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For owners of the 2008-2010 Hummer H3 Alpha with the OEM V8 (5.3L), the power steering pump assembly represents a key component in the hydraulic steering system. The factory part, GM 25932020 (which supersedes earlier numbers 20810993 and original 15867424), integrates the pump with the reservoir and provides the necessary pressure for assisted steering. As of January 2026, this assembly has become unavailable through standard channels after an exhaustive search across GM dealers, major aftermarket suppliers, online marketplaces like eBay and Amazon, and junkyards where matching components prove difficult to source reliably. Many owners face this reality as a preemptive maintenance concern rather than an immediate failure, since the part shows as discontinued on GM parts sites and is often listed as a special order with no stock or long delays. Addressing this situation now helps prepare for eventual needs and explores practical paths forward.

The core issue stems from GM’s discontinuation of the 25932020 assembly, leaving no direct new OEM replacements readily available. Searches on official GM parts portals confirm the part’s status as discontinued, with supersessions leading to the same unavailable endpoint. Community discussions on Hummer enthusiast forums frequently highlight similar challenges, including scarcity of the integrated reservoir and complaints about aftermarket options like Cardone units, which some owners report as less durable. This scarcity affects only the Alpha V8 models, as non-Alpha H3 variants use different pumps. Preemptive planning becomes essential to avoid downtime when symptoms like whining, stiff steering, or leaks eventually appear.

One explored alternative involves the power steering pump from the 2012 Chevy Silverado 2500HD (6.0L models), which has been referenced in some Hummer forum threads as a potential cross-reference with adaptations. This pump often requires a new high-pressure line due to its outlet positioning on top rather than downward like the OEM H3 Alpha unit. Additional modifications might include adjustments to hoses or fittings to ensure proper routing and sealing. While this swap has seen some discussion and limited real-world application in the community, it remains untested personally and would demand verification of fitment, pressure output, and compatibility with the Alpha’s steering gear. Photos of the 2500 pump alongside the OEM can illustrate the orientation differences that drive these extra steps.

A more promising direction centers on the Fifth Generation 2010-2015 Camaro LS power steering pump, which stands out because its high-pressure outlet faces downward—matching the OEM H3 Alpha orientation closely. This alignment eliminates the need for a replacement high-pressure line, simplifying the swap considerably. Required adaptations would include a low-pressure return hose, a remote reservoir tank to replace the integrated factory one, and a custom mounting bracket. Designing such a bracket offers an interesting opportunity to tailor the fit precisely while maintaining proper alignment and belt tension. Side-by-side images of the Camaro LS pump and the OEM unit highlight these advantages in outlet placement and potential mounting similarities. As with any cross-application, full compatibility testing would be required before implementation.

Rebuild options provide another avenue for those preferring to retain or refurbish existing components. Several seal kits appear viable based on part comparisons and community notes. The GM Genuine Parts Power Steering Pump Seal Kit 15825938 stands as a strong contender for an OEM-level rebuild, offering comprehensive seals for the pump internals. Aftermarket options include the eBay kit at https://www.ebay.com/itm/227094389191 (compatibility uncertain and worth double-checking against specs), the eBay kit at https://www.ebay.com/itm/324211167329 (possible fit based on listings), and the RockAuto Sunsong 8401612 kit (seals-focused but lacks the bearing/seal, which could pair with a National 221820 shaft seal for completeness). Images of these kits, along with two OEM pump photos and a system diagram, help visualize the components involved in a rebuild process.

