Seal Materials by Brand: Vickers, Denison, Oilgear, Rexroth, Char-Lynn

Every hydraulic manufacturer hides the seal material in a different place. Vickers puts it in an option field on the pump model code. Denison gives it a digit. Oilgear puts it only on the shaft seal part number. Rexroth assigns it a fixed position in the model code. Char-Lynn does not put it in the code at all, and uses separate kit numbers instead.

This page is the decoder for all of them, with what each brand actually offered from the factory. If you need to know which material to choose in the first place, start with the hydraulic seal materials guide.

What each brand actually offered

Brand Buna-N Viton EPDM or EPR PTFE Where the material is coded
Vickers and Eaton Yes, standard Yes, F3 No, not on the V series No Option field in the pump model code
Denison and Parker Denison Yes, class 1 Yes, class 5 Yes, class 4 No Seal class digit, and a part number suffix
Oilgear Yes, -7 Yes, -5 Yes, -9 Yes, -3B Shaft seal part number suffix
Bosch Rexroth Yes, P Yes, V, standard No No Position 08 of the model code
Char-Lynn and Eaton Yes, standard Yes, separate kit numbers No No Not in the model code. Kit number only.
Parker Yes, standard Yes, on the Denison lines Yes, on the Denison lines No Follows the Denison scheme
Sundstrand and Sauer-Danfoss Yes, standard Not cataloged No No No material option. Date code drives the part number.
Kawasaki Yes, standard Not cataloged No No No material option

Read that table one way and it is a buying guide. Only two of these manufacturers, Denison and Oilgear, ever published a factory EPDM or EPR kit. If your machine runs aviation Skydrol and the pump is anything else, there is no catalog number to order and the set has to be built to the dimensions on the pump's own bill of material. We do that work, but you should know in advance that it is a build and not a shelf item.

Vickers and Eaton

Vickers uses an option field in the pump model code. Blank, shown as two dashes, is Buna-N. F3 is Viton. A V20F is simply the Viton build of a V20, and the F carries through onto the kit number.

Model code option Material Example V20 family seal kits
-- (blank) Buna-N, the standard build 02-137555, 02-137557
F3 Viton (FKM) 02-137556, 02-137558

F3 is not the Skydrol kit. This is the most common and most expensive mistake on a Vickers pump. Because F3 is the only alternative material on the Vickers price list, people order it for phosphate ester service and assume it is the special fluid option. On aviation Skydrol, Viton is rated only Poor. Vickers never cataloged an EPDM option for the V series at all. The one exception is the PVX series, where genuine Skydrol kits exist under part numbers HC206052064000, HC206062064000 and HC206072064001. On industrial fire resistant fluid such as Fyrquel or Reolube, the F3 kit is genuinely correct and no custom build is needed. Confirm which fluid you have first.

Denison and Parker Denison

Denison has the most complete material range of any brand we handle, and it is the only one of them that published all three of Buna-N, EPDM and Viton as ordinary catalog options. The material is numbered twice, which catches people out.

Seal class Material In the model code On the part number
S1 Buna-N 1 No suffix, or -0
S4 EPDM, for phosphate ester and water glycol 4 -4
S5 Viton, for high temperature and aggressive fluids 5 -5

So a part number with no suffix is the Buna-N version, and only EPDM and Viton carry one. The same scheme covers the T6 and T7 vane pumps and the Gold Cup piston range, and it continues on Parker branded Denison product, because Parker kept the Denison coding when it acquired the line.

Oilgear

Oilgear puts the material on the shaft seal part number as a suffix, and it is the widest factory choice of any brand here, four materials rather than the usual two.

Suffix Material Use
-7 Buna-N The standard build
-5 Viton High temperature
-9 EPR (ethylene propylene) Skydrol and phosphate ester
-3B Teflon (PTFE) Phosphate ester, and extreme temperature

The base number in front of the suffix is the frame size, so the two together give you the whole part. The same shaft seal spans the PVM and PVG lines at a given frame.

Base number Frame Covers
51154 A PVM-011, PVM-014, PVM-022, PVWH 04, 06, 10
51155 B PVM-025 through PVM-075, PVG-048 through PVG-075
51156 C PVM-064 through PVM-130, PVG-100 and PVG-130

Putting the two together, 51154-9 is the A frame shaft seal in EPR, the correct part for a small PVM on phosphate ester. Oilgear also published a complete parallel EPR set beyond the shaft seal, covering cover plates, SAE A and AA adaptors, the rotation conversion plug and the maximum volume stop, so a full Skydrol conversion on an Oilgear pump can be done entirely with factory part numbers. No other brand in our catalog can say that.

