F-150 9" disk (disc) brake conversion?

[Scott Cee aka 2drx4]

So I grabbed a F-150 9" because it looked like it would just "work" for everything I was doing. I wanted to go to disk brakes and had done a simple Google search before buying it to make sure there was kits available, and yes, there was lots and they weren't very expensive. This is an '81 F-150 axle so it's the later big bearing style, Torino I guess.

Well, it turns out that almost all of those kits are for 5x4.5 or 5x4.75 car lug patterns, or are for the other bearings styles.

Anyone do a DIY from scratch, with a parking brake? Or buy a kit that was decent and not a rip off?


This kit from Speedway will work, I think: Speedway 9 in. Ford Truck Rear End Disc Brake Kit
But it seems overpriced, and they rape me on shipping (about $300). They also do not list what the rotor actually is so you can get a replacement, and the P/N in the instructions is wrong along with the answer in the Q and A section (they claim it's from a 88-91 Chevy K1500, it can't be because those POSs were 6 lug). The calipers are 81ish Cadillac Seville rears and the pads are 87ish G-body fronts. Seems like a shitmix of parts but that combo must be to work with whatever rotor thickness there is.

Summit has this SSBC kit: SSBC-USA A118 SSBC-USA Drum to Disc Brake Conversion Kits | Summit Racing
I have no idea what that caliper is, but the brake pad replacement P/N seems to point to being Ford Mustang/Taurus pads? Expensive kit, but Summit doesn't rape me on shipping. The caliper brackets look like flimsy shit on this kit though.

 

[Scott Cee aka 2drx4]

Looks like that SSBC kit is using a Mustang caliper; I didn't know they had an integrated parking brake caliper. I wonder what rotor they're using, or if it's their own custom rotor?

Edit, the SSBC kit won't fit anyway, I just saw in the notes it's for the 'big bearing' style, not the late big bearing style.

 

[holdmypocket]

79-86 Ford Bronco & Ford Truck Rear Disc Brake Conversion-Broncograveyard.com

Kit: This kit is for the 1979-86 axle with 3/8 studs. 9 inch Ford complete rear disc brake conversion kit includes: brackets grade 8 mounting hardware park brake housing extension spacer plates new 11 9/16 vented rotors Details: All of our rear disc brake conversion...

shop.broncograveyard.com

 

[4Eyedturd]

Explorer 8.8 discs work with a little modification on a 9”. Google is your friend

 

[Scott Cee aka 2drx4]

79-86 Ford Bronco & Ford Truck Rear Disc Brake Conversion-Broncograveyard.com

Kit: This kit is for the 1979-86 axle with 3/8 studs. 9 inch Ford complete rear disc brake conversion kit includes: brackets grade 8 mounting hardware park brake housing extension spacer plates new 11 9/16 vented rotors Details: All of our rear disc brake conversion...

shop.broncograveyard.com

That's a way better deal.

What pads are guys using with the Eldorado calipers? The caddy ones? Edit, it's in there, they're the Caddy/G-body ones that are super common.


2 week lead time to ship blows.

Edit again, custom rotor? Fuck that. Custom wear parts is never a good idea.

 

[Scott Cee aka 2drx4]

Explorer 8.8 discs work with a little modification on a 9”. Google is your friend

Doesn't seem appropriately matched to the front brakes. Which would have been another issue with the Mustang stuff. But I'd have to look at it more to make sure.

 

[Scott Cee aka 2drx4]

I think I figured out what Speedway did with their kit. They bought undrilled rotors for the 88-91 K1500 and drilled them to 5x5.5. The dimensions are the same otherwise and they list a replacement separately. Silly, but I guess there is simply no 5x5.5 rotor out there that's the required 1.035" thick for the Eldorado calipers...

I'm not sure what Bronco Graveyard is doing, but quite possibly the same.

 

[Will Scarlet]

I've used TSM Manufacturing when I had my 94 Jeep Cherokee to do the rear disk conversion and it worked out well. Looking on their site now, it shows the Ford 9" for 5x5.5 pattern:

Ford Truck Rear Disc Brakes

Ford Truck Rear Disc Brakes for Ford 8 and 9 inch, F-100, Ranger, Bronco, Explorer, F-150, F2, F3, Ford Dana 60 and Ford Sterling.

www.tsmmfg.net

Good luck with what ever you choose..

 

[Scott Cee aka 2drx4]

So fuck all this shit.

