Wheels / Tires: Horrible vibration, (Cross post from the Studebaker Truck Farmers.)

[Ron Dame]

I got the '63 Champ all "purty'd up" for the TriState meet in Lake Junaluska today, and was really looking forward to it and showing off the 185 OHV 6 in it. I made it, but not in the truck.

About 10 miles out, I started getting a serious vibration at about 60. Felt it through the seat, not the steering wheel. There's always been a mysterious similar but lesser vibration at this speed that would come and go and was not affected by change on throttle, applying brakes, or anything..sometimes it was just a curve in the road that would cause it to cease, sometimes it just quit, just like it came on. Never a constant, never predictable except it never started below 60, and sometimes would take reducing speed to under 50 to make it stop. It was never bad, just annoying. Sometimes it would go for weeks without vibrating. Today it was pretty bad.

I've had this truck for about 21 years, and it always has done this, no matter what tires or what wheels I've had on it. I've had the drive shaft balanced, replaced U joints, set rear axle end play, had the wheels checked for cracks and roundness,you name it. With the new engine and transmission, new mounts were installed. Maybe 20 years ago, the spring bushings were all replaced, and they still look OK.

So I left the meet early because I wanted to find out what is wrong now...it was a pretty severe vibration today, again, felt through the seat of my pants and not the steering wheel. I expected that I'd find a big lump on one of the 8 year old tires, but did not, and of course am a bit afraid that an axle may be cracked and ready to send me and a wheel in opposite directions. The only thing I did find is that the drive shaft slip yoke is a bit sloppy on the spline, which may be the original lesser vibration, but the tires seem true, even with the truck on jack stands and running at 30 or 40 MPH.

I know an old tire can fail catastrophically, but can it be coming apart but still look really good, no lumps, bumps, or other things while stationary, but at speed really getting out of round or something? Does anyone have any better ideas of what may be going on?

Thanks!

[gordr]

What's the rate of the vibration? If it's driveshaft-related, it's going to be happening at engine RPM, if you are in third gear, no OD. If it's wheel-related, it will be happening at a third to a quarter of that, depending upon your axle ratio.

Does it go away if you step on the clutch, and let the engine idle down, or if you shift to neutral, and let the engine idle down if an automatic? If it does, then it comes from the flywheel assembly, or points forward.

What if you shut the engine down altogether, and roll down a hill in silence? If the vibration is still there, and occurs at driveshaft speed, the slip yoke spline might be the culprit. One way to test it for sure would be to position the truck at the top of a long, but not overly steep hill, remove the driveshaft, and get a helper to push you down the hill. If the vibration is still there, then the driveshaft isn't the cause.

Another thing to try, get the rear axle securely supported on jack stands, and run it through the gears while watching the driveshaft and axles from a respectful distance.

At a road speed corresponding to 2400 RPM, a driveline vibration will be felt and heard as a low hum or buzz at 40 Hertz. That's a deep bass fiddle note. A wheel-related vibration would be from 10 to 13 Hertz, which is below most peoples' hearing range. You will feel a shudder, like you might if you hit a washboard section on a gravel road.

Being as you say it's been with the truck since before the engine change, likely the engine has nothing to do with it. Maybe you have a bent axle, and it's telling you that it is about to break. Or maybe you have a bent or cracked wheel rim. Wouldn't hurt to jack up each wheel in turn, and spin it by hand and look for runout. Pop off the wheel covers, and look closely for cracks around the plane of the bolt circle. When I had a wheel crack on my Wagonaire, it announced itself as a huge vibration.

[PackardV8]

You say you've checked and eliminated all the most common causes. The only possibilities which come to mind:

1. Driveshaft phasing and pinion angle. Most 4WD shops deal with this all the time on jacked-up trucks and Jeeps. I'd have one of these check out the driveline phasing and angles.
2. Front to rear alignment. Once I had a pickup which had suffered some sort of accident which torqued the frame enough so the front and rear axles were no longer parallel. Just the slight misalignment caused a condition similar to yours which a four-wheel alignment found and corrected.
3. Broken rear spring leaf.
4. Failed rear shock.
5. Have the rear tires balanced on the truck. Back in the day your Champ was new, I was a Service Manager at a Goodyear Tire store. Sometimes balancing on the rig was the only thing which worked. Good luck finding someone who still knows how. I'm not sure I'd know where to go here in Spokane any more.

jack vines

[Ron Dame]

