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Been chasing a phantom handling issue and myself (and now my mechanic) are at our whits end. The issue is pretty much a lack of self-centering. Basically, if I turn the wheel, the car will continue to turn in that direction unless I manually turn the wheel back. There’s literally no self-centering at all. Tires are 245/45R18 Nittos and I have 3.5° positive castor. My mechanic thought it was the idler arm being too stiff, but after replacing it (MOOG K6100), the issue is still there.
Anyway, him and I got to talking and I mentioned that I added a 2.0 GPM power steering pump flow restrictor in order to make the steering feel less light and floaty. After mentioning that, he wants to remove the reducer and put the old one back in to see if that helps.
Is it possible that the reducer could be affecting self-centering? Or is the answer staring me in the face (I need more castor)?
3.5* caster is not a lot, especially for those wide tires, but "no centering" at all? hmmm...
Factory Power steering?
Has steering box been rebuilt?
There are two lash adjustments. One of them could be too tight.
It sounds like there is too much friction or binding somewhere.
If you disconnect the PS ram, you basically have manual steering.
With the wheels off the ground, the steering wheel should turn easily.
If not, you have too much friction, somewhere.
Gearbox, rag joint, column, etc.
Last edited by leigh1322; Oct 6, 2025 at 11:22 PM.
3.5* caster is not a lot, especially for those wide tires, but "no centering" at all? hmmm...
Factory Power steering?
Has steering box been rebuilt?
There are two lash adjustments. One of them could be too tight.
It sounds like there is too much friction or binding somewhere.
If you disconnect the PS ram, you basically have manual steering.
With the wheels off the ground, the steering wheel should turn easily.
If not, you have too much friction, somewhere.
Gearbox, rag joint, column, etc.
Whoops, just seeing this!
Yeah, the PS box is new from Corvette Central and was much more difficult to spin than the original I took off. Last week I loosened the lash up top nearly an entire turn, and that helped a tad. Now it returns a bit on left hand turns but none at all on right hand turns. The trade off, however, is the steering is far more vague now. The steering wheel is also cocked -90 degrees so I need to center the power steering valve. I'll try to do that this weekend - hopefully that helps some. If not, I'll have to see what else might be binding.
Yeah, the PS box is new from Corvette Central and was much more difficult to spin than the original I took off. Last week I loosened the lash up top nearly an entire turn, and that helped a tad. Now it returns a bit on left hand turns but none at all on right hand turns. The trade off, however, is the steering is far more vague now. The steering wheel is also cocked -90 degrees so I need to center the power steering valve. I'll try to do that this weekend - hopefully that helps some. If not, I'll have to see what else might be binding.
You are on to something here. A) there is no such thing as a new box, it must have been rebuilt. B) It should not feel tight C) You need to make the 2 box preload adjustments on the bench, not in the car. D) No one rebuilds these as good as GTR1989. His boxes are better than GM made them, with perfect preload & feel & less slop.
Yeah, the PS box is new from Corvette Central and was much more difficult to spin than the original I took off. Last week I loosened the lash up top nearly an entire turn, and that helped a tad. Now it returns a bit on left hand turns but none at all on right hand turns. The trade off, however, is the steering is far more vague now. The steering wheel is also cocked -90 degrees so I need to center the power steering valve. I'll try to do that this weekend - hopefully that helps some. If not, I'll have to see what else might be binding.
What is a power steering box?
Borgeson makes a power steering box. All C3s came with variants of the same manual steering box, with a power assist ram. Post a photo!
If you now have two manual steering boxes, send the original to @GTR1999 to rebuild. He'll mark it for steering center, and lash it correctly. Set your alignment from that point.
If the PSCV is not centered the steering wheel will pull to one side or the other, here's how to balance the PSCV:
If your steering wheel is not centered, here's how to fix that:
Hmm, I’m rather confused now. I was under the impression moving the tie rods in and out was only to make fine adjustments, if the steering wheel was off less than 30° or something. For a full 90°, I thought you had to disconnect the steering box from the pitman arm, and then spin the steering wheel 90° before reattaching it.
Doesn’t the steering box have four notches, meaning it can be installed in the North, South, East, or West positions? Or am I completely off base here?
You are on to something here. A) there is no such thing as a new box, it must have been rebuilt. B) It should not feel tight C) You need to make the 2 box preload adjustments on the bench, not in the car. D) No one rebuilds these as good as GTR1989. His boxes are better than GM made them, with perfect preload & feel & less slop.
