Full Floater

Ok so pull the whole pump and have it checked out, ok. If I knew it was the springs, does the entire pump need to be pulled anyways? or can the back part be removed from the main body of the injection pump? Is there anything else I should have done to the pump while its at the injection shop? Its fairly low mileage, 220.000km so im hoping that it does not need a full rebuild

The external springs in the picture are the throttle return springs. They are both new but the horizontal one replaced what was there from the factory, or at least it looked factory. The other one is just an extra one that I put on for good measure, to be sure that this wasn't casing my issue. All it did was make the pedal stiffer. There is defiantly something going on as it hunts at idle and when I accelerate softly, it does it then to. Its like im going down the road and getting on and off the throttle every second or two, but in reality, im holding it as steady as I possibly can. The entire linkage is tight and no play anywhere So should I look at bushings instead of springs?? I have no idea where to start

Ok so im due for new governor springs in my 79 RS600L, with an EM6-300. Its doing the lopey idle thing with a lopey acceleration. I have never done springs before and this is my first Mack. So, what all is involved? I will be having an injection shop do the work but I need to know if I have to remove the entire injection pump or can I get to the springs another way? I don't even know where the springs are... Thanks fella's, Im looking forward to getting this motor that's in excellent shape, running smoothly!!

The 795GB363AP7 works! It hangs up a little bit on the bottom of the dipstick tube, but with a little finessing, it comes out. I can live with that.

Thank you guys. I will put it 80-90 as that's what I have a lot of.

Hi fellas! I am about to change the tranny oil in my 1978 RS600l with a 12 speed. Question is, what viscosity of gear oil do I use? Are any additives worth putting in to? Thanks a bunch, Kevin

What years were the early V8s? What were there issues?

So you're saying that's most likely whats wrong with the factory pump? Would you recommend that I dig into it and revert back to using it? I will if that's a better way.

Good solid info, thanks Terry. Kevin

Is that in fact a lift pump, or where the pump used to be? I don't see any lines going to or from it. Is it safe to run an electric in conjunction with the factory pump? Im assuming there was an air intrusion issue or drain back problem at one point and someone put and electric on there as a band aid solution. Im happy with how its been working however. I will be buying another electric lift pump to keep in the tool box in case it fails somewhere out in them bushes...

Here you are, pics of the pump. Yeah, that looks just like the electric pump that's on mine. What did these use as a lift pump from the factory? Did the IP pull fuel from the tank on its own? Im having what seems to be a common Mack issue, with it having an irregular idle from what I thought was worn governor springs; but im wondering if the electric pump is pushing fuel at a different psi then what the injection pump requires?? Just a thought that crossed my mind.....

I don't see a hand priming pump on the injection pump or anything that might resemble a lift pump

Oh nice!!!! Thanks so much. I will try that one next week!

The dipstick handle broke off on my EM6-300. Luckily I could fish it out of the dipstick tube...phewww..... This isn't the factory engine so when I ordered a new dipstick from Mack, they ran the trucks serial numbers and I got the wrong dipstick, part #795GB29301P3. They said the numbers of the engine didn't do them any good. The one they sent me had a twist to tighten handle with the rubber seal that expands. Mine had just a plain old hook handle, no seal or anything. It fit into the tube in the picture. Does anyone possibly have part # for an EM6 dipstick??

In my 78 RS600L, I have an EM6-300. Not the original engine and im not sure what the original engine was. I have an electric fuel lift pump mounted behind the fuel filters that is energized by the ignition ON. Is this a factory lift pump? Its working just fine and makes priming the system and fresh filters a breeze. Just curious Don't mind the red wire...that's just a mickey mouse and temporary ground for a marker light I had to jimmy rig recently.

Have you tried replacing the air supply spin on filter? Seemed to help a little when I was (still am) having issues with the reverse selector. Damn now im paranoid about those bolts. Did I tighten them enough??? hmmmm

Did they come out of a Hayes off roader or something? Just curious. I had one, 68 HDX with a 12v71 that came from Rupert

Im thinking that its either a sticking locking pin or an air blockage/pressure issue. When the cover is off, everything seems to be fine, as long as the high-low is in its neutral position, the reverse ram will work well. This is with air and not touching the ram itself. Yeah maybe there is silicone somewhere. I put a THIN layer on the first time I set the lid on but I let it set up mostly before I set the lid on, then once I realized I was going to be taking that thing on and off a few times, I cleaned off all the silicone with a rag so it wouldn't start making a mess. I was careful not to get any in the gearbox

Good to know, thanks. I'll check that out. I cant hear any air escaping but who knows.

Ok I got it!! I ended up using a screwdriver as you described and the selector is now working as it should, thanks! however; im kinda back to the same problem. When the trans has warmed up, it becomes very stubborn to get reverse again. Today when I test drove it, all was well so I went and did a load, and about 10 miles into the run, no reverse for the life of me. If I had tools with me I would have popped that cover now that im familiar with it but I didn't have any tools really. So I attempted to pour cool water on it for a while to get the temp down (it was just barely warm), that did nothing, I tapped it with a hammer a bunch and that's when I finally got it to engage. Which was good because I was faced into a dead end road. I engaged and disengaged it a number of times to try and free something up , then 5 miles later, same thing, no reverse. But after working the toggle a bunch and rocking the truck back and forth, it engaged. Then on the way home it was ok, not that easy but there was not much fighting to get it to engage. And that's where I left it now that darkness is upon us. I made sure I was at or over 100lbs of air, the filter is new, there is tons of pressure at the air line when its disconnected and the inlet fitting is free of obstructions. So, im 99.9% sure that it is getting all the air it needs. I lightly coated the rams and all the orings with grease when I installed them to lube everything up nice.

Wow thanks for taking the time to scan those pages. I didn't know about that adjustment procedure. I'll save that part for later and I'll make sure those forks are in those positions, which I don't think they were; tomorrow morning. Thanks! And yeah, another day id like to hear that story of the bolt falling off. So id better double check that they are tight!!

Yeah that's what I would like to try. And to select neutral on the shift forks in the trans, what am I looking for? Do I just want the forks to sit freely? The trans and selector were in neutral when I removed the cover, and im attempting to assemble with the shifter and selector in neutral. So I guess all that im looking for is the forks to be in neutral to now... I think..

With the Hi Lo selector in the middle (locking pin) position, the reverse ram will move to the reverse position when air is applied to the side port. And back to neutral when air to the rear port. When the reverse ram is in neutral, the Hi Lo will function properly also. Do the selector forks in the trans have to be in a specific position when installing the cover?

Nevermind, now I can move it, just had to reposition the other one in order to allow the reverse one to move

I was able to peak through as I was lowering the lid to ensure that the doo hickeys were in there slots. I have the cover off again, I cannot move the neutral reverse doo hickey/ram at all. I noticed this a I put it on to but just didn't think much about it. I think it may be an issue with the locking pin?? As I kind fiddled with it to get the rams back in