W.F. Brown- III

Four new tires on the old '48 Plymouth and the low speed wobble problem is now gone. Thanks to everyone who gave suggestions about the possible cause. They encouraged me to look closely at the tires and when I did, I discovered what could have been a catastrophic failure. Again, thanks everyone.

Uniroyal

When I discovered this it scared the crap out of me to think I'd been driving around on that tire.

Right about that!

Looks like I may have found the source of the wobble problem. I had to look closely to find this. Looks like a new set of tires will be my next investment.

I'm beginning to lean towards u joints as being the most likely culprit.

I just got back from doing a little "experimenting" with the wobble issue on my '48 Plymouth. I discovered I was wrong about it stopping once the car had sufficiently warmed up and had been driven for several miles. Previously, the wobble problem was noticed when I started the car and pulled out of the driveway. What I learned today was that when I first pull out and begin going through the gears, I am moving rather slow (the way the drive enters into the highway plays a part in this). However, after any other stop, when starting out I tend to go through the gears much faster and build speed much quicker. So, what I did was to pick a nice long and secluded straightaway and do some experimenting. All this was after the car had been driven several miles and the motor, tires, etc. were sufficiently warmed up. I discovered, when just barely creeping along in first gear the car had a distinct wobble (real distinct). There is no "shimmy" in the steering wheel, however. With tut the clutch in and still just barely moving, the wobble is still there but not quite as bad as under power. As the speed increases and as I move up through the gears the wobble disappears (or at least is not noticeable any more). I repeated this process several times with the same results. The slower the speed (like down to almost a crawl), the more the wobble. The faster the speed, the less the wobble until it is gone. From this experiment, I would think that should discount a "flat spot" on the tires. The motor/transmission mounts have been mentioned, but I would think that if these were bad it would show not only when moving but when stopped and the motor revved. The driveshaft issue might be a problem, but I would think the faster it was moving the greater the vibration would be (I could be wrong about that). The kingpin issue is something I don't have a clue about, and don't have the resources to check myself. Given all this, any further ideas? I just got back from doing a little "experimenting" with the wobble issue on my '48 Plymouth. I discovered I was wrong about it stopping once the car had sufficiently warmed up and had been driven for several miles. Previously, the wobble problem was noticed when I started the car and pulled out of the driveway. What I learned today was that when I first pull out and begin going through the gears, I am moving rather slow (the way the drive enters into the highway plays a part in this). However, after any other stop, when starting out I tend to go through the gears much faster and build speed much quicker. So, what I did was to pick a nice long and secluded straightaway and do some experimenting. All this was after the car had been driven several miles and the motor, tires, etc. were sufficiently warmed up. I discovered, when just barely creeping along in first gear the car had a distinct wobble (real distinct). There is no "shimmy" in the steering wheel, however. With tut the clutch in and still just barely moving, the wobble is still there but not quite as bad as under power. As the speed increases and as I move up through the gears the wobble disappears (or at least is not noticeable any more). I repeated this process several times with the same results. The slower the speed (like down to almost a crawl), the more the wobble. The faster the speed, the less the wobble until it is gone. From this experiment, I would think that should discount a "flat spot" on the tires. The motor/transmission mounts have been mentioned, but I would think that if these were bad it would show not only when moving but when stopped and the motor revved. The driveshaft issue might be a problem, but I would think the faster it was moving the greater the vibration would be (I could be wrong about that). The kingpin issue is something I don't have a clue about, and don't have the resources to check myself. Given all this, any further ideas?

This just started a couple weeks ago, so I haven't really done anything yet (other than pay close attention to see if I can determine some kind of "pattern" for the wobble). After these suggestions, I plan on trying the carpet scraps under the tires first. If that doesn't work, then rotating the tires. Hopefully, I can rule out the "simple" fix (inexpensive fix), before moving on to having a mechanic check it out.

The problem only started a couple weeks ago. Nice, dry and warm weather. No problems before, even during the extreme cold we had this winter.

