New project truck- 1980 F100

Hi Guys,
My wife allowed me to buy a new project truck for my 50th birthday. 1980 F100 fresh imported here in the UK. 4.9 straight 6 manual trans. 2wd lwb.
It will be a long term project working on it as and when I can. Initial plans are to convert to v8, either 5.0 or 460.
4" lift on 33's or 35's. Body off to restore the frame then weld in new metal to repair the cab corners etc.
First jobs will be to sort out the siezed brakes and fix the poor running engine.
No doubt I will be bugging you all for help and info along the way.

Alan

Alan - That's a cool project.  Sounds like your wife is like Janey - an enabler.  

Just fyi, some of the F100's have a smaller bolt circle on the wheels.  You can read about that on the F100's tab on the page at Documentation/Bullnose FAQ's.

And if you go with a 460 you need to be aware that the engine crossmember for a 460, or diesel, is different.  It is "dented" to allow the oil filter/cooler fitting to fit.  So you might have to run a remote oil filter to get it to work.

Last, when you run 35's you'll need to re-gear.  I'm running 33's with stock 3.55 gearing and the 460 manages them fine.  But 35's would be questionable with that gearing.

Also, I see why you asked for multiple stickers!  I hope to get them shipped today.

Hi Gary,
I've been doing a bit of research on here regarding the F100 and noticed the smaller pcd pattern. Not a problem as I can obtain that pattern wheels easily. I'll bear in mind about the crossmember.
I have another 9" from a bronco with 3.55's that needs rebuilding so may fit that with 4.11's. I have that same ratio in my F150 on 33's.
The truck will be getting parked up for a while as I need to concentrate on other projects at the moment. Hopefully it will be resurrected next year.
Thanks again for the info and stickers

Alan

Hi Gary,
The stickers have arrived!!
Many thanks sir👍

Quick question, the smaller pcd (4.5) rotors on my F100, are they the same as the later 2wd rotors with the larger 5.5 pcd? With just the bolt pattern being different?
The reason I ask is I have a spare set of 5.5" pattern wheels for my other truck. Rather than buy another set of wheels, can I not just fit later 2wd rotors with the larger pcd and use my existing wheels?
I have a spare set of axle shafts and drums with the larger pcd already to fit to the rear axle.

Alan

Alan - Excellent!  Glad they made it so quickly.  Like maybe 10 days?  Give us a few pics when you get them installed?

On the rotors, I think the answer is no.  But I'm tagging Dave/Fuzzface2 as I think he's been through this.

Dave - Everything is different between the two bolt patterns.  Right?

From what I can see cross referencing part numbers on Rockauto, the early rotor diameters are 11.040" and the later rotors are 11.720"
The height of the early rotors are 4.280" and the later rotors are 5.387" I believe this is just down to the rotor thickness being 1.185" on the later rotors and 0.875" on the earlier rotors.

The spindle, wheel bearings and caliper part numbers are the same for both early and later 2wd. Perhaps the only difference is the brake pad thickness, pcd and rotor thickness.

Alan

Blacktop wrote

From what I can see cross referencing part numbers on Rockauto, the early rotor diameters are 11.040" and the later rotors are 11.720"
The height of the early rotors are 4.280" and the later rotors are 5.387" I believe this is just down to the rotor thickness being 1.185" on the later rotors and 0.875" on the earlier rotors.

The spindle, wheel bearings and caliper part numbers are the same for both early and later 2wd. Perhaps the only difference is the brake pad thickness, pcd and rotor thickness.

Alan

You may want to re-check all the part numbers.
I cant remember if the bearings & races inner / outer are the same between the 2 sizes and same with the seal as I did not get that far with a swap when it all fell apart.

Back ground I had 2 - 1981 trucks to make 1 good truck.
The truck I wanted to put on the road had the large WBP (wheel bolt pattern) of 5.5 x 5
The parts truck had the small WBP 4.5 x 5

The road truck had frozen king pins so the plan was to take the front suspension from the parts truck and bolt it in to the road truck. Once it was in and I wanted to roll the truck around is when I found out about the WBP. I did not have wheels that fit the small WBP so I went to install my after market wheels and would not fit.

My plan was to swap rotors so I could use the wheels I had but then found out the rotors did not fit the spindles. IIRC there was a off set and the rotor hit the brake caliper mount.
That is when I did more digging and found the kingpins are different sizes so I could not swap spindles to the beams.
So I had to use my old frozen kingpin beams & spindles after new kingpins.

