Steering "return to center" is ill-defined - returning to alignment shop

[82DMC12]

Hey everyone,

I think I know what my next move is but I wanted to throw this out and see if anyone else has commentary.

I've recently completed a full frame-off on my car which included of course total restoration / replacement of the suspension and brake system. A few details:


DPI Spec front and rear suspension setup with added rear camber adjustment (upper arms), front caster limiting arms, but no front upper camber control
Grady steering rack (recently had it out to replace springs/cups and set tie rod pre-tension)
New tie rod ends
Amsteer ball joints
Superflex sway bar end bushings and DPNW front extension mount bushings
Superflex upper A arm bushings
DPI coilovers with ride height set to slightly lower than even wheel arch gap (made sure the frame was parallel to the ground, measured from the sides of the front and rear crossmembers)
There is zero play in the steering wheel
Hankook tires with under 1500 miles wear, set to 25 PSI front and 32 PSI rear
Just had an alignment done and the end results are below.


My only suspension/steering complaint is the "return to center" isn't very sharp and automatic like, for example my daily driver Audi. In fact I'm sure the DeLorean did a better job of this prior to the frame-off work too. What I mean is, on my daily driver I can take a turn, and as I come out of the turn the wheel basically goes straight without any assistance. In the DeLorean, it goes most of the way straight but then I need to give it a slight turn to "finish the turn" and go completely straight, and then once again I am tracking forward with no wandering or anything. It's not bad but it's not right.

I had the front end off the ground this morning and made sure there is no rubbing or notchy feel to the steering when turning lock to lock - it feels very smooth and doesn't feel worn in the center.

I assume the issue to be alignment related. It's been suggested that it is tire scrub which could be reduced by adding camber adjustment to the front. That is something I'm willing to do if there's no other solution.

As I said, I just had the alignment done and I got the feeling the shop wasn't very skilled on the alignment rack. The main alignment guy is out due to back surgery (he seemed VERY good last time I was in) and they have agreed to give it another look and set it to any adjustment I want because I'm not satisfied with it. They said they want me on the shop floor to confirm everything and sign off before they are done. Cool with me.

See the alignment below - the passenger side caster isn't equal to the driver side which I think is probably an issue. Also I think the toe in needs to be stronger so it's closer to 0.12 inches per wheel (shown here in degrees, but total toe should about 0.50 degrees according to the alignment service bulletin rather than 0.41 as I have now). I'm also going to make sure they loosen the sway bar to frame attachment points before adjusting caster with the limiting arms so that the LCA bushings aren't being tugged fore or aft. I noticed that the passenger side caster arm is about 1/4" shorter (screwed in) more than the driver side. I know the frame, etc can affect the squareness of it but I want them to try this again.

I'm considering raising the car up perhaps 1/2" front and rear to help out the front camber. Is there anything else I can tell the alignment shop to look for that could be contributing to this issue? It's possible that whoever ran the machine (Hunter) didn't set up the reflectors or whatever they are correctly on the wheels?

Just looking for ideas since I can't just go to the alignment place repeatedly every time I think of something else.

Here is my current ride height as well as the print out from the alignment last week.

69857

69858

[ssdelorean]

With all your "new" parts, did you put on new steering u-joints (both upper and lower)?
I had same issue as you are having (a couple of times) and it was my original u-joints. I cleaned them a couple of times but eventually replaced them with the new stainless Borgesen (sp?) units. Just wondering if yours are original and all gummed up like mine were.

[82DMC12]

With all your "new" parts, did you put on new steering u-joints (both upper and lower)?
I had same issue as you are having (a couple of times) and it was my original u-joints. I cleaned them a couple of times but eventually replaced them with the new stainless Borgesen (sp?) units. Just wondering if yours are original and all gummed up like mine were.

Good question, I actually have a steering shaft and U-joints from Darryl Tinnerstet, these are ball bearing U-joints and they have no play or notchy-ness..... still working exceptionally even though it's been many years since I installed them. Maybe I can loosen all the screws that lock the joints to the shafts/pinion and slide them up and down a bit to make sure one of them isn't binding, though I would think if that's the case I would feel the binding when turning the wheel even if the front end off the ground. Was that your experience? Did it feel notchy with the wheels in the air?

[ssdelorean]

I didn't know Darryl made any with bearings in them. Yeah, I would guess you would easily feel notchiness when moving while raised off the ground. Are they sealed bearings or could some road junk have gotten in there? Might be worth a cleaning either way.

Mine were so bad, my wheels would not go back to straight while making a turn all by them selves. The car would keep turning if I never touched the steering wheel. They were definitely worn down and gunk in the u-joints themselves. Even with gunk cleaned out, there were rough spots and hard to rotate.

