This page last revised 2/25/05.
These tips are from my experience installing a brand new steering box into my '84 RX-7 GSL-SE. All GSL-SE's have air conditioning, and few have the optional power steering. The steering box is the same for all manual steering '82½ through '85 RX-7s, so the presence or absence of A/C should be the only variable to deal with for those years. Mazda's billing recommendation to its dealers calls for 4 hours of labor to remove and install a steering box and column shaft. (It took me 8 hours, but I didn't have the tips that you're looking at now. It should take you the recommended 4 hours.) These times do not include time for rebuilding a used box.
I had originally tried adjusting the steering gear -- there's a removable cover, lock nut and adjusting bolt at the top of the box -- but each of the two times I did this, the steering became loose again within a week or two. Not meaning to dash anybody's hopes, but the steering felt as good as new immediately after these adjustments, but it just didn't last. You should at least try the adjustment before you go ahead and replace the box, and if you do, make sure that you only tighten the bolt enough to remove the slack. Tightening too much will just cause premature wear at the center of the steering gear, and then you'll really need a new box.
There's another wear point that you should look into, as well: the idler arm bushings. The idler arm is located in the engine compartment, in the same place as the steering box but on the passenger's side. The idler arm bushings have a tendency to wear out faster than the steering box, and will result in the exact same kind of play in the steering. Think about it -- they're made of rubber and are fairly close to the exhaust manifold; naturally, they will wear faster than the metal components of the steering box. You can check them pretty easily just by reaching into the engine compartment and trying to wiggle the arm. If you think you have any play, replace the bushings. Fortunately, they only cost about $10 (US) at the dealer, and they take all of about 15 minutes to replace. No lift necessary, just a cool engine compartment and a socket wrench. If the idler arm bushings are OK, then it's back to our steering box replacement....
The new box cost me $565 (US) before taxes. I had originally sought out only the steering sector shaft -- about $200 and half-an-hour labor to install -- but two dealers told me that it is no longer available. I only wanted to do this job once, so I opted for a new box rather than a used one from a junk yard.
There are other steering box replacement pages on the Web. You may wish to check out Jon Booker's 1st Gen FAQ. Also, check out Paul Mullen's web site for three good articles on steering box repair and maintenance.
This page is based on comments to the '84 Mazda RX-7 Shop Manual. As a matter of convention, instructions from the shop manual will be in italics. Comments are in normal print.
If anyone else has any other tips pertinent to any first generation RX-7s, please e-mail me and I'll be happy to add your comments to this page, anonymously if you wish. -- James Rothe
2. Remove the horn cap and steering wheel.
The horn cap will pry off, even though it feels a little stiff. It's just a hard rubber disc that secures to the wheel like a great big coat-button. There are no clips or bolts holding it on.
Cautions
a) Before removing the steering wheel, apply identification marks on the steering column shaft and steering wheel.
You can possible save yourself a little trouble later on by driving the car perfectly straight into your work area before you even start. Some people who have done this job have found that their steering wheel wasn't straight after they did the job. Sometimes the steering wheel can be a real pain-in-the-neck to get off, so you'll want to take every precaution you can to get it back on straight the first time.
b) Do not strike the steering column shaft end with a hammer. Striking shaft will damage the bearing or collapsible shaft.
The steering column is actually a telescoping rod within the black column jacket that runs from the steering wheel to the box. The column is not much more than a half-inch thick, and it's designed to collapse in the event of an accident. The two plastic rivets that keep the telescoping column at its full length will not break easily, but a hammer blow could be enough to render useless your new $565 steering box and column.
In the event that you do break the collapsible shaft, I've heard of a few remedies. One is to remove the steering box and shaft, and then tack weld the column to the correct length. Another suggestion that I've heard was to drill a hole through the shaft where the plastic rivets are, and replace them with nylon screws. (Aftermarket license plate screws are often made of nylon or plastic.)
The best suggestion that I've heard came from Dave Barniger at KD Rotary, and it can be done with the column and steering gear in place: turn the steering wheel so that the wheels are straight ahead and position the wheel so that you have the desired clearance between the wheel and the plastic steering column covers. From the floorboard, measure 7.5" up the column, and then drill a 1/2" hole into the bottom of the steel column jacket. Then, through that hole, drill a quarter or eighth inch hole through the collapsible shaft. Install a quarter or eighth inch ALUMINUM pop rivet into the hole and you're done! The idea behind using an aluminum rivet is to retain the safety factor of the collapsible shaft. I should note that I've never done tried this repair, but it sure sounds like a great tip. Dave says he's done it probably twenty times, and it only takes 15 minutes or so.
c) Use suitable puller to remove the steering wheel.
