Early 90's Corolla: Noise and tire cupping

Maintenance/Repairs
1

I’ve had some noise while doing slow turns for the past 9 months or so, seemingly coming from the rear of the car. It’s sort of a rrrrr ----rrrrrr -rrrrr noise, but it has a slight buzz to it too, like something is vibrating. It’s hard to say which side it is coming from. It only occurs when turning to the right. But recently it sometimes occurs when going straight, but slow, like when approaching a stop light. Braking seems to have no effect. The other symptom is the left rear tire has very definite cupping. There are easy to see flat spots on the surface of the tire. The tire isn’t perfectly round in other words, but more like an alternating sequence of flat spots. The other 3 tires don’t have this cupping, they show a normal wear pattern.

I jacked up the rear of the car and tested each tire to see if I could detect anything wrong. I pulled, pushed, twisted. I could detect no play at all in either tire. I spun the tires by hand, and there was no unusual noise. They both just spun quietly, freely, with no apparent wobble or anything unusual. The service manual says the rear wheel bearing is bad if there is 0.2 mm of axial play. I doubt I could have detected 0.2 mm of play the way I did it, just pulling on the tire.

The only other thing I noticed is that the (rear) toe-in adjustment is different on the left than on the left. By this I mean the eccentric bolt-gadget is set on different marks on each side. The right one looks like it is set to have more toe in that the left. The right one is 4 marks positive toe-in, the left is 1 marks positive toe-in. I’m assuming these marks are just for reference, and don’t represent the actual toe-in, just that’s the setting it took to get the rear wheel alignment correct when the car was built.

So what do you think? Do I have a rear wheel bearing problem? A rear-tire alignment problem? Something else?

2

Did this problem start after an accident, or hitting a big bump?

3

The strut on that left rear tire is totally shot and not dampening the spring oscillation. That is causing the cupping and noticable out-of-roundness of the tire. I’ll bet that you could remove that strut and move the piston in and out with almost no resistance.

4

Does the noise get louder the faster you go? It sounds like you have two problems the bearing with a noise and a alignment issue with the cupping.

5

@auto-owner … No accident and didn’t start after hitting any big bumps.

@BustedKnuckles … good idea. I wouldn’t have thought of that. I did notice during my inspection the rubber boot that is supposed to cover the strut (inside of the coil spring) is torn and kaput. Maybe the problem is just the strut causing the tire to cup, and the noise is just the cupped tire causing a vibration.

@SteveC76 … no, the noise isn’t evident above 15 mph. It’s most clearly heard at 5-10 mph, when turning to the right. It may be the noise is there at higher speeds, but masked by other road noises. You are right that there may be two problems, maybe both the bearing and the strut, or the bearing and alignment problem, and my method described above for testing the bearing isn’t good enough.

For testing the bearing the shop manual says to remove the wheel and use a dial indicator to measure the axial play, hub to axel, which is supposed to measure less than 0.2 mm if the bearing is ok. I don’t have a dial indicator, that is the problem. I’ll have to get one it appears.

For the second problem I’m sort of leaning toward the strut being bad, rather than alignment, simply b/c while I might have curbed the right rear tire at some point and bent the alignment a tad askew, it is unlikely that would happen to the left rear. And it is the left side that has the cupping problem.

One other idea for the cause of the cupping I had thought of was the tire is out of balance Like maybe a wheel weight or two fell off that tire since the last time I purchased tires (and had them balanced), maybe 40 K miles ago.

6

The tire is no longer balanceable due to it’s anomalous wear, but the cause of that wear is the suspension.

There’s no doubt in my mind that Busted is correct, but I would expand the suggestion to include new front struts and a good, thorough checkup of the chassis. You probably have shrunken, cracked bushings perhaps even with chunks missing. You have a lot of old rubber under there. And, assuming the front struts are original too, I seriously doubt if the strut’s damper is working anymore.

By the way, your rubber spring bushings and strut mounts are certainly shot too. Changing them when you do the struts will almost certainly reduce a lot of road noise, and, along with fixing any other problems found, will almost certainly restore the car’s handling. The difference will amaze you.

Now, I know I’m suggesting a lot of work on an old car, but if he cost is a problem you can do the rear now and the front later. Or buy a case of beer and the parts and visit a mechanically knowledgeable buddy. Just be sure to save the beer until after the work is done. I remember years ago inviting two coworkers of mine, over to assemble a steel shed. There we were, a Sr. Quality Engineer, a Sr. Manufacturing Engineer, and a Sr. Design engineer, with a big box of parts and a case of beer. We started on the beer before we started on the shed. The next day I had to take the shed apart and put it back together properly. We had a blast that day, but the assembly wasn’t a job to be proud of.

