thoughts on vibrations

[blueskies]

Had a very busy day with my plymouth today... Posting from home, so pictures will have to wait till tomorrow.

Installed new heater motor, new driveline, dash clock, visibolts in rear bumper, and a flex radiator fan.

I was hoping that when I went for a test drive, my car would be vibration free. No such luck.

At about 60mph, a fairly heavy vibration sets in, and I'm hoping it's not the new driveline. I had the tires remounted, and they only did weights on the inside of the wheels, because they were afraid of scratching the new powdercoat on the wheels. It may be that the vibration is in the wheels, so I will start there, by rebalancing with weights on both sides of the wheels. If that's not it, I'll be pissed. The old vibration before replacing the driveline was very cyclical, sort of a thrum-thrum-thrum. Now it seems constant and steady, and is only noticable at speed.

The new driveline fits like a glove to the transmission and rear end, which is great. I noticed on the old driveline, that the new rubber boots I put on the ball and trunion joints are already rotten and torn, and they are only about a year old.

Most of the chatter that I thought was in the clutch is now gone, and it is much more smooth on takeoff. There is a bit of chatter when I let the clutch out with the brake on, and it sort of rattles through the driveline to the rear end.

Which brings me to my worry, the rear end. It is the only part of the car that I have not opened up and re-done. Wondering if the vibration could be in the rear end, maybe the pinion bearing(s)? I did replace the axle bearings and seals, so that part should be fine. Just the center section is original with about 99,000 miles or so on it. Could this vibration be in the center section? Ugh, I hate vibrations in cars.

Installing the driveline and flex fan kicked my butt today, I'm hitting the sack. And a bit dissapointed...

Pete

[cwcars88]

Pete Rather then redo your wheels, do you have a buddy that will let you use his tires and wheels. If your problems go away or are still there you will know if it is your tire balance or not. Wayne

[blueskies]

...do you have a buddy that will let you use his tires and wheels...

Unfortunately, no... I don't know anyone with anything that would fit my car. And I'm the only old plymouth owner within about 300 miles...

Re-balancing the wheels is not a big deal, just time to drive down to the tire store again. I'd prefer the weights to be on both sides of the wheel anyway.

Pete

[Normspeed]

Mine has the thrum thrum thrum vibe above 70 mph. I assumed it's my old original driveshaft.

Pete, if the vibration only really came up after the last round of work, likely that the problem is there. I'd try rechecking all the fasteners that hold in the new setup, and pull one end loose and rotate the shaft 180 and reinstall. Heck, you knew that though. I'm just blabberin'.

[Dodgeb4ya]

If it`s an overdrive car, the trans back 1/2 case W/the planetary gear set could be worn . The annulus gear to case clearance could be excessive-cause of a cyclic rumble. Disconnect driveline@ back of trans and firmly try to rock the brake drum and output shaft- should be NO movement sideways or in or out. Make sure drum nut is tight too.

Bob

[Young Ed]

Pete my car has a slight vibration at highway speed too. I can't hear it but I can feel it in the steering wheel. Took about a 120mile round trip down to a friends house tonight. When we got there my buddy who was following me said at slower speeds my LR wheel looked like it was wobbling. So I think mine is maybe a bent rim. Another thing to consider

[Rodney Bullock]

The wobble wheel is a good point. ON my Plymouth I was getting my wheels from a junk yard and the guy warned me that the wheels were 64 years old expect imperfection! To be on the safe side I took them to a place about 60 miles from me to have the wheel itself balanced, of the 6 wheels that I bought in 5 were out of balance. I did this before having the wheels sandblasted and painted as a result the 40 never vibrated. On another note my car does not top 70 miles an hour. WOW you cats aer flying down the road. Pete your car is a inspiration to us all, we refer to it alot when we are talking. I know you will find the exact cause of your problem.

[Don Coatney]

Pete;

I mentioned the splined slider on your first driveshaft picture post below.

Is this spline keyed so it will only go in one way? It is hard to tell from

the picture if it is in phase. Out of phase will cause vibrations. Even if it

is off by one or two splines it could cause a problem.

[Don Coatney]

When Greg G was following me down the road last summer on the way to Bill Willards stable he noticed and told me my left rear wheel had a slight wobble. Strange thing is my tire is wearing evenly and I do not have any vibration even when running 85 MPH. What I do have is a slight left rear wheel to fender rub when my back seat and trunk are laden with extra weight and I make a right turn. I believe this is due to the differential I have installed being one inch wider than stock and the slight bulge of the radial tires. This rub is not enough to leave a mark on the tire. It just makes a slight audible noise.