Yeah I wish I had known that beforehand. The Steering box was such a pain in the *** to get in the first time around, I’d hate to have to pull it out and then struggle to get it back in again. But if that’s what I have to do then I’ll have to suck it up.
Borgeson makes a power steering box. All C3s came with variants of the same manual steering box, with a power assist ram. Post a photo!
If you now have two manual steering boxes, send the original to @GTR1999 to rebuild. He'll mark it for steering center, and lash it correctly. Set your alignment from that point.
Yes sorry, I know it’s technically a manual box, but I’ve gotten into the habit of calling it power. I didn’t realize there were different boxes. I simply bought the one CC had listed for an ‘81.
The old box is painted and looks gross, so I’d hate to send it out to get rebuild if it’s gonna look like crap. I’ll do the adjustments needed to get the PSCV and steering wheel centered, and if those don’t fix my issue, then maybe I’ll see if he wants to rebuild the “new” one.
Yes sorry, I know it’s technically a manual box, but I’ve gotten into the habit of calling it power. I didn’t realize there were different boxes. I simply bought the one CC had listed for an ‘81.
The old box is painted and looks gross, so I’d hate to send it out to get rebuild if it’s gonna look like crap. I’ll do the adjustments needed to get the PSCV and steering wheel centered, and if those don’t fix my issue, then maybe I’ll see if he wants to rebuild the “new” one.
So you have a stock C3 (manual) steering box from an 81, along with a PSCV that needs to be aligned, and a stock power steering ram.
There were changes to that box over the years, but the big change is the spline count. I sent a 79 box to @GTR1999 to be rebuilt. It needed everything, so I got it back with early internals, which changed the spline count. No problem, I just needed a new coupler (half of the rag-joint assembly), which I needed anyway. Ask him, but he will paint it, too, so I'm sure he has a hot tank to remove your old paint. It won't look gross when you get it back.
If the box didn't come marked, you will need to find "high center". All alignment adjustments come from there (including the tie-rods). Make sure your steering wheel is at 0 degrees when the box is at high center.
If your PSCV offends thee, cut it off! You can replace it with the Borgeson 990002 manual drag link adapter (Amazon link), to get immediate manual steering, and be halfway to a Borgeson power steering conversion, which I highly recommend over mucking about with stock power steering.
Here's my rebuilt box from @GTR1999, marked for high center, and repainted (a PO had powdercoated the lid, which I asked to keep, otherwise it would look OEM as well).
Last edited by Bikespace; Oct 24, 2025 at 12:01 PM.
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Originally Posted by rabinaba
Hmm, I’m rather confused now. I was under the impression moving the tie rods in and out was only to make fine adjustments, if the steering wheel was off less than 3% or so. For a full 30°, I thought you had to disconnect the steering box from the pitman arm, and then spin the steering wheel 90° before reattaching it.
Doesn’t the steering box have four notches, meaning it can be installed in the North, South, East, or West positions? Or am I completely off base here?
Often, when the PSCV is replaced, the gap between the old and new components differs, which can cause issues with the steering wheel.
That is when you need to adjust the tie rod ends.
You said that your steering wheel is off by 30% so the steering box or the pitman arm is where you should look first.
Often, when the PSCV is replaced, the gap between the old and new components differs, which can cause issues with the steering wheel.
That is when you need to adjust the tie rod ends.
You said that your steering wheel is off by 90% so the steering box or the pitman arm is where you should look first.
So you have a stock C3 (manual) steering box from an 81, along with a PSCV that needs to be aligned, and a stock power steering ram.
There were changes to that box over the years, but the big change is the spline count. I sent a 79 box to @GTR1999 to be rebuilt. It needed everything, so I got it back with early internals, which changed the spline count. No problem, I just needed a new coupler (half of the rag-joint assembly), which I needed anyway. Ask him, but he will paint it, too, so I'm sure he has a hot tank to remove your old paint. It won't look gross when you get it back.
If the box didn't come marked, you will need to find "high center". All alignment adjustments come from there (including the tie-rods). Make sure your steering wheel is at 0 degrees when the box is at high center.
If your PSCV offends thee, cut it off! You can replace it with the Borgeson 990002 manual drag link adapter (Amazon link), to get immediate manual steering, and be halfway to a Borgeson power steering conversion, which I highly recommend over mucking about with stock power steering.