The Eldorado calipers fit a rotor that is 1.035" thick/.957" discard, 10.5" diameter (Speedway kit uses 11.6" rotors with them)

94 Bronco rotor is 1.024" thick/.961" discard, 11.7" diameter. Seems close enough.

2 Caddy calipers, 2 Bronco rotors, buck the brackets out of some 1/2" and shim accordingly?

I do not understand having a one-off wear part that you're at the mercy of some random single manufacturer to make if you need in the future, and you can't get if you're in a hurry.

How were guys using the Caddy calipers on their 14 bolt/D70/etc conversions that used the 78 K-20 rotor (1.295" thick)? Will it fit over them? If it does then you could just use the same 81 F-150 front rotor (1.19" thick) in the back, or so I'd think, because you should be able to take up 100 thou of slack and not have the piston fall out of the caliper before the pads wear.

 

[DannyK]

Ask Shawn at Lugnut4x4:

8 Lug Disc Brake Conversion Kits | Lugnut4x4

Whatever 8 Lug Axle You Have – 14 Bolt, Dana 60, Dana 70, Sterling 10.25, Eaton – We've Got A Disc Brake Conversion Kit At A Great Value.

lugnut4x4.com

 

[Scott Cee aka 2drx4]

Ask Shawn at Lugnut4x4:

8 Lug Disc Brake Conversion Kits | Lugnut4x4

Whatever 8 Lug Axle You Have – 14 Bolt, Dana 60, Dana 70, Sterling 10.25, Eaton – We've Got A Disc Brake Conversion Kit At A Great Value.

lugnut4x4.com

His calipers aren't actually Caddy calipers... Not sure if that changes how it works?


Edit, I looked, guys are literally slapping the Caddy calipers/pads on the K-20 rotors and it just works. So a guy could just buy the F-150 front rotor and go. Or so I'd assume. Why the hell did all the kits use some weird custom rotor then?

 

[welndmn]

I would not buy a caddy caliper, they are just a poor design.
If you don't want to use a kit that used the Explorer design rear parking drum, just get a normal GM1/2 ton caliper and a weld on bracket.
Then you can use the VW or Ford EV electric parking brake caliper.

 

['84 Bronco II]

Doesn't seem appropriately matched to the front brakes. Which would have been another issue with the Mustang stuff. But I'd have to look at it more to make sure.

I don't understand why you think that, 11.75" rotor and locks my 37" tires just fine.

The Explorer stuff should just bolt on, all you have to do is drill out the rotor to get 5 on 5.5".

 

[Scott Cee aka 2drx4]

I don't understand why you think that, 11.75" rotor and locks my 37" tires just fine.

The Explorer stuff should just bolt on, all you have to do is drill out the rotor to get 5 on 5.5".

They're 11.2" and they're only a half inch thick. Not vented. They're basically trash. Sure it locks your 37 up, congrats, that's not the point of brakes nor a metric that should be used to determine if they're effective or not.

Now, can I get away with it? Probably, but it would likely offer no performance gain over the factory 11" F-150 drums. It may well be a downgrade.

And yes, I have run Explorer brakes. I'm not just talking out of my ass.

 

[Scott Cee aka 2drx4]

I would not buy a caddy caliper, they are just a poor design.
If you don't want to use a kit that used the Explorer design rear parking drum, just get a normal GM1/2 ton caliper and a weld on bracket.
Then you can use the VW or Ford EV electric parking brake caliper.

I've never run them but I know guys bitched about them. I'm not sure if that's because they didn't adjust the parking brake correctly, so they dragged, or what. Did Lugnut improve the design enough to solve the issues? His calipers are cheap enough I could buy some spares, but that only makes sense if the design is really an improvement.

I don't suppose any OEM truck manufacturer has gone to electric ebrakes? Rivian is 5x5.5 and probably is, but fuck having anything to do with those parts.

 

[Scott Cee aka 2drx4]

Then you can use the VW or Ford EV electric parking brake caliper.

What ones of these can actually be used on a thick (1.2"~) rotor? I don't know year ranges so I'm not sure what to look at. The only Ford EV I know of is the Mach-E and it uses dinky brakes because they intend to regen only, the rotors are like .43" thick or something. That would potentially work great for a tcase/driveline brake I guess.

 

[Scott Cee aka 2drx4]

The 2003-2006ish Econoline E-150 van probably has the brakes I want. 13" vented rotor and drum in hat. 5x5.5 pattern.

But eh, I ain't gonna find one to donate the parts, assuming they would even fit.

 

['84 Bronco II]

They're 11.2" and they're only a half inch thick. Not vented. They're basically trash. Sure it locks your 37 up, congrats, that's not the point of brakes nor a metric that should be used to determine if they're effective or not.

