bumpytruck

Thanks Guys Runs good

I have and old dumptruck I'm trying to keep running. It dropped a valve and I replaced the piston and the head. The motor came set up with a Jacobs engine brake. It did not work. My parts motor had a Dynatard on it. I did not care if the engine brake worked or not, so I replaced the Jacobs with the dynatard components because it was a much simpler set up. Will this work? I don't care it the engine brake does not work, my concern is that the Dynatard system has a special camshaft that my motor with the Jake brake does not have. My question is... will the motor run properly like this? I understand I will not have a engine brake.

Hi, I have a 1980 DM686.My back-up alarm was working and it has now stopped. I jumped it out in the rear and the alarm and back up light are working. The wiring seems fine as I traced it up to the front of the truck.However I cannot seem to find were it goes into the transmission.The truck has the two shifters one for hi-lo-r and the other for 1-5.Were shouild I be looking to find out were my problem is?Is there a switch on the trans or inside the trans?

There is a manual pump but I thought that only gets fuel from the tank to the pump.I have it running! Thanks

I just finished putting a E-6 300 into my DM.The motor was used and has not ran in about a year.I have fuel up to the IP but I think I have air in the lines from the pump to the injectors.If you beleive that this is my problem,can I just crank the motor till its out and it starts or do I have to crack the lines loose at the motor? My batteries are low and on a charge now,but I did have it cranking pretty good for about 2 min total letting the starter cool off in between attemps.Any help would be great Thanks in advance! Its a 2 valve mech. pump

Is anyone close enough to check out a E6 Mack 300 motor for me.I will pay for the right person. Thanks Joe

It was about 60 cold and 30 hot and back up to 50-60 going down the road and it has dropped to about 25 at idle and it goes up to 40-50 going down the road.But it has bad blow by.

I dont use the truck alot nor everyday,I use it for my concrete business.I did see some manuals on ebay but not the correct ones,I just thought there might be another place besides a Mack dealer.The oil does not go up when the rpm goes down.I lose about 10 psi when its warmed up.

I have a few questions. First I have a 1980 DM Dump truck. It has the original motor however I am uncertain as to what has been done to it.I believe it has approx. 800,000 miles on it. It has blow by pretty bad and the oil pressuer is starting to flucuate a bit. I want to make thru my season. (nov)I would than like to do a rebuild on the motor.I have done many gasoline motors in my years but have never tackled a diesel of any kind.I just put a new turbo on this motor in july.I can pull the motor if need be but would perfer doing a in frame.Any advice would be greatly appreciated. Can someone advise were to purchase a manual for rebuilding this motor.What special tools are required.(Mack Specific)

Worked great,Excellent directions! Thanks Joe

Ok all the parts are available ,not cheap,but I can still get them.They cost about $200 but now my heat/air will be right!

My cowl vent on my DM is inoperable.It seems free outside under the hood however I cannot twist the knob that operates it.What can be done?(new cable?) and how difficult a fix is it? Thanks Joe

Well, I found out that my system is aftermarket heat and air.Its made by Kysor,its a minibrute.I was able to find all my pics online. Now if I can still get parts for it,I'll be all set.Why someone would take the heat and defrost controls out is beyond me.(left the air stuff alone)

I'm going to change my leaking line-s on my 300 .And I was wondering if there was a special socket that would be able to access the lines at the injector side.They seem to be kind of down and in a tight place to get a wrench on them.If so were can I purchase such an item? Thanks Joe.

I would like to know,how to remove the metal panels on the doors of my DM. I can figure out the whole screw thing,my question is in reguards to the door latch and the window crank system.It appears that the mechenisms for these two are also screwed to the metal panel.Or are the just screwed to the panel for added support? I guess I could figure this out by trial and error,but I'm sure somebody here can fill me in on what to expect. I'm taking this apart for preventive maintainace,oil things up and make them work smoother.Thanks Joe

Does anybody have pictures of the heater- A/C box from a 1980 DM or any crossover model thats the same.I'm looking for interior pictures of the switches and vents.

I can uhderstand that you guys can only do so much from your keyboards and thats cool.I am no expert at all,but I would not consider the blowby excesive.The truck has 800,000 miles on it. As far as the fuel leak I'm going to try and tighten the lines and see what happens.The motor is cleaned upand the leak is not severe I just noticed a small spot on my driveway(6"x6") and found that to be the culprit.

Just found this place,and purchased my first Mack 1980 DM686S tri axle Dump. I have alot of questions so lets get started.

Hi I'm new here. I just purchased my first Mack. Its a 1980 DM686S TRI AXEL DUMP. I drove it home about 50 miles mostly freeway. And when I got home I noticed fuel that had leaked from what appears to be the lines at the pump. If it is indeed the pump. The throtle cable goes to it. The seller stated that he recently replaced the steering pump and pointed behind this ijection pump. I'm guessing that the lines proberly need to be snugged up after the 50 mile drive.Is this correct or should I not touch these lines? Also is the blowby that comes from the tube under the truck normal? It does not smoke at start up and feels real strong,should I be concerned? Thanks in advance Joe