Gord; being tone deaf and rhythmically challenged, I can't say much about bass fiddle notes, but I'd put the rate more like a washboard road at 60...how's that? Pushing in the clutch and/or changing to neutral makes no change, nor does acceleration, deceleration or float. Based on what you are saying, it sounds like wheel speed rather than driveline speed. On jack stands, I saw no run-out on the wheels, not much on the tires. They were balanced about 6 weeks ago while I had them off replacing the brake cylinders. My fear is that I may have an axle about to break, since those who've experienced that say they had warning of a heavy vibration just before it let go. Would this show up as a wobble while on jack stands?
Jack; Along with balancing the driveshaft I made sure the phasing was correct and checked the pinion angles. Shocks have maybe 10K miles at most on them, and the spring bushings, although about 20 years old, appear OK...I can't move the shackles or spring eyes in relation to the bolts, and the bolts appear centered in the bushing. Springs are not broken, but on one side, there is a gap at the ends, probably from when I mis-communicated with a front end loader operator and got a full ton (or more) in the bed of the 1/2 ton truck!

What I do know about the history of the truck: At one time, the PO had new tires installed, and the shop did not tighten the left rear lugs...the wheel came off, sheared the lugs, and there was some damage to the bed. When I painted the truck 11 years ago, there was a huge amount of bondo in the left side of the bed and the left rear cab corner from some sort of collision...I don't know if this was a result of the wheel coming off and a subsequent wreck, or another wreck. What I can say is that I never was able to get the bed-to-cab gap equal on both sides. So this could indicate that the frame is bent, but I recall diagonally measuring it as best as I could with the cab on (bed off) and did not see that. The wheel coming off could also have bent that axle.

It seems like the change in severity is likely one of 2 things though, from what I am hearing: The axle is failing or maybe the 8 year old tires are. Since the tires are aged-out and should be changed anyway, I'll start with them, and if it's not cured, pull the axles and have them magnifluxed, if I can find anyone competent around here...always a challenge.

Here's some more info from the STF questions: The vibration is there, but much lesser while on jack stands...I still see no significant run-out or out-of-roundness on tires or wheels. The vibration is definitely from the rear, the steering is all new and the steering wheel is steady and smooth. Transmission was rebuilt 1500 miles ago, which includes the output bearing. Axles end play was checked and is OK.

I'm going to cross-post the the STF site too since some of them don't check here often

Thanks!

[PackardV8]

2. Front to rear alignment. Once I had a pickup which had suffered some sort of accident which torqued the frame enough so the front and rear axles were no longer parallel. Just the slight misalignment caused a condition similar to yours which a four-wheel alignment found and corrected.

there was a huge amount of bondo in the left side of the bed and the left rear cab corner from some sort of collision..

There's a clue. I'd find a good alignment shop which can measure the alignment of all four wheels. If they detect a bent frame, it will have to go to a collision repair shop with a frame plate to be straightened.

FWIW, back in the CASO days, I once compensated for a bent frame problem by moving the center bolt hole in one rear spring main leaf 1/2" forward. This got the axles back in parallel. Kids, don't try this at home.

jack vines

[jclary]

OK...I am still in misery and medicated...so this post should be viewed with my disclaimer in mind. Unless my ability to comprehend what I have read has been affected by my condition, I don't see much mention of the outer axle bearings. Is it possible that they could be the culprit? I know that all my Studebaker rear axles require periodic lubricating since they are not serviced by the rear end reservoir. A dry, or simi-dry rear axle bearing could be failing and responding to lack of lubrication by delaminating rollers, stuck rollers, flat-spotting rollers, and a spinning race. These conditions can cause the vibrations to come and go depending on "load" changes caused as the vehicle drives down the road.

That is why it is difficult to check this on jack stands. You can duplicate the speeds on jack stands, but not the load conditions that sets up the vibration. I suggest pulling the axles and inspecting the condition of lubrication, bearings, race, and axles. A lot of sweaty messy work, but worth the peace of mind.

Good luck with it. I wish I was able to come up, watch you work and make very irritating comments and suggestions as you bust your knuckles!

[Ron Dame]

There's a clue. I'd find a good alignment shop which can measure the alignment of all four wheels. If they detect a bent frame, it will have to go to a collision repair shop with a frame plate to be straightened.

FWIW, back in the CASO days, I once compensated for a bent frame problem by moving the center bolt hole in one rear spring main leaf 1/2" forward. This got the axles back in parallel. Kids, don't try this at home.

jack vines

That'll be on the to do list, however it does not explain why after 20+ years it suddenly got much worse.

[Ron Dame]

OK...I am still in misery and medicated...so this post should be viewed with my disclaimer in mind. Unless my ability to comprehend what I have read has been affected by my condition, I don't see much mention of the outer axle bearings. Is it possible that they could be the culprit? I know that all my Studebaker rear axles require periodic lubricating since they are not serviced by the rear end reservoir. A dry, or simi-dry rear axle bearing could be failing and responding to lack of lubrication by delaminating rollers, stuck rollers, flat-spotting rollers, and a spinning race. These conditions can cause the vibrations to come and go depending on "load" changes caused as the vehicle drives down the road.

