PRO 1.5+ Vibrator Motor Assembly Parts

Shop genuine OEM parts for the Northrock PRO 1.5+ (25L1 / 25L1QD) 1.5 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 1.5+ (25L1)

About 80% of PRO 1.5+ service issues come down to these six parts. Diagnose in this order before replacing anything larger:

PRO 1.5+ (25L1) Full Parts List

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. 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. Apply a 1/16" coat of lithium grease to the core; do not over-grease.

Model-specific parts — do not cross-swap

The armature (475B1), field coil (480B1), and end bell (420B1) are unique to the 1.5 HP motor. The PRO 2+ uses 475A1 / 480A1 / 420B1; the PRO 3+ uses 475C1 / 480C1 / 420D1. Verify the part number against your motor before ordering.

Power cord replacement (Ref #19, P/N 505H1)

Do not tape damaged cords. Replace any cord with nicks, cracked strain relief, or plug damage. The 505H1 fits both PRO 1.5+ and PRO 2+; the PRO 3+ uses the heavier 505J1.

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 470A1)

Inspect every 40 hours. Replace when gray with embedded concrete dust. Never run the motor without the filter installed.

Maintenance Schedule

• Every shift: Inspect cord, plug, switch, housing. Clean concrete dust off exterior.
• Every 40 hrs: Clean or replace air filter.
• Every 50 hrs: Pull flex shaft core, inspect, re-grease with lithium grease (1/16" coat max).
• Every 200 hrs: Check brush length through service port. Replace pair if worn.
• Every 500 hrs: Inspect commutator for glazing or grooving.
• Annually (heavy use): Replace ball bearings.

Extension Cord Sizing (13 A draw)

Outdoor cords must be marked W-A (e.g. SOW-A). 3-conductor grounded only. Use a GFCI in damp conditions. Undersized cords cause voltage drop, which increases amp draw and burns brushes, armature, and field windings.

Shaft & Head Compatibility

Head diameter limits

The PRO 1.5+ is rated for heads up to 1-1/2" (up to 1-3/4" on QD configurations). Approved head sizes: 3/4", 1", 1-1/4", 1-1/2". Do not run 2" or 2-1/2" heads — the motor will overload and burn brushes, bearings, and windings. Use a PRO 2+ or PRO 3+ for larger heads.

Shaft lengths

Single shafts 2–21 ft. Maximum reach 42 ft using a Northrock shaft connector.

Multi-brand adapter chart

The PRO 1.5+ countershaft is universal. With the correct core adapter (160-series) and casing adapter (150-series), it runs shafts and heads from:

Brand not listed? Call +1 (202) 630-1027 or email [email protected] with your shaft brand, model, and head size.