The Universal Mount Bottom Outlet GM Type II Pump with Reservoir (HP1 Series) SKU: 001-601670-0 from Turn One Steering (product link: https://turnonesteering.com/product/universal-mount-bottom-outlet-gm-type-ii-pump-with-reservoir-hp1/) serves as a high-performance upgrade option built on a true GM Type II core with modified internals for better efficiency, including reduced fluid temperatures and lower horsepower consumption compared to stock pumps. It features a bottom-oriented high-pressure outlet to improve hose routing and clearance in tight accessory drive layouts, an integral baffled reservoir suitable for top or side mounting, a lightweight aluminum housing, 1500 PSI pressure capacity, 3.0 gpm flow rate, and GM Metric O-Ring Pressure Fitting, Stock GM Slip-Fit Reservoir Return Connection, Threaded Mounting Pads, with all components new, hand-built in the USA, and dyno-tested. Priced around $550 (with occasional discounts), this pump suits a wide range of applications like race cars, restomods, hot rods, or performance swaps on LS-based engines (including truck accessories), and its universal mount design with threaded pads suggests it could potentially bolt in more directly to setups like the H3 Alpha’s 5.3L V8 accessory drive—especially given the matching bottom outlet orientation that aligns with the OEM H3 Alpha pump’s downward high-pressure port. Clearance for the integral reservoir, pulley alignment (it accepts common billet pulleys like 6 3/8″ Corvette-style, though not included standard), belt tension, and any minor bracket adjustments would be the primary considerations during installation, as custom mounting elements may still apply in non-standard bays. This makes it a compelling aftermarket choice for H3 Alpha owners seeking a reliable, pre-built performance replacement that preserves steering feel without excessive parasitic drag, though verifying exact bolt pattern compatibility and required non interference with engine bay against the factory GM 12567922 bracket remains advisable before proceeding.

Several related components tie into the power steering system and warrant attention during any repair or swap. The power steering pump assembly (GM 25932020) generates hydraulic pressure and originally includes the integrated reservoir for fluid storage. The pulley presses onto the pump shaft to transfer drive from the serpentine belt, which itself forms part of the accessory drive system and requires proper tensioning. High-pressure lines route pressurized fluid from the pump outlet to the steering gear, while low-pressure return hoses carry fluid back to the reservoir or inlet. A remote reservoir becomes necessary in adaptations like the Camaro swap, and GM-spec amber power steering fluid remains recommended to avoid compatibility issues noted in service bulletins. Seals and bearings (addressed in the kits above) prevent leaks at shafts and interfaces, ensuring long-term reliability.

Here is a short list of vehicles that share/use the same power steering pump bracket (GM part 12567922, described as a multi-purpose bracket for generator/alternator & power steering pump, including spacer). This is compiled from verified GM parts sources, dealer catalogs, and eBay/OEM listings for this exact part number—focusing on applications where it mounts the PS pump (often alongside the alternator) on GM’s Gen III/IV small-block V8 engines (primarily 4.8L, 5.3L, 6.0L variants).

• Chevrolet Silverado / GMC Sierra (various 1500/2500/3500 series, 2003-2021): Commonly fits 4.8L, 5.3L, and 6.0L V8 engines; used on gas models for PS pump and alternator mounting.
• Chevrolet Tahoe / GMC Yukon / Yukon XL (2003-2014+): Applies to 4.8L, 5.3L, and 6.0L V8 applications; bracket supports PS pump in these full-size SUVs.
• Chevrolet Suburban / GMC Yukon XL (2003-2014+): Same as above for 5.3L and 6.0L engines.
• Chevrolet Express / GMC Savana vans (2003-2020+): Fits 4.8L, 5.3L, 6.0L gas engines; multi-purpose bracket for auxiliary components including PS pump.
• Hummer H3 Alpha (2008-2010, 5.3L V8): Compatible with this bracket for PS pump mounting (ties into your vehicle context; shares the LS-based 5.3L setup).
• Other GM trucks/SUVs with 5.3L/6.0L (general 2003-2020 range): Includes select Cadillac Escalade, Chevrolet Avalanche, etc., where the 5.3L or 6.0L V8 uses this style bracket for PS pump and generator positioning.

Here an updated and expanded list for all the parts related to the power steering (PS) pump system on the 2008-2010 Hummer H3 Alpha (5.3L V8 models).

