I recently purchased a 1990 740 wagon. The rear wiper motor was burned out and I bought a used one to replace it with. The problem I have is I haven't touched the wiper linkage that goes thru the glass, but there is no way I can get the wiper to sweep more then a 15 degree arch. The motor stalls when attached and even with the motor off, there are two curved arms (about 3 inches long) at the end of the linkage arm. They both either strike a pivot or the wiper shaft preventing the wiper from sweeping? I was a mechanic in an earlier life, but I am lost on this one!!
I thought that maybe the linkage was removed and replaced wrong and burned the motor out. But it appears the wiper arm is corroded to the shaft, so that doesn't seem to be the answer. None of the linkage arms appear to be bent, either.

Any one???? Thanks, Tom

 

Where it attaches to the motor might be out of time.
Thats why it is not working properly.

 

I thought of that, but even unattached, the linkage runs out of travel. I tried it with the shaft motor loosely attached and there is not enough travel on the linkage to get a full rotation of the motor. I even thought I had the motor wired backwards, but it was correct.

Thanks for the input.

 

One day it took me 2 hours to get one timed and working properly.

 

I fixed it, but not without help. I called a Volvo mechanic who told me that it sounded like the linkage got over center. He described that the rivet is hitting and the curved arm needed to be over that. Possibly the arm was held while the motor functioned, like a frozen blade. It took quite some prying with a screw driver, but I got it where it belongs. It took about 15 minutes to get the timing right. (Sorry, I used to be a machine designer, so the timing part was easy)

Now I know why the motor was bad, Thanks.

 

Hi

I thinkj I have exactly the same problem.

Do you by chance have a photo ogf your linkage you could send me?

Thanks

Tony

 

I LOVED finding this thread. I was equally stumped with my rear wiper linkage, after replacing the dead motor. Problem solved