Wiper goes down before they go up - The 1947 - Present Chevrolet & GMC Truck Message Board Network

blazerowner71 · 05-29-2025, 05:29 PM

Why do my windshield wipers go down slightly before they go up?

blazerowner71 · 06-02-2025, 10:53 AM

Ttt

**Sheepdip** · 06-02-2025, 04:52 PM

I'm no expert but I would think the park position is slightly off from the bottom of the crank rotation. Mine do it and probably every one of these I ever owned did it, just never cared, I guess.

HO455 · 06-02-2025, 05:37 PM

I'm not sure there's a way to adjust the system to solve the issue. The crank only fits on the motor shaft one of two ways each 180 degrees from each other. The motor has no adjustment in its mounts. The park position is non-adjustable inside the motor.

The park contacts are operated by a lug on the side of the shaft drive gear. That gear would have to spin on the drive shaft for the park position to change locations. Which might happen but once the gear spun it's likely to keep spinning. Most likely in my opinion the gear wasn't installed on the drive shaft exactly where it should have been when the wiper motor was assembled at the factory.

Go to post 1074 in the link for photos of the inside of a wiper motor.

https://www.67-72chevytrucks.com/vbo...698377&page=43

05-29-2025, 05:29 PM	#1
blazerowner71 Registered User Join Date: Apr 2003 Location: N.W. Ohio Posts: 177	Wiper goes down before they go up Why do my windshield wipers go down slightly before they go up?

06-02-2025, 10:53 AM	#2
blazerowner71 Registered User Join Date: Apr 2003 Location: N.W. Ohio Posts: 177	Re: Wiper goes down before they go up Ttt

06-02-2025, 04:52 PM	#3
Sheepdip Senior Member Join Date: Nov 2018 Location: Waterford California Posts: 2,893	Re: Wiper goes down before they go up I'm no expert but I would think the park position is slightly off from the bottom of the crank rotation. Mine do it and probably every one of these I ever owned did it, just never cared, I guess.

06-02-2025, 05:37 PM	#4
HO455 Registered User Join Date: Feb 2016 Location: Portland Oregon Posts: 12,411	Re: Wiper goes down before they go up I'm not sure there's a way to adjust the system to solve the issue. The crank only fits on the motor shaft one of two ways each 180 degrees from each other. The motor has no adjustment in its mounts. The park position is non-adjustable inside the motor. The park contacts are operated by a lug on the side of the shaft drive gear. That gear would have to spin on the drive shaft for the park position to change locations. Which might happen but once the gear spun it's likely to keep spinning. Most likely in my opinion the gear wasn't installed on the drive shaft exactly where it should have been when the wiper motor was assembled at the factory. Go to post 1074 in the link for photos of the inside of a wiper motor. https://www.67-72chevytrucks.com/vbo...698377&page=43 __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377



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