Gunny65

Finally, here are some pictures.

Soooo, I was looking to get a repair and/or service manual for this truck. $304.00??? Totally ridiculous. I found some others that I Think are for the correct years but not sure. Still kind of expensive but better. Anyone know where to get manuals for my truck in a more reasonable price range?

Not sure where the brake light switch is located. It isn’t in the cab. Pictures later that might show it but not sure.

JoeH, You are correct. I am not very familiar with them. I used double clutch when I was a young man in the military but that was a long time ago and not often. This trans is a single stick, reverse, with 5 gears. I did try the double clutch method but either I didn't do it right or it just didn't work. I think I pushed the pedal to the floor when trying the double clutch. I also tried a quick push/release to disengage, and then another quick push/release to re-engage. I tried to keep the rpms up when double clutching but no luck for me. I never tried to change gears without using the clutch. I still have some learning to do. LOL. Oh, and you are correct the way I adjusted the clutch pedal was not correct but it was just enough to get me home. An emergency fix. My knee was up by the steering wheel after moving the bolt about a quarter inch. It wasn't comfortable. From the beginning, the clutch pedal had no play. It was under tension immediately and disengaged, in about that two inches, of the initial movement. I assumed that was why the clutch was slipping when I started up the first major hill we came to. Unfortunately, I didn't notice the slip until I saw some smoke and smelled it. I thought the truck was just bogging down due to the hill. I will read up on how to adjust the clutch correctly as I had no idea. Thanks for the heads up. I did not know the clutch brake is only used when stopped. I thought it stopped them while driving as well. You know, to synchronize when shifting. Is this only in older trucks? Big trucks? or all trucks that use a clutch? Thanks for the help. That is exactly why I come to these types of forums when I get a new to me piece of equipment.

I got the truck home today. Drove it 115 miles with no break downs. I couldn’t find anyone coming this way to deliver it so just took a chance and drove it. I had to adjust the clutch pedal as the clutch was slipping. I can’t down shift at all. Trans won’t stop rotation when down shifting and just wants to grind. Clutch started slipping going uphill. That is when I stopped and adjusted the clutch pedal return bolt just to make it home. Lots of little things wrong. Rpm, speed and fuel gauges do not work. Got the brake lights working. Bad wiring and rusty bolts were the problem there. Anyway, it is home. More pics coming in a day or two. Guess I should start a thread in the proper forum after posting pics. Thanks everyone for the welcome and help.

I am picking up a 1979 Mach Dump Truck and the brake lights do not work. The turn signals work, reverse lights work and running lights work but no brake lights (both sides do not work). I am going to pick up the truck tomorrow and need to figure out how to get them working before I leave the yard. Do these trucks use glass tube fuzes? Where is the fuze box located? Is there a "switch" on the brake pedal that could be bad? Do they come on when the air pressure is high enough or does the pressure even matter? Any suggestions on what to look for first or how to do an emergency bypass just to get it home would be appreciated. I have a fluke meter and a "basic" understanding of how to use it. Attached is the only picture of the truck I have at this time. Thanks.

Sorry, it took me longer to reply than intended. Work and life. Thank you all for responding. I do not have the truck in hand yet. I paid for it but the front tires were in rough shape and no brake lights. I am having a guy I know deliver it. It's going to cost more but I do not have a CDL and it is in another state. So crossing state lines, no CDL, bad front tires and no brake lights...I decided to have it delivered. Sometime next week. I will get more pictures when I get the truck here. I am chomping at the bit. I want to get to working on it. Cleaning it up. You know, making it mine. Once it is on the property, I will tear into it to fix the brake lights and get two good front tires. Surprisingly, the rears are all in okay to very good shape. Thank you again and more pictures to come. OH, and the first two letters in the VIN are DM. So, DM600 something for the model?

I just bought a 1979 Mack T/A rotating bed dump truck. I know nothing about it other than it was used on the railroad. The railroad track wheels have been removed but the rest of the hydraulic mechanism is still attached and working. The bed rotates easily to both sides and raises and lowers as it should. It is hard to start but when I do get it running, it runs fine. Really, I know nothing about Mack Trucks other than the name. I don't even know what engine it has, the transmission, how some of the controls work, etc. I just got a very good deal and I needed a dump truck for working around on my property. It is a well-used but still a good looking truck. I want to get it running better. Find out what I have, model #, engine, trans, etc. It has years of gunk built up on it (motor, drive train, you name it). I am joining this site in order to read and gather information on the truck and get it into a trustworthy addition to my property enhancement equipment. I previously bought a 1991 M934A2 6x6 military truck and got it running and fixed up using a similar forum for military iron. I then bought a "well-used" excavator and used a similar heavy equipment forum and got it running/fixed up. Now I am hoping to access the cumulative knowledge here and then give back what I can. Thanks. Oh, and if anybody has an initial idea of what I have, other than a Mack dump truck, please feel free to let me know. I like to know what I have and how to keep them running. Again, thanks.