Whizbang

So i bought my newest rx7 and thinking i bought a good running car, i got yet another thing to fix. On the way home a loud noise developed from the rear of the car. At first i thought it was the bald as tires on the car. maybe a belt broke or it had a flat spot or something. But when we got back home on got it up on the lift, we inspected somethings.

We checked the differential fluid, and found it to be black and a very low viscosity, like motor oil. And metal shavings. flush itand changed it out with good 80w and LSD additive. Test drive made NO difference in the noise.

But the thing is the noise never changed if you changed the load on the car. (on / off throttle) It was constant and only changed with speed. i've never had a rear go bad and NOT be affected by load. Plus we drove it 200 miles to get home and didnt have it lock up or anything. (which is a good thing!!)

So the other option im looking at then is it could be a wheel bearing. Sat for a while and a ball might have become inept.

Whizbang

i've been reading around and im thinking more and more that its the wheel bearing. Its alot more of a low tone growl, not a whine.

Bruceman

iTrader: (5)

Jack car up, insert jack stands, start engine, put into 2nd gear walk around car and identify where the noise is coming from.

Black91n/a

Two things to check: one is the backlash on the diff (car in neutral, rotate the driveshaft back and forth and see how much play there is), two is the free play on the wheels (push/pull top and bottom and side to side and see if the wheel can rock back and forth at all). If there's significant backlash, then it's probably the diff, if there's play in the wheels, then it's the wheel bearings.

It does sound like bearings though, as the diff will be affected by loads, whereas the beaarings will be mostly speed dependant.

It may not have been intentional to sell you a broken car, it could be just some really bad luck for you, and good timing for the previous owner. These things can start up quite suddenly.

Whizbang

ill be putting up on the lift tm night and seeing what the deal is.

Turbo II Rotor

iTrader: (2)

Sounds like a bearing, this is what a bad ring and pinion sound like.

http://youtube.com/watch?v=hWSHd9NbaEM

Whizbang

yea that video is most definately NOT what im hearing. You cant even hear it outside the car really.

classicauto

iTrader: (3)

Just lift up the back and check the wheel.

Grab the top and bottom and push in and out. If there's play - new bearings are in order. You can also diagnose it while driving, although its more definetive on the front. But if a bearing is bad, it will make more noise with more load on it, so if you're taking a long sweeping left hand corner, and the noise gets louder while doing so, your right front bearing is bad as its making more noise while loaded up.

Whizbang

i tried that last night actually. when i turned to the right even at lower speeds the noise got much quieter. So im assuming its the passenger side. Im going to finish it tonight i think.

MmSadda

iTrader: (2)

This is good information to have!

btw, I believeit's wheel bearings. does it sound kinda like you have a flat rear tire when driving at freeway speeds?

Whizbang

dead on like that. That is why we thought it was the tires for awhile.

MmSadda

iTrader: (2)

^I am having the exact same problem. Just got my car back from the shop for other work, and the guy (experience rx7 mechanic) said that I need new rear wheel bearings, said he heard that from inside the car, and said that an untrained ear such as mine would likely think I was hearing a flat tire.

lo and behold, I drove 2 hours up to Cleveland listening for it, and freaked out thinking I had a flat tire.

BTW, I see you're in Cleveland, coincidentally. I just called rx7store in Columbus, and they'll do rear bearings for $480 total

Whizbang

gah. the bearing itself is only 47 dollars with a DBA account through napa. 72 otherwise.

ah the joys of doing things oneself

MmSadda

iTrader: (2)

Aren't you better off doing both sides at the same time? I'm about 90% sure that's the case.

If you do it soon, LI, let me know how it goes... I'm considering attempting it myself, partially 'cuz I want to do shocks, too.

Black91n/a

Do both, it'll be cheaper than having to go back in a month when the other one goes. It has just as many miles on it and has seen all the same loadings as the other one, so it's likely not long for this world either.

Whizbang

i just did the one that was obviously bad last night. And it was REAL bad.

the other side still has no play AND i didnt have 50 dollars for the other side. Or the time to do it. Takes a little while to press things out, especially when the bearing seperates on you and you have to get creative to get the race off the hub. Didnt help that there was a broken caliper mounting bolt to contend with either...

Black91n/a

I'd still reccomend doing it soon, better to be proactive and do it when you decide, and not be forced to do it when it's not a good time for you because it broke.

rotorhead1983

My car has been doing exactly te same thing but its been more difficult to troubleshoot but after reading this thread I'm pretty sure its the rear bearings now so I'm going that route. They probally need replacing anyway now I just need to round up some money lol. I am spending most of my savings on windows since some jerks smashed both of them out and jacked all my stuff. I hate Albuquerque

rurounixblade

iTrader: (1)

reviving but i need this answered go the wheel bearings need to be pressed in by machine or can any avg joe do it in there driveway?

BLK FC3S

The bearings need to be pressed out of the hubs. If you have a press you can do it yourself, if not, take the hubs to a shop.
http://www.teamfc3s.org/main/factory...rear_Axles.pdf

rurounixblade

iTrader: (1)

ok ty and love the avatar xD

cobaltss81

iTrader: (2)

Ah, it appears my recent five lug swap is showing the same signs. I just got my car back going and I also experienced the whole "feels like I have a flat tire" from the rear of my car above 30 mph...

-Vincent