Wheel bearings and how to tell if they are bad

White Lincoln

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New Mexico
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1994 Mercury Cougar XR7, 3.8L, all stock
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On the way home last Friday from an appt, I was hitting 90 on the freeway and the vibration in the steering wheel was really bad. It seems to start around 70 or so and just gets worse.

I took the car into Costco on Monday to have them check the balance of the tires and wheels and they said they were fine. He mentioned wheel bearings so I looked in my service list and found I never touched them in the 25 years I have had the car. From what I know about testing wheel bearings is you lift the car and shake the wheel back and forth for play.

I have no play what so ever and the wheels spin really nice still.

Thoughts on the vibration at high speeds and testing the wheel bearings? I went through the front end a few weeks back for other vibration/rattles and could not find anything loose. But I might have found the culprit in the catback exhaust. I really need to get a descent exhaust put in some day.
 
LOL. You found the "resonance frequency" of the crappy ass stock driveshaft. BTDT. The least expensive solution is a 3.5" aluminum driveshaft from Precision Shaft Technologies.
I've bought 3 of them so far. :)
I found the same problem as you did. If you don't fix it, it will waste your diff, transmission, and wheel bearings, I found. When I changed it out, it was in two pieces, delaminated from each other. The problem went away immediately. We had a group buy at the other place; when I bought the last one, they gave me the $450 price as the group buy. It's been 10 years, tho. The drive shaft length they want is center to center of the u-joint , which is listed in the trans forum.


If by some small chance you can find a 93 mark viii ib a local jy, they have a one piece aluminum driveshaft. But that's the only way to find one cheap.
 
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I'd change wheel bearings before drive shaft my 97 will cruise at 90 with no vibration on a stock drive shaft with 350k miles on it motor and trans don't have 350 but orginal drive shaft. Finding a bad front wheel bearing is hard the old lift the car and grab the wheel doesn't always work due to the design of theses bearings so replace them and the rear ones which have to be pressed in/out.
 
When wheel bearings start to let go, they most obviously manifest first as an audible growl. This is a distinct sound that goes away or dramatically improves when you make a turn, due to the weight transfer to the wheels on the outside of the turn taking load off that bearing.

When the car is in the air you can also ID a bad wheel bearing by grabbing the top and bottom (or front and back) of the wheel and trying to rock it back and forth; the wheel will move with the rotor but the caliper/spindle will not. Bad ball joints, bushings, or tie rods would move the spindle and brake caliper too when you grab and try to move the tire.
 
Having had bearings on my 97 go twice due to badly-fit wheels, the sound is the most prominent sign. The first time it sounded like I was constantly being chased by a Spitfire, with a distinct prop-plane engine sound. The second time it was less prop-like, but still gave a constant hum. And yeah, if you take a turn you hear the sound shift.
 
Wow, you guys are awesome. I would never had thought the drive shaft was an issue. I had the drive shaft balanced back in 2017 (10k back). But I have heard a lot about owners complaining about the drive shafts and what crap they are. As for the bearings, I was figuring that I would replace those anyway just due to the mileage on them and never being serviced.

Thanks again everyone. Will be a while before I get anything replaced. But I will follow up.

LOL. You found the "resonance frequency" of the crappy ass stock driveshaft. BTDT. The least expensive solution is a 3.5" aluminum driveshaft from Precision Shaft Technologies.
Thank you Grog, I am glad I am not the only one with crap rattling under the trunk. Now, $500 for a drive shaft is a bit steep for a tight wad like myself, so I will see what else I can find. Thanks for the insight Grog.

I'd change wheel bearings before drive shaft my 97 will cruise at 90 with no vibration on a stock drive shaft with 350k miles on it motor and trans don't have 350 but orginal drive shaft. Finding a bad front wheel bearing is hard the old lift the car and grab the wheel doesn't always work due to the design of theses bearings so replace them and the rear ones which have to be pressed in/out.
I agree on that. Mileage alone would dictate they be replaced. Though the front wheel bearings on the Town Car have 200k on them, but I have not done the shake test yet.

When wheel bearings start to let go, they most obviously manifest first as an audible growl. This is a distinct sound that goes away or dramatically improves when you make a turn, due to the weight transfer to the wheels on the outside of the turn taking load off that bearing.

