Ford 9" Disk Brake Conversion

[Herzog]

Yeah, everything I look at just puts me right back at the Ford 44 rotors, and grinding down the axle flanges as you describe. Unfortunately that means I have to wait for the axle to be installed before I can build my brakes. I wanted to have the axles all complete and ready to go before I started building the suspension.

Can you rig something up that will spin the axles on a bearing for you? Build a quick little crank handle with some spare tube and have somebody spin the pinion fast and steady while you grind.

 

[Meat_]

Yeah, everything I look at just puts me right back at the Ford 44 rotors, and grinding down the axle flanges as you describe. Unfortunately that means I have to wait for the axle to be installed before I can build my brakes. I wanted to have the axles all complete and ready to go before I started building the suspension.

I know this one guy in Draper that has a machine shop..... he seems to be partial to the offroad crowd.... especially those RME types

 

[Milner]

When I did mine, I was pushed for time and ended up putting the rotors behind the flange. Pressed together with the same studs as the front. IIRC I had to drill the rotors to 19/32" for the knurl of the studs to press in. Not an ideal situation, because I have to pull the axle to change the rotor, but....

 

[Gravy]

RockMonkey; my friend Daniel is doing the same thing with Maxima rear calipers and tracker rotors on his 9". In order to grind down the flange we just hooked a drill up to the pinion and held a grinder to the flange.

Do 3 axleshafts though so you have a spare that fits.

 

[Cody]

I used this from www.bcbroncos.com

http://bcbroncos.com/store/product_info.php?cPath=22_73&products_id=348

Bracket Kit
This is the basic kit for those who would like to acquire the rest of the parts on their own. With these brackets, you will still need to acquire the rotors, calipers and brake lines separately. Kit includes:

* Left & Right BC Broncos Caliper Brackets
* Spacers
* Shock relocation kit
* Wheel studs
* All Necessary hardware

I then re-used my stock front brakelines on the back (kinda ghetto), used the CJ7 rotors they recomended as well as the s10 calipers. If you want a parking brake, the cadillac el-dorado or seville calipers will work.

I know it's more than you wanted to spend but it worked for me.

Evco can make any length and type of brakeline you need. I get a pretty good price over there so let me know if you need something built.

 

[RockMonkey]

When I did mine, I was pushed for time and ended up putting the rotors behind the flange. Pressed together with the same studs as the front. IIRC I had to drill the rotors to 19/32" for the knurl of the studs to press in. Not an ideal situation, because I have to pull the axle to change the rotor, but....

I had exactly this thought while I was laying in bed last night. Put the rotor on first, then use the front studs which will hold and center the rotor and prevent all grinding. I just haven't had a chance to see if the rear stud holes are the same size as the front. Have you had any issues with the studs being the only thing that holds the rotors? Normally they are pressed onto the hub and centered by it, so I'm a little concerned about shearing studs with the rotor behind the flange.

 

[I Lean]

I had exactly this thought while I was laying in bed last night. Put the rotor on first, then use the front studs which will hold and center the rotor and prevent all grinding. I just haven't had a chance to see if the rear stud holes are the same size as the front. Have you had any issues with the studs being the only thing that holds the rotors? Normally they are pressed onto the hub and centered by it, so I'm a little concerned about shearing studs with the rotor behind the flange.

The rotor hat is pretty thin, so the knurled part of the stud should still be engaged into the axle flange--and once a wheel is on there, it'll provide the clamping force to make sure nothing moves. If a wheel stud were to shear, it'd be outside the axle flange, which is where it would shear without a rotor anyway.

Aside from the PITA of pressing studs in/out if you need to change shafts or rotors, I don't really see a downside. Changing those items won't likely be a regular deal, so you should be good.

 

[RockMonkey]

The rotor hat is pretty thin, so the knurled part of the stud should still be engaged into the axle flange--and once a wheel is on there, it'll provide the clamping force to make sure nothing moves. If a wheel stud were to shear, it'd be outside the axle flange, which is where it would shear without a rotor anyway.

Aside from the PITA of pressing studs in/out if you need to change shafts or rotors, I don't really see a downside. Changing those items won't likely be a regular deal, so you should be good.