• GM 25932020 (supersedes 20810993 and original 15867424) — Power Steering Pump Assembly Complete OEM hydraulic power steering pump with integrated reservoir; generates pressurized fluid for steering assist; discontinued and currently unavailable new through GM channels after exhaustive searches.
• GM 19417110 (supersedes numbers like 20933947, 25960637, 25891150) — Hose & Tube Assembly (Power Steering Gear Inlet & Outlet) Combined high-pressure inlet/outlet hose and tube from pump to steering gear; handles fluid delivery and return for the 5.3L setup; fits H3/H3T Alpha models; often discontinued but key for routing in the PS circuit.
• GM 12605507 — Power Steering Pump Pulley Press-fit pulley for the 5.3L engine; mounts directly to the pump shaft to transfer drive from the serpentine belt; essential for pump operation and reusable in swaps if shaft matches.
• GM 11515758 — Multi-Purpose Bolt (M8x1.25×30) Hex-head bolt used to secure components like the power steering pump, front cover, or related brackets; versatile fastener with built-in washer face; common in mounting the pump assembly on LS-based 5.3L engines.
• GM 12567922 — Bracket Assembly, Generator & Power Steering Pump Mounting bracket that supports both the alternator and power steering pump (includes spacer); positions the pump correctly for belt alignment and tension; fits various 5.3L/6.0L applications including H3 Alpha equivalents.
• GM 25851373 — Power Steering Fluid Reservoir Kit Replacement reservoir kit for fluid storage, filtration, and return; useful in adaptations requiring a remote reservoir (e.g., Camaro LS swap) where the integrated OEM one is removed.
• GM 15825938 — Power Steering Pump Seal Kit (Genuine GM) Full OEM seal rebuild kit for pump internals; includes seals for shafts, O-rings, and fittings to restore leak-free performance; strong option for refurbishing donor or existing pumps.
• National 221820 (or GM-equivalent shaft seal) — Power Steering Pump Shaft Seal Input shaft seal preventing fluid leaks at the drive end; pairs with partial seal kits (e.g., Sunsong equivalents) for complete rebuilds.
• Serpentine Accessory Drive Belt (GM OEM belt for 5.3L V8) — Drive Belt for Power Steering Pump Multi-rib belt powering the PS pump pulley alongside other accessories; check tension and condition during pump work or swaps.
• Low-Pressure/Return Power Steering Hose (GM OEM or adaptable) — Power Steering Return Hose Low-pressure line returning fluid from steering gear to reservoir/inlet; adaptable in remote setups or cross-swaps.
• Power Steering Reservoir Cap (GM OEM, often with reservoir kits) — Power Steering Reservoir Cap Seals the reservoir to prevent contamination and maintain system integrity; needed in remote reservoir conversions.
• GM-Spec Power Steering Fluid (amber-colored, per GM specifications) — Power Steering Fluid Factory-recommended fluid for viscosity, lubrication, and seal compatibility; use for refills, flushes, or post-repair bleeding.

These parts integrate into the H3 Alpha’s PS hydraulic system: the pump (25932020) pressurizes fluid, the pulley (12605507) drives it via the belt, the bracket (12567922) and bolts (11515758) mount it securely, hoses like 19417110 route pressurized/low-pressure fluid to/from the steering gear, and the reservoir (25851373 or integrated) stores/conditions it. For swaps (e.g., 2012 Camaro LS or 2500HD), components like the remote reservoir, custom brackets, and hose adaptations become critical.

With ingenuity and creative solutions, the power steering pump challenges for the H3 Alpha can and will be resolved. Among the most straightforward paths forward stands the Universal Mount Bottom Outlet GM Type II Pump with Reservoir (HP1 Series) from Turn One Steering, which aligns closely with the OEM’s bottom-outlet design and could prove one of the easiest fixes for preemptive replacement—potentially a near-direct bolt-in with only minor clearance considerations for the integral reservoir, pulley alignment, belt tension, or accessory drive spacing in the H3 engine bay. This hand-built, USA-made unit starts from a true GM Type II core with upgraded internals for improved efficiency, reduced fluid temperatures, lower horsepower draw, 1500 PSI pressure, and 3.0 gpm flow, while including a lightweight aluminum housing, baffled reservoir for top/side mounting, and compatibility with common billet pulleys (though not included standard). Enthusiasts continue to share findings on forums and in communities, contributing to collective knowledge on viable paths like this performance-oriented option that preserves steering feel without excessive parasitic losses. H3 Alpha owners with experience sourcing pumps, attempting swaps, succeeding with rebuilds, or exploring aftermarket solutions such as Turn One products are encouraged to share details, part numbers, photos, or installation notes in the comments below—this ongoing exchange highlights thoughtful adaptations that keep these vehicles operational and resilient.