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Ford 9" disc brakes for under $100

85K views 71 replies 31 participants last post by  brewchief 
#1 ·
not long after putting 35's on my 89' F-150, I realized my stock drums just weren't up to the task. After tearing itno the stock brakes, I noticed that a stock ford rotor looked like it would fit over the axle

After checking all the rotors Napa had to offer in that bolt pattern I found that no stock rotors would fit stock. Rotors from a 94-02 dodge would clear over the axle flange but were to small in the centering hole to fit the stock 9" axles. CJ rotors, pre 94 dodge rotors and ford dana 44 rotors would all fit, but were to small to fit over the axle flange. Since the ford rotors seemed the closest fit, I bought them, $25.99 each at napa. I then just ground the axle down to fit them.



 
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#2 ·
Now just cut a plate to mate up the calipers of choice, I used ones from a 82' K-10 4x4. The pl;ates were simple 3/8" steel. First I madea templet with cardboard and then chalked it onto the steel.



Then I blasted it out with a plasma cutter. After grinding it smooth, I got it into place on the axle, and welded it.



Test fitting plate


half ton 4wd chevy calipers, $7.99 lines from napa, $9.99 for pads. calipers were $10 each at the junk yard.


And the 15" rims even clear it.


looks much better than rusty stock drums..



Can I get a "bling bling"? 31 spline ford 9 inch, with a mini spool, and disc brakes, all for $230?? hell yes.



How does it stop?
Much better than stock, and the stock proportioning vlave seems to work quite well, only under extremely hard braking can I get the 35" BFG's to lock up on pavment. On snow, it brakes a bit different from stock, but the braking is still fairly well balanced, but the rears do seem more agressive than before.

Still tons better than the stock rear drums.
 
#4 ·
I had to grind it down about 1/16" or so all the way around, not enough to make any structural difference.
 
#6 ·
What did you do with the gap between the axle bearing flange and the actual bearing cup where the old backing plate used to sit? I thought of cutting the old backing plate into a spacer to make up the difference. Looks good this is the next mod to be done to my 9, thanks, judd
 
#7 ·
well, I thought about cutting out the center of the back plate as well, but then just found 4 washers the same thickness, and put them in there as shims. Since it's a sealed bearing, it won't leak anything.
 
#13 ·
the rotors I used were number 4885611 from napa, 25.99 each.

The dodge rotors I think might fit(never got to actually test them) are 4886447 $36.99 each
 
#15 ·
wuzabronco said:
You can order Howe weld on caliper brackets from Summit racing.
http://www.summitracing.com/

Part # HRE-340, $25.39

do those fit the calipers mentioned above? if not, then what kind / is there enough material/room on them to modify for the calipers mentioned?

i don't have a plasma or a torch, so cutting it out with a grinder or sawzall would be loads of fun.. thanks
 
#17 ·
Kickass thread! Just what I was looking for. Does anyone know if those 9" brackets like the Summit one and the ones you get from race supply houses will accept the Cadillac calipers with the e-brake provisions?

Also, I've heard many people have great success using the stock h-blocks that come with 4-wheel drum setups when they go with 4-wheel disk, but other insist on getting a disk/disk proportioing valve. Anyone know of a specific reason why one is a must over the other? (of course I'll switch to a disk/disk or drum/drum MC)
 
#20 ·
Fireguy50 said:
You screwed up bad dude!
the rotor is not true on the axle, look at all that rust and junk you left.
AND the rotor is not centered on the studs, bad idea
Here is mine:
http://fordfuelinjection.com/bronco/brakes.html
I've seen yours, it looks good..

As for them not being centered.. The dial incator says they are, there isn't any runout, or anything strange going on driving down the road, or under light or hard braking.
 
#23 ·
even if the rotor is perfectly centered it will spin on the flange hitting the studs each time you brake.

I'm not sure what this force will do to the lugs, but those little spacers I made do lots of things to help the rotor stay centered.

Not sure how important that is to you. My Bronco will go 110+MPH on the highway if the cop's aint watching :flipoff2:
So any vibration can be a death wobble at speed
 
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