1956 with strange noise

[JohnD1956]

Hi all, Looking for some ideas where to search for a noise in my 56. This noise sounds like a tire with a broken tread. A flapping noise if you will, not metallic, but more solid, almost like knocking on a wooden door.

I've had this noise for several years. It is more pronounced when you let off the gas to slow down. However, under power, if you pass a guard rail or something else to shorten the echo range, I can hear the noise.

Here's what I checked and replaced.

Water pump and fuel pump replaced. Tires checked, and all brake linings inspected. Front wheel bearings replaced, Rims replaced, tail pipes replaced and all pipes rehung to ensure no frame contact. The Generator has been rebuilt also, but the power steering pump is still original. Also, the outer rear axle bearings were replaced a decade or longer ago, but I have not put many miles on them, Probably less than 10 K since I've owned it in 1974.I did have my shop put it on a lift and listen to the rear axle while the car was running in drive. We never heard the same noise, but they told me the rear was a bit noisy and probably could use a rebuild.

Last summer, I was going to isolate the power steering pump, even though the noise definitely sounds like it is coming from the left rear side. In doing so, I found my harmonic balancer was broken. It could rotate it back and forth to the tune of an inch or so. I got a replacement, had it rebuilt by Damper doc, and then put on a new timing chain and gear since I had it open.

I finally got it out last weekend, and thought I'd be clear sailing figuring that balancer was the problem but not so. Same noise under the same conditions?

It almost sounds like a baffle in the muffler had collapsed, and this may be possible still. The mufflers are over ten years old, but with such little use, they are still solid on the outside with practically no visible rust, so I did not replace them when I had the tail pipes done.

Before I sink another useless dime in this car, I was hoping someone else may have had a similar problem and can share their experience.

[Guest imported_bjr]

The first thing I would try because it is the easiest to do, is drive the car with the power steering belt removed. That would eliminate the ps unit as a cause. Next I would try a different set of tires. Someone around you must have a set mounted on Buick, Cad or Olds rims that you could borrow and bolt on. Does the flapping increase with road speed? If you get going about 50 and put the car in neutral and let it coast does it go away? If the sound increases with road speed but does not go away when coasting in neutral, it's not from the engine/exhaust, but from wheels/tires or rear end. One other thing, is there anything hanging under the car that the wind could make flap? Like a rubber weather strip or seal? Good luck, hope this helps. Brian

[JohnD1956]

Thanks These sound like good ideas. It's snowing this week here, so I'll have to give these a try in a few weeks.

[BUICK RACER]

Also what type of tires do you have on it? As I was going to recommend putting it up in the air and then I reread your message and saw you already did that, one thing that happens is the dynaflow rear seal can leak into the torque tube and reduce your rear axle fluid viscouscity(sp) to next to nothing, and then the rear axle gears start to wear very quickly! Possibly the cause of your rear axle noise. Where are you in NY snow country?

[JohnD1956]

I know my rear seal leaks, but I pulled the plug for the rear axel and the fluid level was right. So I don't think I have leakage into the rear axel. I have a set of economy radials on the factory rims. I bought them at an independent Goodyear dealer. I am in Schenectady NY. I am hoping to try what BJR suggested tomorrow. Since I get the noise at slower speeds, after I try slipping it into neutral, I then plan to try and shut the engine down. That should isolate Engine, transmission and exhaust. If I still get the noise, then I am planning to have the rear axel rebuilt and to have the transmission leak fixed at the same time. Just in time for the world to run out of gas I suspect. And gas is already so expensive, it may just be a good year to have this done, and then I won't have to feel bad about not driving it.

[Pete Phillips]

I hesitate to even suggest this, but are your red plastic center emblems in the wheelcovers making the noise? When I had a '56 (also happens on '58s), the clips that hold the center emblems can get loose or break off, and you get a loud click when the car is moving, if the emblems are loose.

Pete Phillips, BCA #7338

[Mrbuick714]

Drive between two rows of big buildings slowly.If you hear an odd noise,check for wear of the differential side gears where they go through the carrier.The noise will occur at twice wheel rotation frequency.

[JohnD1956]

Thanks for the suggestions. It can't be the hubcaps, they are not on the car.

How do you check the side gears? Is this something that could be done while in the car? Or only upon pulling the rear axle?

[Mrbuick714]

Find a "Concrete Canyon",and with no other cars around,roll your windows down and listen. Yhe cure is to find a newer assembly. That 56 & up rear axle is not easy to work on,and that is the understatement of the day..

[JohnD1956]

I suspect you are right about that noise. I failed to get the car out this past weekend, but am going to try for Saturday. If get the noise while rolling and the engine off, then I guess it's rear axle rebuilding time. It may be tough to work on, but I think I'll try to keep it stock.

Thanks for your help.