HOWTO: Power steering conversion (67-72 trucks)

[shifty]

Posting this over here, per request from the masses. Posted this for another member in the main forum, apparently some people thought it was worthy of sharing

First, I want to say that I don't agree with buying used parts myself. Steering is a big deal - your life depends on it. Is it worth saving $80 to use something you got in a junkyard? My life is worth more than that (and you never know how much life is left in a used part, so it may not even be easier on the wallet).

http://www.satellitehead.com/gallery...s.php?album=10

This is my '68 stepside, I took pics while I was tearing down the steering and building it back up. I want to share what I learned.

Frist, notice the vertical "divot" in the frame in this picture between the four bolt holes:

If your '68 came with the correct frame, it should have that divot. The '67 didn't have this provision - basically, that divot is a provision for power steering gearbox. Any power steering gearbox for a 68-72 will fit in the 67-72 model trucks - you can either get a remanufactured one at the parts store or go buy a newer one from "AGR" at the Summit Racing website (or your favorite racing website, I guess). It's really your call.

Now, the driver side bumper brace is different for a manual steering and a power steering truck. If you have a manual steering bumper brace, you will need to grind a divot in it to make it fit using an angle grinder or bench grinder (the power gearbox is larger, and needs more room to live in that spot - you will understand when you do the swap). It's easiest to remove this brace while working on this swap. Bumper removal is not necessary. You can just buy a power steering bumper brace if you want.

NOTE: This info about bumper braces is true for the 67-68, but the 71-72 trucks use different bumper braces, so it may not be true for that year range. I do not know about 69-70 trucks.

When you're ready, here is a list of parts you will need to put new tie rods, idler arm, pitman arm (power uses diff't one than manual!). The are Moog part numbers (Moog is also "Federal Mogul" or "TRW" brand now, after the buyout). Any parts store can cross-reference these for you:

(Part numbers taken from their catalog lookup utility that I found HERE)



Here's what you need:

-- Mandatory --
(1) Power steering gearbox
(1) Power steering Pitman arm
(1) Idler arm (this goes on passenger side)
(1) Rag joint (found in the 'Help' section of local auto parts store).

(you will also need the fluid resevoir, the correct pulley, and any brackets to fit your engine. might be able to buy all three as a kit from summitracing.com or a similar website! you will also need your hydraulic hose lines, more info at end of this post)

-- Optional --
(2) Tie rod sleeves (adjusting sleeves)
(2) outer tie rods (1 left and 1 right)
(2) innner tie rods (1 left and 1 right)

If you're smart, you will get a "tie rod separator" and a "pitman arm puller" from the store for ~$10/each at most local auto parts stores if rebuilding all the steering, which is worthwhile if you're down there tearing sh*t apart already. These tools are in the 'Help' section, I think --- Ask if you need to. Both are essentially going to keep you from spending 6 hours taking off the tie rods and the pitman arm.

Buy the gearbox reman'd from auto part store, aroung $160? I forget...The rest of the parts are no more than $140 for everything else in that list, if memory serves correct. I bought all mine from Advance Auto parts.


The process:

Buying a service manual is a godsend here and will help you better than my instructions will. I will give some pics they won't, though.

Straighten your wheels out so your idler arm and pitman arm will theoretically be parallel to one another. If you are swapping tie rods also, make a visual note of how many threads are seen on either end of your existing tie rod sleeves (for both sides - 4 numbers total!!). I hear it's important to jot this down to get the best possible alignment after re-install. Also, make a visual note of the position of the pitman arm directionally and the idler arm.

Look at the pictures in the first link above. It's been a while, but here is the explanation.

First, take the nut off that is holding the manual steering pitman arm to the bottom of the gearbox. Use the gear puller. Save the nut!! Remove the pitman arm. Toss it, if you want. It's easiest to pull this bastard now than to wait for later. Go to the other side and repeat this process with the idler arm. Remove both items from the center link (the long bar from wheel to wheel or tie rod to tie rod).

Three bolts to remove inside the framerail to get the manual gearbox off. I would loosen up the two bolts holding the steering column rag joint to the gearbox if I were you. Save them, just in case. In fact, save all your nuts and bolts just for S&G if nothing else.

Remove the manual gearbox (three things hold it in: rag joint to column, pitman arm, bolts to frame).

If you are not replacing the tie rods, just skip the section in italics here:
Make a note or take a picture of the center link position (which way it points) for later reference. Unbolt your tie rods from the center link. Unbolt the other end of the tie rod from the spindle/knuckle area your drum or disc is attached to. Pull both tie rods off and eject to the side.

Screw both of your new tie rods (1 inner, 1 outer for each side) together with a sleeve. Adjust the sleeve to the same threads and distance from point to point as the two you just removed and replace. Tighten loosely to the knuckle and the center link, which will now be reinstalled.


Now, on to the nitty gritty.

Bolt the power steering gearbox back up. The steering column will collapse a bit if needed, there is a plastic pin or two in the middle of the shaft it that can be punched or drilled out, this will let the shaft reduce in size (it's usually siezed up though from time and rust), it might need to be beaten in a bit - safety feature, in case you get in a wreck, it collapses. Bolt the rag joint up to join the column and gearbox.

Install the pitman arm. Just a note!! This confused the crap out of me (I'm an idiot). The pitman arm DOES NOT screw down all the way. Here is a super high-resolution closeup picture of how much mine screwed on (the gear is tapered!):



Notice there is only like ~1 thread there on the other side of the nut. A lot of the old-timers here SWEAR by putting anti-sieze on this joker for future ease of removal. I didn't, and I am sure I will regret it.

Once this is back on, you should be ready to check and make sure the center link is in place and aligned (equal distance from the crossmember on pass side and driver side), and you can start tightening crap down again. When all is secure, don't forget to put your cotter pins through the castle nuts on everything, where applicable.

Before you get all gung ho, you will need to install your power steering lines, fill up with your fluid, get your brackets and belts in place...then, and this is IMPORTANT, follow the instructions that came with your power steering gerabox on how to fill, prime and flush your gearbox. It's supposed to be pretty easy to waste a power steering setup by not doing this properly. The general process is like ... fill with fluid, jack up the front end, start the vehicle, turn wheel from lock to lock, then fill, turn lock to lock again, then flush and repeat. I haven't done this yet because my engine is about 2% of the way from being service-ready.

I think that's about it. I am sure I missed a step, which is why a manual is pretty important. I might not have told you the "right" way either, but it's more than what anyone around here gave me when I was doing mine!!

Be sure to have the truck realigned afterwards.

OH - don't forget to buy your power steering lines also! GMCPauls sells them on the cheap www.GMCPauls.com (so do other board vendors, but these guys are close to us and nice to deal with) - great to deal with to boot. You need the high pressure line and the return line, they will cost around $40 shipped for the pair? I think. Shop that out first. None of the local auto parts stores sell the damned return line, they just sell a rubber hose. It's a joke.

Good luck.

[shifty]

I just want to reiterate that I haven't tested my setup yet, and won't for at least another few weeks. However, installation went without a hitch. I undoubtedly left some surprises out, and every install is going to be different and you will face new challenges with each install. I hope the info is true, accurate, and advisable for any person to do...but I would make sure you have a Helms, Chiltons or factory service manual handy just to make sure you're doing things "by the book".

This post is more about inspiration and the overview to do it so you're encouraged (it's a pretty simple process, just takes some time and sweat). The payoff is supposed to be great, so I can't wait

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