issue

[67 GT350]

Wondering, why power steering can sometimes be hard to steer? Belt not loose. Reminds me of newer car with rack and pinion when they go bad.

[Bob Gaines]

Wondering, why power steering can sometimes be hard to steer? Belt not loose. Reminds me of newer car with rack and pinion when they go bad.

Low fluid can cause that symptom but usually followed with squealing sound out of pump. Internals of pump maybe going bad.

[shelbydoug]

There is an internal impeller that can break.

[67 GT350]

So you both are saying it is a pump issue?
Is it safe to drive for now, like until I can service it?

[JD]

Check the fluid level, if low add "Type F" (Ford) and see if it changes the situation.

[Bob Gaines]

Safe is a relative question in that context. When the pump fails completely it will be much harder to drive then if it had manual steering so you have to consider the possible circumstance you may be in at the time of its demise. Remember that when you replace the pump that the sheet metal reservoir can that press on the cast inner core is specific to a Shelby compared to a regular Mustang. Two manufacture's Ford Thompson and TRW that were used in 67 Shelby production for the power steering pump. The cast iron inner core is the part that goes bad . The Ford Thompson core has a FOMOCO trademark on the front of the casting. The TRW core has a W . The Ford Thompson pump is painted the blue teal and the TRW is painted black . The metal tag that is held on to the back side with a thin large nut is marked HBA-BH ,or BH1 on the first line . The MFG designation of F or W is on the second line.   

[Bob Gaines]

Check the fluid level, if low add "Type F" (Ford) and see if it changes the situation.

I have already mentioned the low fluid however JD brings up a good point in that if type F fluid is not used then it can cause problems . I had a squealing pump in a car I recently bought and when I checked the fluid it was almost clear. That indicated that the type F was not used. Type f has a distinctive red color and is the same as used in the Ford automatic transmissions. You should be able to tell by what is on the dipstick. If yours is red don't waste your time draining because it will not help. In my case a change to proper fluid did help. I drained all of the fluid out which is a pain because you have to disconnect the return hose at the chassis bracket connection and let drain out . I turned the steering wheel left all the way and then right to push as much of the fluid out of the ram as possible before filling back up with correct fluid. Once running you have to check level again then turn wheel left and right to get air out off the system then check level again. 

[Royce Peterson]

What Bob said - if the technician used clear fluid it is a dead giveaway, and the pump failing is the usual result. Once in a while you will get lucky and be able to change the fluid for the proper type and have everything start working right. I have never been that lucky.

[67 GT350]

Its red.

[BryanT]

Pump is a vain pump and I would think failure would be rare. Could be a problem with relief valve, Pressure valve. or the Power Steering Control Valve. Good luck.

Bryan

[67 GT350]

Please someone refresh me:

Check level HOT. Do you warm up the car, then shut it off and look at eh PS dipstick, with engine OFF? Or do you check it once warmed up, RUNNING?
Or do I have that mixed up with automatic fluid check?

[Rickmustang]

Doesn't have to be hot, but definitely don't overfill

[Bob Gaines]

Doesn't have to be hot, but definitely don't overfill

The dipstick reads "check hot" however I agree it doesn't have to be but don't over fill.

[Royce Peterson]

The car is off when you check the PS fluid level.

[98SVT - was 06GT]

Wondering, why power steering can sometimes be hard to steer? Belt not loose.

Since it's not constant I'd bet the vanes are hanging up in their slots. Or something in the system is keeping a valve from sealing. Drain and flush it out with solvent to assure some crud in the system isn't causing your problem.

If the vanes don't make constant contact with the outside of their housing (or a valve is leaking) the pressure will be less making it harder to steer. https://youtu.be/H7S0gag_a4k?t=345