Thread: Need diagnostic help on SEVERE steering wheel shake

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Would appreciate some ideas as to what is causing the following and how to resolve it:

Have an intermittent problem with severe (& I mean SEVERE) steering wheel side to side shake! Starts for no apparent reason, stops only after I make a full stop and start up again. Can be traveling a steady 55 mph and the steering wheel slowly starts to feel "bumpy" then begin to have a rapidly increasing side to side shake. Gets so severe that you cannot hold the wheel. The entire time the car will be driving straight. Slight improvement if I slow down, but doesn't stop until I apply the brakes. Car does seem to pull to the right slightly when I apply the brakes, but not enough to seem to be a major issue in itself. Problem started after rebuild which included a replacement of all the suspension bushings, addition of a brake booster, new rims, wheels, etc. So I cannot look at just one area of issue, though it seemed worst with smaller wheels.

Here's what I'm running:
'34 Ford Model 40 sedan 350/350 B&M Street stick,
Mustang front end 9" ford rear, (all bushings new- checked by 2 different mechanics and no issues seen)
Edelbrock carb (original)
chassis mounted dual master cylinder with dual 7" boosters, (new)
new rear slave cylinders (drum)
no scoring on front disc brakes,
185/60/15 front tires balanced on Rocket rims 15x6
225/15 rear tires balanced on 15x7 rockets
balanced all wheels and aligned yesterday

I was originally running 155/60/15's on the front when the problem started, replaced with the 185's yesterday (new) to eliminate tires as an issue after an alignment and visual inspection of the front suspension failed to resolve the problem.

I don't see anything abnormal under there.

Could the problem be somehow related to the front discs? This was one area we didn't redo... but the problem came up after everything else was done... maybe related to the addition of power brakes from manual. As an aside, before the power brakes, it felt like I was pushing on a brick to stop the car.

Please advise...

Sounds like a classic case of death wobble, but generally that occurs in straight axle front ends, like early Fords had. But I guess it can happen in any type of front end, just never thought about that.

I have heard that MMII frontend kits are not all created equal. Some omit the steady rods (or whatever the proper term is) from what the factory had originally installed. I have seen articles about how it is important to keep these in place, but really didn't pay much attention as I have never used one of these in a car.

I think we need more info so one of the guys on here who know these can help you more. Whose front end kit is it? Did you install it or have it done, or maybe you bought the car this way. Has it always done this, or did it just start. You provided a lot of info, which is good, but I think you need to give more specific info about the front suspension/steering, as that is probably what is causing it.

Don

Originally Posted by Itoldyouso

Sounds like a classic case of death wobble, ... Whose front end kit is it? Did you install it or have it done, or maybe you bought the car this way. Has it always done this, or did it just start. You provided a lot of info, which is good, but I think you need to give more specific info about the front suspension/steering, as that is probably what is causing it.

Don

Car came with the front end as is, as near as I can tell it's an early 1980's Mustang II front end. manual rack/pinion. All I did with it was add adjustable coil overs and replaced all the bushings. My buddy, a shade-tree mechanic, races a Mustang with the same front end set up, just larger discs, so he was familiar with it. After which, the last thing done was to replace the manual brakes with power. It did not do this until after my buddy & I replaced the manual brake system with power booster/dual master...
Classic case of "don't fix it if it's not broken"?

Before the coilovers and power brakes, did the car ever have any issues? How many miles do you think you drove it prior to the new work? Do you know whose kit was used to put the MMII stuff on the car? Are those rods I mentioned in place or omitted?

Don

Originally Posted by Itoldyouso

Before the coilovers and power brakes, did the car ever have any issues? How many miles do you think you drove it prior to the new work? Do you know whose kit was used to put the MMII stuff on the car? Are those rods I mentioned in place or omitted?

Don

Only issues were related to some wandering and hard as a brick braking... drove the car a couple hundred miles before laying her up to work on. No "Death Wobble" at all. Sorry, Don't know whose kit was used as the installation was done almost 20 years ago and PO has no idea. Don't see an steady rods installed.

