Hey, I know this has been asked before. But I've searched and can't find what I'm looking for. I was hoping maybe someone on here could help me out.

Anyways, I just acquired a '52 F-6 with a M.H. conversion. The VIN reads:
F6R2HM20489

GVWR 16,000 But the M.H. tag says 17,000

The VIN plate says 6.80 gear ratio, 158 wheelbase....and a whopping 96hp @ 3400rpm

There is another number on the plate that reads:
20CDN112

My question is....what's up with these axles? Are they actually made by M.H.? What's the difference between the 52 axles and the 56+ axles.....other than lug pattern? I know about the 5 vs. 6 lug and the infamous Widowmakers....and that's not really my main concern. Other than the lug pattern, is there any advantage to swapping them for 56+ axles? I just really need to know who makes the axles and what the model number is. I'm trying to figure out if I can even get parts for these things or not. Also, how strong is front axle? Other than the huge center section......the rest doesn't look very beefy. Can these things really hold up a 17,000 pound truck?

THANKS!!

 

Well, for starters, your truck doesn't weigh 17,000 pounds. That is the gross vehicle weight rating (GVWR), which is the maximum hauling capacity the truck is designed to handle. Can the axles really hold up the weight, I would say yes, since they were designed to do so, otherwise they wouldn't be there. And they have been there for nearly 60 years.

 

.......But, when the truck is fully loaded to the maximum GVWR.......it weighs 17,000 pounds I understand that the bare chassis probably weighs less than my 05 F-150.

Have you actually SEEN these axles?? The springs and hangers look like something that came off an old flatfender Jeep. And, unless it's an optical illusion, the tubes and knuckles don't even look Dana 60 class. They just "LOOK" like they would fold if you took it down anything other than a graded gravel road. I know they have been holding the truck off the ground for 60 years. But how would they hold up to abuse? What if I wanted to install a motor with more than 96 horsepower?

I'm not trying to sound unappreciative, but I asked some specific questions......and instead get "schooled" on the meaning of GVWR

 

I'm sorry if you felt my specific answers to your specific questions were lame. Please allow me to do better.

Assuming your axles and suspension were installed originally by either Ford or Marmon-Herrington when the truck was built, they would be plenty capable of operating the vehicle fully loaded to it's rated capacity, under normal conditions, with it's original equipment powertrain. But to be fair, you did ask if the axles were capable of holding up "a 17,000 pound truck". And I believe I did answer that question quite specifically. I can't be held responsible if you didn't care for the answer.

Have I seen the axles? Since you have not offered photos, and since I haven't been to your house, wherever that is, the answer would be no. Again, I am only offering specific answers to your specific questions, to the best of my ability using the information given.

If your plan is to abuse the truck, or replace the powertrain with something capable of delivering greater than the rated horsepower level, (not that either of these scenerios were offered in the original specific questions) I'm afraid that would be voiding your warranty, and guessing how long your axles will live under that kind of undue stress would be akin to a crapshoot. I hope that is specific enough. Given the information offered, that's the best I can do without a higher engineering degree. ;-)

 

No, I don't have any pics.....yet. I haven't gotten it home, and the truck is not in the most convenient location for for posing for a picture. I was hoping maybe someone who had experience with this setup would chime in. I wasn't exactly relying on someone, who had never seen one, to examine a picture and say "yeah, that'll work".

I'll give you an example....maybe this will help you understand what I'm saying. I have a 79 F-350 4x4 with a Dana 60 front axle. The truck came from the factory with about 150hp and 30" tires. It even has a front GAWR that is actually LOWER than my 05 F-150. But, it's pretty much an accepted fact that I could install a 300hp big block with 40" tires and go play in the mud without breaking anything. This is because the axles is designed to handle much heavier use than specd by Ford. The axe manufacturer actually rates the axle capacity about 1000 lbs heavier than Ford GAWR. It's the same thing with the rear axle on my F-150. My door tag says 3850. However, Visteon rates the axle at 4500. What this means is that I could load either my F-150 or F-350 to the maximum GVWR and have no worries about taking them off-road. There is an extra margin of safety to make up for anything unexpected.

Now back to the F-6.... I have no doubt the truck will "carry" 17,000 lbs. But is that the breaking point? Or does it have a little extra to handle the occasional "oops" that is typically encountered when you leave the pavement. And, are these things so rare that I could never find a replacement part if I was to break something.

 

Let's see if I can answer your "specific" questions to hopefully avoid the abuse Wayne got.