The first time I did pulled a steering gear out of a car, the steering wheel just WOULD NOT let go of the column splines. Since then, I've pulled and reinstalled two other boxes, and both of those times I was able to just rock the wheel back and forth until it let go of the splines. P'Baster or a similar penetrating sovent helps.
But as for that first instance....
"Suitable puller" meant making a bracket to put behind the steering wheel and securing a steering wheel puller to the bracket, not to the wheel itself. The steering wheel is incredibly flimsy on this car, and it will bend as soon as you start tightening the puller.
We used some steel bracket/plates and inserted them behind the wheel. The plastic collar that surrounds the base of the steering wheel will bend if you squeeze the sides of the collar. That should give you enough space behind the wheel to cram your brackets in there.
We bolted four of these plates together and then secured the puller to our homemade bracket so that pressure from the puller would be distributed across the entire back of the steering wheel, instead of just at the wheel's two puller holes. If we had done this from the start, we would have saved an hour or so, and we wouldn't have bent the steering wheel like we did. It was easy enough to bend back into perfect shape with a vice, though.
3. Remove the steering column covers.
4. Remove the air duct and disconnect the couplers of the combination switch.
5. Remove the combination switch assembly.
It pulls straight off, but what the manual doesn't say is that there's a plastic tab on the top, towards the back, that you have to lift up in order to release the switch.
6. Remove the steering lock assembly referring to page xxxx.
Steps 6 and 7 both suggest that you need to move the steering lock assembly from the old column jacket to the new one. Why not just remove the column jacket and steering lock assembly as a unit, and reuse them with the new steering box and column. Duh!!! This bright idea didn't occur to me until after I did my first steering box. So if you insist on going by the book, I still have some more comments on these two steps....
Mazda seems to think we all want to buy new steering locks when we do this job. (Maybe their assumption is that no one would ever be digging into the steering column unless the ignition lock was damaged by a theft attempt. Whatever....) The manual's pages on the steering lock suggest using a chisel to "loosen" the bolts that hold the lock in place. When you get to this point, you'll see that these "bolts" do not have a hex-head or screwdriver slots or anything to grab hold of. We decided to bypass this step and pull the column jacket (with lock in place) out through the interior after the next step.
7. Remove the column jacket fixing bracket.
It's underneath the column and bolts to the underside of the dash with four bolts into the column and two into the dash. These two bolts into the dash are the only ones that you'll need to concern yourself with if you're going to re-use the column jacket and lock assembly. But if you're not going to re-use them....
By taking the column jacket off, we could work on the lock's bolts at our workbench with a vice and a hacksaw. (Yes, I said hacksaw.) The jacket just slides out of the steering box, up through the interior . It's held in place by the rubber washer which surrounds it at the steering box end. Do this slowly and carefully -- there's a wire (probably to ground the horn when depressed) which connects the top portion of the collapsible steering column to the bottom half. It's not extremely fragile, but you don't want to break it. You might want to look at this on your new (or used replacement?) steering box and column assembly.
The two bolts that hold the lock in place have smooth concave heads. We cut slots into these heads with a hacksaw and were then able to unscrew them with a large flathead screwdriver. The steering lock section of the manual discusses reassembly of the lock & column: position a new steering lock assembly to the column jacket and tighten the bolts until the head of the bolts snap off. I can only assume that this means that a new lock assembly has bolts with a conventional hex head which is designed to snap off when you torque them to a certain point, leaving just the smooth head we see here. Will this stop a car thief from removing your steering lock? No! He's just going to part the car out, and probably doesn't care about replacing the lock that he broke, anyway.
8. Mark the bonnet hinge locations on the bonnet and remove the bonnet.
"Bonnet" means "hood" for all of you yanks out there. You might as well remove the air conditioning compressor bracket at this point. You'll never get the new box and column in with the compressor and bracket in its working location. Take the battery out, too.
One of the other "tips" pages that I mentioned suggests removing the compressor and hoses as well, thus requiring a recharge. In my experience, I didn't have to do this, perhaps because we had already removed the column jacket. You'll still need a second person to hold the compressor out of the way while you remove/install the steering box and column.
9. Raise the front end of the vehicle and support it with stands.
10. Disconnect the center link from the pitman arm with puller.
The shop manual refers to a special tool (number 49 0118 850C). Quite frankly, I have no idea what we used! I did this at a friend's car-rental agency shop, and we used his tools. Probably just a standard hub puller.