[82DMC12]

I didn't know Darryl made any with bearings in them. Yeah, I would guess you would easily feel notchiness when moving while raised off the ground. Are they sealed bearings or could some road junk have gotten in there? Might be worth a cleaning either way.

Mine were so bad, my wheels would not go back to straight while making a turn all by them selves. The car would keep turning if I never touched the steering wheel. They were definitely worn down and gunk in the u-joints themselves. Even with gunk cleaned out, there were rough spots and hard to rotate.

Wow, that sounds like they were pretty bad!

These joints are sealed so it doesn't look like there's a good way to re-lube them. But, I had them completely out of the car and in my hands and they didn't have a worrisome feel to them. Maybe I'll put the front on ramps and try to re-seat / align them so that the full weight is in place though I doubt that makes a difference. Good thought though.

I recall Darryl marketing them as "ball bearing race U-joints" and they came with a new steering intermediate shaft. They are painted (not powder coated) black.

[mark w]

Deloreans dont have much caster so with a fresh and stiff steering rack, you may not get much return to center of the wheel.

[82DMC12]

Well last night and this morning I raised the car's ride height by about 3/4" front and back. With half a gas tank, it's now more where I originally intended to set it anyway, but I think I did it too fast before and it settled low. I actually ended up raising the rear by about 3 threads and the front by 2 threads. Now I can get my low-pro floor jack with a 2x4 on it under the front crossmember easily which was also getting annoying the way it was set before.

I've gone back and forth measuring from different places on the frame and it's about as good as it gets now. It's not an exact science for sure. Definitely don't use the body, the quarter panel wheel arch varies by about 1/2" side to side. That has no effect on the suspension so I only care about getting the frame as flat and parallel as possible.

I'll be going back to the shop on Thursday AM and I'm simply going to ask them to give it another look while I stand with them on the floor, let's try to get the caster as even as possible side to side and get the toe back to 0.25" total. If they can do that I'll be satisfied that they did everything they can do.

Can a Hunter alignment unit check tire scrub? Is that what they are doing when the machine asks them to turn the steering wheel lock to lock?

[81dmc]

Well last night and this morning I raised the car's ride height by about 3/4" front and back. With half a gas tank, it's now more where I originally intended to set it anyway, but I think I did it too fast before and it settled low. I actually ended up raising the rear by about 3 threads and the front by 2 threads. Now I can get my low-pro floor jack with a 2x4 on it under the front crossmember easily which was also getting annoying the way it was set before.

I've gone back and forth measuring from different places on the frame and it's about as good as it gets now. It's not an exact science for sure. Definitely don't use the body, the quarter panel wheel arch varies by about 1/2" side to side. That has no effect on the suspension so I only care about getting the frame as flat and parallel as possible.

I'll be going back to the shop on Thursday AM and I'm simply going to ask them to give it another look while I stand with them on the floor, let's try to get the caster as even as possible side to side and get the toe back to 0.25" total. If they can do that I'll be satisfied that they did everything they can do.

Can a Hunter alignment unit check tire scrub? Is that what they are doing when the machine asks them to turn the steering wheel lock to lock?
When you turn wheels lock to lock on an alignment machine, it's only used to measure caster angle and establish straight track.

As for return to center, mine has an aggressive feel until you go full lock. Once full lock, it will stay turning unless you move steering wheel.

[David T]

Well last night and this morning I raised the car's ride height by about 3/4" front and back. With half a gas tank, it's now more where I originally intended to set it anyway, but I think I did it too fast before and it settled low. I actually ended up raising the rear by about 3 threads and the front by 2 threads. Now I can get my low-pro floor jack with a 2x4 on it under the front crossmember easily which was also getting annoying the way it was set before.

I've gone back and forth measuring from different places on the frame and it's about as good as it gets now. It's not an exact science for sure. Definitely don't use the body, the quarter panel wheel arch varies by about 1/2" side to side. That has no effect on the suspension so I only care about getting the frame as flat and parallel as possible.

I'll be going back to the shop on Thursday AM and I'm simply going to ask them to give it another look while I stand with them on the floor, let's try to get the caster as even as possible side to side and get the toe back to 0.25" total. If they can do that I'll be satisfied that they did everything they can do.

Can a Hunter alignment unit check tire scrub? Is that what they are doing when the machine asks them to turn the steering wheel lock to lock?

