Noise from Rear end...
 

I have two odd noises coming from the rear end of the car right now. Sounds like one is right in the center of the diff, and one is on the psgr side outer edge.

The one in teh center only happens when there is a load on the driveline (aka, no noise when the clutch is depressed) sounds like a metallic whine, constant, varies with RPM and Load. Thinking maybe the rear of the driveshaft needs some grease, the pinion bearing is going bad, or its just the noise from having Coilovers now.

the noise on the outside of the psgr side axle sounds almost like a metal on metal grind, but more along the lines of a metalic brake pad on a rotor. It only happens when I am turning LEFT at moderate speed.

Neither noise was present before, when It was GSL-SE Housing, GSL Diff, SE Axles, SE Brakes, Same wheels, same brake pads. Stock suspension/bushings.
The only noise I had was a bad wheel bearing on the psgr side rear.

I just put in all poly bushings (everywhere, front and rear), 4 new Wheel Bearings, new hard Brakelines on the rear, RESpeed Coilovers/ Tociko 5 ways.
less than 100 miles of driving so far.


Now, I know the Coilovers are going to transfer ALOT more noise into the car, and I could see the first noise coming from that, but the noise on the outer axle you can hear from outside the car. Im gonna be tearing it down this week, im just really not sure what to look for, since I JUST replaced the wheel bearing/ oil seals. I inspected the housing for wear, and everything looked to be ok. Why would it only be making a noise when turning LEFT?!?!?!?

Thanks for any sugguestions!

rear U-joint, and loose/mis-adjusted caliper maybe? wheel rubbing? old car?

Concerning the noise from the passenger side:

Who actually pressed the new axle bearing on the axle when you had it replaced? Was it a very experienced person / shop?

Maybe the collar that holds the bearing in place is loose; maybe someone tried to reuse an old one, or a loose one. The very tight press fit collar is all the holds the bearing and the axle in place. If the collar was loose and allowed the axle to move in and out, then the brake rotor would be moving around and could make the brake rotor sounds you are hearing.

It is a common problem for 1st gens that do hard cornering to have the collar work loose. Some racers (like me) put one small tack weld between the collar and the axle to keep that from happening. This tack weld process was also recommended by Racing Beat when I first started racing rotaries 26 years ago.

I watched the guy do it (friend of mine) Brand new parts. He heated up the collar and slid it on, hammered it a few hits, then used the press. so doubt its the collar, even though that would make sense for the noise.

bump for some other suggestions please! wont be able to take it apart till this Thursday...

i'm dealing with the same issue with noise in the differential. upon further investigation and tear down, it turned out that the pinion bearings were at fault. the bearings themselves were ok however the races were pitted and grooved.

speedturn mentioned above about the collar holding the axle in place. this is not completely correct. the collar's job is to keep the bearing in place should it ever wiggle loose..which most likely will never happen if teh car is not abused. the axle is a "press fit" so to speak and is retained by four through bolts on the backing plate.

Well if the coller isnt tight the axle will still move in and out some what.. I have been fighting a similar problem in my car. and well the only place this car gets driven is on the track and hard left handers i do get a grinding sound. my next step is wheel bearings to see if that helps.

well... still raining like hell... haven't gotten to work yet...

Everyone who lowers their car more than an inch will have this problem. It's caused by drive shaft plunge into the transmission tail shaft, which which causes rear U-Joint misalignment and transmission tail shaft and pinnion bearing wear. The only fix for this is new upper links or a 3 link. If you're running coilovers and slammed your car, be prepaired to go through plenty of rear ends until you get this corrected. Ask me how I know...

what upper links do I need to run then? Im on a respeed coils and def. lowered a bit...

The noise on the outer psgr side definitely sounds like a wheel bearing is loose
or going.

The description of how your buddy put the collar on is not the way the FSM
describes putting it on. Heating it up in fact may be a no-no. What I remember
the FSM saying is that it had to be pressed on with a minimum of like 5 tons
pressure and if it slides on with any less, you need to try a different collar. I
think you might want to do the tac weld thing mention above.

which upper links would I need to get?

also just found out my psgr side rear caliper is seized (brand new caliper) taking it apart right now...

update:

started taking the brake off and see a odd wear pattern in the inner pad. the rotor is FUBAR. The rotor is warped very bad, bad enough to touch the caliper mtg. bracket. Caliper works fine.

Still have noise after I took the rotor off though...

Something to check...

When I swapped over suspension on my 85, I removed the little rubber pads on top of the coil springs... turns out these pads dampen A LOT of sound that would otherwise be trasmitted from your axel to your body. Sounded like constant metal on metal rubing.. like a bearing was going out. After thinking back through resent changes to my car, I just swapped the rubber pads back in and now ABSOLUTLY quite.

Your problem may be WAY more complicated than this, but, it sure doesn't take much to confirm your rubber pad isolaters are still in a healthy condition.

Good luck!!

That makes alot of sence. but wouldn't it be easyer/cheaper to have a custom drive shaft made. theres alot of crazy suspention and drivetrain geometry in the first gens. the motors mounted twards one side, the rear end moves over when you lower the car. 3 link sounds funner though.

Can you use the rubber pads with the respeed adj. coilover kit? I figured not. maybe if you cant, I can fab something up and see if that takes away the sound Im hearing.

[QUOTE=jinxed4dub;9625302]wouldn't it be easyer/cheaper to have a custom drive shaft made. [quote]

my current car has a SBC with a driveshaft from GrannysSpeedShop. i think its supposedly made for a car lowered a bit, but Im not 100%

The problem is not in the legnth of the drive shaft it's the angle of the rear end once you lower the car. the rear end geometry needs to be fixed by making the uper locater on the axle adjustable. if you put heim joints on the stock location upper links it will only increase bind. Hense to redesign mounting points and go with a properly setup 4 link of one that works with Jim susco's trilink.
www.gforceengineering.net

I guess I still dont fully understand. is the problem the pinion angle? I really need a picture of a car with said parts needed to fix the problem, or a much more detailed description of what actually changes. Im missing something since I can (with no struts on the car) raise/lower the rear diff and I dont see real problems even all the way at the top of the stroke. The driveshaft still seems not to bind up (not too long) and the pinion angle, while I never paid very close attention, never looked to be messed up along the entire travel.

lol i got he same prob let me know what you find out my rear end is out of a 84 gsl but the car is not lowerd just changed the tires to 15,s

Considering you only changed wheels my best guess is rear axle bearings. Depending on the offset of said wheels, and additional weight of them you might have caused added stress on the bearings and, however unlikely, you might have failing axle bearings.

back to whats goin on with mine, do you have any pix or better exp. of what is causing the pinion wear???

can anyone explain a bit on this issue?

its pretty simple it mis alligns when the car is lowered. how hard is that to understand. put your car on jack stands and pull out your rear springs and look at what happens when you move the axle housing up and down...