AMC20 rear disk conversion

[gogmorgo]

Has anyone done it? I've seen some threads on here from 7+ years ago asking about it but if anything happened they were never updated. 

Generic diy's and full kits exist for the CJ and FSJ axles, but it's hard to say whether or not the MJ 20 is going to be the same as either of those.

 

The inspiration for this is basically that there's an AMC 20/d30 pair with 4.10's currently about 600 miles away from me. I got the phone call today that my insurance in Manitoba is no longer valid so I need to get the MJ inspected in Alberta ASAP, and given my rear brakes need completely redone I'd rather not put money into drums. And other stuff needs addressed. I have an 8.25 with disks sitting back home in Manitoba but once you factor in gas I'd only be $200 up by going to get my axle, plus it won't bolt right in, and the extra $200 would also net me a matching front, instead of regearing so in my mind I'm already better off driving to Montana.

But I'm still wondering about the disc swap. 

[HOrnbrod]

THIS conversion looks pretty easy, and cheap too. But I haven't done it........

 

[gogmorgo]

Yeah I've seen a couple different variations on that. It doesn't really look like there's all that much room on the rotors for redrilling to 5x4.5.

in my quick search I didn't really confirm whether the MJ axles were similar enough to the other AMC20's to make it work. I don't see why they wouldn't be but given the different bolt pattern it's hard to say. Not sure on the hub size/wheel mounting surface either, and wouldn't really want to end up lug-centric on either the wheels or rotors.

In other news I'm driving to Montana next weekend. Seller voluntarily lowered his price to make up for the exchange rate so it's at the point where it's worth it just for the 4.10 d30 vs regearing the one I have or picking up something local. 

[HOrnbrod]

I'm sure there's a way to convert the AMC20 to disks other than an expensive aftermarket kit, like the SSBC one. And you'll have time to find it after you bolt it in and use the drums along with the D30 with the right ratios. It's a good sensible move.  

[DirtyComanche]

If you're willing to make brackets I'm sure you could use the Isuzu calipers/Explorer rotor setup I used on my D44.

 

Otherwise I would investigate the more common options as the bearing retainer pattern is probably close enough to use the backing plates from one of those axles.

[gogmorgo]

The SSBC kit looks a lot like it's mostly just the common DIYs with all new components. I can easily hack down the backing plates into something reasonable myself, but finding 30-year-old Nissan parts in a yard up here will be a trick. But I'll have time to figure it out. 

 

Just realized though my driveshaft will probably be too long... There goes my plan of swapping the axles in before I cross the border and pretending nothing happened...lol. 

[HOrnbrod]

2 hours ago, gogmorgo said:

Just realized though my driveshaft will probably be too long... There goes my plan of swapping the axles in before I cross the border and pretending nothing happened...lol. 

 

Maybe. I know if you're going from a D35 to D44, yes, too long, but maybe not for the AMC20? Also the pinion yoke on the 20 used either a 1310 or 1350 series u-joint depending on application. Don't know which one was used for the 86 MJs w. the AMC20.

[DirtyComanche]

19 minutes ago, HOrnbrod said:

 

Maybe. I know if you're going from a D35 to D44, yes, too long, but maybe not for the AMC20? Also the pinion yoke on the 20 used either a 1310 or 1350 series u-joint depending on application. Don't know which one was used for the 86 MJs w. the AMC20.

 

The AMC 20 is fairly short in the pinion snout, IIRC, so yeah, might work out.

 

I doubt it would use a 1350 yoke in a MJ, but hey, it's AMC...  If so a 1310 to 1350 conversion ujoint can be easily had.

[gogmorgo]

Any of the AMC20 vs d35 lengths listed here take an inch out for the 20, so that's what I'm basing my guess off. Not sure how much lift would make up for it but it's probably best not to swap in unknown components immediately before a long(ish) drive, and I wouldnt want to get partway in and then realize I can't make it work and then have to reinstall pieces that didn't necessarily come off intact. That would suck. My plan with the 8.25 was that I'd be manual swapping it, at the same time which would make up for the extra snout length.

 

It is however true that not much data exists on the MJ version. Well, that's not entirely true, but what is out there is so scattered that it's hard to tell what comes from an authoritative source and what is conjecture based on other applications. The fact that two other major applications in the Jeep world aren't the same as each other doesn't help much either. 

Maybe once I have it in hand I need to make a thread so you guys can

[HOrnbrod]

88whitemanche recently installed an AMC20 in his rig as I recall. Maybe he'll chime in..........

[88whitemanche]

What’s up fellas 

don’t have much to say about disc brakes...

i did find that link hornbrod mentioned above but it seemed too much of custom fab to try and swap over to disc brakes...

