Vladislav

The trunnion cap could be for oil in those days. At least my 1945 trunnion was made that way. Sure you can use greese in that spot too and I suggest it's only better. Especially if the seal of the spring seat over the trunnion bar is bad which is common. Later Macks had grease nipple and a pressure release nipple at the other side. What is on your picture more looks like a breather. But if so there should be a filling plug. And my setup had the plug exactly in that place. Central bolt - almost as Paul said. Your's look generally Ok. That top end has a nut attached to it, you can see it in that cavit if remove all derbits from there. Strange at one side the bolt is slightly offset, But I think it's not bad, just the holes in the leaves are a bit large. Or you will soon learn by noting leaves travel if the bolt is broken and than take the spring pack apart. Which I guess is not a job you really lust to do without hard reason. The condition of the trunnion spindels is very questional where the spring seats spin on it. Worth to check out at least for knowing the situation. You need to jack the axles for that or just yard drive with the steering wheels maxed out to the left or right and ask anybody to look at the rear bogie on possible shift of springs against the trunnion bar.

I made that alone. Attached a can of fuel higher than the pump inlet. So the stream was forced by gravity. Very sharp way of setting, a pump shop calibrates plungers that way. But care and attention is needed when removing the delivery valve. And sure a piece of old fuel line.

Macungie is overkill in emotions. Dutch show multiplied by twenty

Too probably. But isn't that right side a home made part fabricated of a piece of U-channel?

Strange. I'm pretty sure the steering column fitment to the cab dash support plank is almost similar (the same) in DM and R-model cabs. And the door position too. Driver seat is the same mounting either so I can't imagine the distane between the wheel and the vent window differs anyhow. If only the offset cab allows better look to the left side for anything nice or desirable so the driver leans against that bad spoken piece of glass.

Glad to hear the problem is solved. That old valve at the right of the picture - can't you take it apart and check the inside out? There must be a sort of spring and a plunger/ball/a diaphragm which could be bad.

Interesting. Thank you for explanations. A plan is to take the governor apart to sandblast and paint the housing. But I don't know if I can do that and keep the key mech parts together to not loose settings. Or set them back in. Another task was to increase the RPM's up to 2300 since that's a hobby truck and I'd like to rev it up between shiftings sometimes. I asked the pump guy on my desires but he explained the matters only in general. He's not a specialist in Mack pumps/governors and I'm pretty sure there are neither of them in all the country. But he's very experienced fuel tech and said he could do the job if the settings are known. But they are not.

Ok, so actually it turns out the weights try to pull the fuel rack back but you add pre-load to the spring just by your foot moving the linkage further up?

Yes, now I remember that dowel. That time I didn't reset/check the timing. Just needed to get the truck yard driving (actually to take it off the street into my property. One plunger got stuck and I couldn't get it free until took the pump off the engine.

Yes, I see. And I have that small cover removed from my pump at the moment. And saw that srew, I remember it. Just can't imagine how physically a srew which limits linkage that is supposed to move the rack can affect the rev limiting device. If you sure that is that way and the matter is difficult to explain I can take this on trust and just experiment with the screw. Bad thing I didn't know that when the pump was on a test bench. Much easier to check than on a truck.

Yes, you do Jojo. Thank you. I once took Robert Bosch pump off an engine. But that was E6 (or EM6) not E7. As I remember I didn't take the front engine cover off (and that small cover on it either).

Some good reading before the sleep. No kidding

Are you sue that's high RPM stop? Much more seemed as just a limiter for the rack travel. Top RPM's are limited by that rotating weights setup. Can its operation be corrected just by a set screw in the throttle drive? Yes, I'm talking about Ambac PLM at the moment, as on the picture. Had been to a pump shop a couple days ago, they reassembled and calibrated my pump. But the guy said he had no exact idea on how to correct the governor settings.

Jojo, life's good but I haven't understood two simple things. And probably the guy too. First - do you need to disconnect (unscrew) anything under the engine front cover to just remove the pump off the engine? I belive the pump has composite coupling with splines and you just pull if off. Both on E7 and E6. Second. When you set timing you may go two ways. Rotate the pump housing OR rotate a gear under the engine front cover which has 4 bolts. Right? I honestly forgot if the pump is rotatable in its place or has stationary mount.

No, Ambac pump needs 18 degree initial advance. 22 deg is for Bosch. On the same engine!

What pump is this arrangement for? I'm looking for info on how to increase top RPM's of Mabac pump. Currently it is set for 2000RPM.

Did the truck have an off-set cab? I honestly can't imagine a full one part hood made of steel. DM or DMM or RD800 could have steel nose but the engine gets accessed through a baterfly hood shells. Unified fiberglass nose is a different story. And with super singles at the front it was the most probably DM or DMM model. But all this just my guesses.

Ok, no sun - no timing

E6-4V came into production in 1985 if I'm not wrong. And many were equipped with Ambac pumps, Robert Bosch took place closer to 89. Trucks with E6-350 4V were 688 trucks - R688, MR688 etc. Trucks with generally similar EM6-300 4V were 690 trucks - R690, DM690 and so on.

That was interesting note Bob about that big difference in properties of 300 4V compared to 350 4V. I belive 300 4V was EM6 so Maxidyne and E6-350 is Econodyne. But physically they're both almost the same engines. The difference must be in the fuel pump settings and the turbo (if I'm not wrong). So the fact you shared surprizes me a bit. I have both types of engines in my trucks right at the moment. But didn't experienced 300 4V on a highway since it's not road ready.

Did it have the chassis mounted aftercooler? I just wonder if some (late?) U's used that grill and was there the reason having CMCAC?

Thanks the great!

Finally purchased my example of the book today. Looks like plenty of reading in it.

Wow! Many thanks for sharing! I was on a hunt for that number myself. Just wasn't the need of the day. If you spread your honesty a bit more sharing the shocks # that will make my day.

As fjh said just detach the release cable. A trouble may be found if the input shaft got seized in the disc splines or the bearing in the flywheel but those cases are seldom. BTW it worth to apply some grease to the points along the reassembly. Of other things you need to bottle jack the flywheel housing to free up rear engine mounts since they're on the tranny housing (as was mentioned above), detach the shift linkage and the prop shaft. There may/should be some air lines in your case, just common marks on which one goes to and that's all I belive. Ok, a speedo cable may be.