Rotor and Bearing Temperature

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Old 02-21-16, 08:58 AM
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Rotor and Bearing Temperature

I'm trying to diagnose a wheel oscillation and vibration issue that's been going in for several years and driving me nuts. Vehicle is a 2004 Toyota Tundra 2WD. The truck came with the larger 13WL calipers and I just replaced them last summer. The issues I am experiencing:

1) Vibration, most noticeable at highway speeds. Sometimes so bad it feels like my tires are oval shaped.

2) Greatly accelerated rotor "warping". I've replaced the rotors multiple times and the issue goes away but progressively gets worse over only a few hundred miles.

3) Suspesion bounces when braking, most significant at 23 mph and 45 mph. There is very little if any vibration felt through the brake pedal. It is mostly felt through the suspension.

4) Subtle bouncing while driving at 23 mph and 45 mph. If I apply steady pressure to the brakes while holding my speed steady at either of these speeds, the bouncing is continuous.

5) Scraping sound when rotating hub my hand (caliper removed). No apparent looseness. Of course me tugging on it with my hands is much different than the actual forces when driving.

Things I've replaced: Calipers, rotors, pads, tires, wheels, lower control arms, tie rod ends, lower ball joints. None of these things resolved the issue.

There is no perceivable play in the when shaking the wheels at 6 and 12 and there is a little movement when shaking the wheels at 3 and 9, but the opposite wheel moves in unison and there is no slop. There are no audible noises, pops, or clunks. Just vibrations and hopping.

The only suspect parts I haven't replaced are the steering rack and the wheel bearings. I mention the steering rack only because the seals are leaking, but the steering feels nice and tight and the power assist is good. The wheel bearings are highly suspect because I would imagine if they arw bad that there would be vibrations at high speeds and since the hub is connected to the bearing and the rotors to the hubs, this would cause the rotors to warp quickly. I recorded some temperatures after driving about 15 miles, over half of which was 50+ mph and the remainder 35 mph. Things cooled down about 10 minutes before my measurements and the ambient temperature was 50 F:

Left rotor: 300 F
Right rotor: 400F
Left caliper: 175 F
Right caliper: 230 F
Left bearing: 100 F
Right bearing: 125 F

As you can see, the temperature of the right components are significantly higher. Whether or not these temperatures are typical is beyond me.

What do you guys think? Bad wheel bearings?
 

Last edited by mossman; 02-21-16 at 09:43 AM.
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Old 02-21-16, 10:17 AM
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You didn't say anything about struts/springs?...
 
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Old 02-21-16, 10:28 AM
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Oh yeah, new struts but original springs, top mounts, and hardware. The problem existed with the original struts and actually got worse with the new ones, presumably because they are stiffer (Bilstein 5100 ride height adjustable). Forgot to mention the truck has 140k miles on it.
 

Last edited by mossman; 02-21-16 at 11:28 AM.
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Old 02-21-16, 12:25 PM
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have you tried brake hoses?
 
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Old 02-21-16, 01:31 PM
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No, I haven't replaced the brake hoses. I hadn't even thought of that. Are you thinking deteriorated rubber hoses releasing pieces into the caliper and making it stick, causing uneven rotor wear and subsequent vibrations? Come to think of it, the fluid in my reservoir looks pretty dark, and I just purged and replaced most of the fluid last summer after doing the calipers and rear cylinders. I believe there were fine black particles in the old fluid. Brake pedal feels a little spongy too. Fluid level is good.

Should also mention that both front tires are wearing on the outer edges. They've done that for as long as I can remember though. I just had it aligned and after many years of experimenting, I know it is exactly where it needs to be. Tires are Michelin Latitude Tour and have been road force balanced with less than 5 lbs of road force.
 

Last edited by mossman; 02-21-16 at 01:58 PM.
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Old 02-21-16, 01:56 PM
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suspect you have more than one issue but brake hoses can swell inside and actually cause the caliper not to release pressure.
but for the vibration at highway speeds its probably not a brake related problem.
 
