Another stupid idea, ignore this thread.

[montaillou]

So...I was thinking and hashing out ideas with a friend. What if an additional tank was connected to the air pack, utilizing 1 way valves, such that should an air line spring a leak, this additional tank would provide emergency air for stopping? It would be a redundancy system and activated by loss of pressure.

Depending on the size of the tank, could even provide a few stops.

I've been looking, the deuce tanks are rated to 250psi, and I'm not adverse to using them, only finding a spot to mount 2 and the cost of the tanks/brackets is a little steep. Many modern tanks have brackets built in, but mostly I'm seeing 200psi. Going with 1 larger tank
(I have an air dryer, so I don't need a second tank to collect moisture) would be easier to find a spot to mount.

With the understanding that, yes, I don't deserve and/or am not educated/skilled enough to drive this truck, what other CONSTRUCTIVE suggestions might someone have about this topic? Is there a reason why this won't work?

Has this come up already?

 

[frank8003]

More than enough HP air will work as long the the Air Pac does.

 

[Elk1111]

I believe you still wouldn’t have any brakes due to the leak itself and the fact that itall one circuit. To truly fix this issue would be to isolate each axle so that if you had a leak you would still have 4 wheels with functional brakes.
Of course even better would be 3 master cylinders connected to 3 air packs connected to 3 axles.
Can it be done???? Anything can be done with enough money, imagination and time.

 

[montaillou]

3 master cylinders connected to 3 air packs connected to 3 axles.

Yeah, I've thought about this.

However, I have more imagination and time than money.

More than enough HP air will work as long the the Air Pac does.

I'm afraid I don't quite understand what you're saying here. Couple years back, on the freeway, one of my bleeder valves failed. The air warning told me I was low on air. I was in the right lane, and was able to get onto the side of the road and immediately started slowing the truck down, air ran out just as the truck came to a stop. Had I not been able to get over right away or been on a hill, I'm not sure I would've been able to stop in time.

With a single circuit system, I get a leak or failure anywhere and I'm SOL. Yes, I would like to get a dual circuit system, and it's on my rather long, to-do list, but, unless my initial post has some major flaws, I also like a redundancy fail safe system. A separate air tank and some hose, connected only to the air pack and activated only on loss of air, doesn't sound as expensive as doubling or tripling up air packs/circuits and would address other parts of the system that can fail.

 

[Mullaney]

Yeah, I've thought about this.

However, I have more imagination and time than money.

.
Don't we all!?

 

[98G]

The most probable failure modality is a leak on the hydraulic side. Additional air won't resolve that.

This has been beaten to death multiple times. Everyone who gets a deuce decides to resolve the brake problem.

Unfortunately, there is no really slick way to do it. Options are -

1) dual circuit systems, but these can't be retrofitted easily.

2) just convert to a real airbrake system with springbrakes that activate if you lose air. This is neither cheap nor easy. M1 guy in California did thus on his M818. I don't know of anyone who did it to a deuce.

3) Meticulous maintenance and treat every stop as if you might suddenly lose all braking ability. This unfortunately is the most realistic solution and what the vast majority of us do.

4) remote master cylinder reservoir. This gives you notice on leaks, and perhaps a bit of extra warning if you burst a line. But not really a satisfying solution.

There's certainly no harm in additional air, partitioned behind a valve or not. It just doesn't fix the most likely fail.

Come up with a good solution and we'll all employ it...

 

[simp5782]

Pinion brake only use a air disc brake caliper pad set. Modify the mounting bracket.

Add a trolley valve to your truck that can apply that force as needed to stop.

Mrap air disc stuff was abundant and cheap for awhile there.

 

[JD4044M]

Was told on some School Buses there is a emergency air tank incase the brakes lock up on train tracks, intersections ect you can use to move the bus full of kids to safety. I know what your talking about needing extra air once in a while. My M1078 is great except in Parades going like slow walking speed and stopping off and on for a mile or so! I had to start kicking it out of gear so I could get the air over 90 psi. Darn tape covered buzzer is loud! I have a Fresh Air Pack tank rated 4200 psi and was thinking hey with a regulator you could solve a idle engine slow speed ride the brake issue. Convoys on USFS dirt roads on hills can also burn up air out of your control. So a air tank has passed my mind. I had one inside my Water Tender so I could put on a air supplied Full Face Mask and drive thru thick smoke still. Liked going home from wildfires cheap insurance.

 

[M37M35]

So...I was thinking and hashing out ideas with a friend. What if an additional tank was connected to the air pack, utilizing 1 way valves, such that should an air line spring a leak, this additional tank would provide emergency air for stopping? It would be a redundancy system and activated by loss of pressure.

Would be easy to do. Just tee the new tank into the line going to the airpac, and put a check valve between the tee and the factory tank. It would provide air only to the airpac and the check valve would isolate it from the rest of the system.

 

[montaillou]

Would be easy to do. Just tee the new tank into the line going to the airpac, and put a check valve between the tee and the factory tank. It would provide air only to the airpac and the check valve would isolate it from the rest of the system.

