Caterpillar SR21
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar SR21 is a passive, hydraulically driven two-stage snow blower work tool that mounts to a skid-steer or compact loader rather than operating as a standalone machine. It carries no engine, ECM, hydraulic tank, or fuel system of its own — every function, auger, impeller, chute rotation, and deflector, runs off hydraulic power and controls routed from the host carrier through quick-disconnect couplers. Cat did not publish a standalone operating weight or exact production-year window for the SR21 in surviving factory literature, but it carries a 2159mm (85in) intake width, a 457mm (18in) auger, and a 914mm (36in) cutting height. It was built as the largest unit in a three-model family alongside the smaller SR17 and mid-size SR18, all covered by the same factory manual and identified by their own serial prefixes. Cat offered it in this single width/auger configuration rather than a spread of displacement or engine options, since none of those variables apply to a purely hydraulic attachment.
Across this family, the core two-stage auger-and-impeller layout and hydraulic-only drive stayed constant; what changed generation to generation was mostly hardware detail and naming. Caterpillar's current snow blower lineup uses a different serial-prefix family and adds features like a non-metallic chute liner and corrosion-resistant chute chain, with a same-size-class model occupying the 85in/18in-auger footprint the SR21 once held, plus larger high-flow units above it for bigger carriers. In the used and parts market, the SR21 still matters because plenty of these attachments remain in service on older Cat skid-steer fleets doing municipal and commercial snow work, and because it has no engine to wear out, its resale condition hinges almost entirely on auger and impeller bearing health, gearbox oil condition, and chute/chain wear rather than engine hours. Parts and service knowledge also carry across its SR17/SR18 siblings, since all three share the same factory manual family for gearbox, bearing, and chain components.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Caterpillar SR21 specifications
Engine
| Power source | No onboard engine. This is a passive, hydraulically driven work tool — auger, impeller, chute and deflector are all actuated by the carrier machine's auxiliary hydraulic circuit. |
| Carrier machine | Mounts to a skid steer loader, compact track loader, or multi terrain loader with sufficient auxiliary hydraulic flow. It belongs to the same size tier as the frame it replaced in the lineup, so it needs a mid-to-large frame carrier. |
| Emissions tier | Not applicable — no engine or ECM on the tool itself. |
Weights
| Operating weight | Not independently published for this exact unit. The same size-class successor in this family lists roughly 555 kg (1,220 lb) in one factory sheet edition and about 591 kg (1,303 lb) in a later edition — treat as a same-class reference, not a confirmed figure; verify with your dealer. |
| Shipping weight | Not documented in available sources. |
| Ground pressure | Not applicable — mounted work tool, no ground-bearing undercarriage of its own. |
Dimensions
| Intake / overall width | 2159 mm (85 in) — confirmed directly for this unit. |
| Auger diameter | 457 mm (18 in) — confirmed directly for this unit. |
| Cutting height | 914 mm (36 in) — confirmed directly for this unit. |
| Housing overall width | Approx. 2223 mm (87.5 in) per the same-class successor's factory sheet; not independently confirmed for this exact model. |
| Overall height | Reported as either about 1735 mm (68.3 in) or about 883 mm (35 in) depending on factory-sheet edition for the same-class successor — figures vary by edition/series and are not independently confirmed for this exact unit. |
| Overall length | Approx. 1440 mm (56.7 in) per the same-class successor's factory sheet; not independently confirmed for this exact model. |
| Impeller/fan diameter | Approx. 679 mm (27 in) per the same-class successor's factory sheet; not independently confirmed for this exact model. |
| Impeller/fan width | Approx. 279 mm (11 in) per the same-class successor's factory sheet; not independently confirmed for this exact model. |
Performance
| Chute rotation | 180 degrees, letting snow discharge to the front or either side to keep it off the operator. |
| Maximum throw distance | Approx. 12.2 m (40 ft), per the same-class successor's factory sheet; not independently confirmed for this exact model. |
| Required hydraulic flow | Roughly 68-87 L/min (18-23 gpm) across factory-sheet editions for the same-class successor — varies by edition/series; not independently confirmed for this exact model. |
| Hydraulic operating pressure | Approx. 230 bar (3,340 psi) per the same-class successor's factory sheet; not independently confirmed for this exact model. |
