A Compressor Is Four Separate Purchase Decisions — Bus Air Conditioning Compressors, Clutches, Seals and Internals

1. Why This Page Is Organised by Layer, Not by Product

When a bus air-conditioning compressor stops working, the first question a workshop asks is not *which compressor do I buy* — it is which layer has failed. Those are different questions and they lead to different parts, different prices and different downtime.

A compressor is not one item. It is an assembly with three peripheral layers: something drives it (the clutch), something keeps the refrigerant inside it (the shaft seal), and inside it there are parts that wear (valve, connecting rod, crankshaft). Treating all four as one purchase is how a workshop ends up replacing a whole compressor when a seal would have done the job.

This page is the index for that whole assembly. Each layer has its own working page; the index below maps every part number we carry onto the layer it belongs to.

2. Layer 1 — The Compressor Assembly

We carry renewed and refurbished compressors across four platforms: the Bitzer 4-series (4NFCY / 4PFCY / 4TFCY), GEA / BOCK FK40 in 655K, 560K and 470K, BOCK FKX40, and the Carrier 05G six-cylinder unit.

Two things separate these platforms in practice: how many cylinders and how much displacement the unit carries, and which refrigerant and drive arrangement the vehicle uses. All of the units on this page are stated by the manufacturer as R134a and 24 V, which is the standard configuration for bus air conditioning in this class.

3. Layer 2 — The Drive Side: Magnetic Clutches

A clutch is the part that decides whether the compressor turns. It is also the part that is most often bought by the wrong dimension, because it has two independent interfaces: an electrical one (the coil) and a mechanical one (the pulley and its groove).

Our clutch range covers 260/210 mm 2A2b, 260 × 216 mm, and 226/197 mm 2A2B groove forms, at 24 V with coil power from 60 W upward. Groove designations in this range are written 2A2B / 2A-2B / 2A+2B — the manufacturer does not use PK notation on these listings.

4. Layer 3 — The Sealing Side: Shaft Seals and Kits

The shaft seal is where a compressor normally leaks first, and where the repair is cheapest. We hold four references: 80023 for BOCK FK40 / FK50 and FKX40 4N / 4P / 4T, 37403604 for the Bitzer 4-series, and 22-1101 and 22-1103 for Thermo King X426 and X430.

Some of these references are sold as a single seal and some as a kit — the 80023 kit listing is identified as a BOCK shaft seal, and the 37403604 kit contents are stated as ring, seal, gasket, spring and screw. Knowing which one you are buying matters: a kit restores the joint, a single seal replaces one component.

5. Layer 4 — The Internals

When the damage is inside the crankcase rather than at the shaft, the compressor can often still be rebuilt. The three parts we carry for that job are the 08082 shut-off valve for GEA BOCK FK40, the FK40 560 / 655 piston and connecting rod, and the FK40 655K crankshaft.

These are the parts that justify rebuilding rather than replacing: the housing and the drive end usually survive, and the cost of a rebuild sits in a small number of internal components.

6. Model and Reference Index

Every part number on this page, mapped onto the layer and the platform it belongs to. Quote the number in the first column and we will confirm the platform before dispatch.

Layer 1 — renewed Bitzer 4-series bus air compressor (4NFCY / 4PFCY / 4TFCY).

Layer 1 — refurbished BOCK FKX40 / FK40 unit, 655K / 560K / 470K variants.

Layer 2 — 260/210 2A2b magnetic clutch, 24 V, for FKX40 and the 4-series.

Layer 3 — shaft seal 80023 for BOCK FK40 / FK50 and FKX40 4N / 4P / 4T.

Layer 4 — 08082 shut-off valve for GEA BOCK FK40.

7. How to Order From This Index

1. Identify the layer first. A compressor that will not engage is a clutch question, not a compressor question.

2. Then quote the part number from the index — 80023, 37403604, R-05G-41-TRAILER, 18-00097-07 — or send a photograph of the plate on your old unit.

3. Tell us the platform if you know it: Bitzer 4-series, GEA / BOCK FK40, BOCK FKX40 or Carrier 05G.

4. We confirm the reference before dispatch and reply within 24 hours.

Q1. Which layer should I start with when the air conditioning stops cooling?

Check whether the clutch engages first. If the compressor does not turn, no amount of refrigerant will help and the part you need is in layer 2. If it turns but does not cool, the fault is downstream — refrigerant charge, condenser or expansion valve.

