slow moving, in a time that most passenger cars had single circuits as well, where much sturdier and there was less traffic anyway. These trucks were made to drive, not to brake. Today, with our MV hobby, we go out on public roads in traffic moving much more quicker, drivers not paying attention (phones, texting), and lots of kids running around getting in front of cars while playing.

I will gladly install a second MC and airpack from these trucks and make it dual; even today the individual components are good enough for the trucks to use in daily traffic.
As to the single circuit system, what was good enough 60 years ago today just does not cut the cake anymore.

 

[Djstorm100]

Good thinking. Stopping is important.



Before we go any further, I want to ask why you think it needs upgrading. My personal truck will lock all 10 tires at speed.................. and that's with a 100% stock system with old airpacks. If the stock braking system exceeds the capacity of the tires, what good will additional stopping power do? This sounds smart alecky, but it isn't.

A lot of people say the brakes on these vehicles needs upgrading, but I think they must have trucks with brake system problems because when the system works right, it is extremely effective.

I am sure there is some way to rig up a couple more air tanks and valve them in a way that mimics the safety brakes on an M105A2 but I think the complexity of creating such a backup would far exceed the statistical probability of such an event ever occurring.


Since no one offers prebent lines, you'll need to buy bulk brake lines and bend/flare them to match your factory units.

It's not stopping power I'm worried about, but while it is great to think about upgrading it if necessary, it's the single system going out. I saw peashooters post last night and was reading up on it, just don't fully understand how each system would be independent of one another unless there is a one way valve/check valve of some sort. Dual systems do not have 2 wheel cylinders per wheel but tie back in together as one system before the brake lines meet the wheel cylinder.

The thing you should be more worried about is that it is a single circuit system. Blow any line and you have no brakes.

You'll have brakes (if air blows) but if hyd line goes, well you can't Fred Flintstone it to stop.

 

[m-35tom]

dual MC, 2 airpacks, one for the front one for the rear.

 

[Pugsley]

Correct me if I am wrong... But you can mount the second air pack any were you want as long as you run the lines to it and it is orientated in the right direction?

 

[ke5eua]

I can say from experience you can indeed stop a deuce with no air. You might have to throw your pants away afterwards but you can.

As far as a 60 year old system not cutting it anymore. As long as it is maintained properly it is still good.

My 818 has air over hydraulic and I have locked all 10 up a couple times due to 4 wheelers.

 

[nk14zp]

Good thinking. Stopping is important.



Before we go any further, I want to ask why you think it needs upgrading. My personal truck will lock all 10 tires at speed.................. and that's with a 100% stock system with old airpacks. If the stock braking system exceeds the capacity of the tires, what good will additional stopping power do? This sounds smart alecky, but it isn't.

A lot of people say the brakes on these vehicles needs upgrading, but I think they must have trucks with brake system problems because when the system works right, it is extremely effective.



I am sure there is some way to rig up a couple more air tanks and valve them in a way that mimics the safety brakes on an M105A2 but I think the complexity of creating such a backup would far exceed the statistical probability of such an event ever occurring.




Since no one offers prebent lines, you'll need to buy bulk brake lines and bend/flare them to match your factory units.

Ditto. If your brakes are in spec. they don't need upgrading.

 

[m-35tom]

Correct me if I am wrong... But you can mount the second air pack any were you want as long as you run the lines to it and it is orientated in the right direction?

correct but there is no orientation, just a top. you can mount them anywhere on the truck, facing any direction. mine replaced the spare tire.

 

[welldigger]

Just keep in mind how expensive converting a single circuit system to a dual circuit system will be. My best advice is to find a truck with this system in place already if you want to go that route.

Keep the single circuit system maintained and you shouldn't really have any problems.

 

[jamasonodom]

Well i have just converted my 91' m35a2 to air brakes. Man its not been too bad either. We use this rig just to pull out school buses on these muddy south ga roads and the brakes have been crazy since they bought this thing. So with a little math and time she has brakes on the first rear axle. This week i will b finishing up on the rear most axle. Best thing it has all been stripped off an old school bus we had! Cheap conversion for us

 

[jamasonodom]

I took a bunch of pictures too will try to post once i figure it out

 

[Robo McDuff]

I can say from experience you can indeed stop a deuce with no air. You might have to throw your pants away afterwards but you can.

As far as a 60 year old system not cutting it anymore. As long as it is maintained properly it is still good.

My 818 has air over hydraulic and I have locked all 10 up a couple times due to 4 wheelers.

I made an emergency stop when the DoT inspector asked me to on a test ride. I warned him that it might be too good. He would not listen so almost hit his head to the windows when I stopped the truck extremely good and quick. That is not the point. The system functions perfect even today. Unfortunately, it does not have a back-up. So if a brand-new seal or line breaks (can always happen) you have NOTHING left to fall back upon. A second identical air pack and master cylinder and splitting that 60-year old system in two 60-year old systems. That, I will trust my family's lives with.

Dual-circuits were not introduced because the actual braking action is better. It aims to save your behind when the unexpected happens and the "should not happen" becomes "oh my, just did happen"

 

[m-35tom]

Just keep in mind how expensive converting a single circuit system to a dual circuit system will be. My best advice is to find a truck with this system in place already if you want to go that route.

Keep the single circuit system maintained and you shouldn't really have any problems.

it doesn't have to be expensive. that usually happens when you cannot do it yourself. i re-engineered the entire brake system for around $400 and got an air dryer as well.