atariangamer Posted March 9 Share Posted March 9 Good day all, Recently went through my Z and did some much needed maintenance on my car. However, I ended up introducing some issues in the rear end that I can't sort out. Symptoms: above 15mph there is a "whirring" or light scraping sound from what seems like the right rear. It is not affected by braking or applying the handbrake. It does get slightly louder under acceleration/load, but popping it out of gear doesn't make it go away. It doesn't seem to get louder or more intense with higher speeds... Basically it just starts existing and doesn't go away until the car is no longer moving. This is joined by a very loud resonant whine under acceleration at 50mph (but I'm pretty sure that happened because I put 75w-90 in the rear diff instead of 90w-140). Before: no noticeable noise, but my brakes were definitely not properly adjusted, the shocks were shot, and every rubber bushing was destroyed. Changes: new EKB gas shocks, original springs, original strut casings. Full new set of bushings for all rear suspension components including front and rear diff mounts, upper shock mounts, front and rear control arm bushings... We also temporarily fitted a grease zerk to the half shaft u-joints and flushed all four u-joints with fresh grease, dust seals seemed intact. We did not change or re-pack the rear wheel bearings because there was zero play in them and no noise while testing them on the bench. After all these changes, the tires were now obviously out of round due to the previously shot suspension, so we removed the wheels to get new tires mounted and balanced. Once the new tires came back, we put the wheels on the car and decided to try a proper brake bleed/adjustment. It was after this adjustment that I noticed the introduction of the whirring sound. I don't believe it was there before we changed tires. I have stopped quite a few times and checked to see if any part is getting unreasonably hot to the touch or obviously worn from scraping, but nothing seems to have any glaring issues. ~ Does this sound familiar to anyone? Is there something else I can diagnose or check before having to take it to a shop? I have not yet drained and refilled the diff with the heavier gear oil. Any ideas would be appreciated. ...I'm just hoping that it's not a sign of some dying component I just couldn't hear before because the diff mounts were basically not touching the car anymore. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 9 Share Posted March 9 The drums might be rubbing on the backing plates. Not uncommon to get a bend in it when working on the brakes. You'll see a shiny spot. 1 Quote Link to comment Share on other sites More sharing options...
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