Disc Conversion- Std. bearing race or spacer race ?

Got my rotors and hubs pressed together today with the new studs. All worked out well and rotor fits without movement. The bearing for the hubs are in the mail and I ordered a set of the thicker race cups in case I have centering problems between the rotors and calipers that I have read about.

What is the best way to determine which race I need to use (std or thicker) without having to install one and try it then pull the cup if it is the wrong one? I don't want to damage parts trying to get this right. Most of the threads describing the problem aren't too specific but from what I have been able to piece together.... some setups have an alignment issue of about 1/8" between the rotor and caliper and the solution is to install a thicker bearing cup on the inner bearing. This adds about 1/8" and the seal will then stick out some and the snap ring wont go on the spindle shaft but the brakes align as they should.

Some people don't have this spacing problem and one thread suggested that it mainly occurs on jeeps older than say 65. Since I am using a 66 spindle and new omix hubs it might turn out I won't have the issue at all but I want to try and determine that before I install a set of bearings.

Any ideas how to do that? What measurements or how to test fit the rotors first?

Thanks
Al

 

I just recieved most of my parts to do the conversion my self, I ordered a kit from Complete off Road, today I stripped one side down and did a test fit of the parts (did not grind the knuckel yet) with all new stock parts, (bearings, races and seals) every thing fit and aligned perfectly.
IMHO install the original races and do a test fit ( don't install the seal), worst that can happen is you will have to replace the races.

1968- dana 27a

 

OK but doesn't the seal have to be in place to set get a true fit?
if I do have to remove a race, to try the other one, can I do that without damaging it, in case I have to use it after all? Maybe with a brass punch?

 

correct
if you look inside the wheel hub, you might see two grooves or openings that will allow you to place the punch onto the back side of the race.
just tap evenly from side to side to drive the race out
I wouldn't even pack the bearings with grease just to keep it cleaner during the process until you're ready for final assembly.

 

In the flatfender section there is a post covering this very thing with part #s to help you determine whether you need the thicker race or not. Most likely if you purchased new bearing hubs from omix/crown you will need the thicker race as these hubs are typically machined for the later bearings. The very early hubs that used the thinner bearings and races were machined different and did not need the conversion race from what I've been able to gather

 

Thanks Guys,
I do see the 2 grooves and figured I could use a brass rod to tap it back out but didn't know if that was a risky op or not. I think I may have gotten the era's mixed up as I thought the early hubs needed the thicker race.... nevertheless I ordered both the LM501310 & the thicker LM501311 cup. I guess I will have to pick one to try and then just be careful not to bugger things up if I have to tap it out.
I'll check that other thread - I hadn't seen it.

Thanks
Al

 

ok after reanding more of the comments on this thread I decided to do another dry fit of the rotars and calipers only I grinded the relief in the knuckle this time.
I also ordered new hubs later, model omnix the same as you have.
I have the original bearing races in the hub LM501310.I was able to get the calipers and pads on with no problem but now I can see where the thicker race comes in to play. where the caliper mounts to the backing plate I have about 1/8 inch gap, I think it would work as is but in the long run I will lose that 1/8 ince in pad ware (?)as the caliper move inbound towards the axel.
I will be ordering the thicker race today.
good luck with your project

IMG]http://i1085.photobucket.com/albums/j427/68swamper/bearingracesforconversion004.jpg[/IMG]

 

How'd you get such a clean jeep ???
That picture is worth 1000 words... I too couldn't visualize where the 1/8" came into play.
Take a look at the similar thread in the flatfender section... he has a link to an updated JP article... oh well here it is
http://www.jpmagazine.com/techartic...05_drum_to_disc_brake_swap_plus/photo_08.html
that shows where in the ball you have to grind if you have installed stud heads like I do... you can separate the spindle from the knuckle and see exactly where it hits the ball edge (as shown in another JP picture.) I didn't quite get it from all the other instuctions and threads but these pics are very clear what you have to do.

 

lots of money to get it to look like its clean, I found it in a field in 05 in Florida and talked the PO out of it for $1000 with the title , I should have stoped there and just drove it. but it be came my hobby and several $ later it looks all new and shiny from a distance.
In the last month I have read so much about this conversion I think I have information overload. and I believe I had my self convinced it was going to be harder than it actualy is.
I will not be in stalling the thicker race on this set up as I have no fitment issues with the original races
I need these disc's to stop the 33 X 12.5 boggers i just purchased
I will be monitoring your progress
David

 

You will be a patient person.... or dead if you monitor my progress ... I started rewiring in 2004 and just finished a couple months ago !!! (admittedly I lost interest for a few years). I think I will get this one done sooner though.