In my 1997 850, the driver side windshield wiper randomly quits working. The bolt comes loose so then it won't work. Any suggestions?

 

Make sure there is still enough aluminum at the end of the arm that the arm will tighten down against the serrated stud sticking up.

If the hole isn't too augured out from being loose a couple times you might be able to cure it by using a wire brush (battery brush is what I use) to scrape out any remaining aluminum from the serrations in the post. If any aluminum is left in those grooves it prevents the joint from "biting" into the aluminum. Also the threads on that post for the nut are limited and there aren't a lot of them. If you think it isn't tightening down enough add a washer (stainless if you have or can get) or two on top of the arm to take up space so when tightening down the nut you don't bottom out the nut on the stud before you tighten up the arm buy cutting into the aluminum.
It might not tighten up. You might have to get a new arm if the hole is out of round or goes so far down on the stud it can't be tightened up.

I'm in Minnesota and have done the repair more that I can remember and it's usually caused from snow and ice and people who don't clear their windshield. It's a fragile joint and it's metal against aluminum so if you turn the wipers on to brush off snow sooner or later you'll be doing this or paying someone to do it. Not saying yours was caused this way but most are.

 

Tighten it....

 

+1 with Matt. I had to use a file and cut some groves in the arm slot then keep it tight.

 

wow thanks matty never woulda thought of that... and mines been doin it for a while b4 any snow, just wondered if it was as simple as a washer or if it was a common thing on these

 

LOL... "thank you captain Obvious" Right?

No but seriously this is common on some and may never happen on others..
I my self have had this happen 3 times in the 17 years I have had my 854.
The last time it happend to me was years ago during a hurricane, I was driving home from work and the passenger side one stayed up and the drivers side on came down and got stuck on the pass one... I still had like 10 miles to go in torrential down pours..

The easiest fix is like RSPI said, make sure the splines are ok, if nit get a small file and clean them up a but. Then tighten then down.. It doesnt hurt to use a little loctite on the nut to make sure it doesnt come loose again.

BUT make sure you use the PURPLE loctite, the LOW Strength. Other wise you will have a heck of a time getting the nut off if you ever need to remove them.

 

okay, gives me one more thing to work on now lol thanks guys