Disc brake conversion

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   AMC only used two bearing sets. Drum and most disc brakes used the smaller set. 75-78 disc brakes used the larger bearing set. 75-78 Matador used a thicker rotor and 3.1" piston calipers, as did all 75-76 models. 77-78 small cars (Hornet/Concord/Gremlin/Spirit/Pacer) used a thinner rotor and the later style 2.6" piston caliper, but still used the large bearings. 79+ used small bearings and 2.6" calipers. 

I understand what you're trying to do. As long as the inner diameters match the bearings will fit your spindle, provided the spindle isn't much longer or shorter than the AMC spindle. 

Have you had any luck on the postal Jeep forums? I see part of your problem -- you have the older model. Most of the postal Jeep forums and parts places are for the later model DJ5. Your FJ3A van should have the same equipment as the DJ3A. It may also have the same front end as the Willys Pick-up and Station Wagon though. Same era. Worth asking older Jeep experts about that... or seeing if you can find a parts book or illustration...

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farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19679	Post Options Post Reply Quote farna Report Post Thanks(1) Quote Reply Posted: Dec/29/2014 at 6:08pm
	AMC only used two bearing sets. Drum and most disc brakes used the smaller set. 75-78 disc brakes used the larger bearing set. 75-78 Matador used a thicker rotor and 3.1" piston calipers, as did all 75-76 models. 77-78 small cars (Hornet/Concord/Gremlin/Spirit/Pacer) used a thinner rotor and the later style 2.6" piston caliper, but still used the large bearings. 79+ used small bearings and 2.6" calipers. I understand what you're trying to do. As long as the inner diameters match the bearings will fit your spindle, provided the spindle isn't much longer or shorter than the AMC spindle. Have you had any luck on the postal Jeep forums? I see part of your problem -- you have the older model. Most of the postal Jeep forums and parts places are for the later model DJ5. Your FJ3A van should have the same equipment as the DJ3A. It may also have the same front end as the Willys Pick-up and Station Wagon though. Same era. Worth asking older Jeep experts about that... or seeing if you can find a parts book or illustration...
	Frank Swygert

wmildman Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Dec/05/2014 Location: South Georgia Status: Offline Points: 31	Post Options Post Reply Quote wmildman Report Post Thanks(0) Quote Reply Posted: Dec/29/2014 at 7:00pm
	Most of the postal Jeep guys have the newer stuff DJ5 and even a DJ3 would be a 4 lug hub not 5. I have a front and rear set up for a wagon but that is not close. I need the smaller(?) bearings .75" outer ID and 1.25" inner ID My spindle from face to end is 4" and the pictures I have found the taper looks the same. The Cherokee hub was just a little short. If I could find a Rambler hub I would try that because I believe them to be the same dimensions. Do you have or know of one? I'm not asking for free a reasonable price for an experiment is fair. If just to borrow and send back to answer that question. Thank You Wayne

wmildman Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Dec/05/2014 Location: South Georgia Status: Offline Points: 31	Post Options Post Reply Quote wmildman Report Post Thanks(0) Quote Reply Posted: Dec/29/2014 at 7:16pm
	After re-reading your drum post if I had a correct hub I would probably go that route. That was good info and my original plan was stay stock

wmildman Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Dec/05/2014 Location: South Georgia Status: Offline Points: 31	Post Options Post Reply Quote wmildman Report Post Thanks(0) Quote Reply Posted: Dec/30/2014 at 5:01pm
	Sorry tomj I was tired and confused. Thanks for the information

wmildman Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Dec/05/2014 Location: South Georgia Status: Offline Points: 31	Post Options Post Reply Quote wmildman Report Post Thanks(0) Quote Reply Posted: Jan/02/2015 at 3:57pm
	Does anyone know the spindle length for a 1980 Pacer?

farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19679	Post Options Post Reply Quote farna Report Post Thanks(1) Quote Reply Posted: Jan/02/2015 at 4:27pm
	Same as every other AMC spindle. That would be 5" from the FRONT of the mounting base to the end of the spindle. The base is 1/2" thick on drum brake cars, 7/8" thick on disc brake cars. The disc brake spindle is slightly shorter from the front of the mounting base by 3/8" (5-7/8" overall vs. 5-1/2" overall). I suspect you need the distance between the bearings though. I just went out and measured one. From the BACK of the rear bearing to the BACK of the front bearing is 2-1/2". Distance between bearings depends on the thickness of the rear bearing. AMC used an A2 and A6 bearing (or SET2 and SET6 -- inner is 6 and the larger, outer is 2). A6 bore diameter is 1-1/4", width is 5/8". A2 bore diameter is 3/4", width is 5/8" (the specs from National Bearings are 0.625" and 0.610" on width, so the A2 is just under 5/8").
	Frank Swygert

wmildman Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Dec/05/2014 Location: South Georgia Status: Offline Points: 31	Post Options Post Reply Quote wmildman Report Post Thanks(0) Quote Reply Posted: Jan/02/2015 at 4:50pm
	Thank You My FJ3A spindle is 4.5". I tried a Cherokee hub/rotor and the only thing it was too short with a height of 3.99" I guess that is total front of hub to back of rotor, so now I have ordered one for a 1980 Pacer that is 4.76" and have asked but will not know until it gets here about the other dimensions. It uses the right bearings. I remember a time when the folks at the local parts store could/would look up and tell you everything about a given part but Hello walmart, that just doesn't happen now. I know this has been happening for a while, back in the 80s my wife used to love to go buy parts for my 1978 Ford F-150 I had changed a few things. They always asked engine size and when told 429cu in they thought she was wrong so she proudly raised the hood and watched their chin fall. This project will happen and I really do appreciate the help from everyone on the AMC Forum. I know this is not AMC but everyone likes old vehicles and is trying to help. When finished I would be honored to post pictures of this little guy on here. Thank You again

farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19679	Post Options Post Reply Quote farna Report Post Thanks(1) Quote Reply Posted: Jan/02/2015 at 5:25pm
	The 80 Pacer has the standard disc brake spindle for AMC, so if it works any 79-83 AMC car spindle will work (78 was last year of the big cars which used the bigger bearing spindle). Same with brakes -- 79-83. That should help!
	Frank Swygert

wmildman Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Dec/05/2014 Location: South Georgia Status: Offline Points: 31	Post Options Post Reply Quote wmildman Report Post Thanks(0) Quote Reply Posted: Jan/09/2015 at 5:27pm
	OK I got the Pacer rotor and the rotor hits the knuckle well before the bearings seat. So that didn't work, Darn-it. If the "Hub part had not been recessed so much I believe it would have worked Did AMC come either hub/drum or later hub/rotor? Are there any hub only and then I will find a rotor to fit over it,,,,,, maybe If so do you know of at least one for sale for now. If it works then I would need a second one later. Thanks for all of the help

farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19679	Post Options Post Reply Quote farna Report Post Thanks(1) Quote Reply Posted: Jan/10/2015 at 6:27am
	Get a drum brake and remove the drum. Drive the studs out then the hub will come off the drum. It's not necessarily easy to get the drum off, but the hub will drive out with a block of wood and BFH or a press. The drum won't be useable after as it generally warps the center badly when pressed off. Then you can try a 4x4 rotor. You might try a rear drive XJ Cherokee hub. Not positive it's the same as AMC car, but should be. AMC didn't reinvent the wheel if they didn't have too.
	Frank Swygert