The front axle in a MH conversion is the same that Ford used at the rear, just modified for front use. In an F-6 that should be a split case single speed Timken Model E155. MH added their own steering modifications to the axles and, in my case, they added their own front drums. The Chassis Manual lists a Timken E155 as having a capacity of "13M", which I assume to mean 13,000 lbs. For comparison, the chart lists the F-6's Eaton Model 1350 two speed as having the same rating, and the F-8's Eaton Model 1790-1 single speed as having a capacity of "17M". A 1956 F-600 is shown having four optional axles. Single speed axles were a Timken Model 104 with 14M capacity, a Timken Model 105 with 14M capacity, and a Timken Model 106 with 15M capacity. A two speed Eaton Model 13600 is shown to have 15M capacity.

You mention that the MH data plate over the windshield lists a weight rating of 17,000 lbs while Ford's plate shows 16,000. Probably MH added overload springs or heavier springs would be my guess. In the case of F-2s, all were rated at the same 6800 lbs of an F-3 because MH spec'd them all with heavier springs.

Your 20CDN112 is probably the Production Number. The books give a chart to interpret that info, but seldom do we find that the info follows the book's pattern.

Parts availabilty is the same as any other F-6 as far as the differentials are concerned. Used parts should be plentiful. The MH components will not be plentiful, but you might have luck getting used from Chuck Mantiglia at Chuck's Trucks. He also has differential parts, as would Job Lot. Stu

 

Well, Wayne started it.....

Anyways.......Thanks for the help!! So, the center section is Timken? But everything from the knuckles out is most likely MH? So that means that means all the stuff that is most likely to break will be very hard to replace??

There is no way the front axle keeps the rear's 13,000 lb rating. The tubes neck down to only 2.75 inches at the knuckle!! The leaf springs are only 2 inches wide with a shackle that looks like it came off a motorcycle chain. Any idea what the front GAWR may have been?

Thanks to you and rb48f6, I have a much better idea of what I have now. I'll just let this rest a little until I get it home this weekend.

 

No, I don't find it anywhere. Not even for any of my "R" series trucks. Which I probably should explain too. The Marmon Herrington "R" series includes the F-2 through F-5 models because they all use the same transfer case. Your truck should be in the "V" series, and you'll see that reflected on the large plate that's over the windshield. The F-7 is in the "Q" series. Interestingly, you commonly see the F-8 classed similar to the F-7 but I don't see that in this instance. My "R" series reference makes no mention of the MH F-8 series designation.

You'll probably want to watch eBay to find an old copy of the MH "V" series Maintenance and Parts Manual for that model truck. Or you might check with Chuck Mantiglia to see if he'd let go of a spare copy if he has one. Or, better yet, one of our members had luck getting a pdf copy direct from Marmon Herrington for his "R" series F-5 so they may have have the manual for yours too.

Oh, and I found a second reference that says the rear GAWR of the Timken is 13,000 lbs, and it says it that plainly. What the heck the Chassis Manual "M" designation means I have no clue. Stu

 

One more thing. If you want to have spare axles on hand (an excellent idea), our member Petey Shoes has a spare set that he's mentioned selling. I know they are from a 1.5 or 2 ton and are Timkens, but don't know what Timken model number they are. You might look him up, unless he reads this and finds you. Stu

 

don't have the model numbers off hand, but can get them. 1.5 ton with 13,700 lb rating. (on whole truck). i,m confused with description of shackles. sound rather light for a marmon. keep in mind, these trucks were built with hard work in mind. they will pull till the cows come home! however, with much heavier springs and more crossmembers than stock trucks, they do not have the flex for true "off roading".

 

Petey...where are you located?
Bill

 

bill, i'm about 60 miles west of nyc. intersection of I-84 and rt-17, (soon to be I-86). drivetrain is identical to my 42. both axles, transfer case, underdrive. no driveshafts

 

I will give the new owner of this big job your info and if he wants he will get ahold of you.
I am glad it sold...but it would have made a great truck.
I have a lead on another in N.Y. and when I get up that way...will see if it is worth buying.
A guy from Canada bought mine...and is in Florida now.
He is having a transporter move it today.
This guy doesn't mess around.....LOL
tHANKS

 

I think the answer is that the Marmon Herrington front axle, huge transfer case, crossmember, front driveshaft, etc. and extra leaf springs are the extra 1000 lbs. making the gross maximum weight 17,000 instead of 16,000, so the truck still basically carries the same maximum load as a regular F6. Stu aka truckdog62563 can tell you how heavy that stuff is I'm sure. And as far as handling the load, the chassis may not look heavy enough when you look at the exposed front or rear areas, but if you look underneath you will see that these frames have an extra frame stuffed inside, that doubles the thickness through the area where the most stress would be when loaded. Mark
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1950 1952 1955 V8 Marmon Herrington Rangers

Mark