6 Bolt / 5 Bolt Hub Interchangeability

So here's the question. I am upgrading my Dana 30 to disc brakes but the later model dana 30 disc brake knuckle assemblies I have use the 5 bolt style later model hubs. I would prefer to have the older 6 bolt hubs. Will the two directly swap and if not what are the challenges?

 

6 Bolt? The older jeeps I know are all 5-bolt.

 

The 6 bolts is for the locking hubs, Jeep went to a five bolt locking hub in the early eighties. My understanding is they interchange - I have a set to do the swap on our 86 cj7. The only reason I would keep the 5 bolt hubs is if I wanted to run the factory center caps as I dont think they will fit over the 6 bolt hubs.

 

I'm talking about the locking hub/drive flange mounting bolt/holes. Not the wheel studs

 

as long as the older hub is a disc hub, it will work. the drum hubs do not work, because the rear surface is not machined.

 

The 6 bolt drum brake bearing hubs can be faced up on a lathe to give a flat surface for the rotor.

 

Jeep made both for disc brakes.........In 77-78 Jeep offered there HD Disc brakes on the D-30 calling that a 6 bolt version or the "Big Brake option" that came with 6 bolt hubs , six bolt Warn locking hubs and a 1.125 wide vented rotor with a single 3.1" large piston caliper.............the 5 -bolt version was referred to as a two bolt in parts books and was the 6 bolts weaker cousin.............the 6 bolt reference as will as the 2 bolt reference in parts catalogs has nothing to do with the bolts in the hub......the reference is to the caliper mounting........6 bolts to mount the "Big Brake" and only 2 for mounting the STD 5 bolt version.........................I don't think they will interchange as I believe the hub ID size and bearings are different and I believe the offset of the rotor to the caliper spacing is also different.............I do believe that you can can move all the parts between the early to late axles by re-drilling the pattern in the spindle.............but don't quote me on that.............it's been a while..........and as mentioned above the drum brake hub or stub shaft will not work on the discs.

 

Oh. WAAAY after my time.

 

yes, the drum hubs will work with disc brakes, IF the hub is machined (by you or a shop). also, the two-bolt caliper works fine with the six-bolt locking hub; i've run that combination for a decade.

 

Some misconceptions here. The 77-78 brakes are not any better or worse then the later brakes. The rotor is simply thicker on the 77-78 as Jeep used off the shelf parts to put disc brakes on their product. In 79 they went to a thinner rotor and lighter parts. The push to save fuel was making any rotating parts need to be lighter. In 81 the design was changed again to save even more weight. The bearing hub was lightened and went to a small lightweight locking hub that only used 5 mounting holes. The misconception about heavy duty and light duty brakes starts here. The very lightweight locking hubs were easily broken and did not fair well when actually pushed off road. The very prone to braking locking hubs gave the perception that the 5 hole bearing hubs and thinner rotor brakes were "light weight" In actuality the best setup that was offered on a Dana 30 was the 79-80 7/8" rotors and 6 bolt bearing hubs that can use Warn premium locking hubs. Sometimes internet lore replaces actual real world knowledge and experience. The 6 bolt and 5 bolt bearing hubs are completely interchangeable and use all the same bearings and spindles.

 

Thanks Daryl , for all the info on the Jeep Brakes .............But after doing the math , I still like the so called "Big Brake" Jeep Option.........Bigger piston 3.1" vs the later 2.596" ............more inches of area on the puck , 1.125 vented rotors vs the smaller vented 7/8" , a little taller rotor...........& heavier Yes , but doing the math with the right sized MC equals more Brake Torque at the wheel and probably better heat absorption at the rotor...........choices , nothing but choices.

 

Just trying to point out some of the history to go along with the stories. I would pick the thicker rotors too but I don't like the caliper brackets from 77-78. Just personal preference though nothing mechanical. That is what leads me to constantly search for the 79 to 81 knuckle/caliper brackets. I also like the 86 version that used much stronger knuckles but try to keep those for building 44s with Jeep 30 outers.

 

Yep those are bulky.........In the past I have lightened those up on the mill..............On my latest build using 1-ton components 37" tires w/17" wheels , 14" rotors and two piston calipers.......should stop just fine............just need to finish it.