Q2. Are these genuine Bitzer, BOCK or Carrier parts?

No. These are renewed and refurbished units and replacement parts manufactured by WEILI, cross-referenced to the original numbers so you can order by the number on the unit you are replacing.

Q3. Do you sell the whole compressor or only parts?

Both. Layer 1 is complete compressors; layers 2, 3 and 4 are the clutch, seal and internal parts that let you repair rather than replace.

Q4. Which refrigerants do these units use?

The manufacturer states R134a for the Bitzer 4-series and for the GEA / BOCK FK40 range on this page.

Q5. What warranty applies?

1 year across this range.

8. Quality System and Certification

This part is produced under the same quality system that covers our entire bus and truck air-conditioning range, and the system is independently certified rather than self-declared.

What this means when you buy: the inspection regime is auditable and the test data can be provided to you, so the acceptance criteria are something you can verify rather than take on trust.

9. Certification File: Numbers, Issuers and Validity

Buyers who need to put a certificate in a quality file should not have to accept a claim without a number. Every approval the factory holds is listed below with its own certificate number, issuing body, validity date and, where one was issued, the test report number behind it.

Which certificate applies to which product. The IATF 16949 registration and the ECE E57 type approval are held by the manufacturing company for the plant. The CE, RoHS, Low Voltage/EMC and ECE R10 approvals are held for the brushless fan range; each certificate names the models it covers. Ask for the certificate PDF for the reference you are buying and check it against its own model list.

IATF 16949:2016 registration certificate 126765/A/0001/SM/En — valid to 05 June 2026.

ECE type approval E57*COP*1682, Republic of San Marino — valid to 14/05/2026.

CE / EMC certificate TBC-C-202308-0315-1 — test report TBR-C-202308-0315-1.

RoHS declaration TBC-C-202308-0315-2 — test report TBR-C-202308-0315-2.

Low Voltage / EMC certificate M.2024.206.C110335 — valid to 25.11.2029.

10. Manufacturing Base and Capacity

Production is vertical enough to control the parts that cause most field failures, and the partner network is large enough to absorb seasonal peaks without pushing lead times out.

• Experience — more than 15 years in bus and truck air-conditioning parts.
• Plant — Xiangtan Economic and Technological Development Zone, Hunan Province, China. 80+ employees across 5,000 – 10,000 m².
• Scale and reach — annual sales of over 90 million yuan, an annual output of more than 800,000 units, and exports to more than 50 countries.
• Processes held in-house — motor winding, injection moulding, stamping, and final assembly with testing. The whole chain from a coil to a finished assembly is inside the company, not sub-contracted.
• Elastic capacity — 68 collaborating plants form a flexible supply chain, which is how a peak-season ramp-up or a large order is absorbed without renegotiating the schedule.
• Track record — on Alibaba.com for more than 12 years as a Gold Supplier, store rating 4.7 / 5, on-time delivery rate 91.2%.
• Communication — average response time ≤ 3 hours, timely reply rate 99.07%, and roughly 52% of enquiries answered within five minutes. Workday enquiries are answered the same day, with staff on rotation for time-zone markets.
• Recognised status — a Hunan provincial high-technology enterprise, and platform-rated as a leading factory in air-conditioning systems.

Come and look. A factory visit or audit can be arranged — the address and line access are open to buyers who want to verify capacity before committing to a programme.

11. Inside the Plant: Production Line, Equipment and Warehouse

These are photographs of the plant that builds the part on this page — the shop floor, the winding line, the assembly stations and the warehouse the goods leave from. Nothing here is a stock image, and a factory visit or audit can be arranged if you want to walk the line yourself.

The plant in the Xiangtan Economic and Technological Development Zone, Hunan Province, China.

Assembly line — blower and fan assemblies built and inspected at the bench.

In-house motor winding — stators wound on an automatic winding machine.

Production line — components staged at the stations along the line.

Finished-goods warehouse — export cartons staged for dispatch.

Brand wall and the on-site certificate and reference display at the plant.

Come and see it. The address and line access are open to buyers who want to verify capacity, equipment and quality control before committing to a programme. Ask us to arrange a visit, or send your own or a third-party inspector (SGS, BV or TÜV) — pre-shipment inspection to a standard you nominate is part of the process, not an exception.

12. Order Quantity and Lead Time

Two numbers decide whether a replacement part is worth stocking: the smallest quantity you can order without tying up capital, and how long the goods take to leave the factory. Both are published on the corresponding Alibaba.com listing and reproduced below.

