Bouncing coupe

[philcobill]

Our 29 coupe is bouncing and I am not sure why. The bouncing is worse at 20 to 35 MPH, and seems to bounce much less at 40 to 55 MPH. Some roads seem to be worse than others. I think we pretty much eliminated the engine (a newly installed Burtz engine) because it still bounces to the same degree whether the engine is revving a bit or when the clutch is engaged and the engine is idling. I suspect something like the shocks and or springs. I would not be surprised at anything. The car is okay to ride in, but the bouncing is a bit unnerving at times.

The shocks were looked at when we had the brakes serviced two weeks ago. I am not sure what the mechanic did. He is on vacation until next week, What reasonable questions should I ask him?

What should be our next step?

[daveymc29]

What type of shocks?

[Brentwood Bob]

Did this start after the recent service?

[philcobill]

Originally Posted by Brentwood Bob

Did this start after the recent service?

I am really not sure. The car has been sitting for over two year waiting for the Burtz engine. I had the brakes done when the engine was installed. Before that, I only drove it around for a couple of months, after it had been in storage for over 25 years and rarely started. I am just now fixing things as I come to them. And this bouncing is one of those things

[philcobill]

Originally Posted by daveymc29

What type of shocks?

It has the stock shocks. The mechanic looked at them, and may have done something to at least one of them, but I am not sure what. I am just wondering if the symptoms I am describing could be shock related, and if so, should I just have a full service or replacement given the fact the car sat idle for so long.

[Marshall V. Daut]

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If you think it might be shock related, just disconnect the links or arms and take the car for a short drive. If it continues to bounce, the shocks were not the problem. Keep looking.
Check the wheels for roundness. One or more may be out of round or bent. If the wheels have numerous bent spokes, chances are good that the rim is not true, which will cause the car to bounce and/or vibrate at certain speeds.
Also, Firestones and Goodyear tires from 20-25 years ago were egg-shaped when brand-new. Unless the tires were trued on the wheels by a special cutting machine and then balanced, the car will bounce. In the late 1990's, I put all new 19" Goodyears on my '31 DeLuxe Roadster and until I finally took the car to a hot rod shop to true the tires, the car bounced like a clown car in the circus. If you are running older Firestones or Goodyears from that era on your car, that might explain the bouncing.
Marshall

[jb-ob]

Philcobil,

Addition to Marshall's experience, tires will develop flat spots from sitting for extended periods. If you can afford that new engine, include a new set of 'sneakers'. $.02, jb

[Marshall V. Daut]

Ha, ha, ha! 'Good one, Jim!
M.

[Ray64]

Maybe one shock partially frozen up

[philcobill]

Originally Posted by jb-ob

Philcobil,

Addition to Marshall's experience, tires will develop flat spots from sitting for extended periods. If you can afford that new engine, include a new set of 'sneakers'. $.02, jb

It may come to that. The car has been sitting for so long, that just about anything could have gotten bad. The tires still have their tread, and are not dry rotting. Just another thing to check out.

[Ramman]

Originally Posted by Marshall V. Daut

If you think it might be shock related, just disconnect the links or arms and take the car for a short drive. If it continues to bounce, the shocks were not the problem. Keep looking.

What if the shocks are empty, misadjusted or not functioning as designed?

[TerryO]

If you can afford that new engine, include a new set of 'sneakers'. $.02, jb

I would recommend radial sneakers...


TOB

[Phil Brown]

If all 4 shocks are there and hooked up then it sounds like the shocks might be empty resulting in no resistance to movement. Just along for the ride (a bouncy one )

[updraught]

Originally Posted by Ramman

What if the shocks are empty, misadjusted or not functioning as designed?

We have just got back from a four day crossing of the Simpson Desert (over a thousand sand dunes or something).
The brand new rear shocks blew out on the 4wd after just the first hour. They dumped their oil on the ground. We gained some valuable experience in bouncing. The springs only bounce when you hit a hole or lump.
On the flat it should be smooth sailing.

[gdmn852]

Hello, I would suspect the tires being as old as they are, next bent , out of round rims .After had a blow out with old 12 year old tires,with hardly any miles on them I view old tires with suspicion.

[ronn]

if your tires are radial, you can have a broken band inside. I had that happen on an old taurus and the rear wheel would go airborn at certain speeds. Made it home going 40mph and found the radial totally cracked. Changed the wheel and good to go.

[gdmn852]

That has happened to me also on newer cars, but I doubt this Model A has radials .It may have rayon or early nylon cords , they were notorious for flat spots, recalling my grandfather had tires that would bang around, shaking the car until they warmed up, almost like an amusement ride.