I've had this car for six years. The tires are the same ones that were on the car when I got it and I park it in the same place as I have for those six years. The wobble just started a couple weeks ago.

Will do. Thanks.

The car sits in a dirt floor garage, but I'll try the carpet idea. However, if it actually was a tire with a flat spot wouldn't I feel that in the steering wheel?

They are bias ply tires, but I don't think the car doesn't stay parked long enough to create a flat spot.

Something new has started with my '48 Plymouth Sedan. When starting out, the car wobbles like one of the tires are out of round. After just a short distance and after up to speed, the wobble disappears. Once the car has warmed up, no more wobble even at low speeds. There is no shimmy or vibration felt in the steering wheel. The tires are properly inflated and show no signs of wear. Any ideas?

I plan on doing that. It had to go somewhere.

I couldn't really tell where it leaked from. I don't see anything that would indicate it's around the wheels. The car is parked on the same spot in a dirt floor garage that's been used since my Granddad bought the first family car in 1922, so there's more oil in that spot than in the entire state of Texas. I plan to put an old sheet down to see where a leak may be coming from.

To my surprise, and I must admit also to my embarrassment, I managed to "fix" what was making the noise. It was the oil level in the rear end. I had never had a problem with the oil in the rear end leaking, and always check it about twice a year. Out of desperation to find the problem with the noise, I decided to check the oil level today just to make sure. Well, needless to say, it was extremely low (almost none in there at all). I filled it back up with 90 weight gear oil and took it for a test drive. No sounds whatsoever when shifting or under load. I could have sworn the sounds were coming from the front of the car, but apparently I was wrong. Well, now I have one more place to check on a regular basis. Live and learn. Thanks to all who offered advice.

That's what I was afraid of. Oh well, I guess it could be worse. Thanks.

I checked the oil in the transmission first thing. It was not low.

I had a similar sound start up a year or so ago, but that time it started while driving (not while starting out under a load). Same thing - when clutch was engaged (pedal up) sound, when disengaged (pedal down) no sound. I never got an idea on what it was and before I could get the car to the shop to have a real mechanic take a look, the sound went completely away. I've probabally driven it 2,000 miles since then without issue, then all of a sudden it's back.

I drive the car every couple days. The sound only is there when starting out and in all three gears (plus reverse). After it is up to speed, no sound at all. The sound is only when "under load" when starting. If I put the clutch pedal down (and the car is still moving), the sound immediately stops. Release the clutch and sound starts.

I started out with my '48 Special Deluxe yesterday and had a very unusual sound. The motor starts and runs fine. Shift into first gear and let the clutch out and it sounds like a log chain clanking around. Same with second and third. However, if I push the clutch in, the sound goes away. After the car has built up speed, no sound at all. It runs good and has plenty of power. After several miles of driving the sounds when starting out through the gears becomes less and less noticeable until it eventually disappears. Start out the next day, and same thing again till everything gets good and warmed up. Any ideas as to where I should start looking? Transmission? Clutch or throw out bearing? Any help would be greatly appreciated.

Thanks for the replies. I will look into adjusting the float and/or checking for trash, as that seems the most logical place to start. I don't think it has any relation to engin heat and gas, as this problem just started (and it will also leak with a cold motor).

I’ve got a question for the mechanically inclined members here (I know very little about working on old cars, I just like to drive them). The arrow in the photo below is pointing to a part that will leak gas about 10 seconds after the car is shut off. The car starts fine and runs fine. No leaking while running, even after a drive of well over an hour. No leaking at idle. Only when the motor is shut off, either after just a few seconds of running or an hour or two, will the leak start here (actually just a drip). Not much drips out, but enough to notice. The dripping will last about 30 seconds to one minute (I assume till whatever gas is left in the carburetor drips out). Any ideas short of replacing the part? If replacement is needed, can just that part be replaced or will the entire base of the carburetor require replacement? Thanks in advance for your help.

Great looking car. I hope you will enjoy it for a long time.