Minimum order quantity (MOQ). Standard catalogue items start from as few as 1 – 2 pieces (some blowers from 1 piece, condenser fans from 2 pieces); batch items are typically 6 – 50 pieces; customised items depend on the tooling and process involved. Small-batch trial orders are welcome — the usual route is to test the quality on a small order and scale up once it is proven.

Lead time. Production time is the interval between an order being confirmed and the goods being ready for dispatch. Where the official listing publishes a figure for the reference you need, it is reproduced in the table on this page; the exact figure for your quantity is confirmed on the quotation.

Quote your quantity and we confirm both figures in writing. Order quantity, production time and shipping method are confirmed with the quotation, so nothing depends on an assumption about your volume.

As published on the official listing for each reference above. Production time is the period stated to produce the goods before dispatch; the exact figure for your quantity is confirmed on the quotation.

13. Replacement Coverage and Customer Base

Matching is done on evidence, not on a guess, because a fan or blower that is 10 mm out will not seal and a clutch that is one groove form out will not drive.

Cross-referenced coverage runs across SPAL, Valeo, Thermo King, Webasto, Scania, Yutong, DAF, Mercedes, Volvo and Hwasung Thermo. Where a match cannot be confirmed, the risk is stated up front and a sample is proposed for verification instead.

We supply wholesalers and repair chains in multiple countries, with the Middle East, South America, South East Asia and Eastern Europe as the principal export regions. Long-term partners receive dedicated account service, priority production scheduling and tiered rebates.

14. OEM / ODM and Customisation Process

Four routes cover practically every aftermarket customisation request, from a private label on a part we already build to a component that does not exist yet.

How the project runs: requirement collection, then solution confirmation against your sample or OE dimensions, then sample production (approximately 30 days for standard sample-based work; brand-new tooling depends on mould complexity), then mass production with 40 – 60 days stocking after the sample is approved. A pre-production sample is supplied for your inspection before the batch starts.

Tooling and fees: small changes such as silk-screen, labels or harness length are usually free or carry only a small revision fee. New tooling carries a mould cost, which is refundable or amortised once the agreed order volume is reached. Customised minimum order quantities depend on the tooling and process involved.

15. Buyer FAQ

Q1. Brushed or brushless — which should I stock?

Brushed motors use carbon-brush commutation: proven, economic and easy to maintain, typically 1,000 – 3,000 hours of life, suited to price-sensitive replacement demand. Brushless motors use electronic commutation with no brush wear and reach 10,000 hours or more, with higher efficiency, lower heat and less noise — better for long-running, high-temperature or new-energy vehicles. Both are produced here.

Q2. Why are bus and truck parts mostly 24 V?

Bus and truck electrical systems carry more equipment over longer harness runs, so 24 V reduces the current for the same power, which allows thinner cable and cuts losses and heat. Passenger cars are mainly 12 V. That is why the product range is predominantly 24 V, with 12 V / 24 V universal references covering passenger cars.

Q3. Why is an aftermarket replacement cheaper than a genuine part?

The difference comes from brand premium and channel mark-up on the genuine side, and a shorter route to market on the replacement side. A properly made replacement is matched on material and tested to the same duty, so performance meets the application — which is why it is worth checking for an audited factory and available test data rather than buying on price alone.

Q4. What should I send to avoid a mismatched part?

The most reliable inputs are: the OE number, the brand and model reference, or photographs of the old part together with measurements. Any one of those resolves the fitment in most cases. If a match cannot be confirmed, we will say so rather than ship on an assumption.

Q5. Can you supply test data for the part I am buying?

Yes — component testing covers dynamic balance, electrical performance, high and low temperature, and endurance life on in-house instruments, and the test data can be provided to support your quality file.

Which Layer Do You Need?

Hunan Weili Auto Parts Appliance Co., Ltd. — founded in 2007, ISO 9001 & IATF 16949 certified manufacturer of bus & truck AC parts, electric fans, blowers, lighting and alternator components.

Send us the layer you are working on — or simply the number stamped on the failed part — and we will confirm the reference against your platform within 24 hours.

WhatsApp / WeChat: +86-18670382782 | Landline: +86-0731-82034997 / 82034998

E-Mail: [email protected] | Websites: www.cooliparts.com | www.weilipart.com | www.weiliautomotive.com

Send us your OEM part number, vehicle model or drawing — we will reply within 24 hours with a quotation and technical data sheet.