Flex-o-matic ?

[Kraig]

The '72 F-100 I bought last week has the "Flex-o-matic" rear suspension. What the heck is it supposed to do? Is it desirable or should I remove it as I plan on putting about 1000 lbs of equipment in the truck's bed?

[DuckRyder]

It refers to the rear springs having a lever type arraingement, to improve the ride.

See:

BumpSides

[binder56jd]

That's why you can jack the bumper 4 ft. off the ground and not get a tire off

[FORDification]

The factory explains it best: "The Flex-O-Matic rear spring system was available on all '67-'72 Ford trucks. When the pickup box is empty, Flex-O-Matic provides a long, supple spring to cushion the ride. When a load is added, a compensating shackle pivots into action to shorten the spring's effective length. Result: a shorter, stiffer spring as loads get heavier."

The single-shackle arrangement is for people doing light hauling. The Flex-O-Matic increases your payload limits, so I'd definitely leave it there if you're going to be doing a lot of hauling of heavy items or towing.

[NM5K]

Hummmm.....I thought flex-a-matic came out in 68...Most of my 68 brochures harp on the flex-a-matic as being new, while none of my 67 brochures mention it. But I'm not sure , other than that. With all the junker 67's you have run across, you probably have a better idea. Do some 67's have flex-a-matic? BTW, in 68, it was an option on any model, but it was standard on the f-250's. My 68 has it...Dunno about my 74 1/2 ton...I never looked...
Something to do later.... MK

[FORDification]

You know what? You may be right. I checked a couple of my books and now I can't find where I got that quote from, but none of the '67 books say anything about the Flex-0-Matic, but all the '68 books do. In '67 they're simply referring to 'progressive-rate springs'. So until further research proves otherwise, I think it'll be safe to say that they weren't used until '68. The '68 books do say they were used on all F-250s and heavy-duty F-100s.

[68F250]

Yep, Flex-O-Matic in '68 except for the F100 w/ the standard 950# springs. AFAIK, all the springs were progressive.

[flyboy2610]

My '68 F100 has it. I can load up the bed and it still rides pretty nicely.
I guess I have a 'heavy duty' F100, kind of like Chevy's 'Heavy Half', huh?

[FORDification]

Heck, I've parted out 4 or 5 '68s over the past year or so, and they've all that that. In fact, EVERY '68-'72 truck I've seen has that setup. My original '67 is the only one I've seen with just regular shackles.

[DuckRyder]

Mine has it as well, and it is a base payload long bed.

[68F250]

Robert, what's your truck's GVW?

[DuckRyder]

Robert, what's your truck's GVW?

It is not here right now, but IIRC 4500.

[68F250]

Ok, doing a little numbers chasing, it looks like the F100's standard 950# rear springs of '67 thru '71 were upgraded in '72 to a higher standard rating of 1175#. Maybe that's the difference, so then all '72 F100's got Flex-O-Matic?