When the car is in the air you can also ID a bad wheel bearing by grabbing the top and bottom (or front and back) of the wheel and trying to rock it back and forth; the wheel will move with the rotor but the caliper/spindle will not. Bad ball joints, bushings, or tie rods would move the spindle and brake caliper too when you grab and try to move the tire.
Like I had mentioned, I did the wiggle test and nothing. Solid as a rock..

Having had bearings on my 97 go twice due to badly-fit wheels, the sound is the most prominent sign. The first time it sounded like I was constantly being chased by a Spitfire, with a distinct prop-plane engine sound. The second time it was less prop-like, but still gave a constant hum. And yeah, if you take a turn you hear the sound shift.
That I have not experienced, just the bad vibration at high speeds. My boss told me not go so fast, that will solve it. Ha... in a Cougar? lol

One other question about the rear, is there supposed be some play in the rear half shafts? I was wiggling them yesterday when I was under the rear end looking around. One has more play than the other, but not much, just a wiggle.

I think one of the vibrations I found was the bolted junction of the exhaust from the cat back. I was able to move the exhaust back and forth at that joint. Yikes! I will be addressing that today.
 
Most of the time you will hear a wheel bearing well before you can feel any play in it at the wheel. You will usually start to hear them at 45-50 when they start making noise. The lower the speed you can hear it obviously the worse it is. If the wheel isn't driven you can sometimes hear it if you jack that corner of the car and spin the wheel by hand. Sometimes they can be tricky to figure out. I've had wheel bearings that make noise when loaded and quiet unloaded and I've had them quiet under load and make noise when unloaded. I got sick of trying to figure out front/rear/right/left so I bought a set of chassis ears a few years ago. Makes it much easier.

I would not replace wheel bearings just because unless you really want to.

For halfshafts I will usually hold one end while trying to turn the other. I shoot for almost no play. Have you checked the driveshaft u-joints as well?
 
My wheel bearing screamed when it died, lol. I was like,"wtf is that!" I drove beside a highway wall, and it was obvious. Replacing the bearings in the rear is a job i'd save for when it dies, the front ones die faster. I need to do a writeup on the rear wheel bearings. The important parts are; make sure the bearing is facing the right way. There's an inside and an outside. The inner race differs in size slightly, one fits tight, and presses into the bearing, the other side will be loose. The loose side is the INSIDE. This allows it to preload when you torque the shaft nut to 250 ft-lbs. :) Make sure it's full of grease. You can get timken bearing grease at RA. Rear bearings are "set 49" from Timken.
 
Have you checked the driveshaft u-joints as well?
First thing I did was twist it back and forth and it did not have anymore play than it should. But as I recall others saying, the drive shaft falls apart inside and why it rattles and is junk. The u-joints are new and only 10 k on them. I know when the U joints are going. The make a horrible noise when under load and off load. I had to replace mine on the Town Car cause they started making horrible noise.

Thanks for the tips on the rear half shafts. I will try the holding one end and twisting the other.

I went out today and looked more at the front bearings and really, they seem fine. They don't wiggle and still have some friction when spun (not lose from wear and easy to spin with a slight wobble).

I was looking at used cars last night...

My wheel bearing screamed when it died, lol. I was like,"wtf is that!" I drove beside a highway wall, and it was obvious. Replacing the bearings in the rear is a job i'd save for when it dies, the front ones die faster. I need to do a writeup on the rear wheel bearings. The important parts are; make sure the bearing is facing the right way. There's an inside and an outside. The inner race differs in size slightly, one fits tight, and presses into the bearing, the other side will be loose. The loose side is the INSIDE. This allows it to preload when you torque the shaft nut to 250 ft-lbs. :) Make sure it's full of grease. You can get timken bearing grease at RA. Rear bearings are "set 49" from Timken.
That is what I am expecting too, NOISE that sounds like a cat screaming when practicing "cat juggling".

Looking forward to the write up and appreciate when someone does them too. I know, I have done plenty and they take time to do well.

I had to laugh today while under the front. A while back I replaced the rack and pinion dust boot on one side because it was torn. I am looking around the front end and the one replaced was shrunk up worse than my wanker on a frost morning. Lil' bugger is jammed in there! Going to pry it open and squirt some silicone in so it will slide forward and not look like you know what on a frosty morning.
 
