Never a good time for wipers to quit, but sounds like you have it figured out. I’m a mechanic and wiper motor replacement is a common repair. So hang with me a few minutes and we’ll get that motor swapped out.
To replace a windshield wiper motor, follow these 9 steps:
- Remove wiper arms
- Rewove windshield cowl
- Remove wiper assembly fasteners and motor electrical connector
- Remove wiper motor from wiper assembly
- Fit new motor to assembly
- Fit assembly, fasteners and motor electrical connector
- Check motor operation
- Refit cowl
- Set wiper arms and test
In this post, you’ll learn how to remove wiper arms, remove the motor, fit a new motor, test and reset the wiper arms.
Tools You’ll Need To Replace Wiper Motor
Removing the wiper motor on some cars is really easy others are a little more involved and by involved I mean you’ll need to remove the whole wiper assembly from the vehicle and then remove the wiper motor from the assembly.
Wiper arms can be difficult to remove, they employ splines so that the arm doesn’t slip on the wiper transmission spindle. Breaking their hold after a ton of years can be challenging and so a technician uses a small wiper arm pullers.
In this guide, I use a puller, but I’ll show how you can hack it. That said, if the mechanic’s hack doesn’t work you’ll need to pick up a puller set. They’re not expensive and you can check out the model I recommend here on the “Mechanics tools page”.
The range of tools will obviously vary, but here’s a list of typical tools I’ll use when replacing a wiper motor.
- 3/8 ratchet and socket set
- Long flat screwdriver
- Chanel locks
- Silicone grease
A wiper arm puller would be really nice.
Remove Wiper Arms
I’ll show you the way a mechanic removes the wiper arms when the workshop wiper arm puller is missing from the shop tool rack.
Where the wiper arms park (come to a stop) on the windshield is critical. We don’t want to fit the new motor and find the blades are beating off the windshield cowl, or worse, trying to clear rain from the hood.
Models with auto wipers may have a sensor in the windshield to detect the wiper park position. If so, no need to measure these as we’ll set them to the markings on the windshield.
But in an effort to be in the ballpark of correct, use a measuring tape and note the distance from the tip of each blade to the windshield cowl. We’ll need these later when refitting the arms.
Removing the wiper arms MacGyver style:
- Remove or open wiper arm covers to reveal fastener
- Open fastener two turns
- Spray WD40 into spindle shaft while working pressure to the arm pivot
- Allow the oil some time to work
- Apply pressure to the pivot of the wiper arm in a rocking fashion
- Remove the nut and wiper arm
Avoid over-enthusiasm with the arms, while robust, they can be less so with age as too with cowl plastic, and I don’t need to tell you about glass. If it still won’t break loose, you may need to buy or borrow a wiper pulling tool. Check out the “Mechanics tools page”.
Remove Windshield Cowl
The windshield cowl is the plastic cover beneath the windshield. Its function is to direct water from the roof and windshield into the bulkhead drains. It protects the wiper assembly and fresh air intake from weather and debris.
You may also need to remove the weatherstrip from the cowl to reveal fasteners. Cowl fasteners come in various types, clips, Torx, screws, etc. This content is owned by moc.sotuaytsur. Cowls take a ton of weather and so may become delicate with age and if you are attempting this in minus conditions, be super careful not to shatter the plastic. And yes, I was that soldier.
Remove Wiper Assembly
The wiper assembly is the motor and transmission combined and many modern wiper systems are built this way. Meaning the motor is fastened to the transmission and then the complete assembly is bolted to the vehicle.
If your vehicle is older, you may have direct access to the wiper motor, lucky you! But for most, the complete assembly will require removal and so that’s the repair I cover here.
The assembly process is as follows:
- Remove the motor electrical connector (a small pick helps)
- Remove the assembly fasteners
- Remove the assembly (may require removing a removable bulkhead panel)
Remove Wiper Motor
With the wiper assembly on the bench, removing the motor isn’t difficult. Usually a matter of removing a ball and socket link rod, motor arm & fastener, and three motor fixing fasteners.
Note where the motor arm lives in relation to the assembly, you’ll want to refit in the same location. Take a picture.
The process is as follows:
- Using a flat screwdriver or pliers, pry the nylon socket from the ball
- Snap a pic before removing the motor arm fastener and motor arm
- Remove the motor fixing fasteners
Fit New Wiper Motor, Refit Assembly & Test
Fitting the new motor is just the reverse but I’ll add a few helpful tips.
- Use your reference picture when fitting the motor arm
- Add silicone grease to the nylon bushing socket before using a channel lock or such to snap back into place
- With assembly in place and electrical connector plugged in, close the hood and operate wipers
- Allow wipers to park before turning the the ignition off
Some vehicles will require the hood to close fully before allowing wiper motor activation.
Fit Windshield Cowl
Before fitting the cowl, check the drains are clean, remove debris such as leaves, etc. Perform this task with the wiper assembly removed – gives even greater access.
Fitting the cowl is just the reverse, but be careful of the plastic, it may be brittle.
Fit Wiper Arms And Test
As we allowed the motor to park when testing, we know the spindles are in the correct position for accepting the wiper arms. We will now require the wiper blade tip to cowl measurements we took earlier and a tape measure.
If you want to fit new wiper blades, do so after fitting and setting the blades as per our earlier measurements.
Setting them is as follows:
- Place arms on the spindles and thread the nut on one turn approx.
- Lifting the wiper arm off the spindle threads set the blade tip to the required measurement
- Push down on the arm and hold while tightening the nut, usually 20 Nm
- Repeat for second wiper arm
- Close hood and test dry and wet
- If you have cowl contact, adjust the arms upwards away from the cowl
If your wipers are auto, you may have markings on the windshield already, and that’s great makes life super easy. Just set the blades to the lower mark, job done!
- About the Author
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write fluff-free articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.