I've notice a problem with my '35 Plymouth, that happens when we have four people in the car. When I get up to highway speed, the cars starts swaying back and forth. It never happens when we have just two people and it never happens at lower speeds. It's just a guess that it is the leaf springs.
Is anyone familiar with this symptom? Is there a definitive way to test leaf springs? Can leaf springs be rebuilt or do they need to be replaced?
Any light you can shed on this problem would be greatly appeciated.
Just a guess---I don't recall the set up on the 35 for the spring shackles--are they tight, or are the bushings good?
My car is a '37 with worn out leaf springs. The leaf springs are absolutely flat and straight with the weight of the car on them. The car sits too low to the point I can not get my car lift adapters under the frame without first jacking the front end up. I found new reproduction rear springs but no front springs to be found however I did find a place to make them. I am waiting for the front springs now.
Most of the spring shops now do not have an oven but if you can find a shop that can retemper and re-arch yours that will work. Be sure the shocks are in good shape too.
Upon further reflection---
I base this conjecture on my experience pulling various horse trailers over the years. Are u overloading your tires esp on the rear? The sidewall should give u your max weight per tire. It may be that the added 300 or so pounds from two extra passengers in the rear is overloading your rear tires. Or maYBe u are having a tread separation in progress. Just a thought.
I had a 37 that did the same, once i replaced the king pins (wrist pins) that cured the problem
Good point John! May be low tire pressure too. The maximum pressure is also stamped on the tire sidewall.
Jim
Quote from: John Hendricks on June 18, 2008, 05:12:40 PM
Upon further reflection---
I base this conjecture on my experience pulling various horse trailers over the years.? Are u overloading your tires esp on the rear?? The sidewall should give u your max weight per tire.? It may be that the added 300 or so pounds from two extra passengers in the rear is overloading your rear tires.? Or maYBe u are having a tread separation in progress.? Just a thought.
From what I can see, the spring bushings are fine. I replaced the old spring shackles and the king pins so that shouldn't be a problem.
As far as overloading the tires, I guess I'm not sure what that means. They are biased ply tires and there are four people in the car. Surely the tires are rated for that kind of load. I don't see any signs of tread separation.
Typically the inflation pressure the owners manual lists is for a good ride with an average load. If you are loading the car to the max then you probably want to inflate the tires for their max load rating which is, as I understand it, at or near the maximum inflation pressure listed on the sidewall. If the tires are not inflated enough for the load then they will deform more than they should and this might manifest itself as having the car feel squirrelly.
With four passegers in the car it is not overloaded i have had up to 7 in my car (its a tight fit )but it never affected the ride of the car . i have always ran my 16"bias ply tyres at 28-30lbs . you have replaced the king pins and spring hangers ,have you checked the springs center bolt if one is broken it coud give you the effect that you are getting
Would add to what others have suggested : check the steering box freeplay (should be as close to zero as possible in the center position) and the drag link to the factory specs.. Also the toe in should be checked which is simply done by marking the tires with tape,rolling the car back or forward, etc. and adjusting the tie rod. These adjustments eliminated my car wandering at high speeds.
Also,am not sure if the '35's have a front sway bar, my '36 does.
LR
I believe that 35 was the first year for a sway bar.
If I read your post correctly you may be mixing metaphors. 'Sway' is the side to side movement of a chassis usually felt when going around a corner. 1935 was the 1st year for Plymouth to add a sway bar up front to try to stop this. The bar connects the 2 front sides of the car suspension in antipoise. As the one side of the car tries to dip low on a corner and the other side tries to rise up, the bar connects an opposite pull on the rising side and pulls it down to try and keep it level. One of the ad tapes you can rent from the Club has a big spiel on this in ads for the '35 PJ.
'Pitching' is the movement of a chassis back and forth along it's longitudinal axis. It was caused by the suspension winding up and letting go as the car dropped into depressions on the road. The cause was the 4 leaf springs at the corners loading up in an 'S' curve and then rebounding when they passed the road anomaly. It stopped when coil springs replaced the leaf springs in the front. The pitching moment for coils is vertical. It was this pitching fore and aft that used to make people 'car sick' in the old days.
? You seem not to be experiencing it under low loading because I suspect the chassis 'sprung to unsprung weight ratio' is tight enough to stop the springs from winding up. The unsprung weight, the wheels,brakes,axles and springs are heavy enough to stop the main leaf from backing up on itself and warping. When you add the weight of 4 people, I suspect you upset the ratio enough that the body weight overwelms the unsprung parts and starts the spring winding up scenario.?
Well I'm not sure. The rear end tends to sway side to side making it necessary to make corrections with the steering wheel. It does not feel like it is lurching forward and backward nor does it feel like it is swaying corner to corner like when turning a corner too fast.
Quote from: JimCno on October 07, 2008, 11:04:28 PM
Well I'm not sure. The rear end tends to sway side to side making it necessary to make corrections with the steering wheel. It does not feel like it is lurching forward and backward nor does it feel like it is swaying corner to corner like when turning a corner too fast.
Do you have the "Silent-U" style shackles on the rear axle on that car? The ones on my car were very loose when I first got it and it made for some rather squirrelly handling.
from what you have just described it sounds as if it is just 1935 driving conditions , if you are not to concerned about authenticity fit some radial tyres you won't believe the difference