Bosch Rexroth

Rexroth assigns the sealing material a fixed slot in the model code. On the A10VSO series 31 it is position 08, and there are two values.

Position 08 Material Rated to Cold start from
V FKM (Viton), the standard build +110 C at the case drain port -25 C
P NBR (Buna-N) +85 C at the case drain port -40 C

The interesting part is what Rexroth says about when to use the NBR version. It is not the budget option. Rexroth specifies P only for HFA, HFB and HFC water containing fluids, ordered together with the E version at position 01. In other words, on a Rexroth pump running water glycol, nitrile is the correct material and the fluorocarbon build is the wrong one. Rexroth also excludes Skydrol from the pump entirely, whichever seal you order.

These numbers come from Rexroth data sheet RE 92711 for the A10VSO series 31. Other Rexroth families use the same idea, though the position number varies, so check the data sheet for your exact model.

Char-Lynn and Eaton orbital motors

Char-Lynn is the exception on this page, because the material is not in the motor code anywhere. The middle four digits of a Char-Lynn number do not select the seal kit. Only the family and the design code do that, and the material is then a separate kit part number.

Char-Lynn published Viton versions of many of its seal kits under their own distinct numbers, so the material choice is real, you just cannot read it off the motor. The practical route is to identify the family and design code from the motor, then pick the Buna-N or Viton kit for that combination.

Sundstrand, Kawasaki and the brands with no material option

Not every manufacturer gave you a choice. Sundstrand and Sauer-Danfoss, Kawasaki and Poclain all built to Buna-N and never cataloged an alternative material for the pumps we handle.

Sundstrand has a further complication that has nothing to do with material. Its real key is the date code, not the model number. The same item on the same pump carries different part numbers across date code ranges, so a seal kit request has to include the date code from the nameplate or the answer will be a guess.

For these brands, a non-standard material is a build rather than an order. It is entirely doable, because seal dimensions are on the factory bill of material, but it needs the full nameplate details and a lead time.

What we stock, and what we quote

We hold Buna-N seals and kits in depth across every brand on this page, because that is what the overwhelming majority of pumps were built with.

Viton is different. Our Viton and FKM parts are deepest on Rexroth and Vickers, with a useful spread on Char-Lynn, and thinner elsewhere. Where a brand cataloged a Viton option that we do not hold on the shelf, we quote it against the factory number rather than list it, which is why some of these parts appear as a quote request instead of a price.

EPDM, EPR and PTFE are quote items in every case. Denison and Oilgear have factory numbers, so those quotes are straightforward. For the rest, the quote covers a set built to your pump's bill of material.

Send us the nameplate. Give us the full model code, and the fluid in the system, and we will tell you the seal class it calls for, whether the factory cataloged that material, and what it costs. On a Sundstrand, include the date code. Request a quote.

Frequently asked questions

Which brands offer a factory EPDM seal kit?

Of the brands we handle, Denison and Oilgear. Denison lists it as seal class 4, with a -4 suffix on the part number. Oilgear lists it as EPR with a -9 suffix, and also offers Teflon as -3B. Vickers, Rexroth, Char-Lynn, Sundstrand and Kawasaki never cataloged one for these pumps.

What does F3 mean on a Vickers pump?

F3 is the Viton seal option. A V20F is the Viton build of a V20. A blank option field, written as two dashes, means Buna-N. The F carries onto the seal kit number, so the Buna-N and Viton kits for the same pump are different part numbers.

Does Vickers make a Skydrol seal kit?

Not for the V series. The only Vickers kits actually labeled for Skydrol are on the PVX series, under HC206052064000, HC206062064000 and HC206072064001. For a V series pump on aviation Skydrol, the correct answer is an EPDM set built to the pump's bill of material, not the F3 kit.

What does the seal class digit mean on a Denison pump?

1 is S1 Buna-N, 4 is S4 EPDM for phosphate ester and water glycol, and 5 is S5 Viton for high temperature or aggressive fluids. The same material also shows as a part number suffix, where Buna-N carries no suffix and only EPDM and Viton get one.

What does position 08 mean on a Rexroth model code?

It is the sealing material. V is FKM and is the standard build. P is NBR, and Rexroth specifies it only for HFA, HFB and HFC water containing fluids. So on a Rexroth running water glycol, the nitrile build is the correct one and the fluorocarbon build is not.

Can I get Viton seals for a brand that never offered them?

Usually yes. The dimensions are on the factory bill of material, so the set can be built in another compound even where the manufacturer never listed it. Send the full model code and we will confirm what is possible and what the lead time is.

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