That is what I am expecting too, NOISE that sounds like a cat screaming when practicing "cat juggling".

Looking forward to the write up and appreciate when someone does them too. I know, I have done plenty and they take time to do well.
Bearings make more of a roaring noise. They won't squeal/scream until they are right about to fail.
 
Yeah. I had a 60 mile drive home. It melted, and made a visible depression in the aluminum of the knuckle. I blew it to pieces with the press, and broke that knuckle. My brace slipped with about 20k psi on it. Bought another set of knuckles, and rebuilt those. I still keep a spare set, ready to go.
 
There was a short segment about replacing the rear bearings in the drum-to-disc conversion article I relisted today.

  • Remove circlip from the back of the spindle (holds bearing in place). From rear of spindle, press hub out of the bearing. From front of spindle, press the bearing out of the spindle.
  • From the back of the spindle, press the new bearing all the way in until it is firmly seated. From the front of the knuckle, press the hub back into the bearing until it is firmly seated. Be careful not to push the bearing out of the seated position when you press in the hub. Also, be cautious not to damage the grease seals on the bearing when supporting it while the hub is being pressed in. There should be no "play" when you wiggle the hub after installation. Install the large circlip back into the groove.
 
The support is crucial, You can break the bearing and the knuckle. The press never needs to go over about 200 pounds to be done. Tapping with a hammer, gently, helps. You can see it on the gage. I put "valvoline motor honey" on stuff being pressed together, it makes it go together smoothly.
 
Bearings make more of a roaring noise. They won't squeal/scream until they are right about to fail.
Well, I found out today my bearings are going. I was taking a small test drive around the block, windows down and was hearing a whining noise. Faint, but I could hear it. I drove around some more, stuck my head out the window, opened the door but eventually tracked down the whine to the front end. Applied the breaks, turned the steering wheel and the noise was consistent.

'Thank you' to all of you that put your two cents in, I really appreciate the feedback and information about wheel bearings and what to look for. I will be replacing the bearings soon. And thank you Terminator and Grog for your feedback on replacing the bearings, very much appreciated.
I put "valvoline motor honey" on stuff being pressed together, it makes it go together smoothly.
Good point about using a utility oil product for pressing items together easier. I use the Lucas Assembly Lube for a lot of stuff, especially engine parts replacement.
 
The front ones are easy. I buy the nuts for the rear ones, from ford. They come 3 in a bag. They're 3 stacked nuts in a cage, and will not back off. The front wheel hubs unbolt, and bolt the new ones on. I'd do both at once; they're likely in the same shape.
Don't buy the dorman ones they tear up the spindle badly.
 
The front ones are easy. I buy the nuts for the rear ones, from ford. They come 3 in a bag. They're 3 stacked nuts in a cage, and will not back off. The front wheel hubs unbolt, and bolt the new ones on. I'd do both at once; they're likely in the same shape.
Don't buy the dorman ones they tear up the spindle badly.
I was looking at a pair from Amazon: A-Premium 2 x Front Wheel Bearing and Hub Assembly

I don't know if cheap or expensive applies here or not. I don't romp on the car or 4 wheel with it so I don't need a pair that will last through the apocalypse.... Just something to keep er' goin' for another few years.
 
When wheel bearings start to let go, they most obviously manifest first as an audible growl. This is a distinct sound that goes away or dramatically improves when you make a turn, due to the weight transfer to the wheels on the outside of the turn taking load off that bearing.

When the car is in the air you can also ID a bad wheel bearing by grabbing the top and bottom (or front and back) of the wheel and trying to rock it back and forth; the wheel will move with the rotor but the caliper/spindle will not. Bad ball joints, bushings, or tie rods would move the spindle and brake caliper too when you grab and try to move the tire.
I had a bad wheel bearing on the SC and 3 knowledgeable people did the grab top and bottom left and right and said it wasn't bad but it would do the growl until you turned left. I replaced it and sound went away so for front wheel bearings that doesn't always work.
 
It's not guaranteed to have visible physical play at all stages of failure. As grease dries out and is replaced by foreign contaminants, audible symptoms manifest first. This is accompanied by an increase in heat generation which exponentially increases wear as the process continues. Only in the latter stages of failure will visible sloppiness be apparent.
 
