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Drive line vibration

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BlueHealey1951

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Hi Guys, I have a 67 BJ8. It is 1 year out of restoration, one last bug to fix. A significant vibration develops around 60 mph. It is too fast a vibration to be from the wheels. Pushing in the clutch while at speed does not change the vibration, so it is not the engine. I have replaced the transmission. I have also replaced the drive shaft that has been balanced many times from different shops. I have checked the drive line angles. Removed the bolts from the pan hard rods ( thought they might be rotating the axle). I have placed various shims on the axle mounts to rotate the axle. Changing the pinion angle only makes things worse. The only thing left is the rear pinion/axle assembly. Any ideas on how to check for a worn pinion bearing? The front seal on the pinion has a slight leak.:dejection: Steve

There have been several suggestions about balancing brake drums. The vibration is much faster than a wheel speed vibration. Plus there is a change in the vibration when I'm accelerating or decelerating.
 
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If you feel it in your seat (not steering wheel), that describes how I've had worn U-joints behave, not at complete failure-but close! Maybe a bent rear axle shaft, or bad axle outer bearing? GL. Jim
 
"If you feel it in your seat (not steering wheel), that describes how I've had worn U-joints behave,"

YEP: Or they may have been installed incorrectly.
OR were defective initially.
A Fault in the pinion bearing,Torque or it's seal can also lead to this type vibration.

Some years ago a car came in with this fault but the fault appeared a different speeds at different times. After much checking of the drive line, it was noticed that the pinion had a bit of play in it, further checking revealed the split washer behind the nut had broken .This allowed the slop in the pinion to vary by how much pressure the split washer spinning put on the bearing.--:encouragement:

OH!! I just looked at my old note book. One of my BJ8's had a problem similar to this. i pulled the pumpkin and found a Plastic nozzle off a diff oil filler bottle. Problem solved.---:highly_amused:
 
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If I read it correctly, you have tried 2 transmissions and 2 driveshafts with no change. Several years ago I had a similar high speed vibration that turned out to be the flange on the front of the dif. - it was either bent slightly or had some unusual wear on the inboard end that caused the flange that the u-joint bolts to to run out of square to the pinion shaft, this caused the u-joint and the driveshaft to have considerable run-out. No amount of balancing or replacement u-joints could compensate for the flange being off. I recommend checking the radial run-out of the driveshaft with the shaft installed, if there seems to be too much run-out, disconnect the drive shaft and put a dial indicator on the flange face surface the u-joint bolts to & see what you get - mine wobbled noticeably. Initially I thought the pinion was bent but then I pulled a flange from another dif & put it on and all ran true.
Dave
 
Get your rear brake rums balanced. If you can't find a local place to do them, put them in a HD Rubbermaid container and ship them off to Allen Hendrix. Take a look at his website: https://www.hendrixwirewheel.com/drums.html It's cured a lot of 60 mph vibration, including mine. Not too expensive and worth a shot.
 
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HealeyRick said:
Get your rear brake rums balanced. If you can't find a local place to do them, put them in a HD Rubbermaid container and ship them off to Allen Hendrix. Take a look at his website: https://www.hendrixwirewheel.com/drums.html It's cured a lot of 60 mph vibration, including mine. Not too expensive and worth a sot.
Click to expand...

I couldn't agree more. Those drums are big and heavy, and apparently not balanced at all from the factory. The guys at the machine shop that balanced mine were highly amused by how far mine were out. Balancing them made a huge difference in the vibration in my car.
 
All are good suggestions and perhaps one of the suggestions is the problem. You can perform a run-out on the differential input flange if you have a clamp on dial indicator. That will tell you if it is not running true. Jack the rear wheels, clamp the indicator to the housing somewhere and spin the wheels slowly. I suspect you would have a vibration at other speeds if this were the case but vibration and harmonics are hard to pin down. If you suspect rear drums you can do some experiments with stick on weights if you work one wheel at a time. Just throw some weight on one and go for a drive. If it is worse move the weight 180 degrees. If it is better, move it 45 degrees clockwise or counter clock wise and so on until you get the best ride. Do the other wheel. Very time consuming but you do get to drive the Healey and it requires no tools or expertise for this trial and error method.

I used to have a vibration at 60 to 65 that I felt in the floor boards that would disappear around 70. No vibration below about 60. When I finally crushed my muffler on a speed bump I thought I could clear (nice new stainless steel when I put it on the road ), I pulled the old used plain steel one I had put on the shelf on and VOILA ! Vibration gone. You'd think I would have been able to say it was the muffler but how could that be? It was new and the best available.
 
Over the years I have experienced, and also heard many stories of, vibrations that kick in around 60MPH. The culprit is usually a tire or a wheel that is out of balance. And, in the case of our Big Healeys, a rear brake drum, or two, could be causing your problem. I would start with your brake drums.
 
Hi Blue,

As Rich and others, I also suggest you address your rear drums first. The rear drums not only were not balanced when originally installed and I have heard or seen drums being as much, and even over, 8 oz. out. Add to the potential imbalance on each drum, the fact that the differential will shift the relationship of the imbalance producing the vibration and at times the vibration will be less and at other times it can appear quite robust.

After I completed my total restoration in 1989, my car drove stable to well over 100 with no vibrations anywhere. As time passed, and things wore in, I spent quite some time tracking down developing/exposed vibrations. As you mentioned, your Healey was tight as a result of your restoration and now normal operations are wearing in and loosening suspension components. This allows your Healey to transmit more of the vibrations caused by components being out of balanced. Although I appreciate you have done quite a bit to identify the problem component to date, checking and balancing the drums seems to be an easy and potential next step for you.

Good luck and all the best,
Ray (64BJ8P1)
 
I appreciate all the help. I am going to have the break drums balanced before I dig into the rear axle. By the way, I submitted a post last fall about overheating while at highway speeds. I took out the electric fan and reinstalled the belt driven fan as a few of you suggested. All is well, runs at about 170 degrees. Thanks every one. Steve
 
Just had this problem. Car had no vibrations before changing wheels, tires, pumpkin. Eliminated wheels and tires, changing back to the other rear end gear set solved problem.
 
Since I had the car on jacks, I decided to look at the pinion one more time. The pinion some how got bent about a 1/16 th inch off center. The flange has almost a 1/8 " wobble. When I bought the car it was not in running condition, so I never got a chance to see how it drives. During the restoration there were obvious signs of a front end collision (twice). Thanks again for all the help. Steve
 
Ok, I can see the pinion or ring being misaligned but have no idea how a pinion would be bent. I would expect that the type of force needed to bend a pinion would have caused obvious damage to the bearings and ring gear as well or even smash, or at least crack, the pumpkin. How would something like this happen?

Ray (64BJ8P1)
 
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Ray, As I said earlier, in my case it wasn't the pinion that was bent but the problem was the flange piece. When I took a different flange off another pumpkin and installed it ran true. I have no idea if the flange piece was bent or somehow worn, but replacing it solved the problem for me. So, in this case, I would try a different flange piece before I went thru the work of pulling the pumpkin.
Dave
 
I haven't dug too deeply into things yet. It could be a bad bearing. The axle was out of the car for about 15 years, two moves and shuffled to various places. It may have suffered damage during all the moves. Steve
 
Dave,

The only thing I was initially questioning was Steve's suspicion of a bent pinion and its possible cause. Other sauces of potential damage resulting in drive misalignment and vibration, as your bent or warn flange, are very understandable.

All the best,
Ray (64BJ8P1)
 
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