Catalog

VAG 03H145100C PUMP ASSY - VACUUM

VAG 03H145100C PUMP ASSY - VACUUM
VAG 03H145100C PUMP ASSY - VACUUM
VAG 03H145100C PUMP ASSY - VACUUM
VAG 03H145100C PUMP ASSY - VACUUM

Product Specifications

Product quality
OEM Equivalent Grade
starstarstar
420 sold
Wholesale price USD $30.03
Wholesale price CNY ¥204
bolt MOQ (Minimal order)
50 pcs
local_shipping Production time
45-95 days
package_2 Shipping Weight: 0.55 kg
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VAG 03H145100C
VAG 95511005002
VAG 95511005003
VAG 03H145100B
VAG 03H145100E
Overview & Operating Principle
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The PUMP ASSY - VACUUM is the engine vacuum pump — a mechanically driven positive-displacement pump that generates the sub-atmospheric pressure required to operate the brake booster, vacuum-actuated HVAC control servos, turbocharger wastegate actuators, and other vacuum-dependent systems on diesel engines and on petrol engines whose intake manifold does not provide sufficient natural vacuum for reliable brake booster operation. Unlike petrol engines where the throttle restriction creates substantial intake manifold vacuum at all conditions, diesel engines operate unthrottled and their intake manifolds operate at near-atmospheric pressure; a dedicated vacuum pump is therefore mandatory on every diesel application to supply the brake booster's 0.65–0.80 bar vacuum demand continuously across all engine speeds and load conditions. Most automotive vacuum pumps use a single-vane or tandem-vane rotary sliding vane design: a rotor with one or two radial slots rotates eccentrically within a cylindrical housing; the vane slides in the slot and is held against the housing bore by centrifugal force and a small return spring, creating expanding and contracting chambers as the rotor turns that draw atmospheric air in through the inlet check valve, compress it against the housing bore, and expel it through the outlet check valve; the pump body is typically lubricated by engine oil supplied through a metered oil passage in the pump body, which is essential both for vane and housing bore lubrication and for the oil film that seals the vane tips against the bore to achieve the required vacuum level. On most applications the vacuum pump is driven directly from the camshaft or from a dedicated drive pad on the rear of the camshaft through a coupling that matches the pump's internal rotor geometry.

This unit — VAG 03H145100C — is manufactured to OEM-equivalent specifications: rotor and vane geometry for the required displacement per revolution, housing bore diameter and eccentricity for the correct compression ratio, inlet and outlet check valve opening pressure, oil inlet and outlet port positions and diameter, camshaft drive coupling geometry, pump body dimensions and mounting face for the engine block or head attachment, and vacuum output specification at rated engine speed are matched to the original part. Supplied as a complete pump assembly. Available wholesale from 30.03 USD, MOQ 50 pcs, production lead time 45-95 days.

Vacuum pumps fail through vane wear — the vane's contact face against the housing bore wears from friction, progressively reducing the vane-to-bore contact pressure and allowing compressed air to leak back from the high-pressure side to the low-pressure side, reducing vacuum output; through check valve failure where the inlet or outlet check valve remains partially open and allows the vacuum in the booster line to decay rapidly after the pump stops; through oil supply restriction that starves the vane and bore of lubrication and accelerates wear to the point of vane seizure; and through drive coupling fracture that stops the pump while the engine continues running, producing immediate loss of brake booster assistance.

