wlink14

As of now, the plan for this coming winter is to add a turbocharger, and that means broken axles for most of us with 10 bolt rears. I don't enjoy the idea of my wheel detaching from the car at speed, so the 9 inch has my attention. The problem is they aren't exactly college budget friendly for one built for our cars.
This is where the 70's Ford Bronco rear that I have in the backyard comes in. 65" from the outside of the brake drums, seems wide enough for me. 31 spline axles, 3.00 gears, 3.25" axle tubes. Old style Big ford housing ends. I cannot understand how anyone could break these 31spl axles they are nearly 1.5" diameter when I slid one out.


My dad has access to a full tool and die shop at work. Ill have him re-drill the 5x5.5 bolt pattern to F-body pattern. Ill be fabricating my own torque arm mount, similar to the Quick Performance deal. Buy the RaceCraft suspension brackets($360 shipped), weld them on. Simple right? Right now, I've got all this budgeted out for like $800 including a disc brake swap from quick performance($350 shipped) since the drums are shot. Couple more bucks for seals, fluid, and mini spool. Why is this not more commonplace?
This thread will serve as my build thread once I get to it.

Ill Be fabbing something like this, but using the stock tq arm. I have some 1/2" thick material at home I can make work. Probably 5/8" hardware.


These are the casting numbers on the case ive got. Probably that C7AW one, good enough for me. Ive got an auto trans and no t-brake so it should hold up fine.


Old style big ford housing ends.


nothing special about this pinion support.

slothman

I think the case on the bronco rear is only safe for about 400-500 crank HP. Better be careful with that turbo.

n2xlr8n66

iTrader: (3)

Yep- and they break at the rear pinion bearing. It's rarely the axles or differential that let go- always that one weak point in the case.

OP- maybe yours will be a good one.

wlink14

Maybe I should reconsider with the case. Probably not worth it if it lets go and tears the fresh 4l80e and floorboards up.
I could save some change by cutting the factory brackets off a spare 10 bolt I've got to invest in a aftermarket nodular case. I can get a whole kit(case, upgraded pinion support, gaskets, bearings, hardware, shims, gear marking compound) from Quick Performance for like $530 shipped.
Here are some preliminary measurements that I got last night.



I should have been a mechanical engineer. lol
I based my measurements off the center of the axle because the pinions aren't in the same location.
This project might be getting accelerated because I gave my dad the keys to the car last night to go boil some tires and my good ole 9 bolt might have **** the bed after countless thrashings.
More updates to come!

wlink14

Update:
Turbo is on and I've taken a few drives at 5psi boost, 9 bolt is still alive somehow ha-ha. The 9 bolt has been making this horrible whine on decel, and I read online that it could be improper pinion bearing preload due to over-crushed crush sleeve from too much power. So naturally I did the smart thing and got out my Milwaukee impact and hammered down on the pinion nut. She quieted right down. Dont expect this to last very long lol.
Now I just need to find the funds for the racecraft suspension brackets and quick performance brake kit. This college BS is way too much money. And I might be getting a ring for the girl soon too. I have a nice dirt bike that might be for sale soon....


Bought this piece to give dad a reference. He was able to redrill the f body 5x4.75 pattern, although it was tight with the access hole. He said there's still enough meat there, I'll take his word. Love having a Dad that enjoys doing stuff like this with me!

Found a picture of a DIY torque arm, Ill try to copy something like this.

91 Z28

iTrader: (3)

For the time and energy you're putting into this you could just buy a housing and axle package and be done with it.

For $1095 you could have yourself a quick performance 9" housing and axle package with TA mount.