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About PRO 3+ HP Vibrator Motor Assembly Parts
Shop genuine OEM parts for the Northrock PRO 3+ (25L3 / 25L3QD) 3 HP electric concrete vibrator motor. Click any numbered callout on the diagram below to jump to the exact part. Part numbers match the official Northrock service manual.
DanseUSA is an authorized Northrock dealer. Orders placed before 12 PM ET ship same business day when in stock. Not sure which part? Email [email protected] with your motor's model and serial number.
How to Use the Diagram
Match the Ref # on the exploded view to the row in the parts list. Click the callout → product page → add to cart. Always replace wear parts (brushes, bearings, seals) in pairs.
Most Commonly Replaced Parts on the PRO 3+ (25L3)
About 80% of PRO 3+ service issues come down to these six parts. The PRO 3+ runs at higher amp draw than the PRO 1.5+ and PRO 2+, so brushes and bearings wear faster under continuous-duty loads — diagnose in this order before replacing anything larger:
| Ref # | Part | P/N | Typical Life | Symptom |
|---|---|---|---|---|
| 21 | Carbon Brush (pair) | 490A1 | 150–350 hrs | Weak under load, heavy sparking, burn smell |
| 32 | Air Filter | 470B1 | 40 hrs | Motor runs hot, thermal cutout |
| 8 | Ball Bearing (pair) | 140C300 | 400–1,200 hrs | Grinding, squealing, shaft wobble |
| 19 | Power Cord | 505J1 | As needed | Nicks, cracked strain relief, bad plug |
| 28 | Electric Switch | 425B1 | As needed | Mushy, sticks, won't toggle cleanly |
| 31 | Switch Seal | 430A1 | Replace with switch | Water intrusion, visible wear |
PRO 3+ (25L3) Full Parts List
| Ref # | Description | Part # | Qty |
|---|---|---|---|
| 1 | Screw | 190F150 | 11 |
| 2 | End Cap | 215M1 | 1 |
| 3 | Bolt | 280A225 | 4 |
| 4 | Lock Washer | 285A250 | 4 |
| 5 | End Bell (3 HP specific) | 420D1 | 1 |
| 6 | Baffle Filter (End Bell Side, 3 HP specific) | 470F1 | 1 |
| 7 | Spring Washer | 380A1 | 1 |
| 8 | Ball Bearing | 140C300 | 2 |
| 9 | Armature (3 HP specific) | 475C1 | 1 |
| 10 | Screw | 190E140 | 2 |
| 11 | Lock Washer | 285A187 | 3 |
| 12 | Field Coil (3 HP specific) | 480C1 | 1 |
| 13 | Commutator Service Port Cap | 400B1 | 1 |
| 14 | Motor Housing (3 HP specific) | 105AG1 | 1 |
| 15 | Bolt | 280A312 | 4 |
| 16 | Lock Washer | 285A312 | 4 |
| 17 | Washer | 370A312 | 4 |
| 18 | Frame Assembly (3 HP specific) | 440D1 | 2 |
| 19 | Grounded Power Cord (heavy gauge) | 505J1 | 1 |
| 20 | Brush Holder | 495A1 | 2 |
| 21 | Carbon Brush | 490A1 | 2 |
| 22 | Brush Cap | 500A1 | 2 |
| 23 | Outer Protective Brush Cap | 400C1 | 2 |
| 24 | Cord Mounting Plate | 215CC1 | 1 |
| 25 | Screw | 190F875 | 4 |
| 26 | Set Screw | 190B125 | 2 |
| 27 | Wire Clip | 467C1 | 1 |
| 28 | Electric Switch | 425B1 | 1 |
| 29 | Switch Mounting Plate | 215CB1 | 1 |
| 30 | Screw | 190F850 | 2 |
| 31 | Water-Resistant Switch Seal | 430A1 | 1 |
| 32 | Air Filter (3 HP specific, larger) | 470B1 | 1 |
| 33 | Air Filter Cover (3 HP specific) | 215X1 | 1 |
| 34 | Core Adapter | See compatibility chart | 1 |
| 35 | Casing Adapter | See compatibility chart | 1 |
Repair Tips
Brush replacement (Ref #21, P/N 490A1)
Unplug cord. Remove outer brush cap (400C1) and brush cap (500A1). Pull old brush. If carbon is under 1/4" or cracked, replace both brushes as a pair. Check commutator for glazing — light glaze is OK, grooves or pits mean the armature needs service. The PRO 3+ wears brushes faster than the smaller motors due to higher amp draw; check every 150 hours on continuous-duty applications. Reinstall caps finger-tight plus 1/8 turn.
Bearing replacement (Ref #8, P/N 140C300)
Two sealed bearings, one each end of the armature. Always replace as a pair. Before running the motor again, pull the flex shaft core and check lubrication — a dry core cooks new bearings within 50 hours, and the PRO 3+ is often run with long 21 ft or connected shafts that consume more driveline power. Apply a 1/16" coat of lithium grease to the core; do not over-grease.
Model-specific parts — do not cross-swap
The PRO 3+ has more unique parts than the 1.5+ or 2+. The armature (475C1), field coil (480C1), end bell (420D1), motor housing (105AG1), frame assembly (440D1), baffle filter (470F1), air filter (470B1), air filter cover (215X1), power cord (505J1), and screw 190E140 are all 3 HP specific. The PRO 1.5+ uses 475B1 / 480B1 and the PRO 2+ uses 475A1 / 480A1. Verify every part number against your motor before ordering — a 2 HP armature will not fit a 3 HP motor.
Power cord replacement (Ref #19, P/N 505J1)
Do not tape damaged cords. Replace any cord with nicks, cracked strain relief, or plug damage. The 505J1 is the heavier-gauge cord required for the PRO 3+ and carries a 20A plug. Do not substitute the lighter 505H1 cord from the PRO 1.5+ or PRO 2+ — it will overheat under the 19A load.
Switch + seal (Ref #28, #31)
Always replace the switch (425B1) and the water-resistant seal (430A1) together. A compromised seal lets water into the switch cavity and shorts the motor.
Air filter service (Ref #32, P/N 470B1)
Inspect every 40 hours. Replace when gray with embedded concrete dust. Never run the motor without the filter installed. The PRO 3+ uses a larger filter (470B1) than the PRO 1.5+ and PRO 2+ (470A1) because the 3 HP motor needs more cooling airflow for continuous-duty operation. Do not substitute th
Frequently Asked Questions
Match the Ref. # on the diagram to the row in the parts list at the right. Click a part name to see details, price, and add it to cart.
Confirm your model/series and serial number range on the product page. Many manufacturers have serial breaks, when in doubt, share your model and serial with us and we’ll verify fit.
The Ref. # points to the callout on the drawing. Qty shows how many of that item your machine uses. Parts are sold individually unless noted as a kit.
Yes, we supply genuine OEM parts for all our brands. If a part has an approved replacement, we ship the latest superseded revision
Manufacturers often supersede numbers. Our pages list the current orderable number and show older numbers in the description when available. Your old number will cross-reference to the correct part.
Yes. Some items are not pictured or are shared with other assemblies. Send us the model, serial, and a description (or photo) and we’ll locate it.
Yes. DanseUSA passes the manufacturer’s warranty to you. Coverage applies to defects in materials and workmanship under normal use for 30 days from the purchase date, in line with the manufacturer’s warranty policy. Terms can vary by brand; the product page reflects the applicable policy. If a claim is needed, we’ll help coordinate with the manufacturer.
Yes, most new, uninstalled items can be returned under our standard policy. Please see our Returns & Refunds Policy for eligibility, timeframes, and any exceptions.