How to Replace the Windshield Washer Pump on a Peterbilt 579 Truck

Replacing the Windshield Washer Pump on a Peterbilt 579

Keeping your windshield clear is an essential part of operating any commercial truck safely. On a Peterbilt 579, the windshield washer pump delivers fluid to the windshield to allow the wipers to clear away dirt, grime, salt, and other debris that builds up during long days on the road. Eventually, the pump can fail, leaving you without the ability to spray your windshield. Replacing the windshield washer pump on a Peterbilt 579 is a straightforward repair you can complete yourself in a short time.

Locating the Windshield Washer Pump

On the Peterbilt 579, the windshield washer pump is located behind the front bumper on the passenger side of the truck. To access it, you'll need to remove a small panel on the side of the bumper. This panel is held on with several bolts that can be removed with basic hand tools. Once the panel is off, you'll see the washer fluid reservoir and pump assembly mounted to the frame.

Removing the Old Pump

Start by releasing the pressure in the washer fluid system by running the pump until the fluid stops flowing. Disconnect the electrical connector from the pump. Then loosen the hoses attached to the pump using a wrench. You may want to have a drain pan ready to catch any fluid that leaks out. Once the hoses are detached, remove the bolts holding the pump in place and remove the old pump from the vehicle.

Installing the New Pump

First, transfer the hose fittings from the old pump to the new one using thread sealant to prevent leaks. Mount the new pump in place using the same bolts. Tighten everything down securely. Reconnect the electrical connector plug. Attach the hoses to the pump, again using thread sealant on the fittings. Make sure the hoses are securely seated. Refill the washer fluid reservoir with fresh fluid. Bleed any air out of the system by running the pump for a few seconds to get fluid flowing. Top off the reservoir as needed.

Testing and Final Steps

Turn the wipers on and operate the sprayer to verify that the pump is delivering fluid properly. Spray should come out at a decent pressure and volume to coat the entire windshield. Check for any leaks at the hose connections and tighten if necessary. Reinstall the access panel and replace the bolts to protect the pump. Properly dispose of the old pump, hoses, and any spilled fluid. Be sure to refill the washer fluid reservoir as needed for regular operation.

Troubleshooting Issues With the Windshield Washer Pump

If you complete the replacement but find the washer pump still is not working, there are a few issues that could be causing problems. Here are some things to check:

Electrical Connection

Make sure the wiring harness connector is securely attached to the pump. Remove and reseat the connector and check for any visible damage. The pump may not run if it is not getting power. Use a multimeter to check for voltage at the pump connector with the wash function activated.

Fuse

There may be a blown fuse for the washer pump circuit. Check in the fuse panel under the hood for the windshield washer fuse. Look for any fuses related to the wiper/washer system. Replace any blown fuses with a new one of the correct amperage.

Low Fluid

The pump will not be able to spray if the fluid reservoir is empty. Make sure the reservoir has been filled with new fluid. Bleed any trapped air pockets by cycling the pump a few times. The pump should prime itself and fluid flow should resume.

Faulty Pump

If voltage is present and fluid is full, the pump itself may be bad. Double check your connections, then test the old pump again to see if it works off of the vehicle. If it still fails, replacement is necessary.

Clogged Tubes

Check the spray nozzles on the windshield cowl to see if they are clogged with debris. Use a thin wire to clear out the ports. Make sure the hoses are clear and not kinked. Flush with water if necessary. The system will not spray properly if there are blockages.

Regular Windshield Washer Maintenance

Like any vehicle component, taking care of your Peterbilt 579’s windshield washer system will help prevent breakdowns and keep it operating reliably for the long haul. Here are some good maintenance tips:

Check Fluid Level

Frequently check the fluid level in the reservoir. Top it off with fresh fluid as needed. Use a windshield cleaner fluid that contains antifreeze during colder months to prevent freezing.

Change Fluid Yearly

Replace the windshield washer fluid reservoir completely at least once a year. Fluid can collect dirt and debris over time. Fresh fluid helps optimize cleaning performance.

Clean Nozzles

Use a thin wire or pin to clear out any buildup or blockages from the spray nozzles. Clogged ports can cause poor spray patterns.

Check Filter and Hoses

Inspect the fluid filter screen for contamination and replace if necessary. Check all hoses for cracks or leaks. Repair or replace any degraded hoses.

Test Pump Operation

Run the windshield washer periodically to verify that the pump is delivering a proper spray pattern and volume. Catch any leaks early before they become a bigger problem.

Electrical Connections

Make sure the wiring harness connector is fully seated on the pump. Check any related fuses. Clean corrosion from electrical terminals to maintain optimal power delivery to the pump motor.

Conclusion

Being able to properly clean your windshield is a key factor in safe truck operation. If your Peterbilt 579’s windshield washer fluid pump stops working, replacing it yourself is an easy and affordable repair. With basic hand tools and mechanical skills, the pump can be swapped out in less than an hour. Just be sure to take care of the related maintenance for optimal reliability from your washing system. Follow these tips and your truck will have a clear view of the road ahead.

FAQs

Where is the windshield washer pump located on a Peterbilt 579?

The windshield washer pump is located behind the front bumper on the passenger side of the truck. You'll need to remove an access panel on the bumper to get to it.

What tools do I need to replace the washer pump?

You'll need basic hand tools like wrenches, sockets, a drill, and screwdriver to remove the access panel and disconnect the hoses and electrical connector.

How do I remove the old windshield washer pump?

Start by relieving pressure in the system, then disconnect the hoses and electrical connector. Remove the mounting bolts to free the pump from the truck. Transfer any hose fittings to the new replacement pump.

Why won't fluid come out after replacing the pump?

Make sure the pump connector is secure, check for blown fuses, refill the fluid, and bleed out any air trapped in the hoses. The nozzles may also be clogged, preventing spray.

Should I use any sealant on the pump hose fittings?

Yes, apply thread sealant to the hose fittings when installing the new pump to prevent any fluid leaks. Make sure all fittings are tight.