| Gradeability | Not applicable / not published for this work tool. |
Service capacities (summary)
| Fuel tank | None on the tool — no engine of its own. |
| Hydraulic system | No separate onboard reservoir; runs off the carrier machine's hydraulic system and auxiliary flow circuit. |
| Engine oil | Not applicable — no engine. |
| Cooling system | Not applicable — no engine. |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
SR21 fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Drive gearbox (auger/impeller drive train) | Not documented for this exact model in public sources — verify sight-glass/fill-plug level with your dealer or the SEBP3542 manual | Cat literature for this snow-blower work-tool line points to Cat TDTO (Transmission/Drive Train Oil, TO-4 spec) or an equivalent GL-5 gear lubricant for the worm-gear drive case; exact viscosity grade by climate not confirmed for SR21 specifically |
| Grease points (auger shaft bearings, drive linkage, driveline U-joints) | Per standard lubrication interval, not a fill volume | Cat Multipurpose Grease (NLGI 2 lithium-complex EP grease) at all zerk fittings; no climate-split viscosity note documented for this model |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar SR21 maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 50 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the SR21 beyond the schedule
Predictive Maintenance & Fluid Analysis
The SR21 carries no engine oil, coolant, or ECM to monitor — predictive care centers on the auger gearbox and hydraulic interface. Pull a gearbox oil sample each off-season to check for water intrusion and gear-tooth metal fines before they score bearings. Watch discharge-chute chain deflection and impeller-bearing play as early wear indicators. Because hydraulic power comes entirely from the host carrier, also track that machine's hydraulic fluid condition and flow output, since contaminated host fluid or a weak pump shows up first as sluggish auger and chute response on this attachment.
Corrective & Common Repairs
Most SR21 repairs trace to the auger and discharge chute rather than any powerplant. Bent auger flighting or a cracked impeller blade from packed ice or hidden debris throws the rotating assembly out of balance and accelerates bearing wear. Worn or seized coupler and chute chains cause erratic discharge direction; replace both chain and sprockets together. Leaking quick-disconnect couplers or chafed hoses interrupt drive to the auger motor, so inspect fittings each season. A sheared or elongated drive-protection bolt on the auger points to an ice-jam event and warrants a full driveline check.
Overhaul & Rebuild Points
A full SR21 overhaul centers on the auger gearbox, impeller shaft, and chute rotation assembly. Open the gearbox to check gear backlash and tooth wear before it strips under repeated ice-jam shock loads. Replace auger and impeller bearings and seals as matched sets rather than individually, since uneven wear reintroduces vibration. Inspect the frame and quick-attach mounting plate for stress cracking around bolt holes, a common fatigue point on units run hard on municipal routes. Rebuild the chute liner and rotation drive together to restore free 180-degree swing.
Seasonal & Environment Servicing
Because the SR21 has no engine or fuel system, seasonal prep is entirely mechanical and corrosion-focused. Before storage, pressure-wash packed snow and road-salt residue from the auger housing and chute, then coat exposed metal and cylinder rods with rust-preventive oil and grease every fitting. Keep the hydraulic quick-disconnect couplers mated during storage to keep moisture and dirt out of the circuit. Check monthly for corrosion if stored longer than a year. Before the first storm each season, cycle the chute and auger fully and recheck chain tension and gearbox oil condition.
SR21 attachments & work tools
Machine type and role
The SR21 is itself a two-stage snow blower work tool, not a host machine. It mounts to a skid steer loader (or compatible compact loader carrier) rather than accepting its own attachments; compatibility here refers to which carriers and hydraulic setups it needs.
Carrier compatibility
Built for skid steer loader carriers of its era, in line with the wider Cat two-stage snow blower family that spans skid steer loaders, compact track loaders, and compact wheel loaders. Exact period-correct carrier model list is not documented for this legacy unit; confirm quick-attach frame size and hydraulic package with a dealer before pairing to a specific loader.
Coupler/mounting system
Uses a universal skid-steer quick-attach mounting plate, matching the wedge/pin-style frame common to Cat skid steer work tools. Auger and impeller drive lines connect through the carrier's auxiliary hydraulic quick couplers.
