How to Replace Power Top Components
Follow along as I replace the power top
hydraulic components on this '68 Mustang.
The pump and the reversible electric motor that drives it have a reservoir attached
and are replaced as a unit.
Automatic transmission fluid is pumped under extreme pressure through plastic
lines to the rams ( not a football team). These rams are a cylinder that resemble
a shock absorber, with fittings at the top and bottom, to accommodate the pressure
lines that run from the hydraulic pump.
On this car, the pump failed apparently for the following reasons. Initially,
because the top was rarely used and the pivot joints in the convertible top frame
had not been serviced for aeons. Increased force was necessary to raise the top,
and to a lesser extent, lower the top. Contaminants entered the fluid either from
the seal leakage or possibly from the use of dirty or incorrect fluid. The system
is designed to run on ''Type F '' a.t.f. (not alcohol, tobacco,and firearms). When
the pump was run ''dry'' due to leakage, lubrication was absent which may have caused
the pump to fail.
Overfilling the system can also cause failure due to the expansion of fluid when
heated from being under extreme pressures.
We will begin this article with the rear seat and interior 1/4 panels removed.
The pump and lines can be found easily when the seat back is removed. Start by removing
the straps which hold the plastic pressure lines to the rear seat panel.