Control Valve Details

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While the contents of this webpage deals specifically with the working of the early Ford Mustang power-assist system, most of the information pertains equally to the same system as used on other Ford model lines.

Control Valve Housings varied in four ways: Early Style and Later Style, Pressure Port Size, Restrictor Style and Seat or O'ring.

Notice no area or hole for a Reaction Valve. Spacer plate between housing and End Cap is also unique.

Notice no area or hole for Reaction Valve. The two ports for the power cylinder hoses are also 1/4' ports like the pressure hose port.

1965-1970 Mustangs all used the Later Style valve housings. These were Bendix units and came in other variation based on a common housing style. This style was used on all Fords after about 1960. Some late model Granada valves had holes for a Reaction Valve setup, but had no reaction valve installed. Some late models had a solid housing without any hole at all for the reaction valve.

1965-1967 Mustangs had a 1/4" Pressure Port, where the pressure hose went to the valve. All car lines used this size pressure port until 1968.

1968-1970 Mustangs had a 5/16" Pressure Port, where the pressure hose went to the valve. All car lines used this size pressure port starting in 1968.

NOTE: Port size is based on the outside diameter of the metal tube used in the port, not the diameter of the fitting or hole.

1965-1970 Mustangs had a Check Ball restrictor screwed into the housing under the hose seat of the Return Hose Port. This acted as a restrictor in the system to slow pressure surges in the system. All 1/4" pressure port housings used this check valve restrictor. The 5/16" port valves used this style until about 1976.

Starting about 1976, valves no longer had the Check Valve restrictor but had a Restrictor Orifice pressed into the Pressure Port under the Hose Seat. The restrictor was changed to this design because it was supposed to heat the fluid less than the earlier style.

1965-1970 Mustangs used a Hose Tube Seat in each port to seal against the flare at the end of the hoses. This style was used on all valve housings until the mid 70's.

Starting in the mid 70's, some housings did not have Hose Tube Seats installed, but instead used a different style hose end with a small rubber O'ring on it. These O'rings sealed against a ridge inside the port. These valves were typically used on Granadas/Monarchs and late model Mavericks. These housings can often be converted to use on earlier cars by pressing tube seats into the ports, but the fit is very tight and it is easy to damage the seats during installation.

Early End Caps, up until the late 1950's, had a rounded head and used a gasket to seal to the control valve. Often they were not date coded.

From about 1960 on, End Caps had a flattened end and were machined for a rubber O'ring to seal it to the control valve. The flat surface was date stamped.

From about 1960, the End Caps were date stamped the day they were assembled. The cap on the right has a stampung of " 5L26A " which decodes to an asembly date of November 26, 1965, work shift A

Starting in the 70's, some control valves used a brass tube seat with an O'ring underneath it. They still used the tube flare style hoses. These can often be converted to the aluminum style seat without the O'rings if done properly.

Early control valves using the non-tapered Ball Stud Sleeve with the square slot, used a Ball Stud Bushing made of smooth solid steel. The Ball Stud had to be installed from the inside since there was no "cut out" in the slot for the ball end to fit through.

Most valves made after 1960 used a Ball Stud Bushing that was steel coated with a bronze bearing material. Its surface was dimpled to hold grease and was made to have the Ball Stud installed by dropping in from the top.