Symptoms & Diagnostics
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Hard brake pedal — significantly more foot force required to achieve normal braking deceleration — on a diesel or turbocharged petrol engine — the vacuum pump is not supplying sufficient vacuum to the brake booster; the booster relies on the differential pressure between the vacuum chamber and atmosphere to multiply pedal force; insufficient vacuum eliminates this multiplication and the driver must apply the full braking force mechanically; confirm by measuring vacuum at the booster inlet pipe with a vacuum gauge during engine idle — a serviceable pump achieves 0.65–0.80 bar vacuum within 10–15 seconds of startup.
Brake pedal that is normal on the first application after startup but becomes progressively harder on subsequent applications without engine restart — the pump is building vacuum adequately when running but the brake booster is losing vacuum faster than the pump can replenish it; this pattern suggests the pump's check valve is allowing vacuum to decay through the pump when the booster demand between applications exceeds the pump's replenishment rate; confirm by clamping the vacuum hose between the pump and the booster — if the pedal becomes hard immediately when the hose is clamped and the booster is isolated from the pump, the booster is leaking; if the pedal remains normal when the hose is clamped, the pump check valve is leaking.
Oil consumption from the engine combined with blue smoke at idle — on an engine with a vacuum pump that uses engine oil for lubrication — the pump's oil return passage is restricted or the pump body seal has failed, causing oil to be drawn into the vacuum circuit and consumed through the brake booster and into the intake manifold; inspect the vacuum hose between the pump and the booster for oily deposits — oil in the vacuum circuit confirms the pump is passing oil into the vacuum line.
Vacuum pump that produces a grinding or tapping noise — audible as a rhythmic mechanical noise from the pump area that is engine-speed related — the vane has worn sufficiently that it is no longer sealing against the housing bore and is slapping against the bore at low contact pressure; or the drive coupling has partially fractured and is transmitting drive with an impact on every rotation; confirm the noise source by stethoscope applied to the pump body.
Vacuum gauge reading at the pump outlet that is lower than the OEM specification — below 0.60 bar at idle on a confirmed unobstructed vacuum circuit — worn vanes are allowing excessive back-leakage from the discharge side to the suction side, reducing the differential pressure the pump can achieve; a pump that cannot achieve its rated vacuum output at idle despite a confirmed unobstructed outlet will produce progressively worse booster assist as engine speed and pump load increase.
Complete sudden loss of brake booster assist — the pedal becomes hard instantly rather than progressively — the pump drive coupling has fractured, completely stopping the pump while the engine continues running; the booster vacuum that existed at the moment of coupling failure is rapidly consumed by successive brake applications and the pedal becomes progressively harder with each application; confirm by removing the drive coupling access cover and inspecting the coupling for fracture.
Logistics & Customs
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International HS Code
8414.10
EAEU Customs Code (TN VED)
8414 10 290 0
Typical Net Weight
0.55 kg
Country of Manufacture
China
Standard MOQ
50 pcs
Production Lead Time
45-95 days
Always verify the exact 8-digit or 10-digit subheading with your customs broker for the destination country, as tariff schedules and duty rates vary by jurisdiction.
Installation Tips
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  1. Confirm the oil supply passage to the pump is clear and delivering oil before installation — the vacuum pump's vane lubrication depends entirely on the metered oil supply from the engine gallery; a partially blocked oil supply passage starves the vane and bore and reproduces the wear failure that destroyed the original pump within a short operating period; with the pump removed, temporarily cap the outlet port of the oil supply passage and apply compressed air to the inlet — clear the passage with solvent flushing if flow is restricted before mounting the new pump.
  2. Replace the pump-to-camshaft drive coupling simultaneously with the pump — on camshaft-driven pumps the coupling transmits full pump torque at every engine revolution; a coupling that has been worn or stressed by a failing pump may have internal damage that is not visible externally; a partially failed coupling will fracture completely within a short operating period and produce an immediate loss of brake booster assist; the coupling is a low-cost consumable that should always be renewed with the pump.
  3. Ensure the pump body mounting face and the engine block or head mounting face are clean and free of old gasket material — the pump mounts on a precision face that must be flat and clean for the new pump's gasket to seal the oil circuit connections; residual old gasket material creates a raised surface that causes the new gasket to crush unevenly, producing an oil leak at the pump mounting face on the first heat cycle; use a plastic scraper and brake cleaner to clean both faces thoroughly.
  4. Pre-fill the new pump with clean engine oil before installation — the pump's vane and housing bore require an oil film from the first revolution; a dry pump at initial startup creates metal-to-metal contact on the vane tip and housing bore for the seconds before the oil supply is established; pour a small quantity of clean engine oil into the pump through the inlet port and rotate the pump body by hand to distribute the oil over the vane and bore surfaces before mounting.
  5. Torque the pump mounting bolts to OEM specification in a diagonal sequence — the pump body is typically aluminium or cast iron mounting to an aluminium engine head; uneven tightening distorts the pump body and alters the housing bore roundness, affecting the vane-to-bore clearance and reducing pump efficiency from the first startup; typical pump mounting bolt torque is 10–20 Nm.