The turning lock-to-lock is to measure and center the steering wheel. Castor is non-adjustable on a Delorean but it *can* be adjusted if necessary but if it is out of spec something is wrong and you should not try to adjust it. Steering effort is also a function of tire pressure so don't go below 23 psi for the fronts. Drag (tightness) in the steering will prevent the steering from returning to center. Changing the ride height will affect that too, it changes the castor. "Tire scrub" is what happens if the toe is not correct. In the rear it is called thrust angle. All of the suspension adjustments can affect steering return, some more directly than others. Before you go to an alignment shop you should grease and lubricate the front end, 1/2 tank of gas, replace any loose or worn parts and torn dust seals. Remove all the loose stuff in the trunk and passenger compartment and if you are really fussy use sandbags to simulate the driver's weight. Lube the steering column U joints and bushing. By lowering the ride height you reduce the amount of suspension travel and make the car more susceptible to damage from the road besides messing with all of the alignment specs. One more "tip". By raising the back of the car in relation to the front you shift weight to the front increasing the effort to steer the car and reducing it's ability to return to center. Typically when a car leads to one side, the steering wheel isn't centered, or doesn't return to center, it is a sign that there is a problem with the suspension or tires.

[82DMC12]

Thanks everyone. I might be making it sound worse than it is. It's just that it doesn't snap back to center like other cars (with power steering of course) do but I think I remember it going back to center more readily before too. Maybe I got the pinion tension a bit too tight. But it really does feel good with the wheels off the ground, nice and smooth. Maybe it will wear in once I get the alignment as perfect as possible.

And David my car does have some caster adjustment with the DPI caster arms. I can pull the LCA forward or backward as long as the sway bar attachments at the frame extension have enough slot.

https://deloreanindustries.com/most-popular/1-spec-coil-over-system-front/

[Helirich]

I’ve heard people say “Return to center” can be effected by camber, tire pressure, shocks and all sorts of stuff. But the only things that I have ever experienced do it are caster and too tight steering components. (Usually the sector shaft adjustment) Of course a rack and pinion doesn’t have the sector adjustment. Not sure if the Delorean rack has some kind in that regards, but most likely it’s caster. I read where Dave said there is no caster adjustment, but something could be bent. I don’t recall if you build is mostly stock, but I think you could effect caster with the sway bar. If you have the Delorean industry lower control arm braces, you could definitely effect it. Some other brands may also do this. I hate to sound like a commercial, but that is one upgrade I really believe in.

If you want to do some caster adjustment, remember the bottom of the wheel should go forward or the top back to give more caster. (And return to center) You don’t want to get that backwards.

[82DMC12]

I do have the DPI Caster arms. I'm thinking I might loosen my sway bar to front frame extension bolts and take all the tension off of the caster arm, if there is any. Then roll the car back and forth a bit and then tighten down the sway bar wherever the LCAs end up. Then tighten the caster arms just enough so that they keep the LCA from going backward and they're not influencing the position of the LCA. Then when I get to the alignment shop they have a neutral position to start with.

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[dmcman73]

I do have the DPI Caster arms. I'm thinking I might loosen my sway bar to front frame extension bolts and take all the tension off of the caster arm, if there is any. Then roll the car back and forth a bit and then tighten down the sway bar wherever the LCAs end up. Then tighten the caster arms just enough so that they keep the LCA from going backward and they're not influencing the position of the LCA. Then when I get to the alignment shop they have a neutral position to start with.

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Curious, did you torque all suspension bolts under pre-load when you reassembled everything?

[82DMC12]

Curious, did you torque all suspension bolts under pre-load when you reassembled everything?Yes, absolutely. I know that's not it. Gonna "reset" the DPI caster arms, and if these guys are still struggling with it all tomorrow, I'm bringing it someplace else. This is a fairly large shop but they admitted they basically give all alignments to one guy, he did my initial alignment after the frame off was done and he also found I had something funky going on with the inner tie rods. That guy was good and a pleasure to work with. I got the inner tie rods tuned up and tensioned but then when I went back to get the toe set properly I found out the good tech is out for back surgery and it sounds like the guy who tried to do it was struggling. I'll be back there tomorrow on the shop floor watching and helping whoever is doing it and hopefully we get it sorted.

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[82DMC12]

Yesterday I went back to the alignment shop and, thankfully, I was on the floor working with the tech. I did raise the car up 1/2" so that threw off all the old measurements which meant the alignment had to start from square one again.

As I was walking around the car as he was working, I saw the passenger side front alignment reflector thing that slipped and was no longer centered on the axle. Since the wheel is concave it was also pointing inward a bit too. I pointed this out to the tech "hey not sure if this makes a difference, but looks like this one isn't straight?". He was "surprised", said it "probably doesn't make a difference" but I insisted that he center it again. And of course once he rechecked everything with the computer it was all fucked up.

