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Ford 9" Disc Brake Conversion

57K views 18 replies 5 participants last post by  35pontiaccoupe 
#1 ·
Has anyone converted the Ford 9" to disc brakes using junkyard caliper stands, rotors, and calipers from another vehicle ? Any other thoughs ?

:welcome:
 
#2 ·
Depends which 9" you have and its housing ends. The small bearing axles can be done with the crown vic swap. The late big ford ends can be done with the explorer brakes. I don't know of any early big ford ends that swap directly over, but I could be wrong.

There's lots of info out there on both...
 
#3 ·
I have a 9" 5 X 5.5 with big bearings out of a truck. I plan to have Moser change it to 5 X 4.5 bolt pattern when they narrow it and put in new axles. I have heard that the disc brakes from a older Blazer 4X4 work well with a little hole enlargement and they are cheap.
 
#4 ·
Most likely when moser narrows the rear they will put on late big ford ends. With that, you can use the explorer brakes with no modifications to the brakes-they'll bolt right up. Tell moser that's what you plan to use and they will factor that into the brake spacing. Explorer swap is pretty easy..

You want to get brakes from a 95-99 explorer. You'll have to pull the c clips out of the housing to get the backing plates off. You'll want to get the ebrake cables too. You may have to turn down the axle register or open the rotors. Some of the truck axles have a larger register than the explorer. I would rather have moser turn the axle down so you don't have to open the rotors up every time you replace them..

If you have any questions let me know..
 
#8 ·
I'm running a Big bearing 9" and converted my rear to disc brakes. They sell the caliper bracket which bolt directly up alone for under $60.00 for both sides. The brackets are setup to fit GM calipers which most people opt for the 85 Cadillac Seville rear calipers because they have the emergency brake setup. The Cadillac calipers are tough to adjust but work nicely when you can figure them out. I used Lokar cables which were the easiest to install to the calipers. Do a search on Ford 9" disc conversion kits, they'll sell the bracket only. Another little trick I found on Big bearing rearends is to use the axles from a Scout or Jeep, the axle are .5 inches shorter than the stock axles in the 9 inch Ford and are interchangeable. Works nice if your going with wide rims and need the additional .5 inches of clearance.
 
#9 ·
Mine was done with weld on brackets(speedway motors)"$9.99, rotors from the front of a 85 jeep cherokee $10.00 for 2, 2 new metric calipers $20.00 from napa.Total for rear disc brakes $39.99 but no parking brake which is easily solved by installing a shutoff valve in the rear brake line, just push the brakes shut the valve rear brakes stay applied.Works just like a line lock only manual instead of electric.
 
#10 ·
kleen56 said:
I'm running a Big bearing 9" and converted my rear to disc brakes. They sell the caliper bracket which bolt directly up alone for under $60.00 for both sides. The brackets are setup to fit GM calipers which most people opt for the 85 Cadillac Seville rear calipers because they have the emergency brake setup. The Cadillac calipers are tough to adjust but work nicely when you can figure them out. I used Lokar cables which were the easiest to install to the calipers. Do a search on Ford 9" disc conversion kits, they'll sell the bracket only. Another little trick I found on Big bearing rearends is to use the axles from a Scout or Jeep, the axle are .5 inches shorter than the stock axles in the 9 inch Ford and are interchangeable. Works nice if your going with wide rims and need the additional .5 inches of clearance.
Where do they sell the caliper brackets that bolt on using GM calipers ?
 
#13 ·
35pontiaccoupe said:
Here's a chart on the different housing ends...

Looks like the blazer ends are pretty different from the late big fords that moser would most likely use...
Thanks to your chart I have discovered that my 9" has the preferred new style big ends. I thought all this time that they were the old style. That will save me $100.00 at Moser ....

:) :) :) :)
 
#14 ·
35pontiaccoupe said:
Here's a chart on the different housing ends...

Looks like the blazer ends are pretty different from the late big fords that moser would most likely use...
I now have another issue. The housing ends on my 9" look like the new style ( Torino ) but the bolt pattern is the old style big bearing. It has the 3/4" tee bolts and measures 3.556 X 2.375 . The new style ends say 3.557" X 2.0" . What am I missing here ? :confused:
 
#15 ·
Did you measure everything? In looking around for more charts to see if the early bigs had that same look, I found that the early bigs are actually 3.50 wide and not 3.566 like the chart I posted. Are yours actually 3.566 wide or did you just look at the vertical measurement? I don't know if they made the early large bearing ends that look like the lates. Maybe somebody else can tell us, but I would go by the measurements and not the look.

