While driving around the neighborhood in my 1915 War Wagon, the car feels like it has a pulse. The seat of my pants seems to go left to right and forward and backward in a rythem or pattern. My first instinct was a bent wire wheel. I jack up the car and spin everything and put a cobbled test stand and everything seems to spin true.
Is there something else I should be looking at? I don't hear the engine surge or miss, seems to be drivetrain or chassis related, not engine.
U joint? Driveshaft? Rans drums?
I'll hang up and listen.
Tire(s) out of round?
Several things could be at fault. From your description, I would suspect front axle alignment, wheel balance, or loose parts.
Jack up the front axle and put it on axle stands. Then put one hand on top of a wheel and the other at the bottom and try to rock it back and forth side to side. Look for play in front wheel bearings, spindle bolts(king pins), tie rod ends, pitman arm ends and in the steering shaft. Also check the spindle arms and the spring shackles and the radius rod (wishbone). any looseness in those areas can cause a rythmic shimmy of the wheels. Sometimes the only way to stop the shimmy is to stop the car and then when you get going any bump or pothole and it starts shaking again.
Anyway, if you find looseness in any of those parts, it needs rebuilding and alignment. A good source of information on this would be the club booklet on front axle. It gives step by step instructions on how to do the work.
Do you still have the lowering on your chassis with long shackles? If so, I'd suppose it would sway a lot from side to side when driving without any panhard bar to control sideway sway.
Front axle has no caster or negative caster.
Also, lack of lubrication of spring leaves and shackles.
I'll look at the front end this week. My son had a jeep with the "death wobble" so I am familiar with the feeling.
Is that a photo of the chassis in Roger's photo? If so it sure looks to me like an off set rear spring for a dirt track racer. Look at the spring eye location compared to the ends of the rear cross-member and the location of the riveted ends of the rear axle tube. Also the leaves are long on the left and short on the right. The left side of the spring is long in the arch but the right is abrupt. Might be camera perspective but the ends of the spring and axle tube look way off.
I have one of those off set rear springs but on my car the axle is also short on the right for going in a circle. If that is your package with a standard front end the car is going to be diagonal and the front and rear end are going to fight each other.
Brake drum on R/R wheel but no brake drum on L/R wheel,....???
Spring shackles look long also
Let me take and post a photo of the current front end and the current rear end. This was a photo posted by a fellow forum member in an effort to be helpful, but it was of our donor speedster project and the rear axle has been replaced. So I will post new photos so that we are all talking about the same assumptions.
I would have posted them originally, but I didn't know where we were concentrating until now.
...ask and it shall be given unto you . .
So, I think the front end has "lowered" spindles or dropped or something as the donor vehicle was a speedster set up. I have left the front end as it came other than clean up, prime and paint. New bal cap braket and springs and bolts at the end of the wishbone and it is secure.
The original rear end is what was in the posted photo in a previous post and it has been replaced with a rebuilt 26/27 axle with backing plates and the leaf spring was removed from it's brackets with the previous axle and mounted, I believe, correctly to this set up. To me, the leaf spring appears to be centered on the cross member and over the differential.
These wheels are Model A wire wheels welded to Model T hubs and that is what came on the yellow speedster. I checked them for cracks and roundness prior to painting and mounting on this T. New wheel bearings all around. When jacked up, they appear and feel to spin evenly. I did have an issue with one wheel in a previous video, but it was not mounted tightly on the rear axle and now is.
Hope these photos help.
How much toe-in have you got?
That looks like a stock 27 front axle. It set a little lower than the earlier years and dropped down in the center. What kind of body do you have on it? The rear of the frame appears to set too high. Your rear spring looks like it was made for something heavy like a fordor sedan. With the rear of the frame that high you very likely have negative castor on the front axle. If your car is on a level surface, take a framing square to the axle at the pivot point for the front wheels. The bottom of the axle should be farther forward than the back. If it is either straight up and down or the top is farther forward than the back, you have an alignment problem. A lower rear spring would affect the alignment, so if you plan to replace it or remove leaves from it, do so before you try to adjust the alignment.
Dum question, Is your tire pressure right? That will cause all the symptoms you telling
This is the body I have on it. A little more weight just in front of the rear leaf spring with the machine gun mounted.
I thought I had measured the distance from the frame to the ground during restoration with the body off and was a little surprised to see it within a 1/4" from being dead level.
I will check plumb and level when I pull it out after the rain showers today.
Here's what I got. T square on the front end indicates that I have a slight forward camber on the front axle, which I presume is good. Seemed to be some slop in the wishbone to engine pan springs and bolts, so we will tighten and add shim if necessary.
My frame to ground is even on front and back from side to side, but I do have a 3" difference from the front of the frame to the rear of the frame with the rear end being the higher.
We will tighten wishbone, jack up front end and check front wheel play and then test drive again.
And, check tire pressure in all four while we are at it. I think I'm running 30 psi in my 21" tires and wheels.
When you say forward camber, do you really mean forward caster? And, if by forward caster, you mean that the top of the kingpin is leaning forward with respect to the bottom of the kingpin, then your problem is there. The kingpins need to lean back, with their top ends leaning toward the back of the car.
I'll also ask again, what is your toe in set at?
How much does that gun weigh? Try driving without it. Couple hundred pounds is very noticeable in a modern pickup when it's way up high. Dave in Bellingham,WA
I've got exactly 1/4", but I believe it is tow out, not in. When I use the center tire and tape method, I am 55 1/4" from center tread to center tread across the front of the car. When I rotate the tires 1/2 a rev, I get 54 7/8" across the rear of the tires to each other.
So I'm narrower in the rear of the tire than I am at the front so my tires are pointed out towards the curb, not in towards the crank handle.
Will read the manual, but presume I need to adjust tie rods. Wheel play and bearings feel tight. I do get a little movement when I grab the front wheel at the fornt and back and push and pull it. My son says the wishbone at the springs and bolts to the engine pan is what is moving. Time to put a shim in and tighten that up.
I hate it when someone asks a question on a forum and then never reports back that the asnwers provided did or did not solve the issue.
I'm glad to report that after a full day of just tweeking up the front end suspension parts, we are running smooth.
Added a penny shim to the front radius arm ballcap and clap, put the springs that I had in wrong, correctly. No slop or play. Adjusted my tie rod so that I have 1/4" toe in and added penny shims to the steering rod ballcaps and cplamps as well. Check wheel bearings and tightened both front spindle nuts a little and reinserted split pins and added grease to the grease caps/hub caps.
Noticed a little play in the spindle bolts and some wear on their collars, so it's on the list. But a test drive around the neighborhood indicates that my "surging" and general wallowing down the road is solved.
Thanks to all for pointing me in the correct direction. (pun intended)
Happy to read of your progress.