Anyway now everything was straightened out and we got caster on 3.8 deg each side and toe at 0.25 deg per side. This also got my camber back to within 0.5 degrees equal. Not perfect but without camber adjustment it isn't bad. The rear is pretty good with -0.5 deg camber and toe is within 0.10 deg equal with total toe at 0.44 deg. Could have got the rear toe "perfect" if I had more some half-thick shims but I'm not going to stress it.

End result? Return-to-center is lot better than before. Maybe not as good as my daily driver (power steering too though) but certainly better than it was.

[David T]

Yesterday I went back to the alignment shop and, thankfully, I was on the floor working with the tech. I did raise the car up 1/2" so that threw off all the old measurements which meant the alignment had to start from square one again.

As I was walking around the car as he was working, I saw the passenger side front alignment reflector thing that slipped and was no longer centered on the axle. Since the wheel is concave it was also pointing inward a bit too. I pointed this out to the tech "hey not sure if this makes a difference, but looks like this one isn't straight?". He was "surprised", said it "probably doesn't make a difference" but I insisted that he center it again. And of course once he rechecked everything with the computer it was all fucked up.

Anyway now everything was straightened out and we got caster on 3.8 deg each side and toe at 0.25 deg per side. This also got my camber back to within 0.5 degrees equal. Not perfect but without camber adjustment it isn't bad. The rear is pretty good with -0.5 deg camber and toe is within 0.10 deg equal with total toe at 0.44 deg. Could have got the rear toe "perfect" if I had more some half-thick shims but I'm not going to stress it.

End result? Return-to-center is lot better than before. Maybe not as good as my daily driver (power steering too though) but certainly better than it was.

When the Tech says "probably doesn't make a difference", that would not have instilled any confidence that he knew what he was doing. Too many techs really don't understand alignments, they count on the computer to do it all and tell them what to do. By getting the castor right you corrected your centering problem. Is the steering wheel straight when you are going straight on a flat road? Make sure your tire pressures are all correct, 23 front and 30 rear. Does the car want to go off to the left or right or will it go pretty straight if you take your hands off the wheel? Finally, it should not pull to either side when you apply the brakes. This final one has to do more with the brakes than the alignment.

[Josh]

Like Mark said, the two biggest items you are fighting against is the lack of caster and a stiff steering rack.

Not much you can do about the steering rack. You have adjustable upper control arms, so you can get more caster. You need to ask for this because the guy at the alignment shop will just adjust it to stock specs.
Most modern cars have 5+ deg of caster. A delorean has half of that stock.

Comparing a 40+ year old car to a much newer one will always leave you disappointed. I am not saying to settle, however there is only so much you can do in certain circumstances.

[David T]

Like Mark said, the two biggest items you are fighting against is the lack of caster and a stiff steering rack.

Not much you can do about the steering rack. You have adjustable upper control arms, so you can get more caster. You need to ask for this because the guy at the alignment shop will just adjust it to stock specs.
Most modern cars have 5+ deg of caster. A delorean has half of that stock.

Comparing a 40+ year old car to a much newer one will always leave you disappointed. I am not saying to settle, however there is only so much you can do in certain circumstances.

Be careful adding too much castor. It will increase steering effort and as you know, the Delorean doesn't have power steering to handle a lot of castor. There IS the possibility of adding power steering and if you do then you could consider modifying your alignment specs. All alignment specs are a balance and compromise with a lot of factors. Remember, the suspension was designed and optimized by Lotus Engineering and they did the best they could at the time. They were considered among the very best in suspension technology (and still are!).

[Josh]

Be careful adding too much castor. It will increase steering effort and as you know, the Delorean doesn't have power steering to handle a lot of castor. There IS the possibility of adding power steering and if you do then you could consider modifying your alignment specs. All alignment specs are a balance and compromise with a lot of factors. Remember, the suspension was designed and optimized by Lotus Engineering and they did the best they could at the time. They were considered among the very best in suspension technology (and still are!).

I have about 6deg of caster on my car, as well as some other owners on their cars.
I think you are giving lotus far too much credit for their work on these cars.
The stock suspension on these cars is a compromise to put it nicely, certainly not "optimized" or "the best"

[82DMC12]

All good thoughts guys, thanks. I probably won't find the need to get the alignment looked at again but if I did I would first get adjustable front upper arms so I can get the camber perfect at the same time. It would be interesting to experiment with different levels of caster but I wouldn't let this shop I was at do it!

[FABombjoy]

I too am running 6.5 degrees caster.

Cornering is great but with a manual rack you need to bring your good arms. It's understandable why book spec is way less.