85 Fifth Avenue still vibration in the steering wheel at speed after thousand$ in repairs

[Sloyds85fifth]

The steering wheel shakes hard at 60 plus and then fades at 75. New pitman arm, u joints, swapped rear end, new shocks, rear brakes, spring rests, sway bar links, tires balanced 4 times. Carbuerator freshly rebuilt, full tuneup. Any ideas?

 

[Camtron]

Wheel bearings, tie rod ends, ball joints, control arm bushings, bent control arm/s, k-frame isolator worn, bent wheel, k-frame twisted/weld/s busted.

 

[Mikes5thAve]

Did you swap wheels front to back? Control arm bushings? Are torsion bar bushings good? Shake in the steering wheel is typically front end related.

 

[Sloyds85fifth]

Wheel bearings, tie rod ends, ball joints, control arm bushings, bent control arm/s, k-frame isolator worn, bent wheel, k-frame twisted/weld/s busted.

Great ideas. I had the tie rod ends checked too. I will have the others you mentioned examined.

 

[Aspen500]

It would help narrow down causes if you knew the vibration frequency (Hz). There are electronic vibration analyzers, but a simple small engine mechanical tool will work. It helps to figure out if it's wheel/tire related, driveline, engine, etc.

Just a question. Do the brakes pulse at all? I've run into cases where it'll cause a freeway vibration even without the brakes applied. Out if balance rotors are another vibration cause I've seen. Was an auto tech for 40 years, and one of the worst things to see on an RO was "check for vibration at xx mph" or "vibration during accel from 35 to 50 mph" etc......

As I said though, knowing the vibration frequency makes finding the cause a lot easier.

Another possible: A couple times I was chasing a vibration that seemed to be tire related. They were in perfect balance dynamically. On a hunch, I did Road Force balancing, and they took different weights, in different locations on the wheel. Spinning them dynamically again showed they were out of balance. Took the car on another road test and,,,,,,,smooth as a babies bottom. Just an idea to keep in mind.

 

[Sloyds85fifth]

Actually they do pulse some when braking. And the road force balancing is a great idea. I'm assuming not just any shop can do it? What is the difference exactly and thanks. Another great insight.

 

[Aspen500]

Road force balancing simulates the tire with the cars weight on it, while driving down the road. Easier to show than explain



A good tire shop should have a road force balancer and hopefully, someone that knows how to use it correctly.

If the brakes pulse, the pads will "hit" the rotor even without the brakes applied, and it can transmit a vibration to the steering. Most often shows up at freeway speeds.

Your vibration could be caused by neither of these of course, but are worth a shot.

 

[AHBguru]

You could have a bad tire (belt separation) that might not show up until higher speeds, higher tire temps, etc. The Roadforce balancing is a good idea, but rotating the tires would definitely confirm if it's a tire. Generally, with a steering wheel shake, you're looking at a bad tire, a bad idler or pitman arm, or possibly a bad steering gear or rag joint.

I would also take a careful look at front wheel bearing adjustment. You actually want less than 5 thousands clearance, preferably 1 or 2. Set the preload the old-fashioned way. Tighten em up until you see stars. Back them off a turn or two, retighten, then back off a quarter turn. Check your end-play. Use Timken bearings, and high-temp sodium fiber grease (cop car snot) only.

Because the transverse torsion bar cars do not use a tension strut to locate the lower control arms, the bushings for the torsion bars deserve a further inspection. Typically, the pivot cushion bushings crap out first, but the anchor bushings could also be shot, allowing weird oscillations at different speeds. The entire front suspension largely depends on rubber bushings, much like the later LX/LD cars. I'd say the M-bodies were more durable in that respect, but anyway ...

Although the k-frame issue wouldn't directly cause a vibration, if it's severe enough, it will put excess wear on ball joints, control arm bushings, etc. Check your front ride height per FSM, see where things are at. Follow the TSB's regarding alignment and k-frame diagnosis, as necessary.

