Rear end noise

J

Judson

Junior Member
I have a 1931 Roadster Pickup, all stock. Recently, I noticed a scraping noise which was intermittent which to me sounded like a dragging brake shoe. Then all of a sudden the scraping noise became continual beginning about 15 MPH. when the speed reduces to about 10 MPH, the sound goes away. I removed the rear hubs and cleaned all the brakes and emergency brake band, put everything together but it did not stop the scraping noise. Any suggestions to my noise issue, any input would be appreciated.

Thanks
 
I might check your axle bearings - or more properly remove the hubs and check the cylinders that the hub roller bearings roll on.

In time and use these are wont to get "egg shaped" with wear of the surface occurring on the "lowermost" portion of the cylinder.

This usually isn't a problem until the wear grows severe. Then what can happen is that as you accelerate, action of the driving wheels tend to make the bearing "climb" on the forward side.

As your car sits or rolls slow the force is primarily "down." Now give this a little torque as in acceleration and the bearing "climbs" up for the forward side shifting your up "up" and "forward."

This motion between hub and axle. may be creating an interference between your brake drum and shoe. Or between your brake drum and backing plate (the shoes will tend to compensate themselves for some movement of the drum relative to shoes.)

Is there a difference in the rubbing sound if you apply the brakes?

You can certainly check for egg shape by removing the drum/hub and checking with a micrometer. Also, you can eliminate the brake shoes themselves for a test and see if the rubbing still exists.

Looking for high value testing here. And with 2/3rd of your braking action likely occurring on the front drums you may not notice that much difference in stopping with the rear brakes removed - but be careful.

Joe K
 
Have you greased the U-joint area?? Is one of the rear brake drums rubbing on the backing plate??
Are you sure the noise is coming from the rear end??
Have you lubed the speedo cable??
Paul in CT
 
I did grease the U Joint area and undid the speedo cable and I will check on the drums rubbing on the backing plate
 
Hi Judson,

1. Jack up one rear wheel at a time & place the axle housing on a very steady jack stand -- not a jack.

2. Start engine, place in gear, open throttle, get out of vehicle & listen to rear wheel turning, & place a "long" stick on rear end banjo, L & R axle housing(s) , torque tube, etc., etc., with your ear on other end & listen to try to first find the "location" of the noise.

3. Beats the heck out of going down the road at a fast pace with you best friend or mother-in-law strapped to the underside of the vehicle with a stethoscope in one hand & a flash light in the other trying to find the noise.

Hope this helps to speed up the investigation to find where the noise is coming from.
 
Last edited:
A similar problem occurred in a friend's Model A that had been restored only a couple years previously. There was an additional intermittent clunking noise that accompanied the scraping noise. My friend said it started as a distant metallic scraping sound, which increased in volume in a short period of time, and was now also clunking. I pulled the hubs and checked everything over, as you have done. Finding nothing wrong, I decided to bite the bullet and pull the rear end for disassembly. Fortunately when I pulled the torque tube off, the problem was obvious. The two large pinion bearing nuts had loosened up because the tabs on the keeper ring between the nuts had not been fully tapped over each nut to prevent the nuts from spinning on the pinion gear's threaded snout. You could wiggle the driveshaft by hand because the nuts had backed off that much. Not a good situation. By resetting the pinion bearing preload and tightening the nuts to maintain it, the ears on the lock ring were bent over the nuts, alternating between the front and the rear nuts. Maybe that was overkill, but I didn't want to chance the nuts working loose again. I am told that some of the new repo lock rings are too tall and the unbent ears can scrape the inside of the torque tube as the driveshaft spins unless they are bent over. We bent them over. Problem solved. The scraping and the clunking went away. Apparently the clunking was the worsening of the loose pinion gear striking the ring gear teeth. No apparent damage was done to the teeth on either gear, so we put it back together and my friend has been driving it for six years now with no reoccurrence of scraping or clunking from the rear end.
Check this out in your Model A's rear end if nothing else obvious seems to be the culprit.
Marshall
 
I really appreciate everyone's input, unfortunately, I will not be able to do any further work on the car until the end of April. When I find the problem, I will post for all to see. Thanks again for everyones help
 
You must log in or register to reply here.
Back
Top