Topic: No power steering

[modrisco]

The power steering in my 68 is acting like manual steering. The belt is tight and the pump is turning, no noise. Any suggestions?

[Bossbill]

Pump pressure regulator is stuck is one known issue that causes no p/s.

[modrisco]

How can I  free it if  stuck?

[Bossbill]

Remove coil wire.
Remove p/s hose at control valve and plug.
Remove plug, and hold thumb over end of hose while someone cranks engine while you point hose into container.
If nothing comes out, then pump is at fault.
Pressure valve is in pump end plate.

[Bob Gaines]

Remove coil wire.
Remove p/s hose at control valve and plug.
Remove plug, and hold thumb over end of hose while someone cranks engine while you point hose into container.
If nothing comes out, then pump is at fault.
Pressure valve is in pump end plate.

Just for clarification of directions which hose do you remove at control valve? The larger diameter return hose or the smaller diameter pressure hose?

[Bossbill]

Good point, Bob. I was on my phone where brevity is king.
Since we are trying to see if the p/s pump works at all it would be the small diameter pressure hose.

DO NOT start the engine! If you do there could be p/s fluid everywhere!

Make no mistake -- this can be messy.

Here are a few pics of the internals. I don't know if this a Ford pump or not. Pics are from a friend without note as to which it is.

[modrisco]

I removed the pressure line and cranked the engine. In 5-10 seconds of cranking i got 1/8 of a quart of fluid.  Is the pump putting out enough?

[modrisco]

Changed pump. Same dead steering.

[67350#1242]

May be the control valve is stuck.

[Bossbill]

Sorry, lost track of this thread.

The idea behind the crank test (at about 200 rpm) is to see if there is any volume of fluid and any pressure. One of the no-gauge ways to determine pressure is to place your thumb over the line and see if the pressure is high enough to blow your finger off the hose.
This doesn't mean you have enough pressure -- just that the pump isn't totally without pressure. The real way involves 1500 psi gauges and valves as outlined in the shop manual.

To test the ram you need to source some fittings that will block off each individual port -- with full fluid in the ram. Normally off the car so you can fill the port/ram with fluid. If the rod will move in and out with little effort, the rings are blow out.
Otherwise,  the control valve is the issue.

Testing this system out is difficult ...

[Bob Gaines]

It sounds like by process of elimination the control valve is highly suspect  .

[RoyceP]

Has it ever worked? This symptom can be caused by mis - adjustment of the control valve. The shop manual gives great adjustment instructions. It can also be caused by a failed seal in the slave cylinder. I would start with adjusting the control valve since it costs nothing.

[modrisco]

When I bought the car the pump was removed and hoses to slave cylinder cut. I bought new slave cylinder, control valve and hoses and a used pump. I installed it last summer, power steering worked . This year it started to intermittently  have/not have power steering  now no power steering. I found this only adjustment seems to be side to side bias no pressure adjustment.

There is basically only two adjustments on the Control Valve/Ball Stud assembly.
The Travel Stop is threaded into the end of the Bushing, compressing the Bumper Spring which puts tension on the seats that the Ball Stud sets in. This tension must be great enough to hold the parts together at all times, but there must be enough compression left in the Bumper Spring so that the Ball Stud is not binding. The Adjustment Nut compresses the Centering Spring so that the Spool Valve is centered inside the Housing under non-power situations. This adjusment must be correct or the Spool Valve will not center in the Housing and fluid will not go around it evenly. This will cause the power assist to favor turning one way over the other, or in extreme cases, actually want to turn the car and steering wheel by itself. The adjustment of this nut and the condition of the Centering Spring are important to prevent this from happening.