Tackling ‘memory steer’ starts with taking a close look at the most recently completed chassis work. Often that’s where the problem started.
By Allan Janssen
It’s not uncommon for technical help lines to get calls related to a suspension issue in which the steering wheel doesn’t want to return to center after a turn.
Not to be mistaken for a normal steering pull (which could stem from an alignment issue or a low tire), this condition is called ‘memory steer’ because instead of straightening out, the vehicle continues to pull in the direction it just turned.
In other words, it has a “memory” of that steer.
It can be caused by a number of factors, but many will tell you it can often be traced back to simple installation error.
“The most common occurrence is post-part replacement,” says Mac McGovern, director of marketing and training at KYB Americas Corporation, maker of KYB shocks and struts. “Vehicles don’t often manifest that kind of symptom due to wear or age. Most parts tend to deteriorate or become looser over time, rather than tighter. So, in that sense, memory steer is not so much an ‘Alzheimer’ thing as a ‘youth’ thing. More likely it’s because of a poor quality part, or a poorly installed part, rather than wear, dirt, or fatigue.”
Matt Housewright, a “Guru on Call” with Federal-Mogul’s Garage Gurus Technical Education Network, agrees. He says suspension work is still viewed by some do-it-yourselfers as relatively straight forward. “We’re getting more calls on this than ever on this issue,” he says. “You really have to watch out for errors in DIY jobs.”
He says an increasing number of amateurs tackle steering and suspension work without adequate knowledge of proper procedures or torque specs. So a key question you should ask when trying to diagnose memory steer is, “Did the problem exist prior to installation of new parts?”
If shocks or struts have been replaced, examine all related components, with a particular focus on the upper strut mounts.
“For most modern vehicles with strut suspension, the most common cause of memory steer is the bearing in the upper mounting plate,” says Joe Bacarella, manager of technical research center, and product training for Tenneco’s Monroe brand of shocks and struts.
Lack of free bearing movement will cause the stickiness that people report with memory steer. If you look you can sometimes find evidence that the inner bearing has “skidded” inside the strut mount. That can stem from compression force damage, perhaps from a defective jounce bumper when the vehicle bottomed out. Crushed parts tend to stop functioning smoothly.
“Sticking or binding can be a real problem,” says Bacarella. “And it’s the kind of thing you look for once you’ve seen it before.”
Proper inspection also includes checking the upper mount for degradation, the bearings for grittiness, contamination, and free movement, the upper spring seat for structural integrity, and the dust boots for rips or tears.
“When you take the system apart, you need to pay close attention so you can reassemble them in the right order,” says McGovern. “There are a lot of small parts, like bushings and insulators and washers. You really have to watch those things.”
When you install, connect the upper mount first, but don’t tighten it down. Start one or two of the nuts and leave them fairly loose, so the strut assembly can settle and align in the proper place. Then put the lower mounting bolts on. Lower the car on the alignment rack to proper ride height (not hanging) and jounce it a couple of times to allow the components to settle properly. Then tighten all nuts to specification at the vehicle’s static ride height.
On light trucks, the problem is more likely to be related to ball joints, says Housewright.
“When it comes to ball joints, you can’t stress enough the importance of proper torque procedures and following the step-by-step installation procedures,” he says.
Rookie mistakes like hammering in the ball joints, or using a press on the wrong area of the ball joint, will cause a binding or resistance in the returnability of the steering wheel back to centre.
“If you have memory steer, that returnability is not happening anymore,” he says. “And it’s very unnerving when it happens. When you lose it, you’ll know it!”
Technicians should take the opportunity while the suspension is apart, to remove and clean the camber/caster sleeve so it’s able to move freely. If it’s seized or damaged, replace it. Also inspect the steering knuckle itself for damage. Clean dirt, rust, and burrs from bore and recess, including the recessed area into which the ball joint flange fits.
“That knuckle has to move freely. If it doesn’t do that, the restricted motion will replicate itself on the road,” says Mike Caron, a technical product specialist for Mevotech.
He also cautions against the improper use of a ball joint press. Never use the press without the proper adapter, and make sure the adapter fits the outer flange area. Placing the press directly on the ball joint can cause damage.
“If you press a ball joint and you hit the crown and not the flange—and some applications don’t have much of a flange on them—you could crush the Belleville spring and you will instantly create a memory steer issue,” says Caron.
Finally, use the correct torqueing sequence when installing the ball joint. Start by hand-tightening the lower ball joint. Then place in the camber/caster adjustment sleeve for the upper ball joint. Do not tighten the upper ball joint yet. Just hand-tighten the nut. Using a torque wrench, torque the lower ball joint to about 35 ft-lbs. Then torque the upper ball joint to 70 ft-lbs. Then re-torque the lower ball joint to specification (anywhere from 150 to 190 ft-lbs). Do not use an impact wrench.
“The ball joints have to be torqued to very specific specs,” says Caron. “They have to be installed with a torque wrench that goes ‘Click-click,’ not an impact gun that goes ‘Zzzzt-Zzzzzt!’ The impact guns are great for taking things apart. They save a lot of time. But they’re not designed to put things together.”
Asking the right questions, inspecting all parts thoroughly, and installing new parts carefully are the keys to eliminating memory steer.
Hi, very few information bases have these torque spec’s, they don’t always have the procedure for something even the system considers common knowledge. I’ve usedi both Alldata, which is useless, Mitchell on demand, pretty good and easy to find info to Identafix, good info but hard to locate with in it’s system. How can our industry get to OEM’s to release the required information?
PS; I never hammer them in, I do take care about where i press but always use a air gun to install nuts. Thanks for the info and advise, I will follow all precedures I’m aware of.
I had ball joints replaced by ford and ever since this has happened, my truck pulls wherever the road goes, bumpy road are bad because it is hard to keep it straight and I hav roost control because of it on a little bit of snow. Alignment is good but I have heard it could be a sticky ball joint, the steering wheel
Is never c eyes but mechanics have aperently centres it many times but it never comes
I have the same issue. New ball joints, steering arms/tie rods, steering box, new tires. 3 shops, $2800 I’ve taken it apart myself and cannot get ball joints tightend without locking spindle up. I even changed joints again (mevotech) I just purchased truck from a dealer for $10.000 I’m ready to trade it in go back to GM and take a bath.
I have a 2003 f350 had new ball joints installed the steering wheel returns all but the last 1/4 of the steering wheel both directions , very hard to steer at that point , not sure the shop torqued them correctly , taking it back in next week hope they can fix it or to the dealer I go
I have a 1997 E250 ext van that I’ve owned since it was 6 months old. I have 140k on it and had ball joints done for the second time since I’ve owned it. Now it has horrible memory steer. I replaced shocks, brakes, tires and ball joints at the same time. Ball joints installed by mechanic. Alignment done by another mechanic shop. The mechanic who did the alignment told me to drive over a lot of bumps & pot holes to ‘loosen’ it up. He said I need to put atleast 5k miles on it to ‘break them in’. He told me that there have been alot of similar issue and that it’s the compound they use to make the joints. I think he’s full of sh*t and covering for the other mechanics screw up. Someone else told me be it probably needs 1 degree of positive castor and when I mentioned that to the guy who did the alignment he gave me a long story of how complicated it is to do a castor adjustment. Am I get BS’d or what?
I have a 2019 Acadia just put new Michelins on it it was pulling to the right had an alignment done 2 hours later was pulling to the right again had another alignment done an same thing pulling again after 2 hours or so of driving anybody know what’s going on here