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Posts posted by Scorer128

  1. i will try again to post the umodel    the b model is a 237hp with a "quad box"  has an air starter that I want to change to electric  we couldnt get her to start by pushing   fuel filter was a solid no filtering involved  it may havelast been changed in 1957  local NAPA had one on the shelf for 16$  one tiny push and she was purring like a kitten   love this old steel!

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  2. Hello gentleman...I am in a desperate search for a BLUE bug deflector TO fit a 1980 U model. I’m on a pretty tight budge,t So please ,your best deal.  The one that was on the U model I gave to a friend of a friend paint and they and  the bug shield disappeared.

  3. While in the process of replacing the wiring harness, I removed Three air brake valves from the dash.   I thought I marked them well, air line placement and so forth; however, ( and this is a tip for others) the paper and ink I used was not water-resistant and i now cant tell well most of the lines go.  I have it figured out for the most part as the trailer brake valve and pressure switch is marked differently, but currently there is an open hole that air streams through.  So it's obvious I'm missing something.  MOst of the info I've found only refers to two valves in the dash.  Any help, schematics, drawings pictures-  the service manual isn't giving me much guidance either?  I'm scratching my head.

  4. HELLO GENTLEMEN!  It looks like I've really done it now.  The 1980 U model I've been working on was having intermittent electrical problems and I found that chaffed wires were causing serious issues.  For two weeks I attempted to piece fix the harness and finally tore the whole thing out and replaced the wires per the schematic. minus the Kyser shutdown wiring.  Now, the engine barely cranks over .  Is there something in the scensors that would be telling the engine not to turn? I've read about a jump wire but dont' have enough information to assertain the proper location.  Any help or insight would be  greatly appreciated the old girl has a job waiting on her.  not to mention my pride could use some help!!

  5. hello fellas!  Still working on my Dad's 1980 U model.  I have everything wired and aired up since the last issue, thanks to every ones's advise and information. This is my current issue, some "one" has messed with the fuel pump,  "turned it up". I'm certain this was an unnecessary adjustment as the truck runs worse and throws/blows black soot like she's on fire.  What is the proper procedure for adjusting the fuel injection pump?  I want to turn it down.  The engine is a 237, all stock.

  6. Thank you very much. Every bit of info helps. As you’ve stated deflecting exhaust heat is a concern.  Any suggestions that will try to keep heat from the goings on in the frame rails? Or do you think that wasn’t necessarily a u model issue -but the lack of proper exhaust piping -which allowed the heat direct access ??  Knowing that will help decide how to proceed in that area  Thank you again for your help !!


  7. I am working through a nightmare I’m hoping someone here can help. I inherited my Daddy’s 1980 U model. I believe it was once a single bogie tractor converted to a six wheel dump. It has spent its last thirty years as a home for wayward rodents and waiting for its next job. Well I plan to use her to pull an equipment trailer and do small hauls but .....  the exhaust was hacked (my guess for parts) and melted the ground cable, airlines and frame wires causing a short  that melted the wires and air lines in the dash. I think it sounds worse than it really is but I don’t remember the original layout of the exhaust. Or the size because there’s currently 4 5 and 6 inch pipe on it   The r model wiring schematic I found   for the most part helps me just that I can’t see any of the colors so I plan on re-wiring new harness. 

    If anyone can give me the airline lay out, the exhaust layout and any help with familiarizing  myself with a 1980 U model, it would be greatly appreciated. I plan on using this girl for many years to come in honor of my dad. I don’t plan on doing a complete re-store but would like to get close to original. Thank you advance for your help    happy Trucking!!

  8.  Hello gentlemen. Thank you for such a wonderful informative Mack truck site. I recently acquired a 1980 U model Tractor converted to a six wheel dump truck that once belong to my dad. Although The truck has been decently taking care of it does have some issues that I’m hoping you’ll help me work out. I’m going to go read some articles if I have any questions I’ll be back

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