Steering Rack Rebuild - Too Stiff Now?

[Tom '74 911]

Hello -
I just spent some time cleaning up and rebuilding the steering rack from my '74 911. After reassembly, it seems a little stiffer than before. I'm wondering how stiff is normal?

It slides back and forth smoothly and easily until I tighten down the thrust piece on the back side of the rack, then it gets quite a bit harder to move back & forth. The thrust piece was scored a bit on the face that contacts the rack so I sanded it back to flat with some fine sandpaper on a flat surface. I wouldn't say it's binding, just tough to turn using the coupling flange by hand.

While I didn't check the backlash spec that I found in a thread here for the thrust piece, I did just reassemble everything using the same exact shim stack that pre-existed under the cover plate.

Has anyone else run into this? I almost have to back off the coverplate over the spring completely in order for it to slide smoothly and easily.

Also, I did NOT replace any of the bearings as they both look fine and had no extra free play.

Thanks,
Tom

[Tom '74 911]

Just went back out and disassembled the rack (again) to try to troubleshoot the stiffness. Here's a pic of all the parts. Anything look out-of-whack? While the circle clip and washers shown are off, the ball bearing (#6202) is still on the end of the pinion. Also, the needle bearing (#1712) that goes on the other end of the pinion is still in the main housing.

One further question - where does the rubber O-ring go? I'm pretty sure it came from under the coupling flange, but there doesn't seem to be enough space for it to fit. . . shoulda taken some disassembly pics on the first go around.

Also included a pic from another thread showing a parts diagram of a rack that isn't exactly like mine, but similar. There isn't much info in either PET or the workshop manuals that I've been able to find.

Thanks,
Tom

[E Sully]

I will be working on mine next month, can't offer advice, but this thread might help.
Steering Rack "Rebuild" Procedure

[bavaria911]

I recall rebuilding my rack. On your diagram, if part numbers 7 to 4 were out of sequence or backwards the rack was much different -- harder to move lf/rt.
Good luck.

[zl0ca]

Tom,
Did you ever figure out your problem. I'm facing the same issue. As soon as I put the thrust plate in the rack is stiff and doesn't recenter.
Thanks

[Flieger]

Stiff is normal. It will take a lot of force if you try to push the rack but you should be able to turn the pinion with your fingers if you have the yoke piece installed.

[kuehl]

One issue you may encounter in 'rebuilding' the rack and pinion is you can't rebuild the rack and pinion gears. Once the gear teeth are worn, they are worn. The primary issue is the rack gear. You can clean the non wearable components and replace bearings and bushings.

90% of driving non-track (city and highway) involves trying to keep the vehicle running down a straight line, making subtle adjustments with the steering wheel. Since the pinon gear is located within the center of the rack and these adjustments, or minor turning of the steering wheel, are only a few degrees in either direction the gear teeth in the center of the rack receive all of the attention or wear. The wear on the pinion gear is not as great because its teeth are purposely 'harder' since they will be making more revolutions or turns over the rack gear teeth.

If you find the backlash of the gears is loose in the dead center position and you shim up the shoe that pushes the pinion gear against the rack gear you may find that the rack is harder to turn once the pinion gear moves away from the center teeth of the rack.

Otherwise, overall, the 911 related family manual rack gear and its design is quite durable.

[Tom '74 911]

Originally Posted by zl0ca

Tom,
Did you ever figure out your problem. I'm facing the same issue. As soon as I put the thrust plate in the rack is stiff and doesn't recenter.
Thanks

So sorry for the delayed response. I never found/solved the issue if I recall correctly. I think the rebuilt rack, sitting on the bench, was stiff. But after reinstalling it, with the additional leverage from the steering wheel and all the other steering related components, everything felt normal. I wish I had a better memory of the specifics, but that's all I've got... I'm not even that old and my brain is already losing capacity. : )

Tom

[jjeffries]

I am dealing with this same issue right now. Car is an 82 SC WITH 183k miles. I bought the car apart and did the rack refesh when I replaced the tunnel fuel lines. I bought the correct bearings and, as the rack went back together, felt very pleased with myself (always a bad sign).

Like the OP, I put it back together exactingly, but the finished product was too stiff...binding feel to it. I did a couple more tear downs but eventually put it back in the car and hoped that, once my motor was rebuilt and the car got some miles on it, the rack would loosen up. That has not happened in the ca. 600 miles I've done so far. The guy who aligned it noted that the rack was binding and it even makes some slight groaning noises at parking lot speeds. It needs to be remedied.

I pulled the rack this morning and tiried different combinations of tightening and loosing the rack's components, and verified that it is the shoe/puck which is the variable. I'm wondering if shortening the tension spring or shimming out the cover (say with some home-cut thick gasket material) would yield a satisfactory fix? I understand the rack needs a certain amount of tension. Any thoughts appreciated. John in CT.

[Flieger]

The purpose of the puck is to remove the backlash (slop) in the rack and pinion. However, there does seem to be an excess of force there. I'd say removing some of the factory shims is the easiest method. Just don't lose them and keep notes about how many were there originally.