Did you ever say what this rear was out of?
 
#16 ·
fredbaker said:
I now have another issue. The housing ends on my 9" look like the new style ( Torino ) but the bolt pattern is the old style big bearing. It has the 3/4" tee bolts and measures 3.556 X 2.375 . The new style ends say 3.557" X 2.0" . What am I missing here ? :confused:
I have determined that my 9" has the early big bearing ends with 28 spline axles. The bolt pattern on the ends is correct for the early ones but the shape of them is identical to the later " Torino ' ends. The only thing I have found is some aftermarket old style ends that match mine so maybe this rearend has been narrowed before. I will have Moser weld on the later style ends so that I can install Explorer disc brakes and re-machine the wheel bolt pattern for the 5 X 4.5 pattern as this seems to be the most popular pattern and I already have a set of Crager SS 10" X 15 mags to match the front 5" X 14 .. A set of 2 Cragers are $400.00 these days.....
 
#17 ·
fredbaker said:
I have determined that my 9" has the early big bearing ends with 28 spline axles. The bolt pattern on the ends is correct for the early ones but the shape of them is identical to the later " Torino ' ends. The only thing I have found is some aftermarket old style ends that match mine so maybe this rearend has been narrowed before. I will have Moser weld on the later style ends so that I can install Explorer disc brakes and re-machine the wheel bolt pattern for the 5 X 4.5 pattern as this seems to be the most popular pattern and I already have a set of Crager SS 10" X 15 mags to match the front 5" X 14 .. A set of 2 Cragers are $400.00 these days.....
Glad you made some progress... I'm really at a loss for why they're shaped like Torino ends, but maybe they were produced like that at some point. I honestly don't know!

Are you having Moser narrow the housing and the axles? I don't know that they'll be able to narrow the 28 spline axles. How much narrower are you going? You may end up having to do custom axles...

When you have them do all this, make sure you tell them what brake setup you're going to run so they can figure all that into the equation. The early big bearing axles ran a "brake offset" of 2.375" while the explorer requires 2.5" offset. On that note, ask them if the spacer is needed as well. They should know what you're talking about, but it's basically a spacer that goes between the bearing and the axle retainer to account for the difference in drum backing plate thickness vs. disc backing plate thickness. It's the "preload spacer" in the speedway directions that I posted.

Also, check the axle register diameter to make sure it's less than the rotor opening diameter. I had to shave mine down a little so the rotor would fit on the axles. The opening is 2.800".

Did you decide if you're going to pull the brakes from a junkyard or are you buying the kit from somebody like summit or speedway?

Again, if you have any more questions or need pictures, feel free to PM me or add to this thread. Good luck!
 
#18 ·
I agree the housing ends are a mystery but still old style. Moser will narrow the housing to 42" and weld on new style big bearing ends. Also the axles if they can. He seemed to think it could be done but if not new axles will be the choice. The 28 spline axles I have are quite beefy until the last 4" where they are turned down and splined. I think they may be able to 31 spline them and then change the 2 gears in the carrier to accept the 31 splines or just stay with 28 spline. I really don't see a problem with them shortening the 28 spline axles but who knows. I have located both sides of the Explorer rear disc brakes at a local junkyard for $125.00. What do you mean by the axle register ? That is 1 thing of many I am not familiar with. LOL I really appreciate everyones tolerance with my ignorance....
 
#19 ·
I've heard the axle register be called several things, but basically it's the outer shoulder of the axle that the rotor fits around and keeps it centered. It's measurement "R" in the diagram below.

125 sounds about right for the stuff from a junkyard. Most of my stuff was pretty rough, so I got new rotors and the ebrake hardware was shot so I got that too. Pretty cheap at Napa... Calipers may be ok, depending on how long they've been sitting out.

Try to get the e brake cables if possible. Depending on what you're running for a parking brake, they may be able to tie in to whatever you already have. If not, Lokar makes a set of cables specifically for explorer rears that is pretty slick. That's what I used...
 

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