9" rear
Fleet Mechanic
Joined: Nov 1999
Posts: 1,415
Likes: 0
From: Lower 48
9" rear
This is strictly my spin on things - which doesn't necessarily make it right.
First off measure your spring seats and see if you're going to have to put another set of seats on the 9" housing that matches your existing springs. Next measure from the centerline of your housing, and the 9" to the front of both U-joint yokes. Then see how much your driveshaft will move at the slipjoint - this will tell you if you have to modify your driveshaft. As for the brakes that's going to be a case of see what the differences are. If worse comes to worse you may end up having to mount your backing plates onto the 9" axle. Once that's done you should be set.
Trail Rider
First off measure your spring seats and see if you're going to have to put another set of seats on the 9" housing that matches your existing springs. Next measure from the centerline of your housing, and the 9" to the front of both U-joint yokes. Then see how much your driveshaft will move at the slipjoint - this will tell you if you have to modify your driveshaft. As for the brakes that's going to be a case of see what the differences are. If worse comes to worse you may end up having to mount your backing plates onto the 9" axle. Once that's done you should be set.
Trail Rider
Senior User
Joined: Jun 1999
Posts: 139
Likes: 0
9" rear
From my understanding the rear "antilock" brakes on standard equip. trucks is just line pressure. I guess it reads the line pressure to predict lock up. It doesn't work well at all. I'd disable it anyways if I were you, but I'm not, so....
Guest
Posts: n/a
9" rear
> From my understanding the rear "antilock"
>brakes on standard equip. trucks is
>just line pressure. I guess
>it reads the line pressure to
>predict lock up. It doesn't work
>well at all. I'd disable it
>anyways if I were you, but
>I'm not, so....
Actually, there is a wheel speed sensor in the rear 8.8 and 10.25 axles of Ford pickups and Broncos. How it works is that when the wheel speed sensor sees that the internal excitor ring is slowing down too fast (locked brakes), it releases the rear brake line pressure until the internal excitor ring is back to a reasonable speed. I have an '88 Bronco and an '91 F-250 and I admit the RABS doesn't work all too well. If you are looking for a beefy axle that is compatible with the RABS- use a full-float 10.25" axle from a heavy duty F-250 or F-350. It is a bolt in axle with the only problems being it an 8-lug axle and you will need a new driveshaft with the proper u-joint at the axle end.
>brakes on standard equip. trucks is
>just line pressure. I guess
>it reads the line pressure to
>predict lock up. It doesn't work
>well at all. I'd disable it
>anyways if I were you, but
>I'm not, so....
Actually, there is a wheel speed sensor in the rear 8.8 and 10.25 axles of Ford pickups and Broncos. How it works is that when the wheel speed sensor sees that the internal excitor ring is slowing down too fast (locked brakes), it releases the rear brake line pressure until the internal excitor ring is back to a reasonable speed. I have an '88 Bronco and an '91 F-250 and I admit the RABS doesn't work all too well. If you are looking for a beefy axle that is compatible with the RABS- use a full-float 10.25" axle from a heavy duty F-250 or F-350. It is a bolt in axle with the only problems being it an 8-lug axle and you will need a new driveshaft with the proper u-joint at the axle end.
Elder User
Joined: Nov 1999
Posts: 780
Likes: 1
9" rear
I think Ford phased in the 8.8 over the 9-in. in 1984 or '85. Since the 1/2-ton frame was pretty much the same from '80-'96, it stands to reason that mechanically this swap would be pretty much a bolt-in, so find junker from the early '80's and break out your measuring tape.
Eddie
Eddie
Junior User
Joined: Jan 2000
Posts: 60
Likes: 0
From: Connecticut
9" rear
I tried driving without the rear ABS, and I noticed a diff under hard braking. I was laying a strip where as with the ABS connected I did not. And this was with about 400 pounds in the bed and a tank and a half of gas. I would love to put in the 10.25. Is there anyway to change over the front axles to eight lugs, maybe from the spindles out? They look about the same after that in the exploded diagram.
Thanks
Rob
Thanks
Rob