 

I'm also trying to find new axle shafts for the amc 20 with the 5x4.5 lug pattern (all have 5x5.5) 

 

I haven’t reached out yet to the companies that make them to custom make me a set...

And that’s if they want to

 

as far as driveshafts go, since I already had to cut mine down for the ax15 swap (4cyl) not sure if my current length would help 

[gogmorgo]

Yeah I was reading your build thread. Looked like you did the ax15 swap separate from the AMC 20. Everything's stock with my d35 right now, I guess I've got a 242 instead of the 231 in there but they're the same length, but if you didn't need to shorten the driveshaft again when you put in the amc20 then hopefully I'm okay? I guess I'll find out anyway. 

[HOrnbrod]

5 hours ago, 88whitemanche said:

I'm also trying to find new axle shafts for the amc 20 with the 5x4.5 lug pattern (all have 5x5.5)

 

Will the CJ 2-piece axles fit with spacers?

 

http://www.ebay.com/itm/AMC-20-1-PIECE-AXLE-KIT-COMPLETE-SHAFTS-BEARINGS-SEALS-STUDS-LATE-/252048910935?hash=item3aaf492a57:g:6DAAAOSwImRYbQFW&vxp=mtr

[ride172]

I swapped an amc20 from a 1986 mj with the 2.8l v6 and an auto into my 1988 mj with 4.0l and aw4.  I didn't have to modify the driveshaft on the 86 that got d35 put back in it.  But I did have to get an inch cut off the driveshaft on the 88 that received the 20.  I did the swap for 4.10s.  Surprisingly the 86 with the 2.8 was more pleasurable to drive with the 3.55s.

 

[88whitemanche]

On 10/10/2017 at 12:37 PM, gogmorgo said:

Yeah I was reading your build thread. Looked like you did the ax15 swap separate from the AMC 20. Everything's stock with my d35 right now, I guess I've got a 242 instead of the 231 in there but they're the same length, but if you didn't need to shorten the driveshaft again when you put in the amc20 then hopefully I'm okay? I guess I'll find out anyway. 

No I didn’t have to, the difference was only about 1/2” difference from swapping...

On 10/10/2017 at 1:00 PM, HOrnbrod said:

 

Will the CJ 2-piece axles fit with spacers?

 

http://www.ebay.com/itm/AMC-20-1-PIECE-AXLE-KIT-COMPLETE-SHAFTS-BEARINGS-SEALS-STUDS-LATE-/252048910935?hash=item3aaf492a57:g:6DAAAOSwImRYbQFW&vxp=mtr

I would have to measure the shafts but haven’t found a way to measure the axle shafts to know which ones to get...

Haven’t even been able to pull them for that matter (me being lazy) 

[gogmorgo]

So I'll glean from the above two comments that not only are the MJ AMC 20's different from all the other AMC 20's, no two MJ AMC 20's are the same either 

Guess I just have to wait and see. I hit the road Friday before the crack of dawn.

[ride172]

Both of the trucks involved with my swap were 4wd and both had factory suspension.  The 86 worked out with the slip yoke pulling out of the TC about an inch more. But still had enough on the shaft to seal and cycle the suspension without pulling off.  The 88 bottomed out. Measured the gap on the 86 to determine how much to have hacked off. 

[gogmorgo]

Well now I for sure won't be able to swap them in and pretend nothing happened. I got officially informed that I'm an out-of-province resident so my Manitoba registration isn't valid. Went to get a temporary registration in Alberta and was told the registry agent wasn't authorized to issue a temporary tag to leave the country. She gave me a number to call to get authorization. I called it, it was just the Alberta government switchboard, but I eventually got transferred around to motor vehicles. I waited on hold for 20 minutes, someone picked up then hung up immediately. I look up the number (faster than spending five minutes switchboarding back and forth because the registry agent is closing in three... only open till 4:30), call the number, and then after sitting through the messages about what they're doing with the recordings, and commitment to accessibility and equality, and no I don't need service in French, I get two rings and a recording saying the office is also only open until 4:30.

@#$%ing Alberta. Seriously, the $250 POS Jimmy that had the driver's door striker torn out when I bought it is perfectly legal based on a chicken-scratch bill of sale and no one even asked to look at it before issuing insurance or plates, but just because my MJ is from outside the province it's horribly unsafe and I can't drive it ever?

I have to hit the road tomorrow morning before the registry office opens. Guess I'll be taking the Jimmy...

