Help!!! I've just gotten my first rod registered and it's now street legal. I'm enjoying cruising it every day, or not really, as it's all over the place as soon as it gets over about 40 mph. Specs: Essex 1929 sedan. Stock front axle w. plymouth 11" brakes on (softish)paralell leaves, tube shocks The toe in is ok, the caster is about 3 degrees... Plymouth Volare 7-1/4" rear axle on paralell leaf springs, tube shocks. tires: coker classic L78-15 rears and 7.50-14's up front. Sure, some bump steer is evident, but that's not the whole problem, as it's a real handful to drive even on a straight road, and a real pain over bumps... Any suggestions? The whole story here: www.waasadata.com/essex
Nice car! As I read through your site, which is also very nice, I noticed on page 7 that you changed the arch in the left frame rail. I would check the angle of the shackle at the rear of the spring and see that both sides are now still the same. (Assuming they were before you did this). It could have moved the center line of the axle forward on the left when compared to the right side since you probably moved the front mounting point of the spring forward (slightly) on the left. If it did move forward, strange things would be going on while going down the road and the springs are moving, etc. You might have to put it on a 4 wheel alignment machine to even tell if its "square" or not. While on there you might also check for a little negative camber. It could help in going "straight" but don't overdo, you still want good tire wear and cornering ability. At least that's a starting point. With the alignment specs on a 4 corner, you'll know where you are for sure.
Nice to hear that this car is finally on the road. Those handling problems are sometimes difficult but like previous answer said: put it in to 4 wheel alignment machine for check. 3 deg camber sounds quite small. I have 7 in my 35 ford, but of course it's different suspension.
Sounds a bit simple but get a friend to video the car going down the road both from the rear and the front. In this way you will get a visual clue as to what is going on and it might make it easier to start the diagnosis. Plus its fairly free which is always a good thing... Must concur that a 4 wheel alighment is money well spent, made a big differance to my car but that was stable compaired to what you have described! Good luck and keep us informed. P.
I can't help with the problem, but I will say NICE CAR!! I've only read the first 3 pages of your site so far, but you've done a great job on it.
The front axle has 3* of caster relative to the ground or the frame? If you set up the axle, and then set your ride heights, you may have eliminated any caster you had. Double check your toe-in. Are you sure there is no play in the tie rod? Apologies if you have already addressed these issues. I just want to be sure you don't overlook something simple.
Thank you for all your answers! The caster angle is now some 3 degrees relative to the ground. The toe in is double and triple checked. I had new, bigger wedges made. They'll give some 5-7 degrees of caster, which I feel should be enough. The toe in is double and triple checked. But, I think I've found a great part of the problem! The front Essex suspension is of the parallel leaf spring type, and for instance, when braking, the whole axle rotates a little, and the caster goes bananas. Further, as the steering arm is higher than the springs, it pulls the drag link, causing the car to steer right without driver input! Next up is new caster wedges and more leaves, and perhaps spring clamps in front of the axle, to make it even less flexible. A new lowered steering arm would be a good thing, but that'll have to wait till the cruising season is over. Please comment if you come to think of something, and I'll keep you updated when I have any news.
Yap, you got it, I think... The bump steer is induced by even the smallest of bump and/or steering input! Steering rod will even generate bump steer if car tilts to one side! Once it starts swaying, your'e done for... Same damn problem on some lifted 4x4, but reversed... Either correct geometry for straight steering rod at ride height ( best ), and/or add steering damper ( half bad crutch ) Kbee fed gagnermotor.com
Once you get the new wedges in, try clamping the springs before you add more leaves. The clamps - on the front half of the leaves, assuming the shackles are on the rear - will stiffen up the spring without affecting the ride too much. My experience involved rear leaves, but should still apply. Ralph
How much Toe In is "OK" ? 3 degrees isn't enough Caster. Obviously too much Bump Steer. Get it aligned correctly,and fix the bumpsteer problem.
Congratulations! Good to see you're getting there. What everybody said, I would start with the caster, 6-7 degrees should be OK. I couldn't find a pic of your steering arms though. Just to check the Ackerman. Spring clamps wouldn't hurt either. Adding the steering damper might work as well. My friend's got a lowered-to-death F-1 panel wagon. It had the most horrible death-wobble ever before adding the damper in it.
Also try it with some radial tires. (No flames, I mean 'test', not 'replace the cool Cokers'.) Bias ply are more likely to wander, especially when the tires are cold.
Can you build a dropped steering arm for your spindle that will lower the front of the drag link enough to make it level? Below is an extreme case where the height difference between the steering arm and the axle caused braking induced "bump" steer. Placing the front of the drag link as close to the top of the front axle's main beam will help eliminate the brake steering that can happen with parallel leaf spring set ups.
Thanks again, guys, for all your thoughts! I've done some work on the frontend, so here comes! New caster wedges got me a tad more than 7 degrees of caster, and I changed the tired original Essex leaves for some stiffer ones. I also tried to remedy the brake-bump-steer problem by mounting a very stiff leaf on top of the packs. All of this made quite a difference, as I can now zip down the road at 55 mph without holding the wheel with both hands as I had to do at 40 yesterday! Also now braking causes less "brake steer". That dropped steering arm you suggested, Dave, is on my to do-list but will have to wait till the cruising season is over. In this pic you can see the thick extra "brake torque" leaf on top of the others. It's cut behind the U-bolts
Hey great job on the Essex! My buddy has a 29 coupe that he races, I think he robbed the front axle from a late 50's ch@#y truck but the motor is mopar... He has gone thru no less than 5 rebuilds on the 360 engine in three years of drag racing causing me to call his car the 'Assaches' but that's OK because he calls my truck a 'Stupidbaker' Glad to here all your steering problems are being worked out, keep up the good work.... moe .
Here's an update on my steering problems nearly two years ago. The caster wedges helped a lot, along with the stiffer Toyot¤&´ (sorry 'bout that) spring leaves. After driving two summers, some 6,000 miles, I felt that I had to do something about the "brake bump steer". Here's my solution, still not fully tested, as the roads were icy at the time of the test drive. Here's a sketch: And here's the whole story: http://www.waasadata.com/essex/drive2.html Thanks again for the help and suggestions earlier!
I was wondering what caused the sudden spike in views of a grainy photo of the front suspension of my old '37 Chevy pick up in my Picturetrail album. I see that you have engineered a pretty clever solution to your brake-steer problem. I built a similar, though less sophisticated, piece for my truck. It helped a bunch. I think that you have totally licked your misbehaving Essex.
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