Disabling air brakes on m105a2 for recovery

[swiss]

Reading about a recent fire from another recovery I was wondering if there is a way to disable the air brakes temporarily when towing without an air brake enabled tow vehicle. The trailer will be empty during this time.

Is this necessary? It seems there are some safety features built into the brake system that can activate the brakes when the air pressure is low.

Thanks all

Steven

 

[jasonjc]

The M105 trailer does not need air. As long as no air has been hooked to the trailer you are fine.

 

[hemichallenger]

The brakes do not work without air.

 

[emmado22]

Read the TM, all the answers you need are in there.

 

[swiss]

Fine gentlemen of steel soldiers!

That was what I was hoping, I did not think the air reservoir on the trailer could hold enough air pressure to lock up the brakes.

Thanks for posting answers to sometimes ignorant questions

Steven

 

[gimpyrobb]

You not hooking up air means the brakes will not activate.

BUT!

I have pulled trailers home that needed the brakes backed off.1 Make sure you stop after a couple miles to see if the hubs and or brakes are hot.

 

[swiss]

Yes I have the TM and have been reading. Reading they don't always click in my brain always the first time.

GimpyRob. Understood on backing off the shoes from the drum as necessary!

 

[bjsmith]

if it only has 1 air line no need to worry if it has 2 make sure the air tank on trailer is empty

 

[jasonjc]

They have hand brakes also. So make sure those are releasted

 

[emr]

Read the TM, all the answers you need are in there.

U are kidding right read ? no way man,.. sorry just kidding, But for real i would think if U do not hook up the air line they will still work right ? sure they will if U hook up air sorry still getting over another thread where a guy just asked about a big truck and a cdl, that is going to need its own sticky, I think this site could come up with a good one ...With that said, reading does not always work for me either sometimes, but all in fun life's to short not to laugh

 

[silverstate55]

I recovered 5 M105A2 trailers from Nellis AFB last summer; when I was towing one of them I noticed an increase in resistance from the trailer. I pulled over and felt that the hubs & brake drums were hot. I opened the air tank drain valve and kept it open for the rest of the drive, and the brakes released. I had opened it to drain it before leaving Nellis AFB, but there must have been some residual air buildup in the lines to allow the brakes to activate.

So just open the air tank drain valves and keep them open during your drive; you shouldn't have a problem.

 

[Bighurt]

Some M105's don't have air tanks, just something to note.

 

[swiss]

Silverstate BINGO, that is what I was looking for. Looking at your July recovery you did not have airbrakes on your truck did you? If not then you are validating my concern.

Airbrakes are new to me for some of you that are looking at this as a stupid question, but I am sure that I will probably not be the last steel solders member that has this question.

My concern originally was that a M105 with the dual line air brake assembly might have a mechanical safety that was triggered by low air pressure.

As many of you know it is hard to troubleshoot and understand new equipment without the green metal sitting in your driveway. The key is getting it to your driveway safely

Thank you all who have taken time to reply.

 

[silverstate55]

Silverstate BINGO, that is what I was looking for. Looking at your July recovery you did not have airbrakes on your truck did you? If not then you are validating my concern.

Airbrakes are new to me for some of you that are looking at this as a stupid question, but I am sure that I will probably not be the last steel solders member that has this question.

My concern originally was that a M105 with the dual line air brake assembly might have a mechanical safety that was triggered by low air pressure.

As many of you know it is hard to troubleshoot and understand new equipment without the green metal sitting in your driveway. The key is getting it to your driveway safely

Thank you all who have taken time to reply.

I haven't seen any type of mechanical "fail-safe" mechanism in any of the air systems I've disassembled so far...just an air diaphragm that pushes into the master cylinder to engage brakes. If you open the drain petcock and leave it open, there's no air pressure to activate the diaphragm...therefore, no brakes. Worked for me. It should go easier than you think, barring any unforseen mechanical breakdowns...probably wouldn't hurt to tighten the lug nuts before you hit the road.

And no, my truck does not yet have any compressed air facilities....

Good luck!

 

[quickfarms]

The air brake system includes the air tank, the diaphragm that actuates the master cylinder and a relay valve.

In a two hose air brake system you have the emergency line and the service line. The emergency line charges the air tank and the service line sends air to the relay valve to actuate the brakes.

Air brakes operate between 85 and 130 psi. The low air warning will sound between 55 and 75 psi. The emergency brake should apply between 20 and 45 psi.

At between 20 and 45 psi the relay valve should apply the emergency brakes.

Relay valves are prone to sticking.

Modern, post 1978, air brakes also have spring brakes.

The best thing to do if you want to disable the brakes is to leave the drain open.

 

[swiss]

The air brake system includes the air tank, the diaphragm that actuates the master cylinder and a relay valve.

In a two hose air brake system you have the emergency line and the service line. The emergency line charges the air tank and the service line sends air to the relay valve to actuate the brakes.

Air brakes operate between 85 and 130 psi. The low air warning will sound between 55 and 75 psi. The emergency brake should apply between 20 and 45 psi.

At between 20 and 45 psi the relay valve should apply the emergency brakes.

Relay valves are prone to sticking.

Modern, post 1978, air brakes also have spring brakes.

The best thing to do if you want to disable the brakes is to leave the drain open.

Okay after reading the TM for the 2nd time today on the plane, these operational ranges are definately not in TM 9-2330-213-14&P. The TM is good for how to install and remove. This is Great Stuff, thank you Quickfarm

So the old adage that "Everything is in the TM" may not always be true

 

[quickfarms]

The information I provided was taken out of my CDL manual. I posted a link for an air brake manual a while ago that explains how the different systems work.

 

[Flyingvan911]

Good idea opening up the drain valve in the air tank.

 

[Psywarrior]

Silverstate BINGO, that is what I was looking for. Looking at your July recovery you did not have airbrakes on your truck did you? If not then you are validating my concern.

Airbrakes are new to me for some of you that are looking at this as a stupid question, but I am sure that I will probably not be the last steel solders member that has this question.

My concern originally was that a M105 with the dual line air brake assembly might have a mechanical safety that was triggered by low air pressure.

As many of you know it is hard to troubleshoot and understand new equipment without the green metal sitting in your driveway. The key is getting it to your driveway safely

Thank you all who have taken time to reply.

There are two basic types of air chambers (what some are referring to as a diaphragm) See attached photo. The chamber on the left with what appears to be 2 diaphragms is a spring air chamber that includes a parking brake. It requires air pressure from a reserve tank to release. The air for the tank is supplied by the emergency line which is a constant air supply. The single chamber unit has no parking brake ability and activates only on the service line which allows only air flow during pressing of the brake pedal. If you have a single line system, it will have only the service line and the single diaphragm brake chamber. A dual line system may have either style brake chamber. If the trailer has a manual hand activated parking brake, you will have a single chamber system. If you have a dual chamber, you can "cage" the parking brake by inserting the bolt that is attached to the side of the housing through the rear opening and tightening it down. This will compress the parking brake spring and retract the brakes. On a single diaphragm system, caging is not necessary.

If the pic doesn't show up (since your attachment system is way different from what I am used to), here is a link to an image. http://www.easternmarine.com/media/catalog/category/769_st.jpg

 

[tm america]

Gimpy do you notice more resistence when the trailer is on its side ..is there an adjustment for that to?