M35A3 air pack leaking from the front when depressing brake

[1 Patriot-of-many]

I can't seem to find this second air pack in the TM's that directly connects to the brake pedal linkage. Is there a rebuild kit for this? When I depress the brake pedal it quickly hisses out air at the front of the pack and when I release the pedal, it's like a normal air brake equipped truck sound. Can someone point me to the TM showing this airpack?

 

[1 Patriot-of-many]

Delete this, it's not the air pack.