rear disc brake conversion kit

[moose83772]

ok. so i have finally designed my own rear disc brake conversion kit for my 72 1/2 ton 4x4. i am currently having an engineer run some calcs for me to find the fail weight. im going to have him calc them a 38" tires and at 6000 lbs. if anyone may be interested in one of these kits in the future and has some different parameters please post them on here or send me a pm so i can have the calcs done to see if it is safe. when i have the calcs i will post on the for sale forum so that the sight is supported. this is just to get some input

[moose83772]

oh and by the way all of the parts i used are over the counter parts at any part store. please give me your input

[herb101]

Was there any additional machining required for the rotor hat to go over the axle flange stub? I've been having hell finding an OTC rotor that fits without modification.

The only other thoughts are (and I may be off base - these are based on my assumption from the photo angles):
1) the caliper braket looks kinda thin. with no bends, ribs or gussets, it looks like it would be prone to twist or defection.
2) is the caliper mount capable of taking a Caddy caliper for E-brake provisions?

Herb

[moose83772]

this is the thickest plate that i could use with these calipers. im not sure if these will fit the caddy caliper because i designed it to fit this caliper specifically. there is an after market ebrake set up that you can get to use the cable ebrake with this kit. i havent looked for it yet tho.

[herb101]

Ford Mustangs use what they call an "anti-moan" bracket that may be worth looking at. It bolts to the caliper mounting braket and the triangulates down to the axle tube where it is secured to the tube with a large U-bolt. That would help prevent any unwanted flex that may be there and would be (should be) fairly simple to fabricate.

I know, as far as the E-brake, many folks (like me) will want a functional brake for state safety inspections.

Herb

[mothertrucker424]

i have been looking for a rear caliper set up for my 1/2 12b rearend on my 72 4x4 but will your set up have e brakes??

[moose83772]

i will look into the ebrake setup to add into the package. i may be a little slow getting to it this week as i have a big test this friday. engineering is a rough major. fun but a lot of studying involved.
thanks for the input guys. keep it coming.

[herb101]

Originally Posted by moose83772

i will look into the ebrake setup to add into the package. i may be a little slow getting to it this week as i have a big test this friday. engineering is a rough major. fun but a lot of studying involved.
thanks for the input guys. keep it coming.

Good luck with the test - Engineering is always fun when you have some direct application to 'try' it out with.

You might look into mid to late 80's Caddy calipers. (I think that is the year range...) The calipers have a bracket, a large coil spring and a lever on the back side of the piston pot. The cable basically actuates the piston to clamp the rotor. Depending on what calipers you based the original on, the Caddy's may well be a direct swap. I think there were 2 different designs with the older ones being larger and a better fit. I seem to recall the newer one downsized and would require more work to use.

Herb

[Shane]

Originally Posted by herb101

Was there any additional machining required for the rotor hat to go over the axle flange stub?

I would like to know this as well. Thanks.

[moose83772]

yes there was. i had to turn the center hole out to a larger diameter.

[bad6772]

me three

[Shane]

so you bored the hole on the rotor?

I used '76-'77-'78 Caddy Seville parts for my rear disc conversion ... rotors & calipers. Pulled the axles and turned the center portion of the axles. That way, in the future, I just go purchase a new Caddy rotor and bolt it on ... only had to do the machine work one time.

[herb101]

Originally Posted by Shane

so you bored the hole on the rotor?

I used '76-'77-'78 Caddy Seville parts for my rear disc conversion ... rotors & calipers. Pulled the axles and turned the center portion of the axles. That way, in the future, I just go purchase a new Caddy rotor and bolt it on ... only had to do the machine work one time.

You're runnig the 5 lug then? The 6 lug rotor seems to be my stumbling block so far for getting a home-brewed kit together.

Herb

[PanelDeland]

Herb have you looked into the 6 lug front rotor kits? I don't know whether the rotor is seperate from the hub but if it is it might be the answer for the 6 lug system.Just a thought.

[herb101]

Originally Posted by PanelDeland

Herb have you looked into the 6 lug front rotor kits? I don't know whether the rotor is seperate from the hub but if it is it might be the answer for the 6 lug system.Just a thought.

Not a bad one at all either. I recently redid the fronts on mine and I tried the old front rotor on the rear flange, but the way the hat is cast, it has 'chambers' between each lug location that interfere with the axle flange. I have not had much opportunity to investigate difference among the 6 lug years, but nothing has jumped out in my searches on NAPAonline for size comparisons. NAPA's site lists height, thickness and rotor diameter, so it's been helpfully, but no successful.

BTW - mine is also 4x4, so the front hub is attached to the rotor by pressing the studs through the rotor, into the hub.

I'm hoping to find that a certain range of years had a different rotor hat, but my digging has stopped of late.

Thanks,
Herb

[moose83772]

well i will say this. i already tried the front rotors. took them to a machine shop. paid to have them turned. then realized how stupid i was because the hat of the rotor is about the same diameter as the axle. it wont work.