Hydraulic arrangement
Runs off the carrier's auxiliary hydraulic circuit, which powers separate auger and impeller/fan motors through an internal flow divider. Exact flow and pressure specs for this specific unit are not documented; comparable current two-stage units in this size class run standard-flow circuits in the roughly 20-plus L/min (GPM) class at a few hundred bar, but this varies by configuration and should be confirmed against the carrier's aux-hydraulic rating.
Size class / capacity
Intake/auger width is about 2159mm (85 in), auger diameter about 457mm (18 in), and cutting/intake height about 914mm (36 in), placing it at the larger end of its legacy lineup alongside its same-era siblings. That width roughly matches the size class of today's largest Cat two-stage skid-steer-mount blowers, but no documented successor lineage ties the SR21 directly to a current model - treat any size comparison as class-level, not a confirmed replacement mapping.
Guarding / overload protection
Drivetrain protection follows the family's standard shear-bolt (shear-pin) arrangement, which lets the auger/impeller gearbox release under an overload rather than transmitting shock load back into the carrier. Adjustable skid shoes set ground clearance for the cutting edge, and a bolt-on reversible cutting edge is standard servicing practice across this product family.
Discharge / chute configuration
Discharge chute rotates on a chain-and-sprocket drive (mechanical cable-free rotation) typical of this Cat product line, with a non-metallic chute liner to resist snow buildup and freeze-up. Side drift cutters help the auger penetrate deep or dense snowbanks before it reaches the impeller.
All SR21 assemblies by section
Every catalogued assembly group for the Caterpillar SR21. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Electrical System
212-4564 Wiring Gp-Work Tool -Deflector Control
| 03***49 | Nut-Self Lock; (No.10.Unc) | 1 |
| 15***53 | Film-Information; (Read Omm) | 1 |
| 21***64 | Wiring Group-Work Tool; -Deflector Control | 1 |
261-4419 Wiring Gp-Work Tool
| 10***67 | Washer-Hard; (7.2x25x2-mm Thk) | 2 |
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 3 |
| 11***15 | Relay As; (12-Volt)(Junction Box) | 2 |
227-5499 Wiring Gp-Work Tool -Electric Power
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 10***06 | Receptacle Kit; (Includes Wedge And Receptacle Assem.) | 1 |
| 11***99 | Gasket; (Air Conditioner Control) | 1 |
263-2115 Wiring Gp-Work Tool
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 10***06 | Receptacle Kit; (Includes Wedge And Receptacle Assem.) | 1 |
| 11***99 | Gasket; (Air Conditioner Control) | 1 |
Frame And Body
214-7117 Deflector Gp-Snowblower -67-In
| 03***55 | Locknut; (5/16-18-Thd)(Marked X) | 6 |
| 13***85 | Rivet-Pop | 7 |
| 1D***72 | Bolt-Carriage; (1/2-13x5.5-In) | 6 |
215-1857 Deflector Gp-Snowblower -73-In, 85-In
| 03***55 | Locknut; (5/16-18-Thd)(Marked X) | 6 |
| 09***43 | Pin-Cotter | 1 |
| 13***85 | Rivet-Pop | 7 |
212-4572 Frame Gp-Snowblower -73-In
| 1K***72 | Locknut Horn To Guard | 12 |
| 21***72 | Frame Group-Snowblower; -73-In | 1 |
| 21***22 | Support Group-Work Tool | 2 |
212-4578 Frame Gp-Snowblower -85-In
| 1K***72 | Locknut Horn To Guard | 13 |
| 21***78 | Frame Group-Snowblower; -85-In | 1 |
| 21***75 | Frame As | 1 |
212-4566 Frame Gp-Snowblower -67-In
| 1K***72 | Locknut Horn To Guard | 10 |
| 21***66 | Frame Group-Snowblower; -67-In | 1 |
