Laf12

For the past couple of weeks my 85 SE has been making a terrible grinding sound when I make sharp left turns. I can't tell if it's the wheel rubbing or what. The car is bone stock, with new struts, and rear shocks. What are your opinions on this?? Thanks!

rk970

iTrader: (1)

Could be the right front wheel bearing is going bad.

LongDuck

Sharp turn grinding could be a number of things, but if you're positive it's coming from the Left Front corner, then it could be one of the following - in order from Most Likely to Least Likely;

1) Tire Rub - if you're running wider than stock tires (or wheels), you may have tire rubbing on the inner splash panel or, if lowered at all, on the fender well. Fix this by not turning full lock, securing your inner fender, or rolling your fenders (search).

2) Wheel Bearings - The -SE's have conical bearings on the front with larger spindles than some of the prior years, which is why these spindles are harder to find. When a bearing goes out, you start to get a lot of play in the front end, which would be noticed when driving in a straight line - or noises when turning - when the bearing is under strain. Additionally, there's a factory pre-load setting of about 5-6lbs of force required to turn a properly installed and greased front wheel bearing to ensure it's going to run straight and true. The castle nut and cotter pin hold this tension while the bearing is good, but when it goes bad you can jack up that corner and give the wheel/tire a spin and it will just keep going and going - that's either incorrect pre-load, bearing failure (with clicking sounds), or excess play in the bearings. Normally, the tire/wheel should only make about 2-3 rotations and then come to a smooth stop when properly pre-loaded. Any side-to-side play or back-and-forth play on the spindle is a sign of bad wheel bearings.

3) Brake Caliper - when cornering, the brake disks are under tension against their mounts which can sometimes allow contact between the brake disk and the caliper mount, or push the brake pads into an angle which allows grinding of the pad backing plate against something solid. You should grease your slider pins anytime you change front pads to help with this, and worn pads are more likely to grind because they're closer to the disks when worn down. Also, worn wheel bearings will make this worse, as they allow more play of the disk on the spindle for stuff to rub.

4) Brake Pads - As mentioned above, new pads sit evenly between their mounts, and the metal shims help to keep squealing to a minimum. I use Lock-Tite Brake Pad Quiet when I change pads, which helps to glue the pad backs to the caliper and piston for less vibration and squeal under load.

5) Power Steering - Remote, but if your grinding gets louder as you reach full lock in that direction, it could be your PS pump. Low hydraulic fluid level will cause a grinding noise along with what sounds like belt squeal, which goes away when centered. The PS pump has extremely high pressure at full lock in either direction as the fluid return path to the pump is heavily restricted. Bleeding is done by jacking up both front corners and with the engine running, cycling the steering from L lock to R lock back and forth until the squealing stops. Make sure you're adding fluid when you do this or you'll never get it bled.

Good luck, and post back with what you found after you fix it! (*I hate that a bunch of advice is offered and then the OP disappears and we never knew if he fixed it or drove the car off a cliff...)

Laf12

Well it's going to have to wait until next Friday before I can work on it. I have a automotive class where I can take it up on a lift. What I forgot to mention is that it also has rebuilt front wheel bearings, and new pads and rotors up front. They all have about 750-1000 miles on them. It also doesn't have power steering. Is it possible for the sound to come from the diff? The diff has a leak, so it could be low on oil. Im going to change the diff oil next Friday as well. I'll give an update as soon as I find anything else, or any more questions. Thanks!

LongDuck

Unlikely that the sound is coming from the differential - when you drive with the window's down, you should be able to tell whether it's front or back. Also, the -SE's all came with a LSD, requiring a very specific GM LSD additive be added to the gear oil when you change it.

If you don't add the GM LSD additive, the clutches on your LSD will grind themselves to death and then you'll be looking for a replacement. Don't skimp on this - and the LSD is one of the features that makes an -SE something special. Looks like this:

$15.47 seems like a lot until you factor in the cost of a replacement LSD...

Direct Link: Differential Mounts, Diff Stub Shafts, LSD Additive & Gear Oil

I also like the NeoSynthetic 90w Gear Oil which Mazdatrix sells, as it's worked great in my car for 100k+ miles. Good luck, and report back,

Laf12

It turns out the solution was much simpler than I thought. It was just the rubber mud flap on the inner fender. When the wheels were locked in the left direction, they would rub on the flap. I cut out the area where they were rubbing, and it fixed it! It's a relief knowing it was just something simple like that. Thanks for your help!

LongDuck

Thanks for reporting back. Glad it was something simple,

KansasCityREPU

iTrader: (9)

Do you have something special with your steering/suspension that would cause this to rub? If everything is stock, it shouldn't be rubbing.

Laf12

Everything is stock, I was thinking the same thing. It might have been that the flaps were sticking inward more the the are supposed to be.