{"id":3441,"date":"2026-09-23T11:56:44","date_gmt":"2026-09-23T03:56:44","guid":{"rendered":"http:\/\/www.ibericastonegroup.com\/blog\/?p=3441"},"modified":"2026-09-23T11:56:44","modified_gmt":"2026-09-23T03:56:44","slug":"what-materials-are-other-hydraulic-parts-usually-made-of-4f3b-ca82e6","status":"publish","type":"post","link":"http:\/\/www.ibericastonegroup.com\/blog\/2026\/09\/23\/what-materials-are-other-hydraulic-parts-usually-made-of-4f3b-ca82e6\/","title":{"rendered":"What materials are other hydraulic parts usually made of?"},"content":{"rendered":"

If you\u2019ve ever had a hydraulic system down, you know it\u2019s not just the big, obvious parts\u2014like pumps or cylinders\u2014that matter. It\u2019s all the tiny, easy-to-overlook stuff that keeps everything moving. I\u2019ve been sourcing and selling those \u201cother hydraulic parts\u201d for years, and one question I get nonstop is: what the hell are these things even made of? Not just the basic cast iron you\u2019d expect from a pump, but the random stuff\u2014valve sleeves, O-rings, filter housings, line connectors\u2014that make up 80% of a hydraulic setup. Let me break this down like I would over a coffee with a new guy in the shop, no fancy jargon, just the real stuff we actually use and why. Other Hydraulic Parts<\/a><\/p>\n

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First off, let\u2019s get clear on what \u201cother hydraulic parts\u201d even means here. When a customer calls for parts for their tractor, their factory stamping press, or their construction crane, they might name a cylinder or a pump, but then ask for \u201call the rest.\u201d That includes things like valve spool sleeves, quick-disconnect couplings, filter end caps, pressure gauge adapters, check valve poppets, and the O-rings\/seals that stop leaks. These parts have way more stress than people think: they\u2019re exposed to high pressure, corrosive hydraulic fluid, temperature swings from 0\u00b0F in a Minnesota winter to 120\u00b0F in a Texas summer, and constant friction from moving parts. So their material isn\u2019t just random\u2014it\u2019s chosen for exactly the abuse each part takes.<\/p>\n

Let\u2019s start with the most common one: cast iron. Not the old, crumbly cast iron your grandpa\u2019s lawnmower had, but ductile cast iron, also called nodular cast iron. Why? Because it\u2019s strong, cheap, and takes machining like a dream. We use this for stuff that needs to hold pressure but doesn\u2019t spin or move much under friction\u2014like filter housings, valve bodies, and big coupling nuts. I once had a guy call me panicking because his farm\u2019s hay baler filter housing cracked in the cold. Ductile cast iron would\u2019ve fixed that, because regular cast iron is brittle and shatters when it drops below freezing, but ductile has those little carbon nodules that bend a tiny bit instead of breaking. That\u2019s the stuff we stock 50 units of at all times.<\/p>\n

Next up, steel\u2014specifically, carbon steel and alloy steel, but not the kind you use for a nail. For parts that need to slide or spin, like valve spools and check valve stems, we use cold-drawn carbon steel, usually 1018 or 1045 grade. Wait, but why not ductile cast iron? Because steel has higher tensile strength and resists wear better when it\u2019s moving against another metal. 1018 is soft enough to machine quickly, so it\u2019s perfect for the small, tight spools that sit inside hydraulic valves. If you need something even tougher for high-pressure lines or heavy-duty couplings, we go with alloy steel, like 4140. That one gets heat-treated, so it\u2019s basically unbreakable for stuff that takes constant torque\u2014like the quick-disconnects you plug and unhook every day on a concrete pump. Don\u2019t get me wrong, it\u2019s pricier, but if you\u2019re replacing couplings every month because they snap, you\u2019ll pay the difference in downtime.<\/p>\n

Now, let\u2019s talk about the parts that actually touch the fluid the whole time: seals, O-rings, gaskets. This is where it gets specific, and picking the wrong material is a quick ticket to leaks. The most common we use is Buna-N, or nitrile rubber. Why? It\u2019s cheap, works great with standard petroleum-based hydraulic fluid, handles temperatures from -40\u00b0F to 250\u00b0F, and seals like a champ. 9 out of 10 small farm machines or light industrial setups use Buna-N O-rings. But here\u2019s the catch: if you\u2019re working with synthetic hydraulic fluid, or operating in super high heat (like metal stamping presses that get up to 300\u00b0F), Buna-N melts or swells. For that, we switch to Viton, which is fluoropolymer rubber. Viton is way more chemical-resistant, handles temps up to 400\u00b0F, and doesn\u2019t break down in synthetic fluids. We also carry EPDM for things that work with water-glycol fluids\u2014common in food processing, where petroleum-based fluid isn\u2019t allowed. EPDM holds up great there, but don\u2019t put it in standard hydraulic fluid, it\u2019ll turn to mush. And for the super cold stuff? Like Arctic drilling equipment or snow plows in Alaska? We use silicone O-rings, which stay flexible down to -100\u00b0F, though they only top out around 450\u00b0F, so they\u2019re only for low-heat, frigid jobs.<\/p>\n

Then there\u2019s the stuff that stops gunk from getting into the system: hydraulic filters. The housing? Usually either polypropylene or aluminum, depending on the size. Small inline filters for tractors are polypropylene\u2014super light, cheap, and corrosion-resistant. Big high-flow filters for factory machinery are aluminum, because it can handle way higher pressure, and it\u2019s easy to machine to fit custom setups. The filter media itself is a whole other thing, but that\u2019s not what we\u2019re talking about here, so I\u2019ll stick to the housing. Oh, and the small clips and retainers that hold filters in place? Most are stamped steel, sometimes zinc-plated to stop rust. Easy, cheap, works for their job.<\/p>\n