I don't buy parts from Amazon. Rock auto used to have timken bearings, and they were the oem. Set 49 fits the rear, but ifk for the front.
 
I had issues with the last set of Timken bearings I bought to put on the Mark VIII not long after I got it. They lasted under a year before they started making noise; I had them replaced under warranty. Then the warranty set were making noise only 1000 miles after that! I replaced them with Moogs and they've been fine for the last 65,000 miles.
 
I was wondering, the mustang guys recommended skf. I'd rather do timken and toyo; they've been much better over the years, but timken got bought from toyo
 
You guys are killing me.... It's like I won't buy or sell on eBay anymore, been burned too many times by "dis-honest" vendors and crappy buyers and the price eBay takes off the top is just criminal from the way they used to be. I use Etsy now for a lot of stuff. Amazon at least backs you up better and you just return the crap, no questions asked. But yeah, been burned there too. RockAuto? Of for shitz sake! How many times have they sent me used, broken or stuff that was not made for my car, though posted as such. Do they care? No, just send it back. What a pain in the arse working with them because they have no customer service and their shipping costs have made me step back and think twice about using them.

Hey, Amazon has a Motorcraft wheel hub assembly (one) for $263! "I'll be dipped!"

So what I gather from the above comments, it's hit or miss with what kit you buy. I don't have a press to replace just the bearing so I will have to go with the assembly.

Anyway, thanks guys, you have been most helpful in looking for what suites me best.
 
Couple of comments. I've seen too much counterfeit stuff on ebay and Amazon to trust buying anything on either site unless I know the seller (i.e. an actual OEM dealer for instance). I purchase $8k-$10k of stuff every year from RockAuto and can count on one hand the number of times I've had problems with part deliveries and every time I have had an issue they have corrected it. As far as I know, the front is only available as a complete assembly. I don't think you can just replace the bearing itself since the hub is part of the bearing.
 
It destroys the hub removing the bearing. I have pix somewhere, lol. The front hubs are the wrong kind of bearings, so they wear faster than the rears. The fronts are two rows of ball bearings, which lack the ability to oppose cornering forces like the back. The rear is a SET 49 from timken which are opposed tapered roller bearings. They need 250lbs of preload, to work well. Always spread the inner race if possible and make sure there's actually grease in there. Timken sells bearing grease.
 
technically the outer race is the hub itself so even if you replaced the ball bearings it’s not a fix.

There is a trick to disassemble them though; pull it part way out so only the inboard inner race is still on the spindle and give it a hard yank pulling it diagonally, it’ll open up. Not that there’s any point to it unless you wanted to pack your own choice of axle grease into them.
 
I think I lost track of whether we were talking about front or rear bearings 🤷‍♂️ Either way, you will need a torque wrench capable of 250 ft-lbs to torque the axle or spindle retainer nut.
 
I was under the impression that a few of you had replaced the bearings of the fronts and why I mentioned about getting the assembly.

Dang, I thought my Snap-On torque wrench was 250 or better, its big enough to be that... Found out it is only 200! Yikes!
 
I'll be dipped.... Harbor Freight has one:
PITTSBURGH
3/4 in. Drive 50-300 ft. lb. Click Torque Wrench
for only $89!!!!

(might last one or two uses)

If it torques correctly compared to another torque wrench through various settings, it might be okay. But I would keep checking it before you use it. I have had them fall apart on my, literally while using it. Sold the ones i had to get rid of them and bought some more Craftsman ones, cause I be a pow boy and can't afford Snap-On anymore.
 
honestly the HF torque wrenches are pretty good, at least the 150ftlb one. I have had a snap on one for over a decade but I almost never use it, the HF ones been reliable and accurate for years
 
honestly the HF torque wrenches are pretty good, at least the 150ftlb one. I have had a snap on one for over a decade but I almost never use it, the HF ones been reliable and accurate for years
That's good to hear XR7. Nice to see someone enjoys their products from HF. I have lots of them, but I buy them for the "two time use and break" product and they tend to last much longer than that. I had a saws-all that lasted 4 times and the bushings fell out. I have a staple gun that lasted about 7 times and just jammed up and won't work anymore... 1/4" router that the plastic parts just broke (but I bought another one), but have had a Ryobi router and table that have lasted through hundreds of uses, just saying. Maybe I should get one of the crates of HF return tools and take a chance with what I get...
 

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