That is why it is difficult to check this on jack stands. You can duplicate the speeds on jack stands, but not the load conditions that sets up the vibration. I suggest pulling the axles and inspecting the condition of lubrication, bearings, race, and axles. A lot of sweaty messy work, but worth the peace of mind.

Good luck with it. I wish I was able to come up, watch you work and make very irritating comments and suggestions as you bust your knuckles!

Sorry to hear you are still in misery, but you are clear-headed enough to bring up a point that was not mentioned. I have kept the bearings lubed, and 2 years ago, removed them, cleaned them, and hand packed them. They felt fine. I verified there was still good grease when I replaced the wheel cylinders about 6 weeks ago.

[JoeHall]

This sounds all to familiar with overdrive equipped 56Js. They too, have the fixed yoke T85 tranny, slip yoke driveshaft & carrier bearing. It is sometimes a "whomp, whomp, whomp" rumblle, that sounds cyclic. It comes and goes, or at least seems better on some days than others. It is amplified by the fiber-board headliner in 56Js, and sets up a reverberation similar to a bass sound. Keeping all carrier bearing related parts operating as new seems to help best (u'joint grease; slip joint grease; carrier bushings, carrier bearing). Also, a cloth headliner stops the reverberation, and a one piece driveshaft eliminates it entirely.
I don't know if this applies your Champ, but it sure seems like it and 56Js have a lot in common, in this characteristic.

[Ron Dame]

With a 1 piece driveshaft, the carrier bearing is N/A, though I've felt a similar vibration in old round-fendered Volvos which also have a 2 piece shaft. Thjis is seeming more wheel/tire/axle related, the more information I am getting. New tires this week, and we'll see if it fixes tings...I need them anyway.

And to all, thanks for the ideas. I've been informed that sometimes my brief responses come across as rude, and I certainly don't mean that. I appreciate all of the ideas.

Ron

[PackardV8]

This sounds all to familiar with overdrive equipped 56Js. They too, have the fixed yoke T85 tranny, slip yoke driveshaft & carrier bearing. It is sometimes a "whomp, whomp, whomp" rumblle, that sounds cyclic. It comes and goes, or at least seems better on some days than others. It is amplified by the fiber-board headliner in 56Js, and sets up a reverberation similar to a bass sound. Keeping all carrier bearing related parts operating as new seems to help best (u'joint grease; slip joint grease; carrier bushings, carrier bearing). Also, a cloth headliner stops the reverberation, and a one piece driveshaft eliminates it entirely.
I don't know if this applies your Champ, but it sure seems like it and 56Js have a lot in common, in this characteristic.

Guess I've just been lucky on my T85/T89 and T98 vehicles. None of them ever presented this phenomenon. Wonder what causes it and where it originates?

Here's an embarrassing two-piece driveline anecdote. About twenty years ago, I rebuilt the driveline on my '55 E12 with a T98 four-speed. Each spring, I pumped grease into all the zerk fittings per the Shop Manual. Above the carrier bearing, there was always a pile of slung-out grease. I always wondered why the new bearing would leak so much.

The current project is to convert the truck to a Packard V8. When going through the driveline, I noticed I had used a sealed bearing in the center carrier. For twenty years I had been pumping grease around the outside of the bearing from whence it was immediately flung out.

jack vines

[jclary]

Ron, one more thing to check. (cheap fix) Make sure the tapered hub has no spider cracks emanating from the lug holes. I had that once and it was almost imperceptible with the hub and drum off the vehicle. Under certain conditions, the car would vibrate and make crackling sounds like a bad U joint bearing. The last time I was preparing to pull that drum, I tugged on the flange and discovered that there were several cracks splaying out from the lug bolts. The only fix was to replace the drum assembly.

In addition to the cracks around that flange, the inner tapered hub was cracked at the key slot. That was probably due to the wheel being over tightened at one time or another. Keep digging, you will find the problem with yours.

[WCP]

Don't know anything about Champs, but you suggest that the springs no longer match. Are Champ springs asymmetric? Did the 1+ ton overload deform the axle tubes? Are they in the same plane?

[maxpower1954]

Swap the left and right front tires and see if this doesn't make a differrence, it worked on my 1963 Champ. Different dynamics you know....old timer tip.

Russ Farris

[Ron Dame]

Busted!

The left rear hub is clearly cracked, it and the axle show signs that at one time the key was installed backwards, and has deformed the hub at the slot. Now that the axles are out, they will go get magnafluxed Monday.

Anyone have a hub (drum is OK) for a truck? (8E5). How about a whole axle with hubs and/or drums?