Now, can I get away with it? Probably, but it would likely offer no performance gain over the factory 11" F-150 drums. It may well be a downgrade.

And yes, I have run Explorer brakes. I'm not just talking out of my ass.

All you asked for was cheap and easy disc brake conversion on a 9", why don't you tell people what your application is that you need brakes for then?

Are you towing or racing where you need giant brakes in the rear, or do you just have a fat pig of a vehicle that a factory 9" isn't really appropriate for anyway? If a brake does not have the power to lock up a tire, it is inadequate. You didn't mention that this was some kind of severe service application where fade would be a major concern. Why don't you run your junk through a brake calculator and start by figuring out what size rotors you need to get acceptable performance instead of having people take shots in the dark.

11.75" was just what was stuck in my head, but you're right, 11.2".

 

[BlueNitro]

I run a 9" in the back of my TJ with 35's. Years ago I bought the rear explorer disc brake backing plates from Currie Enterprises. They still sell them, only with complete axle assemblies though. Rotors and calipers where purchased through local parts store. I drilled the rotors to 5 x 5.5 lug pattern. i had to add a .250" long spacer to the inside of the bearing backing plate retainer to compensate for the disc brake backing plate thickness. This setup uses the explorer parking brake shoes inside the rotor setup, works ok for a parking brake, steep incline, it won't hold the jeep.

 

[Scott Cee aka 2drx4]

All you asked for was cheap and easy disc brake conversion on a 9", why don't you tell people what your application is that you need brakes for then?

I thought it was a given that if you're looking to "upgrade" that it actually be an upgrade.

 

[78bronco460]

I wasted a bunch of time trying to make a 76 Lincoln housing and brakes work with truck axles and gave up, did a D60 and made my own disc brake setup with gm front calipers and rotors. Stupid simple. Line lock for the e-brake, wilwood prop. valve, done.

 

[Scott Cee aka 2drx4]

I wasted a bunch of time trying to make a 76 Lincoln housing and brakes work with truck axles and gave up, did a D60 and made my own disc brake setup with gm front calipers and rotors. Stupid simple. Line lock for the e-brake, wilwood prop. valve, done.

I need it to be legal so no line lock. If I can't make the parking brake function I will have to stay with the drums.

 

[78bronco460]

I need it to be legal so no line lock. If I can't make the parking brake function I will have to stay with the drums.

Flipped eldorado calipers would work, I just took the easy and cheap way. I hear the jag kits are nice for 9”, I did the d60 20 years ago and 9” disc rear stuff for truck axles didn’t exist in aftermarket parts.Then I sold the d60 and put in a d70 with drums because doubler behind a 460+ zf5 demanded it.

 

[Scott Cee aka 2drx4]

2019ish and up Ford Ranger uses a caliper with a manual parking brake.

The rotors aren't super thick at .94"/.87" discard and 12.13" diameter. But I suspect the calipers would fit on the Bronco rotor that's 1.024" thick, and the diameter is pretty close at 11.7". Again, this would at least get you a vented rotor that's a reasonable size.

Honestly, that might be a good swap that would ensure parts availability, assume it actually works. Anyone own one of these newfangled rump Rangers that could take some pics of their rear end?

 

[Scott Cee aka 2drx4]

Flipped eldorado calipers would work, I just took the easy and cheap way. I hear the jag kits are nice for 9”, I did the d60 20 years ago and 9” disc rear stuff for truck axles didn’t exist in aftermarket parts.Then I sold the d60 and put in a d70 with drums because doubler behind a 460+ zf5 demanded it.

Not seeing anything Googlings the Jag (jaguar?) kits?

 

[78bronco460]

Not seeing anything Googlings the Jag (jaguar?) kits?

Oops, JBG: Jeff’s Bronco Graveyard.

 

[u2slow]

I think I figured out what Speedway did with their kit. They bought undrilled rotors for the 88-91 K1500 and drilled them to 5x5.5. The dimensions are the same otherwise and they list a replacement separately. Silly, but I guess there is simply no 5x5.5 rotor out there that's the required 1.035" thick for the Eldorado calipers...

The astra/safari AWD uses k1500 knuckles and is 5x5". May be an easier re-drill.

 

[Scott Cee aka 2drx4]

The astra/safari AWD uses k1500 knuckles and is 5x5". May be an easier re-drill.

Still makes no sense if they could have just used the Bronco rotor.

 

[u2slow]

Back mount vs slip-on is my guess.

 

[Scott Cee aka 2drx4]

Back mount vs slip-on is my guess.

It is back mount on a hub, but they clearly machined the back side on all of the ones that have pictures. I guess it might not fit over the axle flange. Hmmm.