Friday, October 30, 2015

Power Steering linkage removal

Before I can put the car up on a frame jig (that I have yet to design and build), I need to get all the parts off the car that are attached to frame sections that will be replaced. With the suspension off, all that's left is the steering system.

All Mustangs had an older type of steering system called 'recirculating ball' up until 1974 with the introduction of the Mustang II when 'rack-and-pinon' steering became the norm. The vast majority of modern cars use rack-and-pinion steering, so most folks under the age of 50 who've never owned a car made before the oil crisis of the 1970's probably haven't seen the older recirculating ball-type, myself included. I'll point out the parts as they come off the car and hopefully give an idea of how it's supposed to work.

The factory service manual is invaluable in this effort - there's lots of good details in there that help spell out how all this fits together. And I hit all these parts with Liquid Wrench a day or so before starting.

67 Mustang power steering linkage
The overall view of the steering system, with nothing else in the way. On the right, the steering column comes in from the cabin and connects to the steering box.


67 Mustang steering box
Close-up view of the steering box. This is the part that converts a turning steering wheel into a left/right motion of the front wheels. The bottom of the box is connected to a pitman arm which ties the box and the center link (or 'drag link).


Here's a close-up view of the pitman arm on the center link. On my car, it's actually connected to the power steering control valve, which is mounted on the end of the center link.


67 Mustang power steering control valve
Here's a view of the other side of the power steering control valve. This guy is what directs the power steering fluid to a hydraulic control ram that pushes or pulls the center link left or right. The control valve sits out in the open wheel well near the drivers side wheel. As such, it's subject to lots of dirt and abuse as the car rolls along. These parts are also notorious for leaking if not properly maintained, and mine is no exception. So, after a while, a layer of power steering fluid and dirt turns into a grimy, nasty mess that is caked on not just the control valve, but all over the bottom of the engine bay.


This pic gives a nice idea of the state of the system and the bottom of the car as a whole. The leaking power steering has resulted in an oily grime layer over the entire area. It's also a good view of the intersection of the power steering control valve, hoses and ram cylinder.  Nasty, nasty, nasty....


67 Mustang power steering ram cylinder
Working down the center link towards the passenger side of the car, the power steering control ram is connected near the center of the control link. This is where the push/pull action of power steering is applied to the steering system. On the left and right of the control ram connection, you can see the inner tie rod ends also connected to the center link. Tie rods - as you might guess - tie the center link to the wheels.


On the far end of the center link is the connection to the idler arm. The idler is mounted to the passenger side frame rail and provides a stable rotation point for the center link as it moves left and right. It's also supposed to help provide some return-to-center force on the steering by way of the integral rubber bushings in the arm. Naturally, all these rubber bits are toast on my car.


My token sideways pic. 
All these pieces are held together with press-fit bolts and castle nuts with cotter pins. While some folks will suggest a pickle-fork to break these joints, I decided to use pitman arm pullers (on loan from Autozone) to reduce the chance of damaging any components. My plan to to have a factory-style steering system with newer components as needed - no rack-and-pinon conversions here - so I want to keep as much as I can for reuse. In particular, I want to be careful with the steering box, pitman arm, and center link.


67 Mustang removing tie rods
Using the pitman arm puller to remove the tie rods from the center link. The control ram came off in the same manner. Just seat the puller as shown, rotate the pullers' captive bolt to push the tie rod bolt out. Each of these bolts let out a 'BANG' as they let go because they're under some load by the puller. Be careful, wear eye protection. The hammer is there mainly to scare to parts into submitting to the pitman arm puller. I didn't have to use it...much.


Pulling the idler arm off the center link. Many turns later, there's a bang and a the arm is off. The idler needs to be unbolted from both the bracket and center link ends before the pulling starts. 


The idler arm bracket is mounted to the frame rail with two bolts through the rail. I think I get a new bracket when I order a new idler arm. But I'm keeping all of the old parts for reference as new parts come in to make sure they match. Good Lady Wife is starting to cast an impatient eye towards my growing pile of parts in the backyard....


 The power steering ram cylinder mounts to the frame via this bracket. Two bolts connect the bracket to the frame via captive nuts. Be careful unbolting the bracket or you could twist the captive nuts out of the frame rail. That's bad. Remember - Liquid Wrench is your friend! Above the bracket you can see the three bolts that hold the steering box to the frame rail.



Blamo! The steering linkage is out. I don't have a pic of the pitman arm coming off the steering box because it was the hardest part of this whole effort to get off. Patience pays off, and it made a bigger bang than all the others.


67 Mustang stock power steering linkage
Here's the linkage out of the car, minus the pitman arm and steering box. Also notice the sway bar and brackets at the top that I pulled out - just about the easiest thing to take off the car. Interesting note - the sway bar measures 15/16" diameter which I think is correct for '67 Shelby GT350's or Competition Handling Package-equipped cars. I'm reusing the sway bar and the center link for sure. I'm still debating if I want to reinstall a rebuilt power steering system or convert the car to manual steering. I want to avoid the floaty, over-boosted feel of a 60's power steering system in a car this light. But I also need to be able to maneuver the car in a parking lot, so... 



Ready for some Heavy Metal R&R (Remove and Replace).

All of this took a solid single afternoon to get off the car. It's not really hard, but I chalk that up to using the right tools and the abundance of leaking hydraulic fluid all over the bottom of the car keeping things from getting rusted in place. I'm running out of parts to take off the car, so at some point, I'm going to have to start actually fixing things. 

Up next - steering column and steering box removal, and then frame jig design and build. 


1 comment:

JM Automotive said...

Nice Post! Keep up writing this type of posts.

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