[Merle Coggins]

It appears to be in phase in the picture. I agree though, an out of phase driveshaft can cause a nasty vibration.

Merle

[martybose]

When I put the new tires on my wheels for my 47, I found a tire dealer that has one of the newest balancing machines that in addition to balancing actually measures the concentricity of the mounted tire. On one of mine they rotated the tire about 90 degrees on the rim to get rid of a high spot that they said might have been noticable at highway speeds.

Marty

[fireman_033]

Pete if your vibration is in the driveline it can feel as though the vibration moves though the car over and over tire balance will start at a certain speed and go away at about 7 -10 mph over that just my 2 cents worth Scott

[blueskies]

....the trans back 1/2 case W/the planetary gear set could be worn ....

Man, I hope that's not it... The vibes are definitely different that before I swapped the driveline and had the wheels powdercoated, so I suspect it's one of the two.

...So I think mine is maybe a bent rim. Another thing to consider...

Ed-

I had all five of my wheels powdercoated, and I have never used the spare wheel before. I'm sure the wheels got mixed, and I don't know which one was the spare. It may be one of the wheels now on the road. It's possible that one of the wheels is bent. I'm going to jack up the rear of the car and run it to see if there is any wobble. If not, I'm going to rotate the tires to see if there is any change. The vibration feels like it is in the either the drive train or the rear wheels.

To be on the safe side I took them to a place about 60 miles from me to have the wheel itself balanced...On another note my car does not top 70 miles an hour. WOW you cats aer flying down the road. Pete your car is a inspiration to us all, we refer to it alot when we are talking. I know you will find the exact cause of your problem.

I suppose it would have been a good idea to have the wheels checked out before spending the money to have them powdercoated, LOL. Only 70??? Rodney, you've got to get with the program! With the BIGGER RACE and all, my car runs like greased lightning.

Pete;

Is this spline keyed so it will only go in one way?

Don-

Not sure if the slip yolk is keyed or not, but I'm fairly sure it is in phase with the other end. When I installed the driveline, I had the e-brake on to keep the transmission from rotating, and I had both rear wheels on the ground to keep the rear end from rotating. The new driveline fit right in without needing to rotate either end. I'm going to double check the bolts and make sure the new flanges on the driveline are seated into the recesses of the transmission and rear end correctly, but I'm sure they are good.

...my left rear wheel had a slight wobble. Strange thing is my tire is wearing evenly and I do not have any vibration even when running 85 MPH. What I do have is a slight left rear wheel to fender rub when my back seat and trunk are laden with extra weight and I make a right turn. I believe this is due to the differential I have installed being one inch wider than stock and the slight bulge of the radial tires. This rub is not enough to leave a mark on the tire. It just makes a slight audible noise.

I have the same issue on my '53 chebby truck. The rear is about an inch too narrow, and came from a junk yard. The car was probably dropped, or wrecked, and I think one of the axles is bent, not the wheel. The tire wears evenly, and doesn't vibrate. I too get the rub, when I run through a deep twist, and the tires squeal on the bed box.

...I found a tire dealer that has one of the newest balancing machines ...

Marty

Marty- I live out in the sticks, and am lucky to have a tire shop close by, LOL. But they do have cheap powder coating!

Pete if your vibration is in the driveline it can feel as though the vibration moves though the car over and over tire balance will start at a certain speed and go away at about 7 -10 mph over that just my 2 cents worth Scott

Scott-

The vibration before any of the changes was cyclical, thrum thruming down the road. It would get worse with speed, over 55-60mph. I drove the car to Tulsa and back to Idaho like this, 3300 miles. Drove me nuts, but I was sure it was the old driveline. I bought one of those Balancemaster mercury filled rings to put on the driveline, and it made it much worse (snakeoil product). The alignment shop ran the car on the lift, moving the balance ring back and forth on the driveline, because they could see the vibration in the driveline. There was no place that was better, so they took it off. Once it was off, the vibes were reduced drastically.

Now that I have changed the driveline and wheels/tires, the vibes start in at about 60mph, and are a constant rapid vibration that gets worse with increased speed. I don't think its the engine or the flex fan, because the vibration does not change when I put in the clutch and coast at idle. I think it's got to be a bent wheel or the new driveline.

