Mack powered 1970 m39 HELP please!

[Shawnb1976]

I have a 1970 mack powered m39 series truck. Im trying to find an air line diagram for the truck, im lost and someone hacked this thing out. Also need to know if this truck has a clutch brake and how to replace it... hard to put in gear and tries to pull when it does go in gear. Any help would be amazing!!

 

[NDT]

Look through these TMs for the air brake diagram, will be in a -20 or -34: TM's for the M39 Series 5-ton | SteelSoldiers

No clutch brake. Clutch probably needs free play adjustment.

 

[msgjd]

I concur with NDT above .. However if you do an adjustment and it still wants to creep or shift hard, it is rare but it does happen that the clutch disk could be beginning to delaminate or is warped... Another thing i have had happen was the clutch disc was sticky/gummy from having an engine rear main seal leak in a very dusty environment , the truck sat a long time afterwards, and basically the concoction gummed everything up