Monarch BSTF 51 – 82 – 83 – 125 Series Centrifugal Self Priming Pump & Repair Parts
Monarch BSTF Series Centrifugal Self-Priming Pump
The Monarch BSTF Series represents a robust line of frame-mounted, centrifugal self-priming pumps designed for reliable liquid transfer. This product page covers the specific Type A variations of the BSTF-51, BSTF-82, BSTF-83, and BSTF-125 models. Known for their durability and industrial-grade construction, these pumps are engineered to handle demanding agricultural, commercial, and industrial applications.
Whether you are performing routine maintenance or a complete overhaul, using genuine Monarch repair parts ensures your equipment operates at peak efficiency. This page provides a detailed exploded view diagram and a comprehensive parts list to help you identify exactly what you need, from transmission housings and shafts to mechanical seals and impellers.
Key Features and Design
The BSTF Series is characterized by its frame-mount design, allowing for flexible coupling with various power sources (electric motors or engines).
- Heavy-Duty Transmission: Features a rugged transmission housing designed to support the shaft and bearings, reducing vibration and wear.
- Versatile Sealing: Equipped with high-quality mechanical seals (available in 5/8″ and 1″ I.D. depending on the model) to prevent leakage and ensure system integrity.
- Corrosion Resistant: Durable casing and impeller materials designed to withstand standard water transfer and mild fluid handling tasks.
- Self-Priming Capability: The casing design facilitates self-priming, making it ideal for applications where the pump is located above the fluid level.
- Serviceability: Designed with maintenance in mind, featuring accessible drain plugs and replaceable wear components like gaskets, seals, and bearings.
Common Applications
- Agriculture: Irrigation, dewatering, and liquid transfer.
- Industrial: Water circulation, sump drainage, and supply systems.
- Commercial: General purpose pumping and booster service.
Technical Specifications & Repair Parts
The table below details the complete list of replacement parts for the BSTF Series (Type A). Please refer to the Exploded View Diagram in the product images to match the Reference Number (Ref.#) with the correct component.
Model Identification Key:
- a = BSTF-51
- b = BSTF-82
- c = BSTF-83
- d = BSTF-125
BSTF Series Repair Parts List
| Ref.# | Code # | a | b | c | d | Description |
|---|---|---|---|---|---|---|
| 1 | 438221 | 1 | Transmission Housing | |||
| 1 | 438222 | 1 | Transmission Housing | |||
| 1 | 437851 | 1 | 1 | Transmission Housing | ||
| 2 | 128230 | 4 | 4 | 4 | 4 | Nut, 3/8″ UNC |
| 3 | 176540 | 4 | 4 | 4 | 4 | Spring Washer, 3/8″ |
| 4 | 120010 | 4 | Bolt, 3/8″ UNC x 1″ (not as shown) | |||
| 4 | 172990 | 4 | 4 | 4 | Stud, 3/8″ UNC x 1 3/4″ SST | |
| 5* | 432010 | 1 | 1 | Key | ||
| 5* | 432280 | 1 | 1 | Key 1″ (for Shaft #437852) | ||
| 432281 | 1 | 1 | Key 1-1/4″ (for Shaft #437854) | |||
| 6* | 438455 | 1 | 1 | Shaft & Bearing Assembly | ||
| 6* | 437852 | 1 | 1 | Shaft (Ext. 1-29/64) | ||
| 437854 | 1 | 1 | Shaft (Ext. 1-47/64)** | |||
| 7 | 110216 | 2 | 2 | Bearing | ||
| 8 | 137930 | 1 | 1 | Retaining Ring | ||
| 8 | 137982 | 1 | 1 | Retaining Ring | ||
| 9 | 199245 | 1 | 1 | Lip Seal | ||
| 10 | 191791 | 1 | 1 | Flinger | ||
| 10 | 190847 | 1 | 1 | Flinger | ||
| 11 | 266008 | 1 | 1 | Sleeve | ||
| 12 | 438246 | 1 | Seal Plate | |||
| 12 | 438243 | 1 | Seal Plate | |||
| 13 | 240316 | 1 | 1 | Mechanical Seal, 5/8″ I.D. | ||
| 13 | 240369 | 1 | 1 | Mechanical Seal, 1 I.D. | ||
| 14 | 193920 | 1 | Gasket | |||
| 14 | 193928 | 1 | 1 | Gasket | ||
| 14 | 193929 | 1 | Gasket | |||
| 15 | 438111 | 1 | Impeller | |||
| 15 | 438131 | 1 | Impeller | |||
| 15 | 438488 | 1 | Impeller | |||
| 15 | 438489 | 1 | Impeller | |||
| 16 | 438021 | 1 | Casing | |||
| 16 | 438057 | 1 | 1 | Casing – yellow | ||
| 16 | 438473 | 1 | Casing | |||
| 17 | 185650 | 2 | 2 | 2 | 2 | Pipe Plug, 3/4″ NPT |
| *Parts suggested for stock. | **Effective September 1995. | ||||||
IMPORTANT ORDERING INSTRUCTIONS:
When ordering parts, always specify the Model and Type, Code Number, and Part Description.
Be careful not to confuse the model and type of the pump with the number code and description of each individual piece.