Strange noise from the rear wheels

[ArtOfRuin]

I'm hearing a stange noise coming from at least the right rear of my GXL when driving (it may also be coming from the left, but I'm not sure). I assume there is something wrong with the rear brakes. The noise sounds like a flat tire, and like a flat tire it's intermittent and increases with speed. It's not a flat since the rear tires are fine and fully inflated, and the noise changes pitch when I press the brakes. It's probably related to the brakes. My best guesses are:

a) A (really) warped rotor
b) Incorrectly installed pads

The P.O. said the rear rotors are Brembo OEM type and the pads are Hawks. I'm going to e-mail him and ask for some more detail, like how long ago the pads/rotors were changed and by whom. Any help would be greatly appreciated.

[Flooder]

Does it make the noise while you're braking? Or when you're decelerating without braking?

[ArtOfRuin]

Yes, and yes. The noise is like a flat tire- you can hear it when the car is moving, and the frequency of the noise increases with speed. The weird thing is that the noise changes pitch when I depress the brake pedal.

[Phoenix7]

any vibrations?

[ArtOfRuin]

Very slight vibration in the brake pedal when braking, but otherwise, no vibrations.

[classicauto]

Wheel bearing.

Do both :)

Be sure to inspect the rotors when taking it apart though as its *possible* that its something else.......but more then likely its the bearings.

[Phoenix7]

Very slight vibration in the brake pedal when braking, but otherwise, no vibrations.in certain gears? All gears (inc. reverse)?

[ArtOfRuin]

in certain gears? All gears (inc. reverse)?

Not sure. I didn't feel any when reversing, but I wasn't going very fast, either. The times I felt vibrations were at around 20-40mph in around town traffic.

Come to think of it, ClassicAuto may be right, since the car is braking OK. I'm going to check the rear brake assemblies tomorrow just in case, provided it doesn't rain.

[Phoenix7]

I'm sure this doesn't need to be said but just in case: Check first buy later. I learned that the hard way.

[SpooledupRacing]

especially with the rear since those bearings need to be poressed out of the hub and spindle.

[ArtOfRuin]

especially with the rear since those bearings need to be poressed out of the hub and spindle.

Great, replacing rear wheel bearings. This sounds like a fun job...

[djmtsu]

Bearings!! Yay fun!!

You can get a special bearing puller/installer that allows you to do it with rear spindles in place. They can be spendy, but for me...its worth it since they work on MANY other cars (your friends will thank you).

[RoughRex]

check your axles out too while your back there. I just encountered this same issue on the right rear of my GXL... some vibration during driving/braking accompanied by a thrumming noise from the rear of the car. I inspected the rear and I noticed that the Right rear outer boot on my axle has aparently split open and is now splattering grease all over as I drive... this could be a result of some other issue but... I bought a used axle yesterday just in case. So DJ...you have a tool to pull that bearing do ya.... :D

[ArtOfRuin]

Axles, too? Boy, did I pick a winner... :40: Well, tomorrow I'm going to get my FC's oil and belts changed (would do it myself if it wasn't going to rain all this week. I hate not having a garage). When it goes up on the lift, I'll take a look and see what I can find back there.

[ArtOfRuin]

I couldn't get the car up on the lift today or check out the rear brake assembiles due to the rain, but the noise now only occurs during braking. There's no vibrations, either.

[SpooledupRacing]

ok sounds like a bar rotor and maybe noisy pads... the pulsation/vibration could have been from a warped rotor..

check all 4 wheels for brakes..

the vibration did u feel it in your seat or in the steering wheel?

[ArtOfRuin]

I initially felt the vibrations in the brake pedal. They were almost imperceptible, but they were there yesterday. Now, they're gone.

[classicauto]

I couldn't get the car up on the lift today or check out the rear brake assembiles due to the rain, but the noise now only occurs during braking. There's no vibrations, either.

If its up in the air, grab the top and bottom of the tire and push it in and out feeling for any play. If its not 100% tight - its the wheel bearing.

