hydros.biz Lowrider hydraulics information

Early Stone or lift-gate pumps had all the plumbing needed to work the lift. Manually, and electrically.

The vent cap on the tanks were needed, this was used as a filler port and as a way to keep vacuum out of a system that was low on fluid.

Early Lowrider gate tanks that have:
the vent cap removed and a return hose stuck into it,
a second hole drilled out to accept the return hose.
The reasons for this was that riders did not know or did not have the means to return the fluid through the block return.

The gate pumps were designed as a complete unit, they already had a check valve and dump valve built in. On these early type, you had to know what was needed to be removed or modified so as not to return fluid through the top of the tank.

To avoid all this hassle with tank returns, you just needed to find a pump with the electric solenoid dump valve. Most times, this wasn't possible.  A lot of pump were stolen and the riders that used them had to make do.

Once truck rentals or delivery companies got tired of pumps being stolen, they would weld the bolts that held the blocks to the plates that supported the blocks. Thing was, a screw driver would get you the motor, and a two sockets and wrench would get you the tank and pump head.  Then the companies started welding metal cages or boxes around the gates.

At the time, a few lives were saved because of the safety chain that was used to keep the platform from  falling was in place.  Some of the cylinders were one way, meaning gravity caused them to come down on their own, and pressure was used to keep them up. You take away the pressure, down goes the platform.