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  • I did not know this.....



    But it's nice to know.
    Alle Kunst ist umsunst Wenn ein Engel auf das Zundloch brunzet (All skill is in vain if an angel pisses down the touch-hole of your musket.) Old German Folk Wisdom.

  • #2
    Re: I did not know this.....

    That's just a standard brake chamber like semis have. Shooting it may or may not disable it. If you hit the service side you might just disable the ability to stop but it will roll. If you hit the emergency side you could either cause the brakes to lock up on that side or just a large air leak or loss of parking brakes. Those brakes are spring activated and and use air pressure to release the brakes. Cut the lines going to the brake pod and it's stuck till the lines are mended or the t bar is used to cage the brake thus releasing the parking brake.
    God, Guns, and Guts made this country...let's keep all three

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    • #3
      Re: I did not know this.....

      Just keep shooting 'till the vehicle comes to a stop. Someone might get out.
      [I]Peace Through Strength, Victory Through Devastation...Strategic Air Command[/I]

      American by birth, made from German parts from Emmingen, Baden-Württemberg

      An unhappy German is a Sour Kraut!

      Das Leben ist zu kurz, um billiges Bier zu trinken!

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      • #4
        Re: I did not know this.....

        I drive trucks for a living and if you damage the air system whick operates at 120psi and get a significant air leak yes you will loose your service brakes and when air preassures drops below about 30psi the spring brakes automatically activate causing the vehicle to stop. It may still be able to operate however it will be severly sluggish.

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        • #5
          Re: I did not know this.....

          Crap, he is right, it will either stop the truck or rip the axle out from under it like what happened on one of the test videos.

          It will take a few hits from something larger caliber to break stuff up in there, and the chamber looks armored but the shape of it means they probably had to do it with mild steel, not the AR500 plate. You would be dumping AP rounds on that point, not trying to precision hit it like some sort of sweet spot. Your rounds need to penetrate and damage some stuff inside, I think a heavy duty rubber diaphragm sort of thing that is self sealing, but can't take a lot of hits before the self sealing feature stops working.

          There is a way that safety system can be bypassed in order to get the vehicle rolling again, but that means rolling without brakes. We had that as a procedure on the 5 tons with that system. They called it caging the brakes, which is what you do after a mine hit or you have taken fire. Takes a few minutes with a large wrench and you can do up to half the brakes on a 5 ton if you roll relatively empty. Advanced driver training involves driving the trucks without brakes, using the engine to slow down the vehicle and then gravity or the cable parking brake to actually stop it, if so equipped. As a mechanic, I routinely drove the predecessor vehicles with failed brake systems, at low speed around the motor pool but it was a half hour to 45 minute process to cage those brakes and disable that automatic lockup mechanism.

          To understand how the brakes work on those system, the natural position is for the brakes to be engaged by spring tension. When you get in the vehicle in the morning and start it up, it will refuse to roll forward until sufficient air pressure builds up in the system in order to release the brakes. Pressing the brake pedal releases air pressure and the springs are what shoves the brake actuators, not air pressure. So you don't need air pressure to stop the vehicle, you need it to let the vehicle roll. If you run the bypass, then the brakes will not work at all, which on flat ground is not really bad news. Vehicle speed can be controlled by downshifting then using the engine to slow down the truck, and once you get to a low speed, go into neutral and the truck will drift to a stop. Where that screws you is in heavy stop and go traffic or lots of hills.

          I had a brake system fail on my truck last year, drove home at low speed with only one of the rear brakes partially working. The fronts and one of the rears had totally failed when the system lost pressure. I would guess that one of those Mraps can function in the city with most of the brakes disabled, but like I said, it is a process to do it, someone has to get under there with a bigass wrench to cage those brakes, and then the vehicle is limited to 10MPH.
          Life, Liberty and the pursuit of those who threaten them.

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          • #6
            Re: I did not know this.....

            RT you are partially right about the brakes. Each parking brake pod has two sections or chambers. One is the parking brake and acts how you said. Spring tension locks the brake until air pressure holds the spring back releasing it. That is how the parking brake side works. The service side which is what stops the truck in normal operation works solely on air. There is a rubber biscuit in each pod that for a the seal for air and as air is applied it moves the rod in the pod and this is what moves the slack adjuster and applies the brakes. When a brake is caged it can still operate if air is going to the service side as all your doing is manually holding the spring loaded portion back. Thus shootng a pod can either disable the parking system or service system or both. FYI there is clamp that holds the pods together that can let you service the biscuits. I imagine if these might be a weak point and if hit cause the pods to loosen resulting in an air leak all the way to no brakes, even parking as the spring would shoot out rendering it useless. Also the service side is closest to the axle and the parking brake chamber is the larger pod furthest away from the axle.
            God, Guns, and Guts made this country...let's keep all three

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            • #7
              Re: I did not know this.....

              All I can say is that if I see an MRAP, I am operating on the theory that if I put a few rounds of .30 AP into that area, it will probably get significantly less mobile.



