I had my '73 aligned a week before Rt66 and failed to give it a proper road test before hitting the road About 70mph it begins to vibrate a bit and ceases around 80mph. Before having it aligned it drove like a dream but ate the front tires. Living in the sticks I don't have a lot of choices so I'm hoping someone can gleam these "before and after" alignment details and make a recommendation so that I can have it set correctly. TIA, Kent PS, click on the pic to view it upright.

Click to view attachment

It is not likely the it is an alignment issue.
There is nothing in the alignment specs that would contribute to a vibration.

Vibrations at speeds above about 40 mph are almost always tire and wheel related.
I personally have never seen a high speed vibration that was alignment but I try not to say "X never causes Y".

Are the wheels stock?
I would be looking at the tires and wheels for balance issues or out of round?
73 should be hub centric wheels so they should be centered properly but I would check anyway.

Jim

Sounds like a wheel balance or bent rim problem. Try putting the rear wheels on the front and see if that makes any difference.

What does look a little odd is the camber difference in the front, it is like they did not adjust that at all.

Same tires or did you replace the fronts?
If same worn tires then they will behave odd as there will not be a flat contact patch.

What's up with the 1* camber difference up front and .5* rear. Laziness?

+2

Looks like they just adjusted the front toe.

If your fronts were scrubbed then the tires are probably out of balance.

I think I run more castor then that but I.d have to check.....been awhile.

How come ya didn.t do it yourself Kent?

The tires are new and balanced when installed. The ride was smooth as ice and I had the alignment done so that they did not wear as the old tires had. After the alignment is when the vibration began. The wheels are OEM Fuch's. I guess it is possible that they are NOT balanced properly. The guy at the alignment shop is easy to work with so I guess I can go back and complain but I was hoping to have some direction for him to follow. I was hoping that there were specs that I could provide the alignment shop with. The thing that has me chasing my tail is that Jim Hoyland posted his alignment specs and they vary from mine. Should I present them with his spec's and ask them to duplicate Jim's settings?

Here are Jim's alignment spec's which he posted here 2-3 mo's ago.

Click to view attachment

So with toe out there's no vibration. With toe at zero you've picked up a vibration.

What shape are the wheel bearings, ball joints, and tie rod ends? Any looseness in these items can introduce vibration.

With toe out, the stress on bearing, ball joints, and tie rod ends is normally in one direction. With toe at zero, it would seem the items might be stressed in both directions thus any play could result in some wobble in the steering wheel.

Net 0 toe in the front is a little aggressive for street driving in my opinion.. even on my car I run just a touch of toe-in on the front for freeway stability. The concrete freeway beds in California make's zero toe, or toe out alignments particularly divergent too.

Also, check your wheel bearing's up front. I've had a bearing that lost preload, and the only indicator was a vibration that got slowly worse in the steering wheel.

Loose tie rods.

Didn't think to check the wheel bearings. They have ~7000 miles but recent reviews do mention a problem with lubrication at point of origin.




I'll check those as well. They have 11000 miles on them.

Jack the car up, grip the tire at 12 o:clock and 6 o:clock and try to wiggle it back and forth. There should be NO play in it at all. (Either that, or your car is just CURSED)

Kent do your own alignment Your smart enough to do the simple math. I do it with strings, and a framing square. A couple of pieces of wood and some grease to make a slip plate. A couple of thick tiles and wax paper will do the same and not make a mess.

Alignment is most likely not the issue. But since they adjusted the tow, make sure all the locking nuts are in place.. etc...

Scott made a really nice fixture for home alignment. I will most likely build a set of hub stands when I get the chance. Sherline had a great set they used to sell that would also do corner weights, with bearings to take off the friction from moving the alignment. Very neat setup. Does not look like they are building the system anymore.

I thought about it but my understanding is that one needs a level floor. My garage floor slopes front to rear and left to right!

Mine is pretty level. I've done it before and my floor is free.

Up to you.

And yes....despite what other people say....I think you might be smart enough.

Susan is a mean cook.

I was fighting similar problems. The front wheel bearing was simply a little too loose.

I had similar issues,

Replaced a worn bearing,
Vibration at 60 went away.

Thanks Rob, I may take you up on that. I need to sort out the bearing and tie rod possibilities first. If nothing changes I will take it in for a tire balance to be sure I didn't chunk a weight before hooking up with you. TIA, Kent

I'm guessing that your front tires are worn slightly funny from the toe-out you had before.

Can't believe they didn't adjust camber to even it up side to side or fix your rear alignment. I like to have even toe in the rear to give a decent thrust line.

Have a look at your front tires and look for wear or feathering. If you can, put your rear wheels on the front and see if you still have some vibration in the steering or if it goes away. The tires/rims could simply need balancing.


Good luck with it. It is easy enough to do a decent alignment with string, jack stands, a ruler and time, but I prefer my alignment machine since I have one.

Tires are new; or were. Have about 1600 miles on them now. And they didn't vibrate before the alignment.

I'd definitely suggest that you swap tires front to rear and if the problem persists, you will find something worn out in the front. Wheel bearing(s), tie-rod(s), ball joint(s) that the previous alignment was masking.

Logical! Makes sense . I will report back but it may not be for a few weeks. There is another car on the rack awaiting parts and vacation begins next week. Thx everyone, Kent

Vinyl floor tiles. A box of those is pretty cheap. A long piece of clear vinyl tubing, some water and food coloring, and you've got a big spirit level. You can measure out how far off you are at the four spots you want your tires to be, then stack up the correct number of tiles to make those four spots level with each other.

If you want things to be repeatable, then paint marks on the floor where the tiles go and how many tiles...

--DD

So basically the only thing adjusted was front toe. Return the car for an actual 4 wheel alignment if that’s what you paid for..
Basic adjustments:
Front: Camber minus 0.3 degrees
Castor. 6 to 6.5 degrees
Toe. Plus 0.3 degrees (total)
Rear: Camber. minus 0.5 to 0.75 degrees (both sides equal)
Toe. plus 0.2- 0.25 degrees (total). Large differences in this adjustment
cause squirreliness at speed and
cornering.

Perfect. TYVM.

Dave is 100% correct you do this with ease. As far as other ways, you can pour an epoxy pad that is self leveling. You can do it by building a damn in the area you want it, and then poor the pad. Once done break down the form and build up the edges to make the transition.

To be honest , I do it on my floor, not level and closer than the shop I used to take it to could get it. They just did not care, that is the biggest difference.

Best of luck Kent.

Been awhile but I (we) nailed it. Thx for everyones input. Shortly before before going on vacation I put the car on the lift and wiggled the front tires to check for slop, per Elliot. The LF had some slack in it so I tightened the bearing. Content that I had found the problem I took it for a quick drive only to discover that it was still present. Fast forward to last week. Some asshole ran a stop sign and when I hit the brakes the left from locked up as I slid to a stop. Why would that happen? No worries, I'll add that to my list of "To does". The next day I noticed some oil on the garage floor under the front end! HUH? There are no oil lines in that area. After a quick sniff I discover it is brake fluid. Add to this; I had been finding brake fluid atop the reservoir for months. I'd wipe it up and it would reappear. I guess this would have been a warning of imminent failure to the average person but I waived it off.
So, while I had it on the lift to R&R the MC I rotated the front & rear wheels per JCD, John and Travis' suggestion. Took it for a 2 1/2 spin this morning and all is well. Any thoughts as to why it doesn't shake the rear as it did the front end! Anyway, thanks for all the tips. I'm enjoying a smooth ride once again.