'69 Cougar - Steering has become non-linear

[Double E]

Stock steering components. Fluid is full in the PS unit.
Recent re-assembly of EVERYTHING on the car.

Steering has become non-linear over the past few times I've driven it. What I mean by non-linear is that traveling about 40mph, on a left-hand curve, steering input will be fine at first, then the wheels seem to no longer respond to input. Then with just a bit more input, steering reacts sharply and requires right steer input to catch it from going into the oncoming lane.

It seems to be more significant on left curves.

I'm confident about the re-assembly needing a once over to make sure everything is tight based on other stuff I've found loose.
Anywhere you'd suggest I look into first?
Thanks in advance.

[Royce Peterson]

Sounds like a problem with either the PS slave cylinder or the PS control valve. I would guess the control valve. The factory shop manual gives great instructions on how to adjust the control valve. I would try that first. If you install a new valve you will need the shop manual instructions too.

[Double E]

Thanks Royce. I was hoping you'd respond. I will look into this.

[charliemcd]

You're sure nothing is loose or has any give in the front suspension, right? Guess you would probably notice this at any speed though...

[Double E]

Right...I'm not 100%. I'll also be doing a nut/bolt session on it soon.
Thanks!

[Flade]

Recommend you rebuild the steering control Valve. contact Dan Chock aka. Chockstang. He is the expert on these systems and will sell you all the parts needed for the rebuild. He’s a good guy, honest and fair prices. He’ll answer all your questions and give you good advice as well. He’s helped me rebuild the suspension and steering on 3 Mustangs. He sells from his home and also on eBay. He frequents the Vintage Mustang Forum, but support all classic Fords.

Chockostang. 214-882-2083

Chockostangclassicmustang dot com

[Royce Peterson]

I can't see any reason for rebuilding or replacing without checking the adjustment first which is 5 minutes with a screwdriver and a wrench. His symptoms are exactly what happens if a novice who doesn't understand how the control valve works adjusts it to eliminate what they think is excessive play at the steering arm. If he had profuse leakage I might agree with you.

Recommend you rebuild the steering control Valve. contact Dan Chock aka. Chockstang. He is the expert on these systems and will sell you all the parts needed for the rebuild. He’s a good guy, honest and fair prices. He’ll answer all your questions and give you good advice as well. He’s helped me rebuild the suspension and steering on 3 Mustangs. He sells from his home and also on eBay. He frequents the Vintage Mustang Forum, but support all classic Fords.

Chockostang. 214-882-2083

Chockostangclassicmustang dot com