Air Pack bypass

[3rdmdqm]

I have recently seen on other forums where Deuce operators have removed the airpack completely from the brake system and kept the braking system with the master cylinder only. I’m curious about this. Others have indicated the brakes work fine with no issues without the airpack. Other than the obvious having to apply more pressure to the brake pedal, has anyone done this long term and are there other issues that are created by doing this that are not obviously apparent?

 

[Barrman]

The airpack is just a brake booster. Sure you can plumb around it.

However, when they work they work really good. The older long style air packs are pretty easy to rebuild with parts out there.

 

[G744]

They were engineered into the brake system to ensure proper operation under any conditions.

Removal would make an accident more likely to occur, especially in today's traffic.

If you don't want to or can't repair everything in the G742 series (or any tactical vehicle, for that matter) trucks, buy new or reliably rebuilt parts, and have them properly installed. The last thing anyone needs is a injury or wrongful death lawsuit, as a result of such thinking.

 

[Guyfang]

If it wasn't needed, you can bet it would not be there.

 

[HDN]

I'd leave the air packs in the system.

"We can go on without easier brakes."
- No one ever

I just hope I never have the experience of losing air on a truck that has dual-circuit brakes, like mine. They're stiff even with air assist!

 

[Guyfang]

Its not that bad. Just have to start stopping sooner. If you have to go a long ways, it will keep your leg in shape.

 

[swbradley1]

I had the pleasure of buying an M813 that the air pack was bad. The truck would stop but like Guyfang says, you plan and look miles in front of you for where you might have to stop and your legs will get a work out. In my case Gimpy drove it home for me and I ran chase.

When we put it in the barn I had already ordered a good used air pack and promptly replaced it. Worked great until I sold the truck.

 

[M813rc]

Planning your stops further back only works when you don't have to try an unplanned stop.

Think about liability. If you get in a serious collision, one of the first questions you'll hear in the lawsuit is "So, you removed part of the vehicle's stock brake system??"
Your insurance will probably be able to exit stage right at that point.

Cheers

 

[HDN]

Planning your stops further back only works when you don't have to try an unplanned stop.

Think about liability. If you get in a serious collision, one of the first questions you'll hear in the lawsuit is "So, you removed part of the vehicle's stock brake system??"
Your insurance will probably be able to exit stage right at that point.

Cheers

This is a pretty big deal right here!

So where can we currently get stuff to rebuild air packs? Last I knew the kits for rebuilding the short air packs didn't work due to wrong-size parts. I'm not sure what the status is for long air packs.

 

[Barrman]

I just searched m35 “airpack rebuild kit” and got multiple hits for kits under $100. They are probably all for long units.

 

[LowTech]

Just picked up an air pack rebuild kit for the long version from Erik's for under $100
www.eriksmilitarysurplus.com

"Sent w/o me knowing"

 

[msgjd]

I "bypassed" a bad air pack and operated that truck for many years that way as a "flatland" haul truck.. But Never was on the road with it... There were no issues to any other part of the system from doing it, but your leg(s) will grow.. Yes it can be done in an emergency if there's a pack failure and you need to get to a safe place, but as everyone has said, plan accordingly for the reduced braking power.. But woe to all involved should someone ahead of you stop suddenly without warning, the extra following distance you had could disappear in a really really big hurry

Open your petcocks and try it off-road at 15-20mph or more.. Then you will know the difference

 

[Jeepsinker]

No way I'd ever condone this outside of a truck that never leaves your yard/ acreage. The brakes aren't great to begin with. Just try stopping it without air pressure and you'll forget about this.