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Old 02-21-16, 02:03 PM
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Is it possible to warp the hub by over tightening lug nuts? The first time I noticed the bouncing was after having my truck serviced at the dealer. I had the carrier bearing replaced and not sure if I had them do anything else that would have required removing the front wheels. Maybe I asked them to rotate and balance. I'm thinking the mechanic could have zipped the lug nuts on with an impact and maybe did some damage. Guess I shouldn't have sold my runout gauge.
 
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Old 02-21-16, 04:58 PM
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Any kind of noise when you spin the hub with the calipers off is usually bad. At this point you might as well change the bearings, not much else left.

When you replaced the rotors did you check runout with them mounted? If the hub is hinky you'd probably see it in runout unless it's just a balance problem.

Was this thing ever in an accident?

Thing is, most of your symptoms seem more like bad tire or suspension, not brake related. If you've got a bad hub or badly warped rotor, you usually feel it in the pedal first.
 
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Old 02-21-16, 05:58 PM
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Never in an accident as far as I know. I bought it in 2006 and I've never wrecked it. No sign of a wreck when I bought it.

Last time I changed the rotors everything was nice and smooth, but after about a week the bouncing sensation resurfaced slowly but surely. I feel like it has to be the hubs. That's next on the list along with the bearings. Think I'll pick up a runout indicator first before tearing the spindles off and taking them to a shop to have the bearings and hubs pressed out. Unfortunately this is my only vehicle so that complicates things.
 
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Old 02-21-16, 07:53 PM
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I ordered a runout gauge and some rotor shims. I'm gonna throw some new rotors on and correct the runout with the shim plates and see if that resolves things. I'll post back in a couple weeks.
 
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Old 02-28-16, 09:36 PM
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So I worked on it again this weekend. I only did the left side because that was the side heating up (got up to 900F on the way home Friday!) Turns out three of the four pistons were seized. I put om a new caliper and new rotor. Prior to doing so, I measured the lateral runout and it was about 0.006". I also decided to measure the radial runout of hat and the perimeter of the old rotor. I couldn't believe my eyes...just over 0.020"!!! What on earth would cause a rotor to have that much radial runout? They weren't cheap rotors (Brembo). Then I installed the new rotor and I also measured radial runout, but not as much. I measured 0.007" at both the hat and the perimeter. I marked the high and low spots, rotated the rotor 90 degrees, and the high/low spots were in the same positions relative to the hub, so that tells me the hub has radial runout. If the hub has radial runout, then the bearings must be worn right? They definitely don't sound good. They sound dry and are making a scraping sound (I had the caliper removed). Puzzling thing to me is that they don't make any loud humming noises when I'm driving and there doesn't seem to be much if any looseness when I shake the tire. Perhaps it gets worse when it's on the ground and under load so it's hard to detect. My best guess is that the bearings are worn just enough that there is a small amount of movement that is causing the rotors to rub against the pads unevenly thus leading to their rapid degradation. For instance, I replaced both rotors last summer and they were trash after only a week or so. Then I had them turned on the truck a month ago and they only lasted a few days (the thickness is still well within tolerance). I ordered new bearings tonight and will be taking my knuckles to a local shop to have them pressed in. I'm anxious to cut into the old bearings and see what kind of condition they are in. I'm wondering if I should replace both hubs as well just to rule them out. I'd hate to have new bearings installed only to find out a few weeks later that the hubs are bad too. I have to remove the entire knuckle to get the bearings pressed out so now would be the time to do it. Unfortunately there don't seem to be any aftermarket hub assemblies for a 2WD Tundra, so I'd have to get them at the dealer for $180 each. Part of me says do it but the other part says take a gamble on the problem only being the bearings. What do you guys think?
 
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Old 02-29-16, 05:47 AM
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Here's a video with the old rotor installed. As shown on the dial, 0.02" of radial runout and you can clearly hear the bearings are dry and scraping: https://youtu.be/waCmgk9il08

BTW, I've decided to replace the hubs. I found a good deal on eBay (OEM parts).
 

Last edited by mossman; 02-29-16 at 06:32 AM.
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