Truckie Harbison

Pretty sure the torsion bar on my 1970 F model cab is broke. Anyone know where I can get one. If not, anyone have any info on converting a torsion bar tilted cab to the newer hydraulic Jack style? I would really like to be able to tilt my cab to work on a few things.

I haven’t updated this post in quite a while. Swapped the injector pump and the truck runs like a champ now.

Thanks for the input. I’ll have to do some searching online to see how to pull the injector and do a compression test.

Haven’t updated in a while cause I’ve been too frustrated. I tried several different things. I replaced the Fuel line from the tank to the filter and the filter to the lift pump. I bypassed the auxiliary filter, I eliminated the fuel tank and ran the line into a jug of diesel. I removed the lift pump, cleaned it, it has new check valves, and a rebuilt a primer and put on it. I just had the truck running ( had to start with a small squirt of ether) and cracked open the injector lines at the engine and made sure each one had fuel. Shut it off, and it wouldn’t restart. here’s what I noticed. When I crack each injector line open at the pump with the truck running, the engine makes a definite change in the way it runs and sounds, except when I crack open the the line for the third cylinder from the front. There is no change at all with that line. That leads me to believe that cylinder isn’t firing and could be the reason it doesn’t want to start or idle at 600 or so rpm’s. Any thoughts? I figure I’ll pull the injector and have it tested m, hoping that it’s plugged, and also do a compression test.

Anyone have any advice or directions on how to adjust the torsion bar for the cab of my F model? It’s my understanding that when I release the latch, the cab should pop up a little and it doesn’t. I see how the torsion bar is adjusted, just didn’t know if there was a specific way to do it.

That makes sense. I wouldn’t think it is addicted since it starts fine on its own each morning, or maybe that would be typical of an addicted engine. When I do have to give it ether to start, it is only a very short spray.

So I gotta ask, how does a truck get addicted to ether?

Ok, so the problem isn’t fixed. It starts fine in the morning. Yesterday I started it and took it for a short drive into town. Came to a stop sign and it died. Wouldn’t restart without ether. Drove it back home fine. right now I have the tank rigged so I can pressurize it. I’ve had pressure on it for a couple hours and I don’t see any leaks yet. I’m wondering if either the hose from the tank to the first filter or the hose from the filter to the lift pump is coming apart inside and the vacuum is collapsing the inside of the hose. Either that or I got a lot worse problems. Any thoughts?

I will get new washers, but considering I leave on vacation tomorrow and will only have a couple days when I get back before Walcott, I wanted to see if it would work. For the washers, I laid a piece of sand paper on a flat piece of steel and sanding each side of the washer in a figure 8 pattern to flatten both sides of the washer. Is it ideal, no, but it works in a pinch. As far as the return line, I plugged the vent on the fuel tank and blew air into the tank through the return line to pressurize the tank and force fuel to the injector pump. Again, probably not how others do it, but worked for me. I didn’t see an issue putting air in the return line since it just goes to the tank anyway. That line is after the filters, lift pump, injector pump and injectors so it shouldn’t force air into them. After letting the truck run for 30 min, I shut it off, waited 10 seconds, and then tried to restart it. It did restart, but I did have to give it throttle to do so. So I would say that it still isn’t right, but it’s better than it was.

Well, I asked someone earlier what a rack was and didn’t get a reply. I do think I have the problem fixed. I really felt it had something to do with the lift pump so I took it off , took it apart, blew it out and made sure everything moved freely. I didn’t have new copper washers for the check valves so I sanded them to make sure they were smooth. Put it all back together, blew air through the return line until fuel was at the injector pump, and it fired up. I’ve gone out a couple more times and it has started each time. I’m guessing there was a little trash in the pump, but I really didn’t notice anything. As long as it continues to work I guess I don’t care.

Ok, but I’m having the exact opposite problem that you described. It’s starts easily in the morning after sitting all night. To me, if there is a leak, sitting all night would cause it to lose prime and not start in the morning. Instead, once I have it running, shut it off, and immediately try to restart it, it won’t start. I hope it’s a line leak, but it seems weird that a leak would cause it to lose prime in a matter of 2 seconds, but sitting overnight helps it start easy.

I appreciate the advice. I’ll get the stuff rounded up and give that a shot. I’m hoping the issue is that simple. It just seems odd that it won’t start 2 seconds after it was running, and that it will start in the morning after sitting all night and not starting the night before (it started this morning no problem)

I plan on trying that tomorrow. This truck has the mechanical fuel shut off. Hoping it’s something simple. Gotta have it ready so my son can take it to Walcott in a couple weeks for the Jamboree.

Just joined the forum and was pleased to come across this thread. It’s amazing how many people knew Mike. He was truly one of a kind and is greatly missed. Before he passed, we spent a lot of time talking about his trucks and he was determined that both of my sons and myself would each get one of his trucks to work on and take to shows. Somehow he convinced my wife that she should consider herself blessed to have Mack’s in her yard. Now we are the proud caretakers for a 1970 F Model, a 1975 R Model, and a 1979 Superliner. Each of these trucks were featured in his daily Facebook posts. Slowly but surely these trucks will be restored how Mike wanted them.

Ruled out a tank venting issue.

Went out this morning and it started right up. Shut it off and tried again and it started. Reset the idle and took it for a short drive. It died pulling in to my driveway and wouldnt restart. No smoke when it won’t start. when I set the idle, it wont idle below 700-750, and it surges up to 800 or 900. Once it falls to 600 rpm’s it’s gonna die. what is the rack? I’m very mechanical, but not a big diesel person.

I took it for a short drive and it acted fine, although I had the idle set too high. I’ve had it running 3 different times for an hour each time idling around 1200 rpms. Each time I shut it off and immediately try to restart it and it won’t fire. Short spray of ether and it fires right off and runs fine. the check valve broke into 2 pieces so pretty confident I got it all. Didn’t have new brass washers so I reused the old ones. They appeared to be ok. I just don’t see how it can lose prime in a matter of 2 seconds.

I’m working on my son’s Superliner and need some help. The truck had sat for quite a while and my brother gave it to my son to restore just before he passed away. The truck ran fine until a few days ago. It started to act up and wouldn’t idle. As long as the rpm’s stayed above 800, it was fine. I went out to start it the other day and it would only run on ether. Determined the plastic check valve on the left side of the pump had broke. Replaced both check valves and now it will run, but won’t start without ether. I let it idle for over an hour, shut it off and tried to start it again right away and it wouldn’t start. The only way it will start is with ether. Any advice would be greatly appreciated