But checking run out on the rotors is certainly a good idea, I wouldn't rule anything out yet, but I just know that the rear wheel bearings in these cars are something that never gets attention. They're not serviceable either. chances are your 20 year old FC has original wheel bearings.......so they're bound to make some noise.

You can also assess this while driving, although its much harder to do when the problems in the back. But go for a drive and turn your radio off. Listen for the noise while doing some gradual hard left and right turns (make sure no ones around, drunk driving suspicions may arise :) )if the noise gets louder while cornering, its almost 100% rear wheel bearings (possibly fronts too...) if it goes away while turning one way or the other chances are only one is bad. If you can imagine the loads being placed on the wheel while cornering you'll unsdertand why thats the case.....

And one more thing - if the bearing is really toast, you can actually get more noise out of it while braking because you're placing more load it and althuogh its different from a cornering load, any load will make it howl more (if its bad)

[SpooledupRacing]

another thing.. if u do a bearing its a good time to replace the bushings back there.. the lower pivot bushing, the upper solid bushing and the dtss (time for elims)

[ArtOfRuin]

I had the car up on a lift today. The rear wheel bearings don't seem to be the cause of the noise; there is no play when the wheels are tugged on. The CV boots are in good shape, too. The front bearings, however, do need to be repacked/replaced. Also turns out I need to replace the thermostat and the oil pan gasket as well. I can do the thermostat and possibly the bearings myself (provided it stops raining), but the oil pan will need to have its gasket repaced at a shop, since I have nothing to support the engine or transmission. Thanks for pointing out the bearings and CV boots to me. I wouldn't have known what to look for past the brakes.

[djmtsu]

FYI- the front wheel bearings are pressed into the spindles, and the hub is pressed into the bearing.

No repacking. Sorry!

[SpooledupRacing]

WRONG... the front bearings are pop offs.. the rears are pressed in..

the frton bearings come out of the hub and have a race on them.. they need to be packed..

http://img.photobucket.com/albums/v88/turboTSI/RX7%20BUILD/0_IMAGE_053.jpg


as u can see greese cap in the front and there is a seal on the back..

u will need 1 inner and 1 outter bearing and 1 inner seal PER hub..

[djmtsu]

Sorry, I was wrong about the bearings. I must have been thinking about my Millenia. But there is a right way, and wrong way to point that out.

FYI- When I had my 1991 FC, Mazda had to replace the front bearings under warranty, and they replaced both hubs. If the races are toast, the whole hub is basically toast. Gotta love aluminum.

[classicauto]

Well, the front races are "pressed" (very lightly) into the hub. I usually weld a bolt across and tap them out, or heat the hub and smack it on the floor, they fall right out.

[SpooledupRacing]

Sorry, I was wrong about the bearings. I must have been thinking about my Millenia. But there is a right way, and wrong way to point that out.

FYI- When I had my 1991 FC, Mazda had to replace the front bearings under warranty, and they replaced both hubs. If the races are toast, the whole hub is basically toast. Gotta love aluminum.

Sorry wasn't trying to be "snappy" just trying to correct the info given.

and if the races are bad the hub is not always bad pull the races out and se what the hub looks like..

I normally will use the old race and put the new bearings in (if the old race is still in good shape)

[djmtsu]

All good.

To the OP, just check the races for heat scarring. Mine were horrible, they nearly welded themselves to the damn hub. And there literally was no sign they were about to fail except I heard a creak one day. The car only had 80K on it too!! Odd.

[TehMonkay]

Mazda only sells the whole hub, other afternarket MFRs sell bearings/races.

[SpooledupRacing]

I have the bearings/races for both front and rear as well as the seals and your oil pan gasket and thermostat..

give me a shout if u need anything..

[TehMonkay]

another thing.. if u do a bearing its a good time to replace the bushings back there.. the lower pivot bushing, the upper solid bushing and the dtss (time for elims)

Can you by anu chance get those upper and lower bushings for a good price or should i just go with the mazdaspeed website for those?