Air stop light switch issue

[rustystud]

I cant give a proper answer, I know I was looking for voltage also, but I went by part number that had been used by someone else.
I "believe" my Napa part was 12 or 24 volt compatible.
I chose the part with lower air pressure requirement to open the switch, the M35A2 air systems are not as high pressure as a full air brake system trucks.

Midland Brake Products
PART #
MBI BE13250

All air-brake systems are 120 PSI and so is the deuce.

 

[TsgtB]

Thanks Rusty, I know I was numb after my research, and thought there was something about air switches being rated at 300lbs or whatever, and thought these were supposed to open at 3-5psi.
But in trying to answer a previous question, I do believe they are 12 and 24v capable.

 

[rustystud]

Thanks Rusty, I know I was numb after my research, and thought there was something about air switches being rated at 300lbs or whatever, and thought these were supposed to open at 3-5psi.
But in trying to answer a previous question, I do believe they are 12 and 24v capable.

The original deuce air-switch was mounted directly into the "Air-Pac" so it had to handle full brake pressure. With the later "modification" the switch was installed into the air line just like any "modern" air switch. That's also why you should not reuse the old switch as it's pressure point is so much higher then it needs to be and many times will not work in the new position. Crack pressure on all brake air switch's should be in the 3-8 PSI range.

 

[dirtwasp]

I cant give a proper answer, I know I was looking for voltage also, but I went by part number that had been used by someone else.
I "believe" my Napa part was 12 or 24 volt compatible.
I chose the part with lower air pressure requirement to open the switch, the M35A2 air systems are not as high pressure as a full air brake system trucks.

Midland Brake Products
PART #
MBI BE13250

okay thx ...well, if it works -its compatible..
also, mine is the dual hyd/air assist...so i have to find the hyd switch.
-have a good one-

 

[cattlerepairman]

mine is the dual hyd/air assist...so i have to find the hyd switch.
-have a good one-

No - that is the whole point of the air operated brake light switch. It replaces the switch on the hydraulic side. The hydraulically operated switch turned out to be a weak spot. If it cracks and breaks, you lose your brakes. That is why the military started replacing the hydraulic switch with a pipe plug and plumbed an air operated switch into the air line that provides brake support. If that one fails, you have an air leak - but still stop.

 

[dirtwasp]

ahhh..good to know, thank you very much for the life saving info! my truck still has the hyd swith attached but the wires were run to the aforementioned air compliment. so now i will quickly replace the hyd switch with a plug. and acquire an air swith from my napa pals -and nice upgrades on yer queen, waterloo looks like a good idea...is it a big difference?
thx

 

[cattlerepairman]

-and nice upgrades on yer queen, waterloo looks like a good idea...is it a big difference?
thx

Driving with the engine at "normal" rpm instead of heading towards redline is very nice, indeed. My LDS is governed at 2500 rpm (should spin up to 2800; I guess the governor was set by a wise mechanic or motor pool SGT) and I am still too chicken to try what the actual top speed is. I feel that 60 mph at still well below 2500 is as much as I want to push it for a period of time.
My butt clenches the seat hard enough at that speed. That makes me either very wise or very wimpy.

 

[rustystud]

Driving with the engine at "normal" rpm instead of heading towards redline is very nice, indeed. My LDS is governed at 2500 rpm (should spin up to 2800; I guess the governor was set by a wise mechanic or motor pool SGT) and I am still too chicken to try what the actual top speed is. I feel that 60 mph at still well below 2500 is as much as I want to push it for a period of time.
My butt clenches the seat hard enough at that speed. That makes me either very wise or very wimpy.

Having been in a truck rollover I can say your being "wise" ! Now whenever I'm in a vehicle and the driver says "it's OK, it always shimmying like this when I go this fast" I ask to get out !

 

[frank8003]

No - that is the whole point of the air operated brake light switch. It replaces the switch on the hydraulic side. The hydraulically operated switch turned out to be a weak spot. If it cracks and breaks, you lose your brakes. That is why the military started replacing the hydraulic switch with a pipe plug and plumbed an air operated switch into the air line that provides brake support. If that one fails, you have an air leak - but still stop.

Is that a work package? Does it have a number, drawings, pictures?
Is this modification in PS magazine someplace?
Any help here would be appreciated.
We don't know "air side" from "hydraulic side"
I am unsure what I don't got
Would like to put it right.

 

[emmado22]

search the forums, it has been covered many times here...