| 21***82 | Impeller As | 1 |
213-7222 Support Gp-Work Tool
| 21***22 | Support Group-Work Tool | 1 |
| 28***93 | Tube As | 1 |
| 28***97 | Pad As; (Stabilizer) | 1 |
Hydraulic System
283-9595 Cylinder Gp-Hydraulic
| 28***95 | Cylinder Group-Hydraulic | 1 |
| 4K***77 | Nut-Self Locking | 1 |
| 7J***04 | Seal-O-Ring (Id=7.65mm) | 2 |
213-7190 Cylinder Gp-Hydraulic
| 21***90 | Cylinder Group-Hydraulic | 1 |
| 21***16 | Kit-Seal | 1 |
261-4425 Hydraulic Ar-Snowblower -85-In
| 21***90 | Cylinder Group-Hydraulic | 1 |
| 26***25 | Hydraulic Ar-Snowblower; -85-In | 1 |
| 26***32 | Lines Group-Connecting; -85-In | 1 |
261-4422 Hydraulic Ar-Snowblower -73-In
| 21***90 | Cylinder Group-Hydraulic | 1 |
| 26***22 | Hydraulic Ar-Snowblower; -73-In | 1 |
| 26***31 | Lines Group-Connecting; -73-In | 1 |
212-4573 Hydraulic Ar-Snowblower -73-In
| 21***73 | Hydraulic Ar-Snowblower; -73-In | 1 |
| 21***76 | Manifold Group-Control | 1 |
| 21***90 | Cylinder Group-Hydraulic | 1 |
212-4579 Hydraulic Ar-Snowblower -85-In
| 21***79 | Hydraulic Ar-Snowblower; -85-In | 1 |
| 21***90 | Cylinder Group-Hydraulic | 1 |
| 21***81 | Lines Group-Connecting; -85-In | 1 |
212-4567 Hydraulic Ar-Snowblower -67-In
| 21***67 | Hydraulic Ar-Snowblower; -67-In | 1 |
| 21***76 | Manifold Group-Control | 1 |
| 21***90 | Cylinder Group-Hydraulic | 1 |
214-3515 Lines Gp-Connecting -73-In
| 10***03 | Plate-Cover | 1 |
| 14***15 | Connector As | 4 |
| 14***16 | Connector Group | 1 |
214-9362 Lines Gp-Connecting -67-Inch
| 10***03 | Plate-Cover | 1 |
| 14***15 | Connector As | 4 |
| 14***16 | Connector Group | 1 |
261-4432 Lines Gp-Connecting -85-In
| 10***03 | Plate-Cover | 1 |
| 14***48 | Fitting As; (Quick Disconnect, Male) | 1 |
| 14***49 | Fitting As; (Quick Disconnect, Female) | 1 |
261-4431 Lines Gp-Connecting -73-In
| 10***03 | Plate-Cover | 1 |
| 14***48 | Fitting As; (Quick Disconnect, Male) | 1 |
| 14***49 | Fitting As; (Quick Disconnect, Female) | 1 |
215-2881 Lines Gp-Connecting -85-In
| 03***55 | Locknut; (5/16-18-Thd)(Marked X) | 2 |
| 19***25 | Fitting As; (Quick Disconnect, Female) | 1 |
| 19***26 | Fitting As; (Quick Disconnect, Male) | 1 |
212-4576 Manifold Gp-Control
| 21***76 | Manifold Group-Control | 1 |
| 21***18 | Valve-Solenoid | 4 |
| 21***19 | Solenoid | 4 |
227-5484 Manifold Gp-Control
| 10***08 | Kit-Seal; (Solenoid Valve, Quick Steer) | 1 |
| 19***27 | Kit-Seal; (Pressure Reducing Valve) | 1 |
| 19***95 | Valve Group-Solenoid; (Swing/Extension) | 2 |
261-4435 Manifold Gp-Control
| 19***95 | Valve Group-Solenoid; (Swing/Extension) | 2 |
| 22***87 | Coil | 4 |
| 22***05 | Valve Group-Relief; (Secondary) | 1 |
213-7192 Motor Gp-Gerotor
| 17***46 | Kit-Seal | 1 |
| 21***92 | Motor Group-Gerotor | 1 |
| 22***72 | Key | 1 |
212-4587 Motor Gp-Gerotor -Deflector
| 1B***14 | Key-Woodruff | 1 |
| 1G***32 | Kit-Seal | 1 |
| 21***87 | Motor Group-Gerotor; -Deflector | 1 |
216-0794 Motor Gp-Gerotor -Auger, 85-In
| 17***46 | Kit-Seal | 1 |
| 21***94 | Motor Group-Gerotor; -Auger, 85-In | 1 |
213-7191 Motor Gp-Gerotor -Auger, 73-In
| 17***46 | Kit-Seal | 1 |
| 21***91 | Motor Group-Gerotor; -Auger, 73-In | 1 |
216-0795 Motor Gp-Gerotor
| 17***46 | Kit-Seal | 1 |
| 21***95 | Motor Group-Gerotor | 1 |
| 22***72 | Key | 1 |
227-5496 Motor Gp-Gerotor
| 17***46 | Kit-Seal | 1 |
| 22***96 | Motor Group-Gerotor | 1 |
| 3J***54 | Packing,Preformed Part Of Kit P/N 5r***27 | 1 |
212-4589 Motor Gp-Gerotor