That's what I thought.

I know it won't solve other problems, ie: air pack leaking, still only one circuit system. But in my real life example, it would've come in handy.

I am looking towards getting a dual circuit system to address that issue. This would be in addition to that, and not very expensive.

 

[Mullaney]

Was told on some School Buses there is a emergency air tank incase the brakes lock up on train tracks, intersections ect you can use to move the bus full of kids to safety. I know what your talking about needing extra air once in a while. My M1078 is great except in Parades going like slow walking speed and stopping off and on for a mile or so! I had to start kicking it out of gear so I could get the air over 90 psi. Darn tape covered buzzer is loud! I have a Fresh Air Pack tank rated 4200 psi and was thinking hey with a regulator you could solve a idle engine slow speed ride the brake issue. Convoys on USFS dirt roads on hills can also burn up air out of your control. So a air tank has passed my mind. I had one inside my Water Tender so I could put on a air supplied Full Face Mask and drive thru thick smoke still. Liked going home from wildfires cheap insurance.View attachment 840752

.
Need to be really careful with Truck Air mixed with Human Consumption Air.

Truck compressors are not filtered. If you need to consider tapping into your truck air, there are filters - cascading levels of filtration - that dive supply stores would sell. Another idea might be to talk to your local Fire Department about how they filter SCBA air.

Oil coating your lungs with your already existing COPD could be a disaster.

---

Adding more air tanks under the bed of your truck is a definite possibility but with the three you already have - that should be enough. Maybe there is a leak? Chock the wheels and attach "house air" (under 150#) to the drivers side glad hand. That will air up your truck. If you have a leak it will be easier to find with the motor off.

 

[montaillou]

The stock tanks are rated to 250psi. Is this military engineering overkill or is there a reason they need to be so high? Looking around for tanks, I see 150psi is pretty common, 200psi is less common.

My solution to driving through smoke is to wear a full face mask with filters.

 

[M37M35]

That's what I thought.

I know it won't solve other problems, ie: air pack leaking, still only one circuit system. But in my real life example, it would've come in handy.

I am looking towards getting a dual circuit system to address that issue. This would be in addition to that, and not very expensive.

Another thought...
Install the extra tank, but instead of a check valve, use a pressure protection valve set for say 70 psi. Then the new tank would add extra capacity to the system for airing up tires or running air tools. But if the main system leaked, the PPV would isolate the extra tank at 70 psi to supply the airpac.

 

[M37M35]

The stock tanks are rated to 250psi. Is this military engineering overkill or is there a reason they need to be so high? Looking around for tanks, I see 150psi is pretty common, 200psi is less common.

As long as that 150 psi is the 'safe working pressure', it'll work fine. The pressure on a deuce should be about 120 psi. Just make sure there's a relief valve in the system in case the governor goes bad and doesn't shut the compressor off.

 

[montaillou]

safe working pressure

Yeah, looking for tanks, they don't always list "working pressure" or "burst pressure". I'm looking at the Haldex 19820 or 19821. Some sellers list 150 as the burst, but Haldex makes them and lists 150 as the working pressure. I figure some sellers just don't have a very detailed description form.

 

[Floridianson]

Myself always thought an air dryer would be a nice thing to add to the Deuce. If not a whole dryer then small water trap / filter on the line that feeds the air pack.

 

[Mullaney]

Myself always thought an air dryer would be a nice thing to add to the Deuce. If not a whole dryer then small water trap / filter on the line that feeds the air pack.

.
Does seem like a dryer would be a nice addition. Then again too, wonder if the old guys who drove a deuce were responsible enough to drain their air tanks daily? Maybe they didn't need an automatic spit valve to manage their air system... I really wonder how dry the air is on the "dried" side of the plumbing?

OR is it just an automatic purge in the low spot of the air system?

 

[Floridianson]

My thought is just to keep any moisture / crap out of the air pack that can cause premature failure. Now when I replaced the air dryer on the 1088 I did a test after driving it. I took a paper towel and taped it to a piece of cardboard. Held it up to wet tank and all the other tanks and opened the pet cocks. One very small drop of moisture was on the paper towel from wet tank. Water traps a little better in the tanks than oil and that is why we need a good oil coalescing filter along with the desiccant filter.

 

[cattlerepairman]

@montaillou I think your idea is interesting and I also do not think it addresses the real weak spot of single circuit air assisted hydraulic brakes. The brakes work fine without air pressure (albeit not as effectively). There is a mechanical connection between the pedal and the hydraulic portion of the brake system. The air part only provides additional "oomph" (augments your thigh muscles working the pedal).

I am not at all worried about stopping in the context of losing air pressure. I am worried about stopping in the context of losing the hydraulic part of the system.

Your idea therefore appears to me as a solution in search of the problem.

A minimum would be a conversion to air brakes (on at least the rear axles) with spring brake chambers that apply the spring brakes in case of system failure.

I agree with @98G

 

[montaillou]

Had a much longer post here, I decided to remove it.

Whatever.