1980's Mack Mr

[linesplice]

What can I be told about the 1980's mack MR? I really don't know much about this model and I was interested in one locally (with a scandia engine?) for hauling antique tractors a short distance. The one I looked at has low ground clearance in front and others have a lot of ground clearance; how come - what's the difference? What is known to go bad on them? Any info would be appreciated!

[Terry T]

Dustin,

Right at the moment ebay and other online classifieds are flooded with Mack MR tractors, both single and tandem axle tractors. These are former US Post Office tractors with a lighter steer axle and on air ride rears (I believe they are on air ride). Typically an MR is a vocational use truck mostly used in refuse or as a platform for concrete pumpers requiring much heavier spec suspensions (typically on camel-back) there-by setting higher than the USPS tractors. I have an interesting pic of my old Ford LTL9000 wrecker with a twin steer MR cab and chassis on the back. I was towing from Advance Mixer (now Terex Advance) to the Mack dealership to have the air ride removed and camelback installed. Apparently someone decided that you can put a concrete pumper on air ride, Advance said ahhhh..... NO! So I towed it to the dealership to switch the suspension and towed it back as the drive line had already been removed and cut to be reinstalled with the bed. For your application an MR tractor would work out real nice and will get you in and out of tight quarters with minimal effort.

Terry

[GearheadGrrrl]

I've covered a lot of miles in Postal Service MRs, and the only complaint I've had is the rough ride on the single rear axle tractors. Though the MR cab looks low, there's at least as much ground clearance underneath as a 4x2 pickup has.

In conclusion, MRs are a bargain because the used truck market prefers conventionals- I wouldn't be afraid to buy one. In fact, I'm tempted to buy one of the old Postal Service tractors.

[linesplice]

Would you think twice about going 500 miles in one? With the large engine hump in the compartment, it doesn't seem very good truck for a companion to travel with you. How loud is the engine in there?

[GearheadGrrrl]

A 500 mile day is no problem- just make sure you have a trailer on if it's a single axle. Also, the MR doesn't have a lot of headroom with an air ride seat- I'm 5'- 8" and had no problem, but some of the taller drivers banged their head against the ceiling. Noise isn't bad- the Mack engine is pretty quiet. Even with the windows open (no air conditioning) I could usually hear my handheld ham radio OK.

[linesplice]

This one had a scania engine in it and not the E-7 Mack that was common. I don't know much about the scania job, but I think it's smaller and has less power?

[linesplice]

This one had a scania engine in it and not the small Mack that was common. I don't know much about the scania job, but I think it's smaller and has less power?

[bulldog man]

i wouldnt mind having a mc/mr TRACTOR to pull a dumptrailer during working season & to pull containers within a 250 o 300 mile radius of Memphis during slow winter months when construction is slow as long as it had a dumpvalve to dump the bags for going off the road in the dirt. buddy of my granddad had a older post office mc/mr model for a lowboy tractor w/ the 5spd in it man that ole would run like ya beat that dog w/ a stick

later

Bulldog (aka )

[GearheadGrrrl]

IIRC the Scania was a 7 litre or so motor putting out 210 horses with a turbo and 140 or so without- OK for light loads but it'd have trouble pulling a trailer. Neptune Moving had some of these with the turbo Scania and I remember seeing one struggling along at 40-45 m.p.h. pulling a big moving van trailer into a headwind.

As for the Postal Service Macks, with the Allison automatic and 135 inch wheelbase they're great for local work. However, for use around Memphis you'd want to install an air conditioner!

[bulldog man]

As for the Postal Service Macks, with the Allison automatic and 135 inch wheelbase they're great for local work. However, for use around Memphis you'd want to install an air conditioner!

Not a problem got a buddy of mine who is ASE Certified in truck repair that has a molbile tire & truck repair service (which i work for some as a helper ) & if he didnt want to fool w/ it id send it to Crows truck which is a REDDOT DEALER down on Lamar (hwy78) & holmes road Gotta have my Air

Later Bulldog (AKA )

[GearheadGrrrl]

Here in Minnesota the MRs were tolerable without air conditioning, but the CHs with there greenhouse windshield were a sauna. Other downsides to the Postal Service MRs are 3.90 gears with direct drive, only 60 gallons fuel capacity, and only 300 horses, and awful aerodynamics. For urban use of course these "drawbacks" are of little consequence. The Postal Service planned to replace the '99 Mack CHs with the Allison "World Transmission" with overdrive and programmable low hole, but management in their infernal wisdom never allowed for growth and ordered the same number of new trucks as they were planning to replace, and didn't buy enough tandems. Thusly a lot of the tandems and '99 CHs won't be sold off for a couple more years.

BTW, thanks to that little 60 gallon tank and an air starter those CH tandems only weight 16,000 pounds with a full fuel tank and this overweight driver on board...