 

[Sloyds85fifth]

Well when I got the thing and had an old set of tires on it.. So I grabbed a set of used tires for it. Then I learned that they were 40 years old lol. So I got a set of new Douglas touring tires cuz they were cheap. The vibration has been the same over all three sets. I definitely wouldn't say that it couldn't be a bad tire. But I've sent this thing to tire discounters. I've taken it to Midas. I've taken it somewhere else and somewhere else other than that too that I can't even remember. Nobody's mentioned anything about the tires. But that would probably be a difficult thing to diagnose without something like that road force balancing. Which I had never heard of before this forum but sounds like a great idea. Yeah I'm definitely going to ask about that rag joint and I'm going to get some road force balancing to see what they think

 

[AHBguru]

Well when I got the thing and had an old set of tires on it.. So I grabbed a set of used tires for it. Then I learned that they were 40 years old lol. So I got a set of new Douglas touring tires cuz they were cheap. The vibration has been the same over all three sets. I definitely wouldn't say that it couldn't be a bad tire. But I've sent this thing to tire discounters. I've taken it to Midas. I've taken it somewhere else and somewhere else other than that too that I can't even remember. Nobody's mentioned anything about the tires. But that would probably be a difficult thing to diagnose without something like that road force balancing. Which I had never heard of before this forum but sounds like a great idea. Yeah I'm definitely going to ask about that rag joint and I'm going to get some road force balancing to see what they think

Douglas is Goodyear, so they should be ok. A bad shake, and only at a certain speed, is probably not the tire. A vibration like that is more likely to be bushings or ball joints.

You could also check the steering gear bolts, and the area of the k-frame it mounts to, to make sure it's not flexing while in use. That's a different issue aside from the aforementioned k-frame problems. Steering gear mount flexing affected many different Chrysler products, well into the ZJ Jeeps. I wouldn't say it's any more or less common with the M-body, but it's easy to check with a helper.

 

[Mikes5thAve]

The problem shouldn't be identical with multiple sets of tires. Swapping wheels front to back should make some difference ifvits a balance problem. Other then Pitman arm and sway bar links you don't have much for front end work on there. Usually worn parts cause chunks pulls and wandering more then vibration in the steering wheel but if it's something loose or worn it shouldn't be that hard to find.
Find an independent garage that's been around a while or don't have franchise looking employees, it's still a hit and miss with knowledge but you'll have a better chance of finding someone who can actually diagnose it and is more then a parts changer.

 

[69-]

Balancing is pretty tricky.
The road force balancing is cool, but relevant at the end is also the unbalanced mass at each wheel - considering especially brake rotors and hub. Even worse at the rear axle.

I have no experience, but some when heard of on car balancing. This combined with road force equipment should really get it smooth, shouldn't it?

 

[AHBguru]

Agreed. One other thing, I had an '85 Fury with an odd vibration/oscillation at a certain speed. The shop found egged-out stud holes in one rim, and the other was bent. One would think they would've caught the bent rim, but I think it was a matter of once one or the other (Never did figure out which) started oscillating, it created a kind of harmonic vibration through the steering system. That's particularly important in a suspension that uses a lot of rubber.

 

[Aspen500]

Slightly off topic but, in the '90's I had an '81 D150. It had a vibration in the rear above 60 mph. I had put brand new wheels and tires on right after buying it, and they were round and balanced. Kind of just lived with it. Then I did the rear brakes, including new drums. After that, smooth as can be. Cause was out of balance brake drums.

 

[Sloyds85fifth]

Okay so a little update here.

Actually they do pulse some when braking. And the road force balancing is a great idea. I'm assuming not just any shop can do it? What is the difference exactly and thanks. Another great insight.

