HPRS MA36 - U-rings

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

Piston and piston rod seal with symmetrical seal lips which are cut at an angle of less than 45°.

Standard material

Polyurethane TPU92

Area of application

reciprocating movements


The HPRS MA36 is a single function piston rod seal in the form of a compact U-ring which, due to its symmetrical seal lips, can be applied as a piston and piston rod seal. Its sealing function is very effective as the seal lips are provided with radial self-energising which is activated by the system pressure. Its compact design and the excellent material characteristics of polyurethane guarantee effective sealing on the one hand at low as well as high pressure loads and, on the other, a particularly long service life.


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 HPRS MA36, 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 or push the piston rod with the seal into the cylinder rod without damaging the seal, 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 1.0
10 0.8
20 0.6
30 0.5
40 0.4

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.