  6. Install the new PUMP ASSY - VACUUM (VAG 03H145100C), connect the vacuum hose and oil supply, start the engine and immediately measure vacuum at the booster inlet with a vacuum gauge — confirm the pump achieves the OEM minimum vacuum within 15 seconds at idle; apply the brakes 3–5 times in rapid succession and confirm the pedal remains firm confirming the check valve is retaining vacuum between applications; inspect the pump mounting for oil leaks after a 10-minute warm idle before returning the vehicle to service.
Tools: vacuum gauge for output specification verification, compressed air for oil supply passage testing, plastic scraper for mounting face cleaning, torque wrench (10–20 Nm), clean engine oil for pump pre-filling, new pump gasket and drive coupling.
Frequently Asked Questions
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How can the vacuum pump be confirmed as the source of reduced brake booster assistance before it is removed for replacement?
The in-situ test uses a vacuum gauge connected to the brake booster's vacuum inlet hose. At idle after a cold start, monitor the vacuum reading as the pump builds from atmospheric pressure — a serviceable pump on a diesel engine should achieve 0.65 bar within 10–15 seconds. Pump output at the rated engine idle speed below 0.60 bar confirms inadequate pump delivery. Second, with the engine running at idle and confirmed adequate vacuum, perform 5 rapid brake applications in quick succession while monitoring the vacuum gauge — the gauge should recover to above 0.55 bar within 2–3 seconds after each application; slow recovery confirms the pump flow rate is insufficient for the booster demand. Third, switch off the engine and monitor vacuum decay over 30 minutes — the gauge should not drop more than 0.05 bar; rapid decay without brake applications confirms a check valve leak in the pump or booster. These three tests distinguish pump output failure, pump flow rate insufficiency, and check valve failure without removing any component. ok.parts supplies vacuum pumps at wholesale MOQ from 30.03 USD per unit.
Does engine oil quality and change interval affect vacuum pump service life?
Engine oil quality is the primary determinant of vacuum pump vane service life — the pump relies entirely on the engine's pressurised oil circuit for vane lubrication, and any factor that reduces oil quality or oil pressure reduces the lubricant film between the vane tip and the housing bore. Degraded oil that has lost its anti-wear additive package from extended service intervals allows metal-to-metal contact at the vane tip on every revolution, accelerating wear at a rate proportional to engine speed. Soot-contaminated oil from a diesel with a partially regenerating DPF increases oil abrasiveness, further accelerating vane wear. Maintaining the OEM oil change interval and using the correct viscosity grade specified for the engine typically allows vacuum pump service lives of 150,000–250,000 km; engines with consistently extended oil change intervals show vacuum pump wear at 60,000–80,000 km from the same abrasive mechanisms that accelerate engine bearing wear.
How does the OEM-equivalent aftermarket unit compare to the genuine OEM part?
OEM-equivalent units in this catalogue replicate the current OEM design geometry and material specification. Quality is verified against OEM cross-reference data. When ordering in bulk, confirm with our team that the specification matches the latest OEM revision for your application.
Is white-label or custom packaging available for wholesale orders?
Yes. ok.parts works directly with the manufacturing facility and can accommodate neutral white-label packaging or fully branded packaging with your company logo, part numbers, and barcode. Minimum order quantities and lead times for custom packaging may differ from standard stock. Contact the team via the inquiry form to discuss your specific requirements.
Frequently Replaced Together
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PartReason for Combined Replacement
Vacuum Pump Drive Coupling
Camshaft or auxiliary drive coupling — application-specific		The drive coupling is a sacrificial component that transmits the pump's full operating torque at every engine revolution and absorbs the torsional shock loads from pump vane engagement and check valve pressure transients. A coupling that has been transmitting drive to a failing pump — whose increasing vane drag creates higher-than-rated torque demand — will have accumulated fatigue damage in the coupling material. Replace the coupling simultaneously with every pump replacement to ensure the new pump receives smooth, shock-free drive from its first revolution.
Brake Booster
OEM ref. varies by vehicle		A vacuum pump that has been delivering oil into the vacuum circuit from a failed pump body seal will have contaminated the brake booster's internal diaphragm with oil. A diaphragm that has been soaked in engine oil degrades from the oil's plasticiser extraction of the diaphragm rubber, causing the diaphragm to crack and fail within a short period after the pump is replaced and the oil supply to the booster is stopped. Inspect the booster's vacuum inlet for oil deposits; if oil contamination is confirmed, replace the booster simultaneously with the pump.
Engine Oil and Filter
Grade and specification per OEM requirement		A vacuum pump that has failed from vane wear has been shedding iron particles from the vane contact face into the engine oil circuit — the pump oil inlet draws from the engine gallery and the pump oil outlet returns to the sump; metallic wear particles from the pump circulate through the engine and reach all bearing surfaces. Perform a complete engine oil and filter change simultaneously with vacuum pump replacement to remove the accumulated metallic contamination from the oil circuit before it reaches other precision-tolerance engine components.