question about a strange noise and vibration

D

dankurth

Member
I saw an ad for a Model A chassis a couple of months ago. When I went to look at it I founf out it was really a speedster. Not a really great wooden body, but kind of cute. The chassis was what I was really interested in and it looked good; supposedly restored. The price was right, the engine fired right up and sounded good, so I drove it onto my trailer and brought it home. It sat in my garage until I fired it up yesterday to take it outside and flush out the cooling system and put in some fresh antifreeze. As I pulled out of the garage I heard a weird noise; not quite a grind but maybe a loud rubbing sound and the car shook a little bit. As I drove around the driveway the noise and the shaking got worse, but it only happened with the clutch engaged. Pushing in the clutch would stop the noise, even though the car was still rolling.
I put the car up on jackstands today, started it and put it in gear. I listened to the drivetrain through a cardboard tube and the noise seemed to be coming from the differential, but with a straight exhaust it was kind of hard to be sure.
If it was a bad throw out bearing, wouldn't it make noise when disengaging the clutch, or all of the time? Clutch operation seems to be smooth.
Does it sound more like a bad pinion bearing? Seems like it should make noise all of the time but maybe coasting with the clutch pushed in takes just enough pressure off to calm it down.
Any ideas? Thanks for your help.
 
Hey Dan. The first thing I would do is drain the rear end grease and inspect it closely for metal fragments and/or debris. Also note the viscosity.

Depending on your findings would dictate the next move. I would not hesitate to pull it down completely, --or remove the driver's side axle housing and then pull the carrier assy out and inspect bearings and shake the pinion in the bearing to see if the preload has backed off.

Why don't you consider doing the drain & inspect procedure first and let's all see what you find to determine what to do next.

.
 
I've seen A's with missing teeth on the ring gear and still drive, pull the oil fill and drain plugs and peer inside first, and go from there.
 
"I've seen A's with missing teeth on the ring gear and still drive, pull the oil fill and drain plugs and peer inside first, and go from there".


Jim:

The first rear end I ever rebuilt was about 25 years ago. It was in a 30 town sedan I had. The car ran fine, I dove it all over the place. I decided I wanted to install a Borg Warner overdrive. I bought the overdrive from Bert Hiller. I aslo bought a complete rear end at the Long Beach swap meet from a street rodder who was selling it cheap. I diassebled this rear end as a learning process. I located all the how-to documents available and studied them. When I was ready to tackle the town sedan I pulled the rear end and disassembled it. It was a disaster. There were two teeth completely missing from the ring gear, the pinion gear had collateral damage, and there were several elements from a bearing drifting loose in the banjo. The banjo was also full of metal debris, yet it had been running just fine. I ended up rebuilding and using the swap meet rear end.

Tom Endy
 
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The little bit of lube left in the banjo was almost as thick as roofing cement. I didn't see any metal in the lube but the ring gear teeth are badly worn. No bananna peels either. I deserved that jab because I really knew better than to ask about it. The car started right up and everything was so smooth the day I got it; I just didn't want to face the fact that I had major repairs to do to a car I've driven less than 1/4 mile. I was hoping for a long shot, like somebody might say something like..."Yeah, my car did that after it sat for a while. The franistan was rusted to the wobble eater shaft. Just drive it a while. It'll be fine." Like I said, I knew better.
I'm not going to do anything with it right away. I picked up a 400-A cowling at Hershey a few years ago and plan to use this chassis to build another huckster, but I'm not investing a lot of time and money until I get the title straight.
Thanks for the advice. I'll post a picture as soon as my daughter in law shows me how.
 
The banana skins was an old OZ gag.

When i was kid, I heard of a lot of dudes, say to fill up a noisy diff with banana skins to quieten it down to sell it.

After 4 decades of working on cars, I have never actually seen evidence of skins in diff.

So was probably just a joke of the era.
 
dankurth said:
I saw an ad for a Model A chassis a couple of months ago. When I went to look at it I founf out it was really a speedster. Not a really great wooden body, but kind of cute. The chassis was what I was really interested in and it looked good; supposedly restored. The price was right, the engine fired right up and sounded good, so I drove it onto my trailer and brought it home. It sat in my garage until I fired it up yesterday to take it outside and flush out the cooling system and put in some fresh antifreeze. As I pulled out of the garage I heard a weird noise; not quite a grind but maybe a loud rubbing sound and the car shook a little bit. As I drove around the driveway the noise and the shaking got worse, but it only happened with the clutch engaged. Pushing in the clutch would stop the noise, even though the car was still rolling.
I put the car up on jackstands today, started it and put it in gear. I listened to the drivetrain through a cardboard tube and the noise seemed to be coming from the differential, but with a straight exhaust it was kind of hard to be sure.
If it was a bad throw out bearing, wouldn't it make noise when disengaging the clutch, or all of the time? Clutch operation seems to be smooth.
Does it sound more like a bad pinion bearing? Seems like it should make noise all of the time but maybe coasting with the clutch pushed in takes just enough pressure off to calm it down.
Any ideas? Thanks for your help.
Click to expand...

Could be the throw out bearing. Might not be releasing all the way when the clutch is out. I would take the inspection plate off and check.
If it was the rear end it would have different sound in each gear with the same engine speed. How does it sound in reverse and out of gear.
Also how about a loose flywheel.
 
A banana peel story.. Years ago in the beginnings of Motor Homes, they were not much more than big echo chambers.. We sold one in which the owner was complaining of a rear end howl, and rightly so.. I had the rear end apart several times and only managed to change the speeds at which the howl occurred.. So we got our friendly local factory rep involved.. Tim and I laid under that thing for another day and a half and didn't improve anything.. Tim disappeared for a few minutes and we saw him walk out of the little grocery store across the street with a bag full of bananas.. Everyone had a couple bananas during their coffee break.. We shoved the peels thru that little hole in the rear cover and took it for a road test,, that truck never came back with a complaint again..
I've seen some factory reps do some pretty strange things, but, this one actually seemed to work..
 
Change all the fluids and lube all the fittings and drive it around and have fun. I'll bet the rear end is fine!
 
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