Wait, I can\u2019t forget about parts that need to resist corrosion like crazy. If you\u2019re on a boat crane or a coastal construction site, salt air will eat through regular steel in months. So we use stainless steel for those parts. Usually 304 or 316 grade. 304 is the common one\u2014holds up to salt water and moisture, works for valve adapters and small couplings. 316 is even better for harsh environments, handles more acid in the hydraulic fluid sometimes, and we use it for anything that\u2019s exposed outside, like line connectors on dock equipment. Yeah, it\u2019s more expensive, but when you don\u2019t have to replace parts every 6 months because of rust, it\u2019s worth it.<\/p>\n

I also get questions about the little stuff, like pressure gauge ports or thread inserts. Those are usually brass or bronze. Brass is soft, so it doesn\u2019t scratch gauge threads, and it\u2019s corrosion-resistant enough for most indoor setups. Bronze is harder, so we use it for bushing inserts in moving parts that get a lot of friction\u2014like the little pivots on hydraulic control levers. Bronze wears way better than steel when it\u2019s rubbing against another metal or even a little grit in the fluid. I had a guy last year whose excavator lever seized up because the brass bushing wore out\u2014swapped it, and he was back to digging in 10 minutes. No joke, that\u2019s the kind of part that people don\u2019t think about until it\u2019s broken.<\/p>\n

A lot of people ask if we use any fancy plastics, and the answer is sometimes, but only for specific, low-stress parts. Like the knobs on hydraulic control valves, or the covers over pressure gauges. Those are usually ABS plastic\u2014cheap, easy to mold, light, and they don\u2019t conduct cold or hot like metal would, so they\u2019re easier to grip in extreme temps. We never use plastic for anything that\u2019s under high pressure, though. Plastic cracks, doesn\u2019t hold up, and if it breaks, it can contaminate the whole hydraulic system with plastic shavings. That\u2019s a nightmare\u2014you have to flush the whole system, replace the pump, replace the cylinders, way more expensive than just using metal.<\/p>\n

Now, here\u2019s the thing I always tell new customers: the material isn\u2019t just about strength or resistance. It\u2019s about matching the part to the job. You don\u2019t put a Viton O-ring in a standard tractor hydraulic system and pay twice as much, and you don\u2019t put a Buna-N O-ring in a 300\u00b0F metal stamping press and have it leak all over the floor. That\u2019s why as a supplier, we don\u2019t just sell \u201cgeneric hydraulic parts\u201d\u2014we ask you what your system uses, what fluid you run, what temperature it operates at, and then hook you up with the right material. We also stock backups for every common part, so if your pump breaks at 2 a.m. on a job site, you can grab the valve adapter or seal you need to get back up and running.<\/p>\n

I\u2019ve been in this game for 12 years, and I\u2019ve seen every mistake. A customer once used a regular cast iron housing instead of ductile, and it shattered during a freeze. Another used EPDM seals in a synthetic fluid, and they swelled up so bad the valve seized. That\u2019s why knowing materials isn\u2019t just a nerd fact\u2014it\u2019s money in your pocket, and keeping your machine from being down for days.<\/p>\n

<\/p>\n

At the end of the day, all those \u201cother hydraulic parts\u201d aren\u2019t afterthoughts. They\u2019re the glue that holds the whole system together, and their material is the reason they work when you need them to. If you\u2019re rebuilding a hydraulic system, replacing a worn part, or just need to make sure you have spares for your fleet, hit us up to talk. We don\u2019t do one-size-fits-all here\u2014we figure out exactly what you need, with the right material, at a price that doesn\u2019t make you cringe.<\/p>\n

Mixer Truck Pivot Arm Assy<\/a> References:
\nHydraulic Component Materials. (n.d.). Fluid Power Technology Association.
\nMaterial Selection Guide for Industrial Hydraulic Parts. (2021). American Society of Mechanical Engineers.
\nRubber Elastomer Compatibility for Hydraulic Fluids. (2019). Society of Tribologists and Lubrication Engineers.<\/p>\n

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Quanzhou Kinnid Auto Parts Co., Ltd.<\/a>
We are one of the most professional hydraulic parts manufacturers and suppliers in China, featured by quality products and good service. Please rest assured to wholesale premium hydraulic parts in stock here from our factory. Contact us for more details.
Address: No.73, Xiameixi Road, Binjiang industrial Park, Xiamei Town, Nan’an County, Quanzhou City, Fujian, China. 362302
E-mail: colin@kinnid.com
WebSite: https:\/\/www.kinnid.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

If you\u2019ve ever had a hydraulic system down, you know it\u2019s not just the big, obvious … What materials are other hydraulic parts usually made of?<\/span>Read more<\/a><\/p>\n","protected":false},"author":952,"featured_media":3441,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3404],"class_list":["post-3441","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-other-hydraulic-parts-49d5-cb9feb"],"_links":{"self":[{"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/posts\/3441","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/users\/952"}],"replies":[{"embeddable":true,"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/comments?post=3441"}],"version-history":[{"count":0,"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/posts\/3441\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/posts\/3441"}],"wp:attachment":[{"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/media?parent=3441"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/categories?post=3441"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.ibericastonegroup.com\/blog\/wp-json\/wp\/v2\/tags?post=3441"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}