With the beams and spindles for the large WBP bolted in the truck I was going to use the parts truck calipers as I was going to use the the power booster from the parts truck.
That is when I found the calipers are different between the 2 trucks and why I say check the part numbers again. Oh the front brake pads are different between the 2 trucks too.

So in short what I found is from the beams on out to the tip of the spindles are totally different between the 2 WBP and no parts inter-change between them.
You can swap the whole suspension as it will bolt in.

It may not be what you wanted to hear but its what I found with my project.
If you need more information let me know.
Dave ----

BTW the rear drum brakes are also different sizes between the WBP.
IIRC the front pads and rear drums are larger on the 5.5 x 5 WBP

Now in my checking of the brake system to change from manual (5.5 x 5 WBP) brakes to power (4.5. x 5 WBP) the caliper piston sizes, the wheel cyl sizes as was the master cyl bore sizes were all the same sizes between the trucks. I did not check on the stroke between the 2 masters the brakes work.

The brake pedals are different between them.
Where the master rod hooks to is at a different distance from the pivot so I had to swap in the power brake pedal when I did the power booster for power brakes.
Dave ----

Dave - Thanks a bunch.  I knew you'd been into this before so wanted you to explain.

Alan - Let me try to bring some part numbers out.  First, the F100's with the small bolt pattern wheels had power brakes and a GVW from 4600 to 4700 lbs.  You can see how I arrived at that conclusion on the F100's tab at Documentation/Bullnose FAQ's.

Ok, given that we can turn to the brakes (Documentation/Driveline/Brakes and the Front Brakes and then Part Numbers tabs).  The F100's and F150's use Parts List #2 and here it is.  You can see that yours takes a different shoe & lining kit from the other F100's & F150's, different brake calipers, and different rear brake cylinders.



And referring back to the info on hubs and rotors, the F100's with small pattern wheels use Front Hub & Rotor Parts List #6 while the other F100's and the F150's use Parts List #15.  And here they are side-by-side so you can see the differences.

different brake calipers, and different rear brake cylinders.

I knew the calipers were different but I did not know the rear wheel cyl were

Then again I may have only looked up the bore size of both the not the part numbers?

Thinking if the bore sizes between all parts, power & non-power, were the same I would be ok to use the power brake booster & master with the manual brake parts at the wheels
Dave ----

Yes, if the bore sizes are the same then I think you'd be ok.  But I don't know how to tell bore sizes, just part numbers.

Wow, thank you Dave and Gary for the indepth info. This is what makes this forum such a goldmine for someone like me.
I guess my easiest option is to ditch the brake swop idea and just source another set of wheels in the smaller bolt pattern. Its right what people say, KISS. Keep It Simple Stupid.
🤣
Many thanks again guys👍
Alan.

Gary Lewis wrote

Yes, if the bore sizes are the same then I think you'd be ok.  But I don't know how to tell bore sizes, just part numbers.

Yea the Ford parts info may not say but the on line parts stores do for the most part and what I went by.

Look up each part for each truck on many sites taking down part numbers and sizes to compare to make sure it would work before jumping of just bolting on the booster / master.
I think it works as the truck stops and at time pretty quickly when needed!

One thing I just now thought of what master / booster is used with the larger brake parts like on my truck?
I am sure they had power brakes with the larger brakes and at some point I may look deeper into it.
Dont fix what aint broke
Dave ----

Blacktop wrote

Wow, thank you Dave and Gary for the indepth info. This is what makes this forum such a goldmine for someone like me.
I guess my easiest option is to ditch the brake swop idea and just source another set of wheels in the smaller bolt pattern. Its right what people say, KISS. Keep It Simple Stupid.
🤣
Many thanks again guys👍
Alan.

Your welcome glad to help before you went through what I did
That is why I know first hand you cant mix n match the 2 systems that way.

Unless you were to swap the whole front suspension the larger WBP will not happen
As for the rear I dont know if you can just swap axle shafts to the larger WBP or if the backing plates need to be swapped also?
Now that I think of it the larger WBP also has larger shoes so the backing plate would most likely need to be swapped too.

So yes KISS would be the best route and just get the smaller WBP wheels.
Dave ----

I agree - KISS!  And happy we could help.