I reread your original post and you said you had it aligned. What specs did they use? Reason I ask is that I think I remember seeing somewhere that if your MMII suspension has power steering they like a little more caster than a stock Pinto/'MMII would call for, something like 3 degrees, I think. Could it be that when you changed the coilovers you also lowered the front end, which would reduce your caster? Insufficient caster can cause some goofy handling issues, like you describe.

Don

Something is loose in the steering/suspension, whoever inspected it missed something. Did they unload the ball joints when they checked? You may not be able to detect a bad ball joint under load. The death wobble Pops refers to on beam axles is usually loose king pins which allow the harmonics of the rotating wheel/tire to do the wobble. Very likely that at least one of the components that holds the wheel straight is loose or broken. Strut rods like Pops mentioned would show up on braking too, so another symptom to check.

Did you check the brake rotors for cracks or warpage? Could be as simple as a wrong sized, loose or worn wheel bearing.... Another possiblity that comes to mind is the center hole on the wheel, is it large enough to fit over the hub correctly and not hold it away from the mounting surface of the brake rotor?

Originally Posted by Dave Severson

Did you check the brake rotors for cracks or warpage? Could be as simple as a wrong sized, loose or worn wheel bearing.... Another possiblity that comes to mind is the center hole on the wheel, is it large enough to fit over the hub correctly and not hold it away from the mounting surface of the brake rotor?

Good idea, didn't check the rotors yet... or the wheel bearings... center hole looks okay... will pull the rotors tomorrow afternoon and check

"20 years ago"

I have over the years repeatedly had occurrances where brake rotors have cracked at the parting line in the inner fins---causing a very violent wobble feeling as when they do start separating the rate increases and the wobble gets worse

You can check the disc thickness with a mike of dial caliper and if this is the case it will be easily measured---new discs are the only fix

Originally Posted by jerry clayton

"20 years ago"

I have over the years repeatedly had occurrances where brake rotors have cracked at the parting line in the inner fins---causing a very violent wobble feeling as when they do start separating the rate increases and the wobble gets worse

You can check the disc thickness with a mike of dial caliper and if this is the case it will be easily measured---new discs are the only fix

I'll have to see if I can borrow a dial caliper, not something in my tool box... I was thinking about replacing the stock discs with something larger, maybe the Wildwood set-up, This might be a good excuse to do it sooner rather than later...

Any-thoughts on whether there could be a problem in the steering column or rack/pinion?

I agree with a post already here..............caster will and can allow this to happen. You do need to check it..........3-4 degrees is what you want , especially at highway speeds.

Originally Posted by sunsetdart

I agree with a post already here..............caster will and can allow this to happen. You do need to check it..........3-4 degrees is what you want , especially at highway speeds.

Asked a buddy of mine who works at a Firestone shop to look it over with me for a third (or fourth) opinion, this morning. He's convinced that the problem is still related to miss-balanced wheels. He pointed out that the stick-on weights were all on the inside, which is cosmetically pleasing, but that due to the wheel size, etc., it would have been very difficult to balance it correctly that way... he'll take the wheels on Monday to his shop and check the balancing, just to be certain that's not the problem... if it still is, I'll start pulling tie rods, etc., next weekend. Then look at replacing calipers, (might as well put the larger brakes on now).

Sure sounds like something is loose or worn badly. Have someone rock the steering wheel back and forth while you look for slack in tie rod ends,etc. Also jack each front tire up at lower control arm just enough to get a long bar under center of tire and pry up to check for worn ball joints. While tire is jacked up, grab tire at top and bottom and try to rock tire/wheel on spindle. Several places where you can find slack there (bearings, upper ball joint, rotor). Might not hurt to check for cracked weld on strg rack mounts. You need to find the problem and fix asap! You need positive caster in both sides and don't need excessive toe out. Zero toe or toe in needed. Let us know what you find.

Is this power or manual rack & pinion steering? Had a buddy in the army way back when that had an old Honda car with power rack & pinion, some internal seal or O-rings gave out and because of the internal leak from the high pressure to return side inside the rack assembly, the steering wheel on his car would do a weird toggling wobble without actually affecting the direction the wheels were pointed.