How to check a replacement parts supplier before your first order

Most first orders go wrong for a boring reason. The buyer compared prices, picked the cheapest quote that looked credible, and never asked who actually makes the part.

We sit on the selling side of this table, so take the following with that in mind. But every check below is one a buyer can run in a week, mostly for free, before wiring money. We would rather a distributor did them and bought from us because of the answers than bought blind and left after one bad shipment.

1. Find out who makes the part

Ask the salesperson, in plain words: does your company produce this item, or buy it? Then ask what machine runs the part, and what the production lead time is from their own line.

A factory answers with specifics. Injection moulding, a certain number of cavities per cycle, a curing time for the rubber, a line that runs this SKU every second week. A reseller answers with lead times in weeks and never mentions equipment, because they are waiting on someone else to tell them.

A video call is more useful than a video. Ask them to walk the phone to the warehouse shelf holding your SKU and hold up a carton. It takes two minutes and settles the question faster than any certificate. If a supplier refuses, or keeps postponing, you have your answer.

2. Run the business license, not the website

Every Chinese company has a unified social credit code. Ask for it, then look the company up on the national credit system (gsxt.gov.cn). You are checking four things:

• Does the registered name match the name on the quotation, the proforma invoice and the bank account? Mismatches are the single most common sign of a middleman using someone else's paperwork.
• Is manufacturing in the business scope? A company registered for trading and import/export is not a factory, whatever the website says.
• How old is it? A two-year-old company can be excellent, but it has no track record with your market. Someone who has shipped to Germany for eight years has already met your compliance questions.
• Is it in the right city? Replacement parts for appliances cluster in Shenzhen, Dongguan, Ningbo and Cixi. A "factory" registered in an office district three provinces away from where the goods ship is worth a second question.

3. Read the catalog for depth, not breadth

A specialist lists 40 filters for 12 vacuum brands and knows the difference between a Gen 1 and a Gen 2 housing. A trader lists 5,000 SKUs across phone cases, LED strips and vacuum filters, all photographed in the same white light.

Breadth is easy to fake. Depth is not. Pick the SKU closest to your own product and test their knowledge: ask which models it fits, what changed between model years, and what the part does not fit. The answer tells you whether you are dealing with someone who has the part on a shelf or someone reading a listing.

4. Make them commit in writing

Vague reassurance is free. Commitments cost something, which is why they are worth asking for. A short table of what to look for:

5. Buy samples with your own money

Two or three SKUs is enough. Pay the sample price, pay the freight, and treat it as a test of the whole pipeline, not just the product. Then do this when the box arrives:

• Measure with calipers. Not against the listing photo, against the original part you took off a machine.
• Fit it. A filter that needs force, or a gasket that needs trimming, is a return waiting to happen.
• Weigh it. A part that is 20% lighter than the original usually has less material in the places that matter.
• Check the packaging. If the carton cannot survive a courier, it will not survive a container.

Note how the samples were packed and labelled, and whether the paperwork matches what was promised. The sample shipment is a small rehearsal of the real one.

6. Ask for a report from a batch that already shipped

Anyone can send a certificate for a type test done once in 2023. Ask for the QC record of a batch that went to another customer last month: dimensions measured, function tested, who signed it. Then ask for photos of the cartons before they were sealed.

If the answer is a PDF with no batch number and no date, you have learned something useful. A supplier who tests every batch keeps those records, because they are the only defence when a customer claims a fault.

7. Sort out payment before you discuss price

Price is the last thing to negotiate, because a 4% discount is meaningless if the terms put your money at risk. Check these first:

• Whose account is on the invoice? Company account with the same name as the license, or a personal account. The second is a warning, not a convenience.
• What is the deposit? 30% deposit and 70% before shipment is normal for replacement parts. 100% upfront on a first order is not.
• Will they take a trade assurance or escrow payment on the first order, even at a small fee?
• Do they issue a proper proforma invoice with HS code, unit price, carton dimensions and gross weight? You need all of it for freight and customs anyway.

Red flags worth walking away from

• A price 40% under everyone else, explained only by "we are the factory".
• Willingness to print any brand on the product and the box, no questions asked.
• No physical address, or an address that turns out to be a residential building.
• A quote that changes after samples are approved.
• Technical questions answered with links to the listing you already read.

A supplier who survives these seven checks is not automatically right for you. Fit, lead time and communication style still have to work. But you will at least be negotiating with the party that makes the part, and that usually decides whether the second order is easier than the first.

If you want to run these checks on us: pick two or three SKUs from our product range, order samples, and ask for the QC record of the last batch we shipped. Details are on the wholesale page, or message the number at the top of this page.