Noise coming from the rear.
Thread Starter
Instructor
Joined: Dec 2004
Posts: 198
Likes: 0
From: Newmarket Ontario
Noise coming from the rear.
I have a 1979 L48 automatic. The last couple of years when you apply the brakes and come to a stop there is a noise almost like the brakes are grabbing when you continue to go. When you pick up speed the snapping grinding sound disappears, but its getting worst. If I put it in neutral and coast, the car rolls just fine which means the brakes have released. I took it to a mechanic who works on Vettes and he has no idea what the problem is at this point. He checked the U joints and axle bearings and they are fine. He checked the brakes and they are ok. The only thing he will try tommorrow is to add an additive to the rear end thinking it might be the clutch plates acting up. Any thoughts would be appreciated as I like going on long trips but feel a little nervous doing that right now.
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
The fact that the brakes haven't worked in years doesn't mean they can't be causing a problem. I would jack up the vehicle and check by turning wheels to isolate noise source.
Pro
Joined: Apr 2007
Posts: 528
Likes: 9
From: Grand Rapids Michigan
Loose or disconnected material could be clunking back and forth within the housing causing your noise on an otherwise healthy braking system. A little additive in your rear end diff won't hurt, though.
Thread Starter
Instructor
Joined: Dec 2004
Posts: 198
Likes: 0
From: Newmarket Ontario
Thanks for your help but tommorow we are checking the parking brake assembly and if it looks ok we have decided to change the rear wheel bearings. I sure hope thats solves the problem.
Instructor
Joined: Jan 2007
Posts: 191
Likes: 1
From: MONTREAL QUEBEC
I just had the same thing happen to me. Most likely your rear calipers aren't releasing after you apply your brakes. Apply your brakes and release them while somebody tries to push the car from behind (while in neutral). They will find it impossible to budge the car for a few seconds until the calipers release even though your foot is no longer on the pedal.
If this is your case as it was mine your rubber brake line hoses are shot and not allowing free flow to your calipers. Simple and cheap fix just change all 4 rubber hoses and problem solved took me no longer than 15 minutes and bleeding after.
If this is your case as it was mine your rubber brake line hoses are shot and not allowing free flow to your calipers. Simple and cheap fix just change all 4 rubber hoses and problem solved took me no longer than 15 minutes and bleeding after.
Thread Starter
Instructor
Joined: Dec 2004
Posts: 198
Likes: 0
From: Newmarket Ontario
The brakes are releasing thats the problem. I wish at this point they were not. It would be less work to fix that problem than bearings. When at low speeds when you crank the wheels hard from side to side you can hear a noise what sounds like the brakes are grabbing. But again sounds like it even though they are not. I leaning towards bad bearing that act up only when torque is applied at from a stop to acceleration and from side to side motion. Who knows maybe I am wrong but I need to do something. But will also look into the parking brake housing when we start stripping it down.
But will also look into the parking brake housing when we start stripping it down.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Pro
Joined: Nov 2002
Posts: 599
Likes: 16
From: vista CA
If you get these noises when driving and moving steering wheel back and forth, and not applying brakes, I suspect your diff could be the culprit. I suggest you drain (use pump to suck out) your old fluid, add new heavy duty fluid (gear lube) and additive vice just adding the additive.
I had this problem in my 79 rear end recently when warm - the sounds were terrible! I thought something on the drive axle (u-joint caps) were loose and hitting the body/frame, or else I was going to need a new diff. But, I replaced the diff with heavier weight gear lube (? forget but maybe 120 weight) and additive. Drove around in figure 8's both directions a few times and no more sounds. Pretty easy to do, and your diff could probably use it anyway even if it is something else.
I had this problem in my 79 rear end recently when warm - the sounds were terrible! I thought something on the drive axle (u-joint caps) were loose and hitting the body/frame, or else I was going to need a new diff. But, I replaced the diff with heavier weight gear lube (? forget but maybe 120 weight) and additive. Drove around in figure 8's both directions a few times and no more sounds. Pretty easy to do, and your diff could probably use it anyway even if it is something else.
Last edited by martinsw; Sep 6, 2007 at 02:23 AM.
Thread Starter
Instructor
Joined: Dec 2004
Posts: 198
Likes: 0
From: Newmarket Ontario
Assembling the bearings on the drivers rear tommorow. Will take it out and see if there is any difference in the noise. If it is still there I am going to suck out the oil from the rear end and replace with heavyer gear lube as suggested. If not I will replace the bearing on the other side. While we had the axle off I put on a new pair of shoes on complete with springs and hardware. I have no idea why they designed the parking brake assembly like that. To change anything in there you have to remove the axle. You would of thought they would of put slots or at least a hole to access the retaining springs for the parking brake shoes.