              Regarding the .30 AP, I don't think you can find the boolets any more, but some of us might have planned ahead, as it were.

              The penetrator in the center of the round is about .250" in diameter, and checks out at a hardness of RC 62 to 64. (Yes. We have the ability to check them, and we did.)

              It works just fine in 7.62x51, .30-06, 7.5 Swiss, and .30-30. Ask me how I know that, and then realize that I still have plenty left to load up, over and above what I already have loaded.

              For 7.62x51, Varget seems to work the best. .30-06 likes 4064. For the 7.5 Swiss, stay with 4895. .30-30 works good with either 4064 or 4895, but I'm shooting .30-30 from a bolt gun. I wouldn't load that way for a lever action.

              There you go.

              Alle Kunst ist umsunst Wenn ein Engel auf das Zundloch brunzet (All skill is in vain if an angel pisses down the touch-hole of your musket.) Old German Folk Wisdom.

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              • #8
                Re: I did not know this.....

                I am far more interested in operational controls on those, how doors and switches work, any unusual security systems, fuel usage rates on and off road, methods of locking and unlocking.

                I will be far far more interested in adding a couple of those to my survival stronghold group inventory than turning them into scrap metal.

                Any scenario where those are to be used on the population with any level of regularity is one where you either play on the patriotic loyalties of someone who has access to them, or the weaknesses and corruption of someone who has access to them.

                Same goes for a lot of other types of equipment that has to be parked overnight somewhere. A big part of my SHTF a decade ago revolved around being able to put a small loyal military unit in business, made up of volunteers from among relatively local recently discharged veterans, National Guardsmen, reservists and our own civilian support personnel. To that end I knew the local National Guard armory inventory fairly well. While I was investigated for and often accused of stealing things the reverse was true. My real intent was to supply the unit in SHTF, not loot it, but that would be in the course of taking control of the loyalty situation and I would re-cache my supplies and mutiny if they pulled any of that Katrina BS on my watch. The difference, those loyal to the right cause will have access to my formidable stash of MREs, ammunition, fuel and medical supplies. The state level planners, thinking the same thing, and having their own doubts over the loyalty of the local units vs patriotism play the same exact game; withholding food, ammo and fuel supplies if they think there is a loyalty issue.

                Fuel and food you can get locally with local supporters assisting you. Ammunition must be stored ahead of time, and for that, we are not talking about just a few boxes here and there, but I kept 2K rounds of belted ammo for the M249 SAWs and the M240bs, and even a case of belted .50 cal. Enough to put two armored Humvees in business, real business, to guard and fight along chokepoint mountain passes leading into the area, moving quickly between hidden safe zones and the fighting area, with the advantage of the vehicles being travel distances covered in short periods of time, and the warning time you get if someone spots hostile aircraft. That, and a couple hundred MREs, and two drums of diesel fuel was my emergency unit supply. I figured if it was just some disaster issue, then I would make it available to the unit, but not the ammo, and in retrospect, I would be far far more selective over who would even know the ammo supply exists. As it was, all the government did was conspire to take my critical supplies. So now, turnabout is fair play if and when the right circumstances arise.

                Those up-armored trucks can serve the same purpose, but lets face it, they are not very stealthy, but at two per middling sized town, they provide survivability to a rapid reaction force that might get hit when moving between a stronghold and a hotspot. In my book, destroying or disabling them is pretty far down on the priority, a last ditch effort to prevent enemy use. If I have sufficient credible warning that some .gov outfit is really after me all that badly, then it is going to be a race to get the best weapons and equipment from accessible resources anyway.

                I am a little curious though, if one of those armored trucks were to be disabled in the motor pool parking lot and left under particularly light guard, do they take relatively common truck parts? Is that the same brake assembly as could be found on a heavy over the road truck or some sort of heavy equipment?

                Any good tutorial videos on how they are driven, if there is anything unusual on that, like the parking brake controls or shifting. It might seem like really boring videos to most people, but not me. Its like the secret fuel shutoff valve behind the panel to the left of the driver on the M113 APCs, I keep forgetting whether pushing it in toward the engine opens it up, or if that's what shuts it off. Ours had a "clifford device" RFID based ignition disabler which of course, every driver learned how to hotwire in an emergency. When a couple got transferred over to the local Sheriffs department as part of that DRMO program, we always kept a close eye on them and even volunteered to do maintenance from time to time in order to keep them in working order, and get access to where they were parked...

                Even if one is "combat locked", the question remains on which size sockets you need for a cordless impact wrench in order to undo the right hatch of panel to get back into it.
                Life, Liberty and the pursuit of those who threaten them.

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                • #9
                  Re: I did not know this.....

                  Best way I see to stop one is shoot the driver either before he gets in or as soon as he gets out to go get coffee and donuts.
                  "some people never let their given word interfere if something they want comes along"
                  The real problem with the world are laws preventing culling.

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