This applies to the vent window style, however it would probably work for the one piece window manual regulators as well.
When I acquired my '86 4runner, the drivers side window regulator was already shot (all the arm teeth were flat). So, last year I bought a replacement on ebay since I couldn't find one locally and nobody wanted to sell one for less than the price of an appendage. Not even 8 months later, this ebay window regulator had failed me. I've been dealing with having to pull it up manually for a while, but as of recently we've had some random flash flood rain which really sucks when you're driving and can't roll your window up. After getting drenched enough I decided to pull that cheap window regulator out and have a look. It turned out to be the opposite of the problem I had with the first window regulator. Now this one was either ground badly or just flimsy:
I wasn't about to put it back in without at least trying something. So I bent back the tab behind the crank gear, then got my drill out and made some holes and tapped them for m6x1.0, which I then slipped in two 10mm m6x1.0 bolts to hold the arm out so the teeth hit the meat on the crank gear:
total cost, somewhere under $1.00 for 2 bolts and a small bit of grease. This is definitely cheap and not at all the best way to go about it, but it beats getting soaking wet while trying to pull over to pull the window up.