Exterior Door Handle

I have a 1995 XJ. Both rear doors open from the inside, but the exterior push button doesn't work. I took the door apart and liberally soaked the anything that moved with PB blaster and wiped it down. Interior function and locks are improved, but no change on the exterior.

Is this a common problem with XJ's? Am I wasting my time trying to repair this or should I just replace the parts?

your description of the problem isn't very clear. are the buttons seized up, or do they work but don't open the door? also didnt say if they never worked or if they just stopped working, or if you have power locks.
it shouldn't be too hard to figure out. it's a simple mechanical linkage.
if both doors have the same issue it might be that a previous owner removed part of the linkage for some reason.

It is a very common problem, at least with the XJs we own. What I've found to work is I removed the entire lock mechanism, and soaked it in solvent, to soften all the old lube in the lock, and thoroughly cleaned them out. They don't get used much, and consequently the grease stiffens up. Once you're happy with the operation, lube them up with a light lube, and reinstall. There is an adjustment to remove the slack from the exterior button, and it involves a small Allen wrench inserted into a slot in the side of the door, adjacent to the button. It's been a long time since I've done mine, and they're starting to get hard to open again.

One word of caution. Resist the temptation to use WD40 or white grease, especially from a spray can. These will attract moisture, and will work great at first, but soon you'll be back where you started.

When I re-did my '92, I installed ZJ outer handles. A better look, and with a few mods, they work great. The lock mechanisms on my '96 need attention again, though...

pull the door panel and make sure the linkages are still attached, and the plastic retainer clips on each end are not cracked or missing.

Linkages are connected, nothing appears broken or cracked, mechanically you can see the mechanism moving, but it doesn't appear it engages enough to release the latch.

The slack adjustment is maxed out. The assembly works when pushing the rods inside of the door manually. The pin just don't engage the mechanism far enough. Maybe just worn out. It looks like there is a lot of slop in the linkages.

When the handles get old and after fighting against a stiffening latch, the metal part under the button bends. If you can get the handles off without shearing the studs, do so and you're likely to be able to see what needs unbending. I don't remember exactly, but this is a problem I've had in the past.

The problem with old ones is that it's really easy to shear off the studs when you try to get the nuts off. If you do shear one off you can grind the broken stud flush, and redrill the insert in the handle with a 1/4 x 20 thread, and then just use a hex bolt. But you must be really careful to drill slowly with a good sharp drill, because if it heats up the brass insert in the handle will melt loose and spin.