Disc brakes for rear FF

[cruiserpilot]

This fellow got to cleaning up an old axle he had. It’s a HZ73 FF rear. Got me wondering, isn’t the basic
axle dimensions the same for these trucks as far as brake sizing, hub dimensions etc. ?
Here is his thread, but I thought we could put our collective heads together and if we can make it work
maybe I’m not the only one wanting rear disc conversion using factory parts?

ID my rear axle: 70 series FF + Disc brake + parking brake

So a few years back I bought this axle and I am finally getting around to cleaning it up and rebuilding it. It will, of course, be far easier to source parts once I am sure what it came out of. It is a full float 70 series rear with disc brakes (and parking brake) I'm going to try to dig up...

forum.ih8mud.com

 

[GTSSportCoupe]

Sounds like HZJ77 full floater were disk from factory: Introduction and 70 Series Rear Disc Brakes Identification

Late 70-series Full Floating rear axle PARTS AVAILABILITY?

Are all service parts available for this axle? For Sale - [OH] Full Floater Axle with Disc Brakes (70-series) Anything I should know if I am considering putting this into my FJ45LV (FJ40) other than needing to move the spring perches, dealing with the parking brake cable and getting the proper...

forum.ih8mud.com

Look for RM183E (1990+ 70 series service manual) on mud. It shows all the rear axle variations for the 1990+ LJ7x/HZJ7x/PZJ7x. Let me know if you don't find it, and I'll look for you.

 

[cruiserpilot]

This should work on 60 rear FF as well, if I'm not mistaken? Worthy of doing for the cost I think.
Looks like Woytovich has been working on this for 3+ yrs! Somewhat faster than me, I see.

 

[cruiserpilot]

double post

 

[stevebradford]

I will take your drum brake parts

 

[stevebradford]

I imagine but don’t know for fact that the calliper mounts to a flange welded to the axle housing. Likely you won’t be able to just order the 70 series parts and put them on your 60 series housing.

You could fab something but if your going to that length might as well use front replaceable spindles and build a whole new axle.

 

[bikersmurf]

On a loosely related matter... I’ve got drum brakes, cylinders, & backing plates from a ‘77 FF Fj45 front axle if anyone needs parts. I’ve gone disc and will never use them. They’re massive and oversized compared to 40 components.

When I converted my FF rear axle +/- 20 years ago, options were limited. I used Blazer callipers and rotors (about 1.25” thick vented rotors). The original design used a 1/4” thick stamped steel plate that bolts to the Chevy knuckles. My original plan was to adapt them to the Toyota axle... Island Rod service instead started from scratch and welded custom mounts to the axle. The owner said it would be easier than adapting them to work... I’m not sure it was since it took a full day to do the work (to the tune of $800). For a while I was choked about the cost, but every time I look at the work I don’t regret paying for the artistry.

I used newer front Landcruiser studs to mount the rotors to the rear of the 45 hubs. Now stock Chevy rotors, callipers, and pads can be replaced for dirt cheap without any modifications. They were used in 6 bolt 4x4 Chevy Blazers, Suburban, and 3/4 ton trucks from ‘75 till the late ‘80s... possibly even the 90s. New callipers are $17/each and rotors are about $60 each. It’s almost not worth the effort to clean them up when I replace the pads... they’re so cheap and easy to get hold of.

 

[woytovich]

For reference... woytovich thread