Help with hole size on brake disc (1 Viewer)

[Mud taxi]

Hello, I have a frankentruck that I'm dealing with, and it appears to have a full floating rear axle (it's an fj45) but heavily modified and not in a good way. I need brake discs for the rear, but it seems that the center hole in the disc is appx. 4.5 inches in diameter... I've tried multiple 4x and 6x series rear brake discs, but can't find any with the correct size hole (too small) anyone able to help?? I'd appreciate it. Pics attached. Red stencil is from the disc.

 

[JohnnyC]

Most likely it was machined larger… like we need to on disc conversions using GM calipers and rotors

 

[Living in the Past]

Think picture of the caliper and backing plate would be more helpful. 8/80 the full floating axles changed from an eight bolt holding the backing plate to just four that was same as the 60 series semi or floating axles. Plus identifying the non stock disc brakes would be easier.

 

[POPO AGIE]

I built mine with the front hub parts with new rotors and reman calipers for a 1978 FJ40. Everything bolted right up with the adapter flanges that were welded to the axle housing.

 

[peesalot]

Are you asking if there is a 6 lug LC disc that will fit over the hub ? A stock disc would bolt to back of hub and I would try Cruiser Outfitters for that, if you have custom brakes it depends on what caliper/ disc thickness you need. The slide over the lugs "Hat" style will reguire slightly trimming the OD of the flange on hub but I do not believe there is one that will work with the oem caliper, meaning I do not think you can replace a bolt to back of hub disc with a slide over hub disc and use same caliper and caliper mount.

 

[TEakins]

I don't know if this helps, but on my FJ40...
Rear brakes are 78-88 GM midsize (Monte Carlo, Cutlass....) front calipers & pads. Rotors are 88-89 Chevy light duty 1/2T, shortbed 4x4 PU truck. The rotors need to be machined out in the center to slip over the larger Cruiser axle flange, but the 6lug bolt pattern is identical.
. Unfortunately I do not know what the dimension is for the center but FJ40Jim knows. He built my resto/mod.