brake light switch upgrade

[Z71]

Are both versions (long and short) of the air pack upgradable to the air operated brake switch type? Is the same kit compatible with all air packs? n My truck air pack is the short type and still has the original fluid operated brake switch in the front.

 

[emmado22]

yes and yes

 

[cattlerepairman]

As emmado said. The only issue I ran into with mine was the need to replace an air fitting that was the wrong diameter in the kit. I think the kit had a 1/2 inch fitting and I needed a 3/4, or the other way around.

 

[welldigger]

If you have the short air pack i would have thought it would already have the air switch. Mine is an air switch and it is mounted towards the front on the t block the air line plumbs into.

 

[clinto]

If you have the short air pack i would have thought it would already have the air switch. Mine is an air switch and it is mounted towards the front on the t block the air line plumbs into.

My '87 A2C has 2 short airpacks and it uses the old style hyd. pressure switch. 2 other '87-89 USAF's I've had were the same way. So they were using the old style switch right up to the end.

 

[welldigger]

Hmm. Didn't know that.

 

[clinto]

I've never had an A3, so I don't know how they are (air or hyd. pressure switch) but after my experience with the '87-'89's, I assumed the military did the air pressure activated switch MWO sometime in the interim between the end of A2 production and the end of A2 usage in the service(s).

I think Emmado22 has a copy of the MWO form, it probably has a date concerning the changeover.

I can also say of all the trucks I've had or worked on, which is probably over 30 at this point, extremely few had the air pressure activated switch.

 

[emmado22]

Why AMG wasnt putting the Air switch on the USAF contracted deuces when they were building them makes no sense.

 

[welldigger]

Actually now that you mention the a3 I'm not sure what type they have either. I'll have to look this weekend. My truck is an a2. I don't know if the army converted my truck or the previous civi owner did. He got the truck strait from DRMO. He also has passed away, hence why I own the truck now. My truck was also depot rebuilt in 91 according to the dash. So honestly there's no telling who did it.

 

[Z71]

The hydraulic switch is a very poor design as it is not failsafe, which is definitely needs to be. Failure of the air pressure switch will merely affect the air assist, but the brakes will still function. The hydraulic switch, if it completely burns through, will cause the brake fluid to leak, and the brakes will fail. I wonder who approved the original design.

 

[doghead]

These trucks were first built in the 1950's. It was common practice back then to use a hydraulic switch. That very same switch was used on many 50's vehicles.

 

[TurboTim]

So does anyone know where to get a replacement air style switch?