The 4204 is a pivot-mounted, spring-centered cylinder. Applying air pressure to either side of the piston will cause the piston rod to move accordingly. This cylinder is mostly used for the control of marine hydraulic reverse reduction gears and serves as s three-position actuator, providing control over the hydraulic clutch valve. With no air pressure in either control port, the output rod is centered. By applying air pressure (minimum 65 PSI), the piston rod stroke is one inch in either direction (total stroke, two inches). The construction is all bronze and stainless steel, and will provide many years of trouble-free service. When used as a three-position control cylinder, order Model 4202-C. The same configuration cylinder is also available for infinite positioning of variable hydraulic delivery valves and pumps. It is possible to infinitely position the output rod by varying the air pressure to either side of cylinder. When ordering this configuration, order model 4204-A. The basic difference between the two configurations is the spring.


• Used in conjunction with Kobelt pressure control head 2543/53 and 2547/57, the 4204-A provides infinite positioning in two directions. It is best suited for accurate positioning of low-force mechanisms.

• Used in conjunction with Kobelt control heads 3604, 3609, 2544/54 and 2545/55, the 4204-C is a compact 3-position, self-centering cylinder.


Weight: 3.3 lbs. (1.5 kg)
Materials: Die-cast silicon bronze and stainless steel
Maximum Input Pressure: 200 PSI (13.79 BAR)
Operating Temperature Range: -40ºC to +90ºC
Pipe Port Size: 1/4” NPT
Stroke: 1” each way


4204-A 2-direction positioner actuator
10-80 PSI range

4204-C 3-position self-centering cylinder
35-65 PSI range


1 1 4204-001 Cylinder Barrel
2 1 1022-0161 Nut
3 1 4204-0002 Piston
4 1 1101-0222 “O” Ring
5 1 4204-0003 Spring Retainer
6 1 1101-0033 “O” Ring
7 1 4204-0004 Front Barrel
8 1 1201-0023 Spring (Clutch Cylinder)
8 1 1201-0024 Spring (Positioner)
9 1 4204-0005 Spring Retainer
10 2 1102-0005 “U” Cup
11 1 4204-0006 Piston Rod
12 1 4204-0007 Swivel Mount
13 2 1029-1037 Snap Ring
14 1 4204-0008 Pin
15 4 1010-0806 Screw

A Repair Kit is available, consisting of all seals.
Order No. 4204- RK.