No brakes!!!

[m1010plowboy]

Air Pak Re-build

I'll call Brian to see what's available.

Gunfreak, you have a good handle on the pieces that failed on your pak.

Can you get me a pic or a schematic for parts number and description....you know how I like pictures? Is there a pic in our Levy manual? Left mine in the shop.

What long term solutions can we come up with?

Obviously if we want to retain the air assist for the future rats that will drive my truck SEALS are going to be one of the challenges.

Is there an 'updated' airpak that can be swapped?

I'm thinking outloud...........that must mean I'm hungry.

 

[m1010plowboy]

5 ton air pak piston swap

I Must read slowly....

Gunfreak......you typed " 5 ton piston swap quite easily "...


Is this a permanent, maintainable solution?

 

[m1010plowboy]

G749 Air Pak schematic

Here's a schematic from the Levy Book.

Actually a couple of schematics to try the macro out on pic 1.

Gunfreak, does she need a new Diapharm? "P"

 

[Gunfreak25]

Long term is always the best solution, I agree. And it all depends on how determined an individual is to keep his/her truck in operating condition.

-The 5 ton piston swap into the GMC air pack is very viable as long term solution since it enables you to use 100% of the 5 ton kits which are still very plentiful as the trucks have only recently been retired from U.S service. Stock up on a few kits, do the piston swap and your golden for life.

-The GMC's use the same braking system as the M35A2's which parts will likely always be very easy to get for. The difference is, the GMC's use a check valve in the AIR PAK and the M35's use a check valve in the master cylinder. So if you had a GMC in need of total brake re-do and wanted another viable long term solution, you could simply swap the GMC air pack/master for an M35 air pack/master. It's simply a matter of re-positioning a few lines and making a bracket to adapt the M35 air pack to the GMC frame.

-Personally, if the original motor is kept and one wanted to have updated brakes they could just install a Hydrovac vacuum booster off a large Chevy C60 or C65 truck.

Anything can be made to be long term these day's.

Here is the rebuild manual for the 5 ton air packs which is 95% similar except it uses a double check valve so you will always have a check valve leftover.

Took me 1 hour to find this stupid thing..... Page 12-12

Direct support and general support level: 5-ton, 6X6, M809 series trucks ... - United States. Dept. of the Army, United States. Dept. of the Air Force - Google Books

 

[Gunfreak25]

Part number CC and GG is what you take from the 5 ton kit and put it in place of the GMC parts.

Excellent picture of the book, Dave.

 

[m1010plowboy]

Data airpak

Have we told lately, how much we appreciate you Gunfreak25?

 

[DDC2StrokePower]

i agree. that you very much for putting so much work into this,

 

[Gunfreak25]

Many members here have been quite good to me. What goes around comes around.

 

[Gunfreak25]

Found the GMC piston seals. I am sending my old ones in for ID and will be shipped 2 new ones along with the manufactures part #. They are roughly $6 each.

The long story: I called Dale at Brake Systems Inc this morning because he is regarded as an expert on these units.
Dale is familiar with all the Military air pack's from the M35's, 5 tons and all 3 types used on the GMC trucks over the years. He said he cannot find most parts for the GMC ones anymore but has all the parts for the newer 5 ton units which is always a good thing.



So for anyone who wants to do the GMC air pack rebuild. Get yourself a 5 ton kit for any M800 series truck, get 2 new piston seals from Brake Systems Inc and use the manual I posted above to perform your rebuild.

Case closed!!
Will post part# when I get it....

 

[DDC2StrokePower]

That is awesome thank you very much