 

[doghead]

http://www.steelsoldiers.com/showthread.php?74240-Brake-light-switch-replacement/page2

 

[frank8003]

http://www.steelsoldiers.com/showthread.php?74240-Brake-light-switch-replacement/page2

Thanks doghead, that is a very good description

also
View attachment brake light switch PS 452.pdf

and TM 9-2320-361-24-1 WP 0112-00 July 1990 already shows modification as being done, mine not done...... yet

 

[frank8003]

Post #1 is a typo

Checked with NAPA and purchased 036036 S14 stop light switch.
That is an valve model SL4
Switches - Stop Light / Lamp - H/D Truck
Part # : TWD H274746
The NPT size is not listed.
Product Line : TW DISTRIBUTION
$16.99 /Each
UNSPSC 39122211



Switches - Stop Light / Lamp - H/D Truck
Part # : TWD VEL036036
This is the ¼” NPT male model
Product Line : TW DISTRIBUTION
$16.69 /Each
UNSPSC 39122211

but it doesn't matter as NAPA says out of stock


update 12262016 I never did find the difference between SI and SL switches. So I bought a Haldex BE13250 Stoplite Switch for under $20 delivered, We'll see .............
12 to 24 VDC

Actuation Pressure 3-5 PSI
Circuit Position Normally Open At 0 Pressure
Design Single Pole, Two Terminal
Pole Size 1/4-18 NPT
Notes Silver Contacts, Snap Action Design To Increase Switch Life, Tested At One Million Cycles At 30 AMPS
Stop Light Switch BE13250 Same As Automann 170.0013, Haldex BE13250, Haldex 13250, Euclid E-MDBE13250N, Dayton AVBE13250, OEM # 3250. Normally Closed At 0 Pressure. 3-5 PSI Actuation Pressure. Single Pole, Two Terminal. 1/4-18 NPT.

 

[rmgill]

I saw two questions but no answers on two particular points.

Switches like these are not voltage dependent unless you're getting above 400 volts. They ARE concerned with total amperage load across the contacts. But for lighting loads, it should not be a concern unless the switch is rated for less than an amp or something.

There also is not usually any polarity with such a switch. It's just a switch. Open or closed.

 

[frank8003]

Post #1 is a typo

Checked with NAPA and purchased 036036 S14 stop light switch.
That is an valve model SL4
Switches - Stop Light / Lamp - H/D Truck
Part # : TWD H274746
The NPT size is not listed.
Product Line : TW DISTRIBUTION
$16.99 /Each
UNSPSC 39122211



Switches - Stop Light / Lamp - H/D Truck
Part # : TWD VEL036036
This is the ¼” NPT male model
Product Line : TW DISTRIBUTION
$16.69 /Each
UNSPSC 39122211

but it doesn't matter as NAPA says out of stock


update 12262016 I never did find the difference between SI and SL switches. So I bought a Haldex BE13250 Stoplite Switch for under $20 delivered, We'll see .............
12 to 24 VDC

Actuation Pressure 3-5 PSI
Circuit Position Normally Open At 0 Pressure
Design Single Pole, Two Terminal
Pole Size 1/4-18 NPT
Notes Silver Contacts, Snap Action Design To Increase Switch Life, Tested At One Million Cycles At 30 AMPS
Stop Light Switch BE13250 Same As Automann 170.0013, Haldex BE13250, Haldex 13250, Euclid E-MDBE13250N, Dayton AVBE13250, OEM # 3250. Normally Closed At 0 Pressure. 3-5 PSI Actuation Pressure. Single Pole, Two Terminal. 1/4-18 NPT.

That switch and 24VDC lamp works perfect.
It be nice to have
View attachment brake lights IMG_2179.MOV

 

[CHIEFSONN]

Can the other stop light switch be used? other meaning the one I just bought to replace the one in the hydraulic line ? the both work on pressure correct.

 

[doghead]

Please be more clear.

You can not use the air switch on the fluid system. It produces thousands of pounds of pressure.

The air system only makes 120 psi.

 

[CHIEFSONN]

Thanks you answered my question. I just purchased one for the fluid line installation (old style set-up) and tonight I just read this thread on removing that switch and plunging the hole.and
installing a switch in the air line. with that being the safer way to go.so I just wanted to know if the fluid operated switch could be used where the pneumatic switch is to be used. no it cannot thank you

 

[gimpyrobb]

I just wanted to know if the fluid operated switch could be used where the pneumatic switch is to be used. no it cannot thank you

Not really, it could work. Just hook up a VOM and test for continuity. If you put 120psi to it, and you get continuity, you should be fine.

 

[frank8003]

Did I misunderstand?
The modification on Deuce of the brake slight switch was done for various reasons one being that when the hydraulic side original OEM switch fails the brake fluid leaks out.
Modification had that hydraulic side plugged and the pipe arrangement changed to adapt and install a new and different air side switch.
Can only loose air if that switch fails.
Go back to post 32


..................and OH NO no more written PS magazines!