39 Baby Mack

In my experience, they never drove in that hard. Remove the plug and drive in with a large socket. Make sure the plug is out before you weld it, pretty sure there's an "O" ring around the plug. Ron Sent from my SM-G900V using Tapatalk

The heavy welch plug you spoke of (like a frost plug) was actually the original style. They could only be installed properly with the steering knuckle off the axle. They had to be installed with a special tool which consisted of a driver and an anvil. You would put the welch plug into the bore with the concave down, rest the knuckle upside down on the anvil and drive the plug down with the driver. It would set the plug in the bore about an 1/8" down from the top. On top of all this you couldn't buy the tool you had to have it made! This was a bad design, in my opinion, and were always a problem with them coming lose. The later ones looked like an inverted top hat with ridges on the part that goes down in the pin bushing bore. They were made to be driven in from the top. They also have a screw in plug that goes into the cap. The plug was to be removed so you could install a pusher bolt in the hole to remove the plug when it was time to service the pins. These were better but as was already said tack weld them in. Ron Sent from my SM-G900V using Tapatalk

Weren't the ones the Post Office had actually MCs? Lighter frames than the MRs had. MCs weren't made very long, they were made as both tractors and platform chassis. Once the Post Office quit ordering them pretty much the end for the MCs. Ron Sent from my SM-G900V using Tapatalk

Very sorry for your loss Matt Sent from my SM-G900V using Tapatalk

Never ever heard of the ED referred to as Express Delivery? It was the smallest truck in the E series that was brought out in 1936. The EB and EC were traffic type units that came out in '36 along with the larger E model conventional trucks. The first conventional trucks were EH, EJ, EM, EQ, and two chain drive models the ER and ES. In 1938, after the joint venture between REO and Mack to produce the Mack Jrs was over, the smaller E models came out those being the ED, EE, EF, and EG. A further edition to the E series line up came in 1939. This last truck had a little heavier rating than an ED and not as heavy a rating as an EE. I never heard this for sure. But it makes sense why it ended with the moniker of DE? They were out of letters! Ron

Unbelievable [emoji54] Sent from my SM-G900V using Tapatalk

There's basically two different heads for a 673. 18 stud or 20 stud. 18 stud heads have a single corner stud on the drivers side. 20 stud heads have double corner studs on the drivers side. All 5/8" studs. One other thing to watch out for, there were two different 18 stud heads. One had all 9/16" studs, the later ones had sixteen 9/16" studs with two 3/4" corner studs in the corners on the drivers side. I hope this helps, you should be able identify them without having to remove the valve covers. Ron

Welcome aboard! Sent from my SM-G900V using Tapatalk

Glenn, Do you remember the first reversing relay, the one that was remotely mounted towards the front of the motor. If memory serves me it was mounted off the thermostat housing. It was made by Fairchild. How many complaints about an air leak did you hear about when somebody would shut one off in gear without setting the spring brakes? Couldn't take your time adjusting the brakes with the truck shut off and in gear or the bleed on the reversing relay would pop the brakes back on! Ron Sent from my SM-G900V using Tapatalk

Thanks for all the well wishes guys. I really do appreciate it! I get this way from time to time, I'll be fine! Ron Sent from my SM-G900V using Tapatalk

The first emission system I saw was a steel line that went from the turbo down to the governor. It wouldn't allow the rack in the pump to open fully until there was sufficient boost to burn the fuel.(eliminating the initial heavy black smoke that the early Maxidynes were known for after an upshift in low RPMs) It eliminated the "puff"! This was fine except for trying to start one of these Maxidyne engines in cold weather. To get these started you needed to hold the accelerator to the floor to have the rack open fully. You couldn't get the rack to open fully with that set up. With the reversing relay the puff limiter didn't work until the spring brakes were released and the truck was ready to go down the road. This allowed for a full rack in the pump to get the engine started when it was cold but set the puff limiter in operation once the truck was put in operation Ron Sent from my SM-G900V using Tapatalk

Sent from my SM-G900V using Tapatalk A quick check to see if it's working. Nail the accelerator with the spring brakes applied, exhaust should look like a house afire. Release the brakes and try it again you should see a very noticeable difference!!! Ron Sent from my SM-G900V using Tapatalk

A quick check to see if it's working. Nail the accelerator with the spring brakes applied, exhaust should look like a house afire. Release the brakes and try it again you should see a very noticeable difference!!! Ron Sent from my SM-G900V using Tapatalk

There was a service bulletin that explained how to test the reversing relay valves. It involved using two gauges and an air regulator. I probably have one but I'm sure somebody else on here could probably lay hands to theirs a lot easier than I could! Ron

Sounds like it's time to roll coal! Ron Sent from my SM-G900V using Tapatalk

Isn't there also a difference in the camshaft between the two engines? Ron Sent from my SM-G900V using Tapatalk

Looks like an original Mack pick-up body to me. Ron

Looks good Mike, best of luck with it! Ron Sent from my SM-G900V using Tapatalk

Glenn, wasn't there a special rear seal housing made to take the later seal. The housing I'm talking about would clear the oil slinger and not require the slinger to be machined off the crank.? Ron Sent from my SM-G900V using Tapatalk

Welcome aboard! and good luck with the ED. just for curiosity sake what's the chassis#? Ron

Mine had the early style headlights on it when I first started working on it. Changed it over to the Corcoran Brown headlights. Always liked them with the parking lights! Ron

Happy Anniversary! Sent from my SM-G900V using Tapatalk

Do you have the special washers that go into the 3/4" corner stud holes for the 9/16" studs? Sent from my SM-G900V using Tapatalk

The first thing I'd check would be the toe-in. That would cause a high speed wander. Ron Sent from my SM-G900V using Tapatalk

[emoji3] Sent from my SM-G900V using Tapatalk