GENERAL MOTORS 26079917 GEAR ASSY POWER
Product Specifications
| GENERAL MOTORS | 26079917 |
The GEAR ASSY POWER is the complete rack and pinion steering gear assembly that converts the rotational input of the steering column into the lateral linear displacement of the steering rack that moves the front wheels through the tie rod ends and steering knuckles, either with hydraulic power assistance provided by a belt-driven pump forcing fluid against the rack piston, or with electric power assistance provided by a torque-sensor-controlled motor acting on the rack or pinion shaft directly. The assembly consists of a precision-machined rack shaft with helical teeth that engage a pinion gear on the steering column input shaft, housed in an aluminium gear housing with integral mounting points for subframe attachment; the rack shaft travels laterally within the housing on PTFE-lined bushings, preloaded by an adjustable yoke spring that eliminates backlash between the rack and pinion teeth while allowing smooth rack travel; and inner tie rod ball joints threaded onto the rack ends that transfer rack motion to the tie rods. On hydraulic power steering racks a double-acting hydraulic cylinder integral to the housing acts on a piston on the rack shaft, with the hydraulic circuit controlled by a rotary valve on the pinion shaft that directs fluid pressure to the appropriate cylinder chamber in proportion to steering torque input. On electric power steering (EPS) racks an electric motor drives the rack through a ball screw or drives the pinion through a worm gear, with steering effort calibrated continuously by the EPS module from the torque sensor signal and vehicle speed.
This unit — GENERAL MOTORS 26079917 — is manufactured to OEM-equivalent specifications: rack travel, pinion gear ratio, housing mounting geometry and subframe bolt pattern, inner tie rod thread size and torque specification, hydraulic port positions and thread sizes on hydraulic units, EPS motor connector pinout and torque sensor characteristics on electric units, and overall assembly dimensions for subframe fitment are matched to the original part. Supplied as a complete assembly ready for installation. Available wholesale from 97.33 USD, MOQ 20 pcs, production lead time 40-50 days.
Steering racks fail through inner tie rod ball joint wear producing steering play and a clunking noise on directional changes, hydraulic cylinder piston seal wear causing fluid bypass that reduces or eliminates power assistance, rack shaft surface wear from abrasive contamination after gaiter failure, and pinion bearing wear causing roughness or notchiness through the straight-ahead position. On EPS racks, motor bearing failure, torque sensor failure, and EPS control module faults are the primary electrical failure modes. Rack replacement is a significant labour operation requiring subframe disturbance on many modern vehicles — always confirm the rack is the fault source by verifying inner tie rod play and hydraulic pressure or EPS motor operation before committing to replacement.
- Centre the steering rack before disconnecting the steering column universal joint — count the full lock-to-lock turns of the steering wheel, divide by two, and position the rack precisely at the centre of its travel; mark the steering column shaft and universal joint yoke with a paint pen to confirm correct re-engagement; a rack installed off-centre causes the steering wheel to sit at an angle at straight-ahead and limits the available lock in one direction, requiring immediate realignment.
- On hydraulic racks, cap all hydraulic ports immediately after disconnecting the supply and return lines — use dedicated port blanking caps to prevent fluid loss and atmospheric contamination of the rack's internal hydraulic circuit; drain the power steering reservoir before removing the lines to minimise spillage; dispose of drained fluid correctly as power steering fluid is a combustion hazard on hot exhaust surfaces.
- Transfer the inner tie rod ends and lock washers to the new rack using an inner tie rod tool — never use an open-ended spanner or improvised tool as this rounds the flats and damages the inner tie rod body; count the exact number of turns to remove each inner tie rod and thread the replacement to the same position on the new rack to preserve the approximate tie rod length for the alignment technician.
- Torque the rack mounting bolts to OEM specification in the correct sequence — on subframe-mounted racks the mounting sequence affects the rack's final position relative to the subframe; an incorrect sequence can stress the rack housing and distort the yoke preload, producing a tight spot that was not present on the old unit; always follow the OEM torquing sequence from the service data.
- On hydraulic racks, fill and bleed the power steering system before starting the engine — fill the reservoir to the cold maximum level, start the engine, turn the steering slowly lock-to-lock three times with the front wheels off the ground, top up the reservoir as the air purges, and confirm fluid level stabilises and no aeration foam is visible before lowering the vehicle; operating a hydraulic rack with air in the system causes pump cavitation damage within minutes.
- Install the new GEAR ASSY POWER (GENERAL MOTORS 26079917), torque all fasteners and tie rod nuts to OEM specification, drive to a wheel alignment shop immediately for a four-wheel alignment — rack replacement changes toe, caster, and on some designs camber — confirm the steering wheel is centred at straight-ahead and all alignment angles are within OEM specification before returning the vehicle to service; on EPS racks perform a steering angle sensor calibration via scan tool after alignment.
| Part | Reason for Combined Replacement |
|---|---|
| Outer Tie Rod Ends Left and right, OEM ref. varies | The outer tie rod ends are removed as part of the rack replacement procedure and are fully accessible at this point. On vehicles where the rack has failed from high mileage, the outer tie rod ends have accumulated the same wear and are at the same wear stage as the inner tie rods. Replacing all four tie rod joints — inner and outer, both sides — simultaneously during rack replacement restores the complete steering linkage to new condition and eliminates all articulation play as a source of future steering complaints. |
| Rack Gaiter / Boot Kit Left and right bellows and clamps | On racks supplied without gaiters, always fit new gaiters before installing the rack. A gaiter failure that allowed road contamination into the rack was the root cause of the original rack failure on most high-mileage replacements — the abrasive contamination scored the rack shaft and accelerated rack bushing and seal wear. Fitting new gaiters on the replacement rack protects the new unit from the same failure mode and ensures the grease fill is retained for the rack's full service life. |
| Power Steering Fluid OEM specification — ATF or dedicated PS fluid | Hydraulic rack replacement requires draining the power steering circuit and refilling with fresh fluid. Old fluid with depleted anti-wear additives and increased acidity accelerates wear of the new rack's hydraulic seals and piston bore. Always refill with fresh fluid of the OEM-specified type — ATF and dedicated power steering fluid are not interchangeable on vehicles specifying a specific fluid type; using the wrong fluid causes immediate seal swell and hydraulic circuit contamination. |