After gloating (for awhile, anyway) that MY sliding door handle won't 
fall off as I have routinely tightened up the screw holding it on, it 
finally happened to me.  Here's the problem and a CHEAP solution.

The handle is held onto a sleeve with a single machine screw.  The 
sleeve is held into the handle mechanism by a small amount of staked
metal and kept from rotating by the square (rounded off) shape of the 
sleeve.  Over time the grease gets old and hard and as one has to 
push/pull/rotate harder to open door, the staked metal gets deformed 
back to the original position or gets sheared off, allowing the 
handle to be pulled out.  The handle mechanism is riveted together
and would be an unreasonable object to re-assemble after dismantling. 
The problem is how to hold the sleeve and handle in place as a unit,
since the sleeve cannot be trusted.
Anyway on to the FIX.

Parts needed: 
5mm x .8 pitch x 20 mm machine screw, price $.20
(phillips head, not the hex head) smaller head that hex
3/16 in x 1 in fender washer, price $.05

Proper fix - Remove door panel, remove both forward and rear door 
mechanisms and grease everything that moves.  The adjustment 
mechanism for the cable to the rear latch is easy to re-adjust so 
don't sweat that, just loosen and disconnect the front c-clip.

The rear latch rotating part must be in the latched position to be 
able to fit through the door panel.  That spring in the rear is a 
tough one, but move the mechanism to all positions to grease 
everything.  The front mechanism is actually actuated by the rear 
latch and cable, slide the cable attach to actuate the front latch.

Re-assemble latches but before installing latch mechanism for open 
position catch install the 25 cent solution.  

Lightly grease flat area where handle end comes through, place washer 
on that spot and screw in machine screw to end of handle inserted 
from outside of door.  Tighten up until screw bottoms out in hole in 
handle.  You might need a screw of slightly different lengths if your 
handle screw hole is of a different depth.

Reason this works:
The fender washer allows the force of pulling the handle OUT to be 
transferred directly to the latch housing instead of to the sleeve.  
The machine screw rotates in the fender washer hole allowing rotation 
for the handle and by bottoming out in the handle the screw won't 
loosen itself up.

Quick fix - 
Just do the screw installation, but you shall at least feel guilty of
NOT greasing the mechanism.

For those of you who have NOT had their handle fall off, do the PM 
and grease your mechanisms.

- Jeff + (2) '80 Westi's, '67 Sqbk, '64 Ford Crewcab, '87 Subaru 4WD
Grass Valley, California, USA, Earth