Anyone know if a 1973 F250 rear end will bolt on to 1951 F1?
Thanks in advance

 

With enough modifications, anything can "bolt" to anything else. If you're asking if it's a drop in, direct swap, the answer is no.

You might do better to explain what you're looking to do and why, for us to be able to help you more accurately.

Welcome to the forum!

 

No, and why would you want to?

.....................read this, .....and there will be a quiz latter.

1948 through 1960 Ford F-1 and F-100 Rear Axle (differential) Swaps .: Articles

(kind of funny, the people that reprimand me for giving newbie’s a hard time don’t answer them at all! Take you pick, a helpful cynical answer or a polite non answer?)

 

One can call it a 'hard time', or one can consider it teaching, much in the same way one goes to school. For those who need/want help, sometimes there is a need for instruction on how, or mabye more appropriately, what, to ask. For us to provide the best answers and most accurate information, sometimes we need a little more information to go by.

 

I guess what I really am asking is do the existing springs bolt on to the F250 axle? If there is a difference in the mounting of the new axle, what is the major difference.
Thanks

 

My question is if you are building a f1 then why are you wanting to put an 8 lug f250 rear axle under it, are you planning to make a 3/4 ton truck out of it.

 

I think the F250 axle is not a good idea, I forgot about the 8 lug wheel pattern. Back to reseach.
Thanks

 

OK, no quiz:

1948 through 1960 Ford F-1 and F-100 Rear Axle (differential) Swaps .: Articles

 

The data in the article will be very helpful.

I just finished getting a Ford 9" for my F1 restoration project. The data in the article is correct....if you can find a 57 to 72 F100 donor vehicle, the axle will bolt directly to the F1 springs.

In retrospect I would have saved some money by buying an 8.8 inch axle from an Explorer. I would have been able to buy a complete axle in good shape with disc brakes attached for around $400. Add $60 for some new spring perches (you'd have to move the spring perches on the Explorer axle)

The 9" was more....$225 to buy it, then I went through it and replaced all of the bearings (including the axle bearings) (that was $300). I also had to replace the brakes (shoes, wheel cylinders, drums, self adjusters and parking brake cables) ($200 more). My labor doesn't count!

The plus is that I know that the axle will outlast the rest of the truck.

Dan

 

Perhaps that is covered in the article. But not having this posted outright there's a point that has to be brough up when you say "Direct Bolt up. I have to half argue with you because while it is true that the 57-72 rear end will bolt to the F1 Springs, it will not do so without either a change in mounting configuration, fabrication of new shock absorber mounts, or adaptation of F3 shock mounts.

The stock F1 Rear End has on outer tube diameter of 2.5 inches and the 9" just slightly over 3 inches. The F1 U-bolts come down from the top and bolt on below the axel tube on the bottom side of the shock mount. Those U-bolts and the shock mount holes they go through and affic under are 2 1/2 inches wide.

In order to bolt up a 9" rear, you would have to use 3" U-bolts which will not go through the stock F1 shock mount. Thus, the shock mount must be elliminated and the U-bolts changed from square end to round end and be mounted in reverse direction from under the axel and bolt above the springs, now, through a plate, and fabricate a shock mount to your axel if desired.

Or, if you can find a set of F3 Shock mounts, you can use those and the procedure is a direct bolt up but with wider U-bolts.

Pictures - before and after (disregard the two blocks in the before pic - they were installed for rake by the PO):







This last picture is of the shock mount. My PO cut and welded in 1/2 inch spacer to compensate for the larger tube diameter. When they replaced the rear springs and went to torque these on, the weld broke on the other mount. Mechanic said I was lucky to be alive!

Edit note. BTW you don't have to have shock absorbers on the back axel. The F2 does not have them. I rode around without shock absorbers for 300 miles stretching out the new springs prior to the weld-up of the new shock mounts in the pictures. In that case though you would still have to change the u-bolts from square to round and bolt them from underneath with a top plate.

 

If you just get the U bolts and retaining hardware with the donor rear, none of this is an issue. The shock mounts attached to the truck 9" can be made to work just fine when doing the swap in an F-1. The biggest hassle of the entire conversion is the driveshaft will need to be about 1" longer (again, I'm talking about F-1 measurements) if everything else is staying the same. If one is doing a complete drivetrain swap along with the rear exchange, that would need to be altered anyway, and is also a non-issue.

 

Yes....sorry...bolt in is a relative term. The F100 axle with its spring perches will fit directly onto your F1 springs. Julie's right...you'll need bigger U-bolts.

For the shock mounts, I was planning to use the F100 shock mounts & put some shock studs onto a crossbar.

A really easy alternative for lower shock mounts is from Chassis Engineering:

page 7

On this page is a U-bolt plate with shock studs already welded on for $40.

It's not a bad idea to use new U-bolts when you're doing a conversion. A lot of the wrecking yards use a cutting torch on the U-bolts so those can be a lost cause.

Dan

 

Some thing else to consider is that used U bolts on axles have been torqued to maximum and stretched considerably. If you watch someone cut them off or torch them they let go with considerable force. In MOP I would not use 'used U bolts' in this situation.

 

You always want to use new U-bolts.

So you are talking about using later truck F-100 rear spring seat caps with the sideways shock studs and moving the upper point that the shocks fit on, right?. Then you are still bolting on from the top and the cap is under the axel tube?

Good because it's going to be a little tough attaching a shock absorber that is welded to the flat plate if the plate has to be installed on the TOP of the spring. It's flat so it can't go under the axel tube - right? Not enough room between spring top and frame stud?

 

If I recall my F3 48 pu has spring mount with a 3 in diam. ED