Thread: solid axle wandering off-center

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I'm having a problem with the solid axle on my 32-framed 29 roadster. The parallel-link four bar suspended solid axle keeps drifting to the right - by that, I mean that the axle is no longer centered between the frame rails, by about 7/8" towards the passenger side. After this happened the first time, I disassembled and corrected all the suspension components so the alignment was PERFECT. After three weeks on the road again, it returned to its off-center position. It is still otherwise aligned (see below), just off-center.

During the re-build, I made certain that the front and rear axles are parallel to each other, and perpendicular to the frame centerline; i.e., what some shops call a "thrust alignment". I also verified that the springs (a Posie's Super Slider) swing free, the caster is 6 degrees, and the toe-in is 1/16". I suspect that the camber may be off, however, because the outer edges of the front tires wear fast, especially the left front.

Any ideas what might be causing this? Anybody else have a similar problem? I'd rather not just swap parts until the probelm goes away.

Thanks,
Dorsey

You might have a broken leaf in the spring pack, causing a bias to one side. I have never encountered what you are describing, but I always use a Panhard rod on an I beam or tube front axle. This keeps everything centered nicely, and prevents the horrible "shackle rock experience", which can cause an immediate change of underwear if it happens at speed. The way I do a panhard rod , I build a bracket off the underside of the driverside framerail just behind the front axle . I use urethane bushed rod ends on each end of the Panhard rod and run it parallel to and just behind the axle. The bracket at the other end gets bolted to the inside of the batwing on the passenger side.

Thanks for that advice. When I rebuilt the front suspension, I determined that no springs were broken, so that's not it. I use a hydraulic damper to prevent shimmy, but not a panhard bar to locate the axle.

Since the axle is located by the center stud of the spring pack, which in my case is dead center, which in turn locates the axle via the shackles, and also the parallel links offer some minor trianbulation, I didn't think that a panhard bar would be required with my setup, but I can certainly see how that would solve the problem.

Since I have to rebuild the front suspension once again anyway, I was thinking that this might be a good opportunity to use that advertised kit to split the solid axle into a "poor man's" IFS. Any experience with that?

Originally posted by Dorsey
...... I was thinking that this might be a good opportunity to use that advertised kit to split the solid axle into a "poor man's" IFS. Any experience with that?

You might notice that fatman's had that axle setup out for nearly 10 years and it's not in wide use. The general consensus with us skeptics is that having the short axles pivoting in the center gives an odd roll center that doesn't "feel" right. Just get a panhard bar kit, or (meaning don't use both on the same car) another option is a dead perch, available from Deuce Factory. It replaces one of your exising perches and doesn't use a shackle (the origin of the term dead).

I know the concept, but it really isn't neccessary, unless you just want to do it to have something different. I have had very good service and driveability from 4" dropped solid axles, 4 bars, and vega cross steering. The roadster pickup I am building now will have the same set up again, just because its so simple and works so well.

and to think everyone used to give me miles of crap over liking straight axels....... .....................scooter

Install a panhard rod. Stay away from Fatman's split axel kit. Does not handle well,to much camber change ,thus high tire wear

My first thought was that the spring center bolt head was not seating into the hole in the front crossmember.
Looking from here, you've probably done that bit correctly.

What may be happening - especially if you've removed a couple of spring leafs in an attempt to either get lower or soften up the ride - is that your spring U-bolt, pad setup is not reaching far enough up into the channel to keep the spring pack seated against the underside of the crossmember.

Some of the U-bolt, spring pad setups come in two pieces, but most come in one piece with a step built in.
The stepped part goes on top and shoves the spring pack up against the underside of the crossmember.

Make sure as well that the spring pad is not bottoming out on the lower flanges of the crossmember.
That will keep the spring from going up against the underside of the crossmember and allow the spring center bolt to drop out of the locating hole.

It doesn't take much to allow the spring center bolt to drop out of the locating hole.
Re-pro front crossmembers - and probably the stockers as well - are 3/16" thick.
When the center bolt is where it's supposed to be, the top of it will be flush with the top of the crossmember.

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Your alignment sounds reasonable.
The tire wear on the outer edges may be due to underinflation or zinging around the corners.
(My wife used to enjoy bombing around the freeway on-ramps - almost always a right turn - and the left front tire wore on the sides worse than the others. Took me a while to figure that out.)

Fwiw - I have 32 roadster with 195/70R-14 front tires and run 30# pressure.
The rear tires - 285/70R-15 passenger tires run 20# pressure.
All tires BF Goodrich fwiw.

Those are the right pressures for the 32 which weighs 2400#.
It runs a 462" Buick engine and T-400 trans and has a top and four point roll bar.

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The guys are right, you do need a panhard bar.
Don't install one just to mask a spring center bolt problem.
Get that squared away first and then add the panhard bar.
The steering will be much more accurate with a panhard.

My opinion: the dead perch (not to be confused with the fish) is simpler, cleaner-looking and just as effective as a panhard bar.

http://www.deucefactory.com/product....38&1=239&3=111

Just a wild guess, not speaking from experience...

I use a Pete n Jake steering damper on my I beam '36, I recall that you have to set it up so that it doesn't fully extend or fully compress.

Assuming one end's clamped to a four-bar, perhaps it's bottoming out on full steering lock and pushing on the four-bar?

Don't know if it's feasible, just an idea

just my 2c worth, but i don't see how the axle could move over 7/8 of an in. and the center bolt is not broke and still in the hole. if you had the front axle, front end set up satisfactory at one time and 1 mo. down the road you are running dog leg down the road again then something would have had to come loose, broke loose, or bent to make it move that much. looks like to me what ever you had to move back into place to realign it would be where the problem is.