Ok so I have a 1986 f150 2wd I paid $800 for it, so I'm rebuilding the motor right now and converting it to carb, but now I also want to have that 4wd, so I was looking at an 84 bronco I found in a junkyard and was wondering if I could rip off the front end with manual locking hubs, manual transfer case, and manual transmission, driveshafts and rear axle, I know it's a lot of work and would probably be easier just to get a 4wd set up already, but these parts are cheap as hell and there won't be any cutting or welding so it shouldn't be to much of a hassle, just need to know if those parts will work or not.

 

Jeremiah,

I created a new thread with this, it doesn't really fit in the WHYDTYTT thread (which is basically a BS thread (not derogatory) where people show off their current accomplishments).

BTW my understanding is yes, you can convert like you described (although the parts won't be any good if you "rip them off" ) but I imagine the Bronco rear driveshaft might need lengthening. Others will know for sure.

 

You'll have to measure frame width. I for some reason I keep thinking the 4x4 frame is different. If you search this has been discussed at length on this forum. It seems like the cross members are different & I keep thinking the frame width is different. Do some searching.

 

Frame width, or frame thickness? I'm honestly not aware of differences in either, but I won't say I'm an expert in this area.

 

Well I'm not gonna just rip them off, gonna take em off. I just can find any 86 4x4s out here, the reason I was going to use the bronco is because it has everything there that I need. I'll measure the rear driveshaft to ensure, but I'll probably have to get another because I have a single cab long bed. So who knows but if everything else will work besides that driveshaft then in gonna go for it.

 

Here's a good write up on the subject:
2x4 to 4x4 for '80 to '96 F-100/150's .: Articles

Short answer, 4wd front axle from an 80-96 F150/Bronco is a direct swap for the 2wd I-beams in any 80-96 2wd F150.

 

Hey love the link man, it's perfect, I appreciate all the help

 

The 4x4 will bolt right in, no problems. You will need to hunt up a rear driveshaft, your old one won't work and the Bronco rear shaft is not going to work either.

 

One more *possible* issue using a bronco as a donor. Pickups could have either a fixed yoke, or slip yoke for the rear output. All Bronco's used a fixed yoke, but it may be slightly different than the one used on pickups, as the Bronco used a "double carden" type CV joint, due to driveshaft angle. A custom shaft, with the double carden front joint *may* be needed, if using a Bronco transfer case.

The Bronco also uses different spacers blocks between the rear leafs and axle. Pickups have a flat 2" block, while the Bronco uses a thinner tapered block to point the pinion upwards a bit. The forward leaf spring hanger is also different, for this same reason.
Easy way around this, buy generic 2" "lift blocks" and stick with the original pickup rear leafs. The blocks are needed to raise the rear up, to match the 1.5-2" higher ride hieght of the front 4wd axle.

 

Ok well they have an f150 transfer case and transmission, Cain use those with driveshafts with bronco 4x4 front axle?

 

Sure. The only difference between F150 and Bronco TC is the output yoke, and I am not 100% positive they are different. I just know that all Broncos used the double carden front joint, while pickups did not.
It goes without saying that you will need to make sure the axle ratio in the front axle matches the rear. Most 80-90 4x4's had either 3.00 or 3.50 ratios (9" rear axle) or 3.08 or 3.55 ratios (8.8" rear axle), though at some point later, the 3.31 ratio was added to the list with the 8.8 axle.
4.10 ratios were available for either style rear axle, but are not very common.
One note here. The 9" axle 4wd's used the exact same ratio F/R, while the 8.8 used a .01 ratio split (3.07/3.08 & 3.54/3.55).
If you mix ratios (3.00 & 3.08/3.50 & 3.55), don't engage 4wd on hard surfaces, as driveline binding will occur, and damage will soon follow.

 

Ok do of anything I should just use bronco front and rear end axles to ensure they are the same, and I think it might just be easier to use the transmission and transfer case as well so all I will need to worry about is that rear driveshaft

 

Using both axles from the donor *should* insure compatibility, but it's always best to double check. A lot can happen to a vehicle in 20+ years of use.......
I was going to use a Bronco for a donor to convert my 80 F150 to 4wd, and simply have the rear DS lengthened to fit. Double carden joints are a bit of a pain to replace/rebuild, but they have advantages.

 

I can confirm this, as when I was looking at my rear differential, the rear said 3.08 while the front said 3.07, just like you say.

Why did they use a .01 ratio split? It seems that exact would be best.

Does .01 really make that much of a difference between 3.07/3.08?

Seems to me, from looking at the ratios, that Ford wanted the front to spin .01 faster than the rear?

 

The split ratio is so the front axle tends to "pull" a bit more, as well as make up for the extra distance the tires travel while making a turn. At least, that's what I'm told.