7

Here’s some new data: I did the “push down really hard and fast test” on all four bumpers, taking note how quickly the bumper returns to the original position. Both rear corners were the same. Both front corners were the same. But the front returned with few if any oscillations, while the rear oscillated a bit, a damped oscillation, maybe a second, second and a half, before returning to the original position. I’m not sure if this means anything, b/c the front and rear have such different weight loads. With much less weight on it, it’s not that surprising the rear would oscillate more than the front. I don’t notice anything in particular going over bumps that would indicate there’s a significant suspension problem. The car’s ride seems to be about the same as always.

I did notice one difference between the rear corners on the “push test”. There was a definite noise heard on the left side, not on the right. Sort of a squishing noise, with a slight “bump” noise. BK and TSM seem like they may be on the right track, struts and bushings are both suspects. Haven’t quite yet committed to replacing the struts and bushings though.

8

@GeorgeSanJose‌, your bump test just confirmed bad struts on the rear. The rear of these cars is very light. The struts should have absolutely no problem preventing any oscillation from happening. If you saw any oscillation, the struts are toast.

9

It should come back to level and stop instantly. Bad struts! Might as well do all bushings to get the best handling you can get.

10

But if the problem is caused by the rear struts being worn out, why does it only affect the left side tire? The amount of oscillation seen is the same (both amplitude and duration) left vs right, but the right side tire has no unusual wear pattern at all.

I’m not disagreeing with the assessment being made by most everybody that the struts are the most likely culprit. On a 20+ year old car with 200K miles, it wouldn’t be that surprising that the rear struts (at least the shock portion) needed replacement. But the reason the left side is the only side with the tire wear pattern remains unexplained.

I have a friend with a newer Corolla and I’ll test that one’s rear suspension vs mine using the push test this weekend.

11

Bounce test is indicative, but not absolute. The condition of that left tire is far more absolute. And, besides, shocks and struts should always be replaced in pairs, so don’t try to save money by not doing the right side. Do the job right.

12

Yes, if I replace the struts, I’ll do both sides. A “strut replacement” is really just replacing the inner shock gadget, right? i.e. You re-use the coil springs. Probably replace the bushings while at it.

Here’s the thing though. I’m not positive the problem is the struts. And I don’t want to replace them if they are still serviceable. Mostly b/c it’s pretty big job and I’m lazy … lol …

The tire wear pattern is a definitely a clear problem. I agree w/that. But it may not have anything to do with the suspension. I’m looking for some irrefutable evidence I guess. It could just be a defective tire for example. Or that – being lazy – I didn’t rotate the tires often enough. Or that tire lost a weight or was never balanced properly in the first place. If a tire is badly out of balance, no matter how well the suspension works you could get some unusual wear patterns. That’s what I’m thinking anyway.

13

George, the tire wear pattern is not a “clear problem”, it’s a clear symptom. The vehicle is roughly 20 years old, an age when struts can be expected to be shot, with symptoms that point directly to struts. Everything I’ve seen in this thread shouts “struts”. And yes, there could also very well be worn out bushing at this age.

I understand that having struts replaced is expensive. But if you want to fix the cause of our cupped tire, you’re simply going to have to “bite the bullet” and change them. And, not to be redundant, but you need to get the bushings checked out too, along with the tie rod ends. It’s simply time for some chassis refreshment.

Technically, you could say that a strut replacement involves only the replacement of the damper (the inner strut thing), but to change that requires that everything around it be disassembled, and to put the old rubbery bits (the upper mount and the spring bushings) back on is really doing a half-hearted job. These parts are all 20 years old and have been hammered for that long under hundreds of pounds of compression (static load) and far more peak load (bumps and vibration). Rubbery bits dry, crack, and harden over time. Compressed under those loads they lose their ability to absorb shock and vibration, and eventually begin to crack and fail totally. Your main cost is in the labor, not the parts. and replacing the rubbery bits doesn’t cost one more dime in labor than putting the old ones back in.

Oh, and it means replacing the bumper stops and the dust boots too. The bumper stop is important because it absorbs the energy when the damper begins to approach its limit, preventing physical damage to the damper. It’s actually like a “backup spring”, in a sense.

In short, doing a strut replacement means replacing all the rubbery bits too. AND it means getting an alignment… after checking out all the other rubbery bits that aren’t on the strut assembly.

You didn’t say exactly what year your Corolla is, but I’ve attached a link to a drawing and parts list for a '92 just to give you an idea what I mean when I say everything has to be disassembled anyway.
http://www.toyotapartsoverstock.com/showAssembly.aspx?ukey_assembly=497790&ukey_make=1060&ukey_model=15430&modelYear=1994&ukey_category=21651

Oh, and I almost forgot, the springs themselves do not usually need to be replaced. Unless they’re broken, or they’re tested and below spec (nobody tests them unless something seems “off”, because they’re spring steel), they’re reinstalled over the new strut.

