LUK Website & Shop FAQ: Control Arm Bushings, Flowmaster 71229, and Davico Catalytic Converters

Every week the same questions show up through the LUK website and the LUK shop: Is this bushing right for my control arm? Does the Flowmaster FlowFX 71229 actually fit? Can I trust those Davico catalytic converter reviews? I've handled OEM and aftermarket parts orders for eight years, and I've personally made (and documented) 14 significant mistakes — roughly $31,000 in wasted budget. That's why I maintain the pre-order checklist we now use for every customer order. Here are the questions people ask most, in the order I learned the answers the hard way.

1. What's the difference between the LUK website and the LUK shop?

The LUK website is the full catalog: product specs, dimensional drawings, material data, all of it. The LUK shop is the ordering portal for distributors, jobbers, and qualified repair shops — you need a registered account, and that's where trade pricing lives.

The mistake I see most often is ordering through a third-party aggregator that re-lists our part numbers with wrong supersessions. I did it myself in 2018: compared "compatible with" listings until I ordered a control arm that was one generation off. The mounting ears were about 6 mm farther apart, which I discovered only after opening the box. Return shipping on a control arm is brutal (and not the phone call you want to make to your customer). Our rule now: if the part number on the LUK website doesn't match the number stamped on the original part, send a photo before ordering.

One more thing: as an IATF 16949-certified plant, we provide PPAP documentation with every production order. That means dimensions and materials are traceable and verifiable. If you're sourcing stamped parts from a new supplier and they don't offer the same, that's worth asking about.

2. How do I choose control arm bushings without getting it wrong?

Don't choose by photo. All bushings look the same in a thumbnail. What matters is inner sleeve OD, outer sleeve OD, overall height, and rubber durometer. Measure the sleeve bore and bolt diameter with a caliper, not a tape measure.

In my first year (2019), I made the classic rookie error: ordered bushings with a 12 mm inner sleeve for a control arm that used a 14 mm bolt. $450 in returns plus an awkward phone call. The drawing said 12, the arm said 14, and I'd verified neither. If the part specification references ASTM D2000, that's a good sign — it's the standard classification for rubber compounds in automotive applications, covering durometer and heat resistance. Stock-type rubber is typically 50–70 Shore A; polyurethane is 80–95 Shore A. If someone sells you "premium performance bushings" and can't tell you the durometer, that's a red flag.

3. Is the Flowmaster FlowFX 71229 a direct fit?

Not really — and to be fair, Flowmaster doesn't claim it is. The FlowFX 71229 is a universal muffler with 2.5-inch center inlet and center outlet, built from 409 stainless steel, which is standard exhaust-grade material. We stamp exhaust shells and heat shields at our plant, so I know what goes into making one. But I can't speak to Flowmaster's internal tuning targets — that's their engineering territory.

Here's where the "it doesn't fit / sounds awful" reviews come from: people who didn't measure anything before ordering. Check your existing pipe diameter (if your truck has 2.25-inch pipes, a 2.5-inch muffler means adapters and more places to leak). Check the shell length against the actual space between your hangers. And confirm your inlet/outlet orientation — center/center is common, but it's not what every vehicle has. Universal means you do the fitting. When the measurements are right, a 409 stainless universal muffler is a perfectly reasonable buy. When they're not, it's an adapter kit and a weekend of swearing.

4. How should I read Davico catalytic converter reviews?

The same way you read any part review: ignore the star count and look at what the reviewer actually installed. Davico makes budget-friendly direct-fit and weld-in converters. Useful reviews mention O2 sensor bung locations, flange flatness, and whether the supplied gasket matched the application. One-line "fits great, check engine light went away" reviews are better than nothing, but not by much.

Also check emissions compliance before you buy: is the converter EPA-approved, and does your state follow California's emissions rules? A federal-only converter may not be street-legal everywhere. I'm not an emissions lawyer, and I won't pretend otherwise, but I've seen a customer install a federal-only converter on a California-registered truck, fail smog, and blame the manufacturer. The converter wasn't the problem; the missed check was. Review paragraphs won't tell you that, because most reviewers aren't asking the right question in the first place.

5. Why do new control arm bushings groan after a few hundred miles?

Because somebody tightened the bolts while the suspension was hanging. That's the number one cause of early bushing failure, and I say that with full authority because I did it on my own car in 2021 — in my driveway, with my neighbor watching. If the control arm is at full droop, the bushing gets pre-loaded the moment the car sits back on its wheels.

Torque the bushing bolts at ride height. Wheels on the ground, or on an alignment rack. Always.

The second thing worth knowing: some newer vehicles don't have replaceable bushings at all. Bonded and hydraulic bushings are showing up on late-model platforms, and the control arm gets serviced as one unit. That's a genuine shift in the past few years — what was the right answer in 2020 (press out the old bushing, press in a fresh one) may not apply anymore. Check the service documentation before you order bushings, or you'll be buying something you never needed. We field that question in the LUK shop at least once a week.

6. Are aftermarket parts as good as OEM in 2025?

Depends on the supplier, and I'm not saying that to be diplomatic. In 2020 my answer was "buy OEM unless the part is discontinued." The aftermarket has honestly closed a lot of the gap since then, mainly because aftermarket brands now use the same kind of tooling — progressive dies, CNC machining, aluminum extrusion — that OEM suppliers have used for years. What was best practice in 2020 may simply be outdated in 2025.

But the fundamentals haven't changed: geometry, material certification, and drawing tolerances matter more than the logo on the box. I do not trust a listing that says "compatible with" and nothing else. I trust a listing that includes a dimensional drawing and material data (ASTM A1008 for cold-rolled stamped parts, as one example). That's not over-engineering. That's the difference between knowing what you're buying and hoping.

7. What's the one question almost nobody asks before ordering?

"Can I see the drawing?" We put dimensional drawings on every parts page of the LUK website, and maybe one in ten customers actually opens the PDF. That one step would have saved me most of the $31,000 in documented mistakes I started with: the wrong sleeve size, the misread part number, the "same specification" that was not the same specification.

If a seller won't share a drawing — not a photo, an actual drawing with tolerances — treat that as the answer. It applies to bushings, control arms, mufflers, converters, everything. A photo can't show you a 1 mm flange offset. A drawing can. Ask for the drawing first.