Here's my rebuilt box from @GTR1999, marked for high center, and repainted (a PO had powdercoated the lid, which I asked to keep, otherwise it would look OEM as well).
I’m assuming by “high center”, you mean the true center point of the box, where it becomes slight tighter/heavier to move through?
I’m assuming by “high center”, you mean the true center point of the box, where it becomes slight tighter/heavier to move through?
Yes, exactly. Ideally, it's at the same point as the center of the left to right swing of the box (turn to the stop, count the turns to the other stop, turn halfway back to the middle).
I'll see if I can find a thread where @GTR1999 describes it better.
This point needs to line up with zero on the steering wheel, or else your turn signals won't work correctly.
Here's a relevant quote:
Originally Posted by GTR1999
As mentioned if the only change was the control valve then I would agree the position on the center link is probably the issue. If the box was rebuilt with new gears or a different box was installed then that most likely is the change in addition to the valve position. If the box was replaced, rebuilt, or just put back on the high center position should be marked clearly, if it was even checked, so you know where the box should be on center. This may not be true center either, you want it on high center. In theory they should both be the same but most of the time they are off up to 90*. Referencing the wrong center will not give the tight straight line driving it should have, then you blame the box as being junk and go out and buy a jeep box or rack system. If setup correctly, all parts functioning as they should, the steering is actually pretty good, convincing some of this though is not worth the efforts anymore.
Yes, exactly. Ideally, it's at the same point as the center of the left to right swing of the box (turn to the stop, count the turns to the other stop, turn halfway back to the middle).
I'll see if I can find a thread where @GTR1999 describes it better.
This point needs to line up with zero on the steering wheel, or else your turn signals won't work correctly.
I'd still 100% suggest manual steering with a stock box, or swap to a Borgeson (or R&P) if you want power steering. Especially in a restomod.
Yea I definitely want power steering. Growing up, my father had classic cars without power steering, so I’ve driven a few and know how much of a pain it can be at times. That’s frankly not what I want for this car - I want it to feel as close to a modern car as this chassis will allow.
The more I think about it, I probably should’ve upgraded to Borg, but I’ve always been apprehensive about cutting up the steering column to make room for it. Not to mention it ain’t cheap and I have leaky calipers begging to be upgraded to Willwoods . I also have a sneaking suspicion I’m going to end up wanting more self-centering than these upper control arms will allow for.
It’s funny, aside from the steering wheel being cocked 90°, the turn signal is how I realized my steering wasn’t centered. Turning on the right blinker is great, left is a crap shoot!
I’ll go through the instructions here, as well as the ones Jim Shea posted on the forum a while back, and see if any of that helps. If not, I’ll have to decide what my other options are.
From what I have read here you should sort out that steering box and get the steering wheel centered up first. Getting Gary to rebuild your original would be a wise choice.
There are other things that can contribute to the non-returning steering wheel.
Have you checked for loose wheel bearings on the front wheels? Even a small amount of play can hinder them returning.
From what I have read here you should sort out that steering box and get the steering wheel centered up first. Getting Gary to rebuild your original would be a wise choice.
There are other things that can contribute to the non-returning steering wheel.
Have you checked for loose wheel bearings on the front wheels? Even a small amount of play can hinder them returning.
I have not, and in all honesty, the wheel bearings are the ONE thing I didn’t address during my rebuild.
Do you have a way to measure caster at home? I have this Longacre package (Amazon Link), but you can get close enough with your phone and a 3D printed adapter. Technically, anything made of wood (like a cross to fit your rims made from 2x4s) was 3D printed by a tree.
I was able to get 6 degrees in my 80 with SPC upper control arms (with manual steering, BTW). Those aren't cheap, and are now twice the pre-COVID price. Perhaps a set of offset UCA shafts is within budget? I have a set of Energy Suspension UCA bushings that I'll never use, if you need them.
If you don't have a front spreader bar, put one of those in, too. I have the Speed Direct Shark Bite spreader bar. Another part that is twice as much as it should be, but really works. https://www.speeddirect.com/shop/196...k#attr=973,975
The wheel bearing issue is worth checking, too, but easy enough to fix!
LS Swap - Power Steering Pump Reducer
. I also have a sneaking suspicion I’m going to end up wanting more self-centering than these upper control arms will allow for.