[Jeep Driver]

3 minutes ago, gogmorgo said:

Well now I for sure won't be able to swap them in and pretend nothing happened. I got officially informed that I'm an out-of-province resident so my Manitoba registration isn't valid. Went to get a temporary registration in Alberta and was told the registry agent wasn't authorized to issue a temporary tag to leave the country. She gave me a number to call to get authorization. I called it, it was just the Alberta government switchboard, but I eventually got transferred around to motor vehicles. I waited on hold for 20 minutes, someone picked up then hung up immediately. I look up the number (faster than spending five minutes switchboarding back and forth because the registry agent is closing in three... only open till 4:30), call the number, and then after sitting through the messages about what they're doing with the recordings, and commitment to accessibility and equality, and no I don't need service in French, I get two rings and a recording saying the office is also only open until 4:30.

@#$%ing Alberta. Seriously, the $250 POS Jimmy that had the driver's door striker torn out when I bought it is perfectly legal based on a chicken-scratch bill of sale and no one even asked to look at it before issuing insurance or plates, but just because my MJ is from outside the province it's horribly unsafe and I can't drive it ever?

I have to hit the road tomorrow morning before the registry office opens. Guess I'll be taking the Jimmy...

Maybe  you should just apply  for a green card. 

 

Or label yourself a 'dreamer'. 

 

 

Gov sucks.

[gogmorgo]

I'm a citizen already. No green cards needed.

You've got much bigger issues than vehicle registration to sort out down there before I'd consider moving. 

[HOrnbrod]

17 minutes ago, gogmorgo said:

Well now I for sure won't be able to swap them in and pretend nothing happened. I got officially informed that I'm an out-of-province resident so my Manitoba registration isn't valid. Went to get a temporary registration in Alberta and was told the registry agent wasn't authorized to issue a temporary tag to leave the country. She gave me a number to call to get authorization. I called it, it was just the Alberta government switchboard, but I eventually got transferred around to motor vehicles. I waited on hold for 20 minutes, someone picked up then hung up immediately. I look up the number (faster than spending five minutes switchboarding back and forth because the registry agent is closing in three... only open till 4:30), call the number, and then after sitting through the messages about what they're doing with the recordings, and commitment to accessibility and equality, and no I don't need service in French, I get two rings and a recording saying the office is also only open until 4:30.

@#$%ing Alberta. Seriously, the $250 POS Jimmy that had the driver's door striker torn out when I bought it is perfectly legal based on a chicken-scratch bill of sale and no one even asked to look at it before issuing insurance or plates, but just because my MJ is from outside the province it's horribly unsafe and I can't drive it ever?

I have to hit the road tomorrow morning before the registry office opens. Guess I'll be taking the Jimmy...

 

I don't care what you call it; DMV, MOT, whatever, they are all the same with few exceptions. They go out of their way to recruit the surliest, nastiest people they can find with IQs of less than 50. I've never had a good experience at the DMV. 

[Jeep Driver]

21 minutes ago, gogmorgo said:

I'm a citizen already. No green cards needed.

You've got much bigger issues than vehicle registration to sort out down there before I'd consider moving. 

US citizen? just curious. 

 

We all got problems, no matter where we are. 

 

 

 

Edit

 

Now that  I think about it, I could not transfer my truck to many of the states for emissions reasons..........no different than your situation I suppose. 

[gogmorgo]

Yes, US citizen.

 

I phoned the registry back home, and they were confused I couldn't get temporary registration to leave the country, since theirs were perfectly valid, even overseas. But they also confirmed that my registration was no longer valid even if I left Alberta, until I could once again be considered a Manitoba resident. 

My issue isn't so much the inspection process, it's more the double standard nature of it. Once a vehicle is in Alberta it's good, and you never need to have it inspected ever again. In Manitoba vehicles need inspected every time they change owners. Both of my vehicles passed with only a couple small repairs within the last five years. But that Ranger rotting out across the street with body panels that flap in the breeze and suspension that sounds like the world falls apart every time it hits a bump that obviously hasn't been inspected ever (new vehicles don't need inspected) is legal and mine that has passed an inspection two years ago can't be unless I get it inspected again?

Everythng seems like a cash-grab here too. In Manitoba (and everywhere else) you can just go to your local mechanic who is authorized to inspect vehicles (95% of them are) and pay him for his time. Here, you have to pay $20 for the request for inspection sheet first, and then if you fail on anything you've only got two weeks to fix things before starting the inspection process all over again. 

[gogmorgo]

Well, ranting is over for now I guess. Totally off topic. 

 

It it took some tetrising to get the axles into the Saint, and he's squatting pretty hard under the weight, but hey, $250 POS so I don't care. Now I'll have to bribe my roommate or something to help me get them out of there, haha. No issues at the border, either,which is shocking. Given the radical paint job I was expecting to get the whole thing torn apart in both directions. 

And no it's not a yoga mat. Insulating pad for a sleeping bag. I brought my tent and camping gear along just in case, most of the drive is following the continental divide and you never know what you could get this time of year.