C3 71 Wipers clash

[Gerard Q.]

My wipers sometime clash with one another. They don't over run the windshield but do hit one another on occasion and sometimes they get locked up. This doesn't happen all the time but when it does it's annoying. I'm trying to understand the adjustment procedure in the aim but.....it talks about cycling the blades on a wet windshield and adjusting the tips of the blades .75 from DLO as shown using screws A. I can see that these screws are on the wiper arm but what does .75 from DLO mean? Would this adjustment whatever it is cure my problem?

Thank for in advance for any help on this.

[Jim K.]

Re: C3 71 Wipers clash

Hi Jerry:
I'm not sure of the DLO right now, without looking at it, but I did adjust mine on the 70 this fall. What I wanted to tell you is that I used a plastic milk jug filled with water set on the roof and poked a small hole in it to provide a wet surface during the adjustment, two might be better. the .75 is 3/4", that much I think I know.
Jim

[Terry M.]

Re: C3 71 Wipers clash

I can't help with DLO (I am curious too), but I can tell you that when making windshield wiper adjustments not only must the windshield be wet, but the engine must be running as well. The voltage to the wiper motor will be higher with the engine operating than with it off. That will make a difference in the wiper operation.
So make your adjustment, and test on a wet windshield with the engine running.

[Chuck S.]

Re: C3 71 Wipers clash

I'll pick the low hanging fruit before John, Art, Bill, et al have to help us. I believe the GM gurus told us before that DLO was Day Light Opening. In this case, it means 3/4 inch from the inside edge of the reveal molding.

[Jack H.]

You've got TWO adjustments here...

One is the 'cant' of the wiper blade. That's the single screw on the base of the wiper arm. It essentially 'fine tunes' the attack angle of the blade(s) relative to the arm(s).

The other adjustment is on the crank plate that rides the wiper motor's drive shaft. You have to remove the wiper door grille plate to get there.

Each wiper arm drive shaft is held pinched to the crank plate and has individual adjustment by loosing the crank plate's bolts and moving the arm's drive shaft in/out.

This is what sets each arm's max excursion across the glass as well as that arm's final rest position. If your wiper blades are canted properly with respect to the arms (horizontal rest position) and they still touch during start-up or park, it's time to pull the wiper door grille and tweak the crank plate to arm adjustment to gain a bit more parked separation between your wiper arms...