All right A little update here fellas. Again I appreciate all your guys great ideas and I am looking into all of them one by one believe me. So just to bring everybody up to speed. I had another $3,000 in work done. The sway bar links done now. Also had new discs and pads put on the front. Rear end swapped out. New spring hangers. Various other things back there. New u-joints. Unfortunately the vibration was exactly the same lol. So when they put the front brakes on they noticed that the front right caliper was sticking a little bit or a lot. They couldn't tell. And they thought that the line might be obstructed. They didn't have either parts available. So I drove it a little bit and found that the brakes with the new pads are now totally stuck. On the front. So I'm thinking that front caliper might have something to do with it or maybe that front right line. The caliper did have a busted seal on the piston. So I think that's a possibility. I also picked up a pair of new shocks for the back of it haven't put them on yet. So I'll update everybody after that. Again keep the ideas coming. I'm going to check every bit of it out. Eventually I'm going to solve it and this will help somebody big time down the road. Thank you all so much

 

[AHBguru]

Stuck calipers are, unfortunately, common in the F/M/J, as they use the slider style caliper. RockAuto should have all that. Hopefully your wheel bearings were replaced when they did the rotors.

Nothing done there, however, would cure a steering wheel shake. It needs a visit to the frame and axle shop, I think you're gonna find your right front shock tower is bent. What happens is with that kind of vertical misalignment in the steering axis, a normal bump in the road can create a violent oscillation in the steering system, similar in nature to death wobble in Jeeps - although the causes are completely different. This also wears out the suspension components very quickly.

Here's what needs to happen:

- Find the k-frame measurement specs from the factory service manual. Use 1989 specs, if you can find them (or maybe someone can put them up here for you).

- Look for the February 1988 TSB regarding the K-frame, it might be posted on the page somewhere.

- Find a good frame and axle alignment facility, and see if they're familiar with the transverse torsion bar suspension. You may not have any luck, but you might find someone willing to take a look at the FSM and TSB material, and get it up in the air for a good hard look. Everything needs to be thoroughly measured, not just alignment specs, but the k-frame and subframe needs to be measured for square in the manner found in the FSM.

- If they do find what I suspect, I would recommend having them repair the shock tower/k-frame as necessary, as the shim kits were really more of a temporary solution. The idea at the time was to fix the cars just enough to get them through their normal service life, which was 1-3 years for squads in those days.

I recall back in the day a couple departments in my area (local sheriff dept and State Patrol, all early '88 models) would get a unit with a bad vibration that couldn't be resolved. The parts cannon would get quite a workout, and it would still shake. It wasn't until the k-frame cracked, and the front end collapsed on a few of them, that the problem was found.

While some of the earlier cars did exhibit problems, the vast majority were the Fenton ('84 - early '87) and Kenosha (mid '87 - early '88) models. Mostly squads, but some retail. I'd call it 60/40. Not all had the problem. Why? I don't think there's any good answer as to why some failed and others were just fine. Probably just plain old luck.

I do believe the "economical" way to resolve it is when the engine is out. Take the k-frame/shock towers in to get inspected and straightened. Have it welded up at the seams, and the shock towers reinforced. Once you get it home, mount it using the poly or steel biscuits.

 

[Sloyds85fifth]

Thank you for the information. Sounds like a possible culprit for sure. I really hope this is not my problem as in I assume this would be the most difficult to rectify.

 

[AHBguru]

Thank you for the information. Sounds like a possible culprit for sure. I really hope this is not my problem as in I assume this would be the most difficult to rectify.

You could shim the shock towers and have the seam welded solid on the k-frame. If the idler arm bracket is bent (common), it can be straightened on the frame rack. At that point, make sure all the bushings are good, the car is aligned to (not just within) spec, and it should be fine for several years.

 

[volare 1977]

Just a thought. Can you mount a camera under the car to see what happens at 60 plus?

 

[Mikes5thAve]

The most common cause of vibrations at those speeds is wheels or something spinning or worn out, definitely get everything checked out well before going deeper.
A good alignment shop should also be able to tell if there is anything out of adjustment or something has been adjusted way more then it should have been in the past which would hint to an issue with the k frame or some other front end damage that occurred at some point.