The front studs go through the rotor first, then into the hub. The front studs have an extended (and larger diameter) section to engage the rotor before it goes into the front hub. If the stud hole in the rear axle flange is the same size as the stud hole in the front hub, it should work perfectly with front studs. Hell I have all this stuff sitting in the garage. I'll go check...

 

[RockMonkey]

Yup, the knurled part of the stud is the same size. The only problem is the hole in the rotor is not big enough to pass over the bearing retainer flange (or whatever you call it). So to get the rotor off you actually have to press off the bearing. That's not a huge deal. I have a press so I can do that. For a trail spare I either have to have the axle ready with a rotor, or run without a rotor until I can get home (or to anywhere that can press the bearing off and back on for me). Whether I run the rotor behind the flange, or grind the flange to accept the rotor the right way I end up with the same problem with trail spares...

 

[Milner]

Yup, the knurled part of the stud is the same size. The only problem is the hole in the rotor is not big enough to pass over the bearing retainer flange (or whatever you call it). So to get the rotor off you actually have to press off the bearing. That's not a huge deal. I have a press so I can do that. For a trail spare I either have to have the axle ready with a rotor, or run without a rotor until I can get home (or to anywhere that can press the bearing off and back on for me). Whether I run the rotor behind the flange, or grind the flange to accept the rotor the right way I end up with the same problem with trail spares...

Opps, I haven't had stock retainers for so long I forgot....I used the horseshoe shaped retainers. Thick plate retainers open just enough at the bottom to slide over the shaft. Moser, Currie, etc have them....maybe even Carl-Plus. I think I still have the drill bit....Also have to drill a hole in the rotor to match the acces hole in the axle flange to make it easier to tighten the retainer studs.

No problems, been that way for a long time....

 

[Milner]

Retainers like these

 

[bobdog]

How much would you have to take of of the axle flange or the inside of the hat to make it fit? Why not just do it right and put one or the other in a lathe? If you don't know anyone PM me I can probably help.

 

[RockMonkey]

How much would you have to take of of the axle flange or the inside of the hat to make it fit? Why not just do it right and put one or the other in a lathe? If you don't know anyone PM me I can probably help.

About 1/16th off the flange would work. It's not that I can't take off the material, I just don't want to. I would rather have something that works together without modification so I can use junkyard and parts-store spares. I can grind down the axle flange at home easy enough, but when I bum a spare axle shaft off someone in the middle of the Rubicon because I broke my spare, I want to be able to use it and have it all bolt together.

 

[RockMonkey]

Retainers like these

I like those u-shaped bearing retainers. That would be the last piece of the puzzle. Carl, Bryson, or Joe, do you have those at T+?

 

[RockMonkey]

They're cheap, too. Summit sells them for $15 for the pair.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=MSR-9800&N=700+115&autoview=sku

 

[bobdog]

About 1/16th off the flange would work. It's not that I can't take off the material, I just don't want to. I would rather have something that works together without modification so I can use junkyard and parts-store spares. I can grind down the axle flange at home easy enough, but when I bum a spare axle shaft off someone in the middle of the Rubicon because I broke my spare, I want to be able to use it and have it all bolt together.

I understand, but if you have enough beef to remove the material from the inside of the rotors stock spare shafts will not be a problem.

 

[RockMonkey]

There might be enough. That would need to be done on a lathe as the fit on the axle flange would be the only thing that centers the rotor. If I just took a die grinder to it I bet I would end up with wobbly rotors.

 

[Herzog]

Whether I run the rotor behind the flange, or grind the flange to accept the rotor the right way I end up with the same problem with trail spares...

You could always put a block inbetween your brake pads and zip tie it in there to mimmick (sp?) a rotor if you ever need to use a spare shaft on the trail. You'd still have 3 other brakes.

edit - to clarify, using a spare would kill your option of putting the rotor back on, so you could leave it off and spoof the rotor between the calipers to retain your use of brakes.

 

[Greg]

What about opening up the inside of the rotor, you said you need about 1/16th of an inch? Get a engine cylinder hone, elec. drill & go to town. It would solve your replacement shaft issue, rear rotors should last a long time so you wouldn't have to deal with modifying them again, you could do it in the garage and the hole would be a consistent size.

 

[yellowbronco]

I love this thread!!! I have wanted rear disc's forever, now thanks to Rockmonkey I can have them!!!

I salute you.