Catalog › Hydraulic and pneumatic seals › Rod seals
Hydraulic Seals, Rod Seals and Wipers — by Kastaş Profile Code
Rod and piston seals, rod seals, wipers, guide rings and back-up rings. Over 5,290 sizes in stock across K21, K06, K22, K23, K33 and other Kastaş profiles.
No single part seals a hydraulic cylinder on its own. On the rod side, the rod seal and gland seal; on the piston side, the piston seal; against the outside, the wiper (dust wiper); the load-bearing guide ring; and the back-up ring that supports the seal from behind at high pressure — all work together. During an overhaul the entire set is usually replaced; replacing only the leaking part often brings the same failure back within a short time.
At Kastaş, every profile has a code: K21, K06, K22, K23, K33 and so on. Ordering requires two pieces of information: the profile code and three dimensions. Dimensions are always written as three numbers — for example K21-040/11 (40 × 50 × 8): two diameters and a height.
The order of the dimensions also tells you where the part fits. If the numbers increase (40 × 50), the part goes onto the rod; if they decrease (63 × 51), it fits onto the piston. In our stock this distinction holds consistently by code: K21, K22, K06, K33, K68 and K37 are rod-side; K23, K18, K69 and K17 are piston-side.
The material is written at the end of the code. PU (polyurethane) is the most wear-resistant option and the standard choice in mobile hydraulics; NBR is an economical solution for mineral-oil systems; FKM (Viton) is for high temperatures and aggressive fluids. The same profile is often stocked in both PU and NBR versions — half of the 1,223 sizes in the K21 family are PU.
If you don't know the profile code, that's not a problem: a photo of the removed part along with the rod diameter, bore diameter and height is enough. Take the measurement from a cleaned, unstretched part, preferably with a caliper; a seal that has been under pressure can deform permanently, so a visual estimate can be misleading.
Brands and series
Kastaş 4,944 products
Series pages are in Turkish; product codes are the same in every language.
Brands and standards in stock
Profile codes in stock
| Profile | Fits on | Sizes in stock | Example item |
|---|---|---|---|
| K21Rod seal — piston gland seal | Rod | 1,223 sizes | K21-008/5 PU · 8 × 14 × 4 |
| K22Rod seal | Rod | 399 sizes | K22-030/1 PU · 30 × 40 × 6 |
| K06Wiper (dust wiper) | Rod | 342 sizes | K06-040 PU · 40 × 48 × 7/5 |
| K23Piston seal | Piston | 328 sizes | K23-014/1 · 14 × 8 × 4,5 |
| K33Gland seal (rod seal) | Rod | 294 sizes | K33-040 PU · 40 × 50 × 10 |
| K68Rod guide ring (guide ring) | Rod | 198 sizes | K68-040/1 · 40 × 44 × 9,5 |
| K37Rod seal | Rod | 197 sizes | K37-006 · 6 × 14 × 6,5 |
| K18Compact piston seal | Piston | 166 sizes | K18 063-051 · 63 × 51 × 20,5 |
| K38Rod seal | Rod | 151 sizes | K38-045 PU · 45 × 53 × 5,8 |
| K69Piston guide ring (guide ring) | Piston | 150 sizes | K69-035/6 · 35 × 30 × 5,4 |
| K09Wiper | Rod | 124 sizes | K09-025 · 25 × 33 × 7/4 |
| K27Double-lip wiper | Rod | 113 sizes | K27-036 · 36 × 44 × 7/5 |
| K01Rod sealing kit | Rod | 106 sizes | K01-080 · 80 × 95 × 22,5 |
| KBT / KPB / KSBGuide ring (bronze-PTFE, polyester, phenolic) | Rod and piston | 63 sizes | KBT-2,5×20 · bronz-teflon |
| K14V-ring (A / S / L type) | Rod | 25 sizes | K14-020 A · A tipi |
| K19Double-acting compact piston seal | Piston | 5 sizes | K19 075-060 · 75 × 60 × 11 |
| K707Back-up ring | Behind the seal | 3 sizes | K707 · 17,5 × 20 × 1,3 |
| K94Wiper (dust wiper) | Rod | 2 sizes | K94-060 · 60 × 70 × 6,3/10 |
The "Fitting location" column is read from the order of the dimensions: a size that increases from inner diameter to outer diameter is rod-side, one that decreases from outer diameter to inner diameter is piston-side. We checked this distinction against the Kastaş catalog and it held for every code in the table. The function column is also taken from the Kastaş catalog; it was left blank for codes where we could not find a match in the catalog. The table lists the profiles we stock the most of; we also source the other profiles in the Kastaş catalog.
Frequently asked questions
What is K21 and where is it used?
K21 is Kastaş's rod seal profile code and the largest sealing family in our stock — we carry 1,223 different sizes. Because its dimensions increase from the inner diameter to the outer diameter (e.g. K21-040/11 · 40 × 50 × 8), it fits onto the rod. It is available in PU, NBR and FKM.
What information do I need to provide to order a seal?
The profile code and three dimensions: inner diameter, outer diameter and height. If you know the code (e.g. K06-040 PU), that alone is enough — we look up the matching dimensions from the code. If you don't have the code, send the three dimensions and a photo of the part.
Which should I choose: PU, NBR or FKM?
PU (polyurethane) is the most wear-resistant; it is the standard choice for high-pressure applications and mobile machinery. NBR is economical and sufficient for mineral-oil systems at normal temperatures. FKM (Viton) is used where there is continuous high temperature, or contact with fuel or chemicals.
I don't know the profile code — how do you find the right seal?
Send a clear photo of the removed part along with its three dimensions. The profile's cross-section (rod seal, U-profile, wiper, guide ring) can be identified from the photo, and the dimensions point us to the matching item in stock. When measuring a used part, keep in mind it may be deformed — if possible, also measure the cylinder's rod and bore diameter.
Can I just replace the leaking seal on its own?
You can, but it often doesn't last long. The leak is usually caused by a worn guide ring letting the rod run off-center, or a wiper letting dust through; in that case the new seal wears out just as fast. Since the cylinder is already disassembled, replacing the entire set is also cheaper in terms of labor.
Get a quote for Rod seals
Send us the size and quantity you need and our sales team will get back to you the same day with pricing and lead time. If you're not sure of the size, a photo of the part you have is enough.