14

Just a note for safety if you do replace the struts yourself you need a spring compressor to compress the springs before you disassemble the strut.

15

Good comments. You folks are sure keeping me on my toes! It looks like I’ll be doing a strut replacement job. I’ll do it right, not going to scrimp and keep the same bushings and other rubber parts, they’ll all be replaced too.

What about the wheel bearing? That was what I first suspected as the cause. But when I did my ameaturish version of a wheel bearing test – jacking the car up, spinning the tire by hand listening for any unusual noise, and pulling and twisting on the tire to see if there is any play – no play, no odd sounds, nothing unusual.

Is there any chance that the left rear wheel bearing could be worn out and contributing to the unusual wear pattern? If so, I’d like to know beforehand b/c I don’t want to replace the struts, replace the tire, then have the new tire do the same thing b/c the left rear wheel bearing is kaput too. It will be easier to replace the wheel bearing if I do it at the same time I replace the struts.

The FSM says the way to test the rear wheel bearing is to remove the tire and measure the axial end play. But here’s the thing about that: The tolerance is 0.05 mm!!! If the axial end play is over 0.05 mm, the wheel bearing is judged bad, and should be replace. 0.05 mm? That’s like a couple dozen atoms! OK, not being serious. But 0.05 mm isn’t much. I couldn’t test for that with my twisting and pulling routine, that’s for sure. Even if I remove the wheel first. I’d have to buy a fancy dial indicator to even measure that amount of end play.

Here’s the question: Is there a more simple way to eliminate the wheel bearing as contributing to the cause of the tire wear problem? It seems like the play would have to be on the order of a mm at least, maybe a couple mm, before it would contribute to a tire wear pattern.

16

Bad bearings will squeal and growl, and really bad bearings will give you noticeable rough spinning and axial play. If you feel none of this, the bearings are most likely good.

17

I recommend that you not use its likely contribution to a tire wear problem as the point at which you consider a bearing as needing replacement. A bad bearing can manifest itself as a much more serious problem, like seizing on the highway.

In addition to elevating the car’s corner and checking for play, spin the wheel as Busted suggested and listen for excessive noise. Sometimes you can also feel a bad bearing as roughness with the wheel removed.

18

Good ideas. As per the OP, I am hearing some rrr-rrrr-rrr noises from the rear of the car when I turn to the right at low speed. That’s in fact why I thought I had a left rear wheel bearing problem in the first place. But now I’m thinking the noise is not from the wheel bearing, but from the tire. I’ll do some tire switching experiments this weekend to see if the noise in fact tracks the tire position, rather than staying on the left rear. I’ll also take the opportunity for a more thorough visual check of the suspension components, looking for broken spring segments and loose mounting points, etc. I’ll take another opportunity at the same time to test the wheel bearing and compare it to the other side, play-wise and noise-wise, this time with the tire off.

I may also remove the strut and have it taken apart. My local auto parts place will do that for me I think. They have a small shop in the back for pressing bearings for their customers, so I expect that can do strut springs too. There’s sort of a catch-22 though. I’d like to take it apart so I could hand-test the shock movement (the center part) to see if it just slides along with little or no damping resistance, which would be a no-questions that shock is bad result. But the FSM says before you remove it, you are supposed to drill some small holes in it to release the gas inside. So I can’t test it after I remove it, because removing it will damage it. Sort of like quantum mechanics I guess, you can’t test it b/c testing it damages it. What’s the purpose of doing that drilling do you think? I mean when you install it into the strut you don’t do that, so why would you do that when removing it from the strut?

19

Most small shops will have both a hydraulic press with fixturing for pressing out/in bearings as well as a “standing” spring compressor for doing struts. Neither is terribly expensive as capital equipment goes, and both are necessary for any shop. They’re far quicker and safer than manual tools, and those things are worth money to shops.

Re: the drilling of the holes, it isn’t really necessary. Dampers are biased toward full expansion, and if you buy them they’ll often come with a strap of some type keeping them partially compressed, but it isn’t a dangerous amount. You can compress the average stock damper by hand. The holes take that load off of the upper mount, but countless dampers are changed every day without any holes being drilled. The spring being compressed and retained safely is the big “load” concern. If you want to disassemble and examine the damper after removal, simply ask the mechanic not to drill holes in it. He’ll probably respond with a quizzical look, 'cause he probably had no intention of doing so anyway, but don’t be afraid to ask. Also bring a box with you and ask that he return all the old parts. Not everybody does unless asked. In the case of dampers, there won’t be any additional charge, because there’s no “core charge”, they’re not returned to manufacturers to be remanufactured.