HRS MA35 - U-rings

Type/Ref.: Rod seal
Pressure (bar): 40/400
Temperature (°C): –40 to + 100
< +40 in HFA; HFB; HFC
Speed (m/s): = <0.5

Piston rod seal with symmetrical seal lips which are cut at an angle of less than 45°. There is a second seal lip on the inner diameter.

Standard material

Polyurethane TPU92

Area of application

reciprocating movements


The HRS MA35 is a single function piston rod seal in the form of a compact U-ring. Its design and the excellent material characteristics of polyurethane guarantee effective sealing at low and zero pressures as well as high pressure loads and a particularly long service life. Due to the second seal lip which provides even greater effectivity of the sealing function, it is particularly well-suited for positioning work in hydraulics.


Hydraulic oils acc. DIN 51524/51525,
lubricating oils, mineral oil based
lubricating fats, non-flammable
hydraulic fluids HFA, HFB, HFC acc.
VDMA 24317

Operational application limits

Pressure (MPa/bar): 40/400
Temperature (°C): –40 to +100
< +40 in HFA, HFB, HFC
Running speed (m/s): <0.5


The HRS MA35, from an inner diameter of 25 mm and a thin profile, can always be installed in cut housing. Due to the high tensile resistance of polyurethane, it is necessary to use installation tools for thick seals. With an inner diameter of less than 25 mm, we recommend axially accessible housing. To push the cylinder head and seal over the piston rod without damaging it, an lead-in chamfer C acc. to the following table is required:

Profile width (mm) Lead-in chamfer C (mm)
4 2
5 2.5
7.5 4
10 5
12.5 6.5
15 7.5
20 10
25 10

The service life of the seal is lengthened if the housing is provided with a metallic fitting on the side opposite the pressure. Within the operating parameters given above, depending on the pressure, a metallic wedge can be fitted between the cylinder head and piston rod acc. to the following table:

Pressure (MPa) Radial wedge G (mm)
5 0.6
10 0.5
20 0.35
30 0.3
40 0.25

Please also follow the general installation instructions.


In addition, we are able to supply other dimensions required. For operating conditions other than the standard applications, further polyurethane materials are available.