I'm off to the garage to trouble shoot...

Pete

[Don Coatney]

Don, do you have that problem with your car with the updated rear end?

Nope

[Young Ed]

Ed-

I had all five of my wheels powdercoated, and I have never used the spare wheel before. I'm sure the wheels got mixed, and I don't know which one was the spare. It may be one of the wheels now on the road. It's possible that one of the wheels is bent. I'm going to jack up the rear of the car and run it to see if there is any wobble. If not, I'm going to rotate the tires to see if there is any change. The vibration feels like it is in the either the drive train or the rear wheels.

Well its raining here so I didn't get my wheel swapped with the spare. Kinda glad I sprang for that 5th matching tire now though!

Don-

Not sure if the slip yolk is keyed or not, but I'm fairly sure it is in phase with the other end. When I installed the driveline, I had the e-brake on to keep the transmission from rotating, and I had both rear wheels on the ground to keep the rear end from rotating. The new driveline fit right in without needing to rotate either end. I'm going to double check the bolts and make sure the new flanges on the driveline are seated into the recesses of the transmission and rear end correctly, but I'm sure they are good.

Pete Because of the slip yoke just keeping the tranny and diff flanges from rotating won't necessarily make it in phase. With the old style one like you removed the phase is built in but not so with the slip yoke style ones.

[JIPJOBXX]

I have noticed with most of the older cars that I have had that usually notable vibrations occur after about 40 to 45 mph. Does your car have any signs that it starts at around that speed? Also someone stated here or somewhere that you could tell if it was in the rear end or maybe the drive shaft by watching your mirror for vibrations. I have noticed with the vibration that I have it seems to go away also if I go up to 55 or 60 any reasons for this? Well good luck on your vibration problem as I know where your at as my old Dodge has always had this problem ever since I restored it.

[blueskies]

Ed-

Pete Because of the slip yoke just keeping the tranny and diff flanges from rotating won't necessarily make it in phase. With the old style one like you removed the phase is built in but not so with the slip yoke style ones.

Ed-

I guess my point was that I don't think the driveline is out of phase by a tooth or two on the yolk, because it was a direct fit from the old in phase driveline. And it is definitely not out of phase by 90 degrees.

Does your car have any signs that it starts at around that speed? Also someone stated here or somewhere that you could tell if it was in the rear end or maybe the drive shaft by watching your mirror for vibrations.

I drove the car to my office a bit ago, and once I got on the two lane stretch of highway, I stepped up the speed to see if I could drive out the vibes. The vibration starts at about 55 or 60mph. It got worse as the speed increased, and was severe at about 75, when I backed off. Everything in the car was vibrating, not just the mirrors... Definitely much worse than when we drove the car to Tulsa last June, damn it.

Before I left, I jacked up the rear of the car and ran it in the garge. One of the rear tires has a very slight side to side ryhthm, and looks like it is the tread on the tire. The other one, is clearly out of round a bit, maybe 1/8" or so. Thinking this one was the spare before the powder coating.

Next, I removed the out of round wheel, and put on the spare to check it out. It was much like the other wheel that had the tread moving slightly side to side, but seemed round for the most part.

Then, I removed both wheels from the rear, and ran it up to speed again. the vibration is still there, leading me to believe it's the driveline or rear end, or transmission, or...

With the car running at speed, and looking at the driveline, the rear end of the driveline looks very smooth, as in no vibration. The front end though, looks like it may have some vibration. I greased the slip yolk before I put it on the car, and I'm wondering if there may be a lump of grease on one side that is throwing it off some. Maybe it will smooth out if so.

I think I'm going to have the tire shop trade wheels with the spare to put the more round one on the ground, and the less round one in the trunk. The tires don't match, so they will have to swap them. Also, I'm going to have them re-balance all of them with weights on both sides. I don't mind seeing the weights, and would prefer them to be better balanced.

Here's a shot of the new driveline and the rear end flage. Pay no attention to the undercoatney all over everything but the new parts...

Pete

[Ed Griffin]

Pete, you've pretty well replaced everything but the rear end? Other words you've been through everything but the rear end. Since you had this problem yet it has gotten worse since you added the new balanced drive shaft it would make one consider that you have only multiplied the problem because the other components are working correctly. With that in mind my thoughts are that the original problem has increased due to the fact that everything is working as it should other than that one area where the existing problem still remains.

