bad_4dr_sho

My buddies 97 Cherokee's alternator just died. Literally from working fine in the morning to dead on the gauge in the afternoon. Driving it home it finally died on the side of the road, battery dead, so I know it's not the gauge that went bad. I want the remove the alternator and take it over to Autozone to test and possibly replace. I see thats its under the A/C compressor. Do I have to move the compressor out of the way, or do I get to the alternator from underneath? Any tips or tricks. Also I called Autozone and ordered the 130amp Alternator, will that fit? Or does it use a different bracket. Any help will be great, thanks.

99FreshenedCherokee

No you dont have to take off the ac compressor.I removed the battery tray and did it from there.It might also be possible to do it from the bottom.

LittleMeanPurpleMachine

Yes you take the tension off the belt disconnect the electrical unbolt and take out from underneath, install in the opposite Manner. Don't know about 130 amp replaced mine with OEM part.

bad_4dr_sho

Just found out the hard way, the 120amp alternator autozone sells does not fit. All the mounting holes are identical, but the unit is larger and will not clear the passanger side frame or the inside of the bracket. Figured this might help someone else out.

CharlesS

Installing a larger rated alternator WILL require that you grind material from the rear aluminum mount and the front stamped steel mounting bracket. This is a common upgrade....
Before removing the studs that mount the aluminum mount to the block; spray them liberally with PB Blaster, attempt to mount the new alternator to the aluminum and steel brackets and you can identify how much material will need to be removed from the brackets to get the larger cased alternator to fit.
There are numerous writeups on this modification.....
Once the alternator bolts line up with the brackets you can smooth out the areas that were ground to provide a 1/8" clearance between the brackets and alternator case.
Reattach the charging cable to the B+ copper stud.
If this is an upgrade from a 90A to a 120A alternator; you should consider upgrading the charging cable to a 4 ga wire and install an inline 125A fuse to replace the fusible link in the factory charging cable.
Reinstall the aluminum mount, alternator and steel bracket.

5-90

Yah - once you go past 117A, the frame size increases and grinding/clearancing is needed.

If you're going to use the full rating, you're going to want to upsize your wiring & fuse protection, since it's typically "just enough" for the OEM application at 30-40% duty cycle at full output (read: "just barely enough.")

Also, it should be borne in mind that the parts house benches border on useless - they'll test output voltage, but test it at 0.5-1.0ADC, which isn't even enough to run a good flashlight. If you want to wring it out after removing it, go to a local shop that does rewinds - they've got a better bench. If you want to wring it out before you remove it, I've posted a writeup on how to do just that here - search for "Battery" "Starter" and "Alternator" in thread titles posted by me, in any combination. You can get better results yourself in 10-15 minutes with simple instructions and a common voltmeter (not the one in the IP, but a handheld test meter.)

I wasted three and a half years in a parts store, and used to repair those benches - so I know they're useless. That's why I devised a better way to test...