I am working on my disc brake conversion using a Toyota Rotor on my 404 axles and was wondering what clearences people had left between the back of the rotor and the front face of the portal box? With the way that I have my Hub machined I have about 1/4" of clearence between the back of the rotor and the front of the portal box. I was thinking about putting a 1/4" spacer between the front of the hub and the back of the rotor which would give me 1/2" clearence for mud and airflow around the portal.

What are people leaving for clearence? What have companies left for clearence on their disc brake conversion?

I had Weps machine my hubs to do the 8-Lug conversion, I have one portal assembled on my bench so I could modify the bracket design. With '78 3/4 ton rotors installed I measure .65 between the inner rotor surface and the closest point on the portal housing; however I am not certain I have the hub pressed all the way onto the spindle I think it may need to go in about .1 so... I think his kit gives 1/2" clearance (roughly).
I have never personally had a problem with mud in DISC brakes so I cant say that I would personally worry about it. Not sure what other conversions give for clearance but most of them look REALLY close. Also remember most OEMs include a backing plate which is generally about 3/16" from the inner surface so I don't know that this spacing is crucial. How much spacing was there between the Toyota backing plate and the Toyota rotor in the original application?

How much spacing was there between the Toyota backing plate and the Toyota rotor in the original application?

That is a very valid point. Probably less then 1/4". I was just of thinking of allowing more airflow through if I could because of the portals ability to heat up. I think I will just leave it like this and start making brackets for calipers.

I wouldn't worry too much about the portals cooling, it used to be stuck in a cast iron brake drum with almost no ventilation. Any airflow will be an improvement over the OE setup. if you build your mounts for the innermost fitment you can probably shim both the rotor and the caliper out later if you need. If you do end up shimming things just keep in mind that you can always adjust your track width later by getting/making wheels with more/less offset.

I have 1985 4 runner rotors and calipers front and rear. 1/4 inch inbetween inside of rotor and portal box. Im running 15x10 3.5" BS so i had to run 1 inch wheel spacers and take some material off the two mounting ears for the caliper so it would hug the portal better. 3/16 from caliper to wheel

Its 100% bolt on setup works really well.

http://i26.photobucket.com/albums/c150/xjweeble/Mobile%20Uploads/jeep007.jpg
http://i26.photobucket.com/albums/c150/xjweeble/Mobile%20Uploads/jeep008.jpg
http://i26.photobucket.com/albums/c150/xjweeble/Mobile%20Uploads/1260931649.jpg

Its not pretty or pimp but it stops great.

could you post a few more picks of your backets as I am also looking to do this.

ill take some more when im installing my new reduction boxes. They are real simple. a 3/8s plate bolts to the portal with 3 bolts. then another to the caliper. With a .625 spacer between the two.

I drive this every day and wheel it pretty hard so far its holding up.

xj, what master cylinder are you running with your setup? are you running the vented rotors or solid ones. Sorry to hijack the thread with my questions but hopefully this will help all looking to do the swap.

Did you just drill the bolt pattern into the hub or did you do the technique weps mentions on his website where it is pressed and welded to a new piece with the bolt pattern.

I turned the hubs down and drilled to 6 lug
http://i26.photobucket.com/albums/c150/xjweeble/Hubs20002.jpg
http://i26.photobucket.com/albums/c150/xjweeble/Machined20Face.jpg

Stock XJ master and solid rotors.

They arnt high performance or anything but it stops as good as a factory XJ

thanks, you wouldn't happen to have s pinion conversion on that axle you could take some pics so one could be made would you.

its a 35spline ford 9" center

http://i26.photobucket.com/albums/c150/xjweeble/IM000277.jpg

I would like to see more pics of your bolt on disc swap, im researching my new build which will be this truck with f/r steer mogs, cummins 24v, nv4500, small exo, and custom frame and h1 wheels/tires for now. brakes are my last problem and u may have solved it, i work in a machine shop so i can do the lathe work, may even make some custom rotor.


http://i199.photobucket.com/albums/aa77/dirty_canadian/SunFeb07175255AmericaChicago2010.jpg

Had to take some material off the surface where the plate bolts to the reduction box to center the caliper on the rotor, I just used a grinder. These arnt the best looking thing around but i have around 8K miles on them and it stops real nice for what i have into it. I made a template out of wood so i can ditch the sketch looking spacers and make it all one piece once im back in a machine shop. I havnt had any bolts loosen up but im drilling them for cotter pins as we speak.

http://i26.photobucket.com/albums/c150/xjweeble/Unimog%20404%20portal%20box/DSCF1606.jpg
http://i26.photobucket.com/albums/c150/xjweeble/Unimog%20404%20portal%20box/DSCF1607.jpg
http://i26.photobucket.com/albums/c150/xjweeble/Unimog%20404%20portal%20box/DSCF1608.jpg

can you post a shot not quite so close up to see everything going on.

can you post a shot not quite so close up to see everything going on.

http://i26.photobucket.com/albums/c150/xjweeble/Unimog%20404%20portal%20box/DSCF1588.jpg

http://i26.photobucket.com/albums/c150/xjweeble/Unimog%20404%20portal%20box/DSCF1590.jpg