| 17***46 | Kit-Seal | 1 |
| 21***89 | Motor Group-Gerotor | 1 |
| 22***72 | Key | 1 |
212-4588 Motor Gp-Gerotor -Auger, 67-In
| 17***46 | Kit-Seal | 1 |
| 21***88 | Motor Group-Gerotor; -Auger, 67-In | 1 |
7x-4286 Motor Gp-Gerotor
| 09***38 | Plug | 1 |
| 5E***56 | Seal | 4 |
| 5E***59 | Seal | 1 |
227-5510 Motor Gp-Gerotor
| 17***46 | Kit-Seal | 1 |
| 22***10 | Motor Group-Gerotor | 1 |
Service Equipment And Supplies
212-4574 Plate & Film Gp -73-Inch
| 12***56 | Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare) | 1 |
| 15***15 | Plate-Identification | 1 |
| 15***16 | Film-Warning; (Flying Debris, Read Omm)(Auger Debris) | 2 |
261-4423 Plate & Film Gp
| 12***56 | Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare) | 1 |
| 15***62 | Film-Information; (Tie-Down Location) | 2 |
| 22***45 | Film-Warning; (Crush Hazard, Stay Back) | 2 |
261-4426 Plate & Film Gp
| 12***56 | Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare) | 1 |
| 15***62 | Film-Information; (Tie-Down Location) | 2 |
| 22***45 | Film-Warning; (Crush Hazard, Stay Back) | 2 |
212-4568 Plate & Film Gp -67-In
| 12***56 | Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare) | 1 |
| 15***16 | Film-Warning; (Flying Debris, Read Omm)(Auger Debris) | 2 |
| 15***17 | Film-Warning; (Entanglement Hazard, Stay Back)(Auger) | 2 |
212-4580 Plate & Film Gp -85-In
| 12***56 | Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare) | 1 |
| 15***16 | Film-Warning; (Flying Debris, Read Omm)(Auger Debris) | 2 |
| 15***17 | Film-Warning; (Entanglement Hazard, Stay Back)(Auger) | 2 |
Work Tool Arrangement
261-4421 Snowblower Ar -85-In
| 21***78 | Frame Group-Snowblower; -85-In | 1 |
| 26***19 | Wiring Group-Work Tool | 1 |
| 26***21 | Snowblower Ar; -85-In | 1 |
212-4542 Snowblower Ar -73-In
| 21***42 | Snowblower Ar; -73-In | 1 |
| 21***64 | Wiring Group-Work Tool; -Deflector Control | 1 |
| 21***71 | Drive Group-Snowblower; -73-In | 1 |
212-4543 Snowblower Ar -85-In
| 21***43 | Snowblower Ar; -85-In | 1 |
| 21***64 | Wiring Group-Work Tool; -Deflector Control | 1 |
| 21***78 | Frame Group-Snowblower; -85-In | 1 |
212-4541 Snowblower Ar -67-In
| 21***41 | Snowblower Ar; -67-In | 1 |
| 21***64 | Wiring Group-Work Tool; -Deflector Control | 1 |
| 21***65 | Drive Group-Snowblower; -67-In | 1 |
227-5500 Snowblower Ar -67-In
| 21***64 | Wiring Group-Work Tool; -Deflector Control | 1 |
| 21***65 | Drive Group-Snowblower; -67-In | 1 |
| 21***66 | Frame Group-Snowblower; -67-In | 1 |
261-4420 Snowblower Ar -73-In
| 21***72 | Frame Group-Snowblower; -73-In | 1 |
| 26***19 | Wiring Group-Work Tool | 1 |
| 26***20 | Snowblower Ar; -73-In | 1 |
227-5502 Snowblower Ar -85-In
| 21***64 | Wiring Group-Work Tool; -Deflector Control | 1 |
| 21***78 | Frame Group-Snowblower; -85-In | 1 |
| 21***79 | Hydraulic Ar-Snowblower; -85-In | 1 |
227-5501 Snowblower Ar -73-In
| 21***64 | Wiring Group-Work Tool; -Deflector Control | 1 |
| 21***71 | Drive Group-Snowblower; -73-In | 1 |
| 21***72 | Frame Group-Snowblower; -73-In | 1 |
Work Tools
261-4424 Drive Gp-Snowblower -73-In, 85-In
| 02***87 | Fitting-Grease; (Universal Joint) | 1 |
| 1K***72 | Locknut Horn To Guard | 18 |
| 21***44 | Sprocket Group; (16-Teeth, Impeller) | 1 |
212-4571 Drive Gp-Snowblower -73-In
| 02***87 | Fitting-Grease; (Universal Joint) | 4 |
| 1K***72 | Locknut Horn To Guard | 18 |
| 21***44 | Sprocket Group; (16-Teeth, Impeller) | 1 |
212-4565 Drive Gp-Snowblower -67-In