You have gotten some good tips on where to look but some do not apply to the excessive vibration you are getting. The wheels can make for a jittery ride but not to the extent that your saying your getting. That's unless they are about to fall off which you know they are not.

I drove an 81 Bronco for 12 years. As time went on it developed a vibration and as time went on I tried to find it. I replaced the inner and outer bearings ( front vibration ), all the tires, all the wheels, had the drive shaft balanced, replaced the U-joints. All the time the truck got smoother and smoother in it's ride yet vibration still would not go away. I was running out of ideas until someone mentioned the CV joints. Turns out that was the problem.

What I'm getting at is look where you haven't been, the rear end. Something else to keep in mind is the fact that you have added the overdrive tranny while you still had this problem. As you know one problem left unattended can cause others. "If it`s an overdrive car, the trans back 1/2 case W/the planetary gear set could be worn . The annulus gear to case clearance could be excessive-cause of a cyclic rumble. Disconnect driveline@ back of trans and firmly try to rock the brake drum and output shaft- should be NO movement sideways or in or out. Make sure drum nut is tight too.

Bob"

If you have done this and everything is stable then personally, I would be directing my attention on the rear end. This is just my two cents worth but you have far better mechanic's here than I to help. I just wanted to pass along my experience in hopes that you do not have to go through everything else before you get to the root of the problem. Whatever the problem is I hope you can find and fix it with little expense because you have already done so much to your car and I know your ready to get the inside finished. Good Luck!

[david lazarus]

One option is as you have done, lift the rear to get wheels free and run it, then remove both rear wheels and run it, then remove driveshaft and run it.

This process of elimination may give you a clue what is happening or at least where the main area if vibration is comming from.

And from left field......could the front wheels be out of balance??

Dave

[blueskies]

One option is as you have done, lift the rear to get wheels free and run it, then remove both rear wheels and run it, then remove driveshaft and run it.

This process of elimination may give you a clue what is happening or at least where the main area if vibration is comming from.

And from left field......could the front wheels be out of balance??

Dave

Dave-

I did all of these things this morning, but remove the driveline (see post above). I think the front wheels probably need better balancing too, but there is no significant vibration in the steering wheel.

Pete

[david lazarus]

Pete

I would pull the driveshaft off then, cause when I replaced my driveshaft ALL vibrations went away, it was like night and day!!

Maybe they forgot to balance your driveshaft.

[blueskies]

Pete

I would pull the driveshaft off then, cause when I replaced my driveshaft ALL vibrations went away, it was like night and day!!

Maybe they forgot to balance your driveshaft.

That'll be the next step, and I'm dreading it..

There is a washer welded on the side of the driveline, which makes me think it was balanced, but maybe they screwed it up somehow...

Pete

[Jerry Roberts]

Welding a washer to the drive shaft was the method that was used to balance my drive shaft too . Mine is OK .

[james curl]

I have used a very primitave method of reducing the vibrations. Get two worm clamps just large enough to go over the drive shaft. Install both on the drive shaft side by side. Take a paint pen and draw a line between the two clamps as a starting point. With the car on jack stands start in high gear and run up the RPM range, note vibrations. stop engine, move both clamps an equal distance from the paint mark in opposite directions. Repeat the run sequence. Continue doing this until the vibrations go away or until you are back to the original location. If you have gotten this far without any improvements try moving both the clamps together the same direction about 10 degrees at a time and run until the vibration is gone are you are back to the mark. This should tell you if it is the driveshaft. Have you used a dial indicated at each end and the middle to be sure that the drive shaft is true when you rotate it 360 degrees by hand? I have seen new made drive shafts that will not run true and they will always vibrate.

[jd52cranbrook]

I have not seen thousands, but quite a few new drive lines made. And I have yet to see one made that was not in balance. It's such a critical item it would be hard for a shop to let one go out the door like that. It would ruin their reputation.

Having said that. I found my dual exhaust would rumble against my frame only around 60-70 mph. I looked underneath and saw one pipe was close to the spare tire well. Got a pry bar, and a couple of good shoves, the vibration is gone. And this sounded exactly like a wheel bearing, out of sync Driveline, or something of that nature.

You might want to look to see how close you pipes are now Pete, something may have moved when they had it on the rack.

Course you may not even be able to read this.