I've done this job twice with the engines out of the car, and that allowed me to remove the pitman arm from the center link by simply removing the cotter pin and castle nut from the end of the pitman arm, and then pounding the center link off by repeatedly dropping a five pound sledge hammer on it from the top. That method took about 2 minutes. I'm not sure, as of this writing, if there's enough room in the engine bay to do this while the engine is in place.
11. Remove the pitman arm from sector shaft with puller.
Another special tool (49 0223 695E) -- we just used what we had. We also had to apply heat with a torch to get the pitman arm to let go of the sector shaft. Keep a fire extinguisher handy! (No, I'm not commenting from any bad experience. It's just a common-sense precaution.) This was another item that just didn't want to let go. All efforts took about an hour and a half for just this one step. Hopefully, your's will take the 2 minutes that the manual assumes it will take.
When I did this job on two cars that already had engines removed, it was for the expressed purpose of swapping those two vehicles' steering boxes. So we swapped them with pitman arms installed. Hopefully, if you're installing a used box, you'll have one with a pitman arm installed.
12. Remove the steering gear housing attaching bolts and remove the steering gear housing assembly through the engine compartment.
Caution: If the car has been in a collision, check the steering wheel for axial play before removing the steering gear assembly. If the steering column shaft is crushed or axial play occurs, replace the steering gear and column shaft as an assembly.
Get to these bolts from underneath the car, and the box will come out from the top. You'll have to take the driver's side front wheel off to get to the bolt heads. The Mazda manual makes no mention of the shims (washers) on these bolts, until it comes time to install the new steering gearbox. Fortunately, one of the other web pages refers to them. My car had two of the three bolts spaced with shims.
Again, you'll need a second person to help with the A/C compressor. You may also want to remove the distributor cap, rotor and cables, just to clear the way. (Mark those cables if you're not familiar with that stuff!)
There's a large rubber grommet that will probably still be in the firewall after you pull out the shaft. A replacement grommet should have come with the new gearbox. The grommet can be pulled out of the firewall and the new one pressed back in by hand.
OK. You're halfway there!
Again, life will be a lot easier if you take the column jacket off before trying to get the column through the grommet in the firewall. And you're about to see why we needed to get the A/C bracket and battery out of the way. Bolt everything together underneath the car as per Mazda's reversed instructions.
1. Place the shim in the original position between the steering gear housing and the frame to obtain the proper column shaft alignment.
2. Install the pitman arm onto the sector shaft, aligning the identical serrations of the pitman arm and sector shaft.
Pitman arm tightening torque: 150-180 N-m (108-130 ft-lb)
Yes -- the pitman arm only goes on one way. I was able to skip to step 5 because I was using a brand new steering box and column.
3. Adjust the backlash between the sector gear and rack, proceed as follows:
a) Move the sector shaft several times from the side of the pitman arm to see that it turns smoothly then stop the pitman arm in the center position of its travel range.
b) Mount a dial indicator and adjust the backlash at the neutral position (center position) of pitman arm by turning the adjusting screw in or out so that the movement of the pitman arm becomes 0 mm.
c) Tighten the adjusting screw lock nut securely.
4. Fit the attachment (49 0180 510A) to the column shaft end and measure the worm shaft preload at the center portion of shaft travel. The preload should be checked then the center link is disconnected from the pitman arm.
Preload (with sector shaft): 0.6-1.2 kg (1.32-2.65 lb)
The first thing you'll want to do in the interior is get that column jacket back on. It should be pretty easy to slide it over the column, through the firewall grommet and into the steering box. Watch out for that wire on the column shaft, though.
Before you put those column covers back on, just get another look at all the wiring harnesses for the combination switch assembly.
5. Align the identification marks on the steering wheel and column shaft.
6. Fill the gear housing with lubricant (API Service GL-4, SAE 90).
Don't forget this! A brand new steering box does not have gear oil in it from the factory.
You should probably check your tire pressure before you get on the road and start thinking that your steering wheel isn't straight. Just for kicks, you might even want to boost it up to 34 or so lbs, just to give you even more responsive steering.
Now go find a good, twisty road and have a blast!
When I was all done, the car felt great. Tight and responsive, like a sports car should be. It even goes down the highway in a straight line. It was well worth the price to get a new box. To have done the same job with a used box, only to have it get loose again after a few dozen miles, would have been a real bummer. As it is, the car feels like new.
Happy rotoring!