| 02***87 | Fitting-Grease; (Universal Joint) | 4 |
| 1K***72 | Locknut Horn To Guard | 18 |
| 21***44 | Sprocket Group; (16-Teeth, Impeller) | 1 |
216-2293 Drive Gp-Snowblower -85-In
| 02***87 | Fitting-Grease; (Universal Joint) | 4 |
| 1K***72 | Locknut Horn To Guard | 18 |
| 21***44 | Sprocket Group; (16-Teeth, Impeller) | 1 |
SR21 serial number reference
The PIN/serial plate on Cat snow blower attachments is riveted to the main frame or gearbox housing, usually near the mount plate or on the side of the moldboard/auger housing - check the carrier-facing side since the plate can be hidden when the attachment is mounted. Read the first 3 letters as the prefix (identifies model/series) and the digits after as the sequential unit number; there is no engine serial to cross-check since this is a passive hydraulic attachment.
| Prefix | Identifies | Notes |
|---|---|---|
| SBC | SR21 snow blower, base/only documented series | Passive skid-steer/CTL-mounted attachment, hydraulically driven by the carrier; no onboard engine or ECM. Range starts SBC1-UP, with running-change sub-splits seen as SBC1-229 and SBC230-UP for the 85-in width configuration. Shares the SEBP3542 parts manual with sibling SR17 (SBA prefix) and SR18 (SBB prefix), plus SR318/SR321 - SBC is specific to SR21, do not borrow SBA or SBB serials for this model. Distinct from the separate SNB-prefix manual (SEBP5210) that covers SR117/SR118/SR121/SR318/SR321 - SR21 is not part of that line. |
Frequently asked questions
What engine does the Caterpillar SR21 use?
None. The SR21 is a passive work tool with no engine, ECM, or fuel system of its own. It runs entirely on hydraulic power supplied by the host skid-steer or compact loader through auxiliary quick-disconnect couplers, so the relevant engine is whatever carrier it is mounted to, not the attachment itself.
What is the operating weight of the Caterpillar SR21?
Cat did not publish a standalone operating weight for the SR21 in surviving factory literature. Its 2159mm (85in) intake width and 457mm (18in) auger match today's similarly sized model in Cat's current lineup, which lists roughly 590kg (1,300 lb), so treat that as a ballpark estimate and confirm the actual weight on your specific unit before matching it to a carrier's lift capacity.
What replaced the Caterpillar SR21?
Caterpillar never issued a direct one-for-one replacement part number for the SR21. It was the largest unit in a legacy three-model snow blower family built to one factory manual, alongside the smaller SR17 and SR18. Cat's current snow blower lineup carries the same 85in/18in-auger size class forward under a newer model family, alongside larger high-flow units for bigger carriers — a size-class successor line rather than a literal model replacement.
What SR21 owners discuss
What do owners say about matching carrier hydraulic flow to the SR21 two-stage blower?
How do shear bolts on the auger drive typically fail, and what's the right way to handle it?
What chute-rotation and chute-liner wear patterns are common on this class of skid-steer snow blower?
What auger gearbox maintenance issues come up most in the field?
How does the impeller housing and skid/wear-shoe area typically wear on units like the SR21?
What should a buyer check before purchasing a used Cat SR21?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Need a specific SR21 part?
Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.