Shaking!

[Yellow Galleon]

Hi guys! Been on these threads for quite a while but haven't posted anything yet until now. I know there's been a lot of posts on the topic of a shaking c body but here are some things specific to my car.

1969 Polara. Back in December, there was a godawful grinding noise coming from the rear. I first went for the rear U-joints and tried to re-grease. They wouldnt take any grease so I replaced them. Soon as I removed the old, all the pin bearings fell out and the old grease was just dried up batter. The front ujoints did take grease so I left those alone.

The grinding noise remained however and after taking a tight corner, I realized my left rear bearing was the culprit. Cut the old one off, machine shopped the new bearing and collar on and the noise disappeared. Also while my car was grounded, I replaced the old oem power ateering pump with a reman Saginaw style pump.
All was well until driving to work one day, a violent shaking from god knows where erupts through the car. It eventually went away but I did notice a high pitch whine from my ps pump.

I took the time to bleed the pump from stop to stop to get all air out. Maybe I didnt do a thorough job, but can this be the culprit of the shaking? At first I thought the wheel bearing worked itself loose and I did set the the axle freeplay from the passenger rear. I also noticed it is more prone to shake on a hot day driving to work. On the way home at night, there is no shaking.

Any help from you wizards would be greatly appreciated!!

 

[CBODY67]

It would take a LOT of wobble in the ps pump pulley to cause a shaking you could feel, much less not throw the belt. Some reman ps pumps whine as a seemingly normal situation.

Get the car on a body-contact lift and have somebody sit in the driver's seat to work the transmission linkage with the car raised and the engine running. That's going to be a good way to look for noises in the rear axle area. Plus observe any out-of-round/straightness pieces which turn.

While under the car, also look at the front u-joint for "wear-related" movement. Just because it will take grease does not mean it's still good. Also check for transmission output shaft/u-joint yoke nose wear, which can also relate to a transmission fluid loss at that location.

Just some thoughts,
CBODY67

 

[Yellow Galleon]

Awesome...will give that a try. As a bit of an update, I was underneath car and got an 1/8th of a turn on all the rear u joint bolts. The car shake was minimal on the way to work in lightly toasted 80 degree weather. Might have to refer to specs on those I only used German torque when I replaced them

 

[FURYGT]

Have you checked your tires? Sometimes they will crack inside the tread or develop a bulge on the inner side wall. I have also experienced tires having a tread shift. You would look at the tire tread from directly in front of the tread and make sure that the tread is 100% vertical.

 

[1970FuryConv]

Hi guys! Been on these threads for quite a while but haven't posted anything yet until now. I know there's been a lot of posts on the topic of a shaking c body but here are some things specific to my car.

1969 Polara. Back in December, there was a godawful grinding noise coming from the rear. I first went for the rear U-joints and tried to re-grease. They wouldnt take any grease so I replaced them. Soon as I removed the old, all the pin bearings fell out and the old grease was just dried up batter. The front ujoints did take grease so I left those alone.

The grinding noise remained however and after taking a tight corner, I realized my left rear bearing was the culprit. Cut the old one off, machine shopped the new bearing and collar on and the noise disappeared. Also while my car was grounded, I replaced the old oem power ateering pump with a reman Saginaw style pump.
All was well until driving to work one day, a violent shaking from god knows where erupts through the car. It eventually went away but I did notice a high pitch whine from my ps pump.

I took the time to bleed the pump from stop to stop to get all air out. Maybe I didnt do a thorough job, but can this be the culprit of the shaking? At first I thought the wheel bearing worked itself loose and I did set the the axle freeplay from the passenger rear. I also noticed it is more prone to shake on a hot day driving to work. On the way home at night, there is no shaking.

Any help from you wizards would be greatly appreciated!!

If it was grinding before and is shaking now, I generally blame what changed in between.
Perhaps, it's a driveshaft problem, like out of balance. I agree with replacing the front u-joint.
I also agree that the power steering pump shouldn't cause shaking.
Does the shaking increase with increase of engine speed?

 

[Yellow Galleon]

Welll... havent had time to really dive into it yet with this whole work thing taking up a bulk of the day But I drove it again yesterday to work. It had almost no issue. On the way home at night, that was the worst its ever been. So now I know its for sure not heat related. It seems to come on during coast and increases intensity when slowing down to stop. Then it lingers for a while after that. Tapping break, varying throttle, or putting it in neutral doesnt tame it. I listen closely when slowing down and its a lope type of feel, like theres roadkill stuck on one of the wheels. It didnt settle down until I was at the final homestretch. But it was bad enough that I didnt want to drive it today.

More I think about it, perhaps the blacksmith machinist in may have dorked up the pressing of the axle bearing and its come loose. This weekend, i will start diving in to all possible causes from what you guys have suggested.

 

[nightman61]

I would have to say check your rear axle. Yea, possibly the bearing you replaced was not installed correctly. I know you mentioned the left side. Did you check the right side? I would check everything in your rear axle.

 

[CBODY67]

I would have to say check your rear axle. Yea, possibly the bearing you replaced was not installed correctly. I know you mentioned the left side. Did you check the right side? I would check everything in your rear axle.

One MORE reason to get the car on a body-contact lift, rather than on jackstands.

 

[Yellow Galleon]

So far this Saturday, I've jacked up rear of car. Checked my left rear axle bearing and it was good. Regreased and reinstalled. Started car and observed driveshaft. There is a small lope on the transmission side. Pretty solid at the rear. I also saw a small out of round lope on the right wheel spin. I got underneath and wiggled front ujoints. There is a some play. I have not spun the left rear yet. I'm about to check my right rear axle.

Circumstances are working against me to get it on a contact lift right now. Perhaps when my vacation starts at the end of the month, I can take it to a shop.

 

[Yellow Galleon]

Needless to say, I think i found the bogie. Bad front ujoints.

 

[SuperDave]

Needless to say, I think i found the bogie. Bad front ujoints.

Yeah, reading this, I was thinking drive train imbalance too. You replaced the rear U-joints but not the front, my recommendation was to replace the front U-joints first and see if it doesn't solve it. Of all the possible culprits, that one is the easiest and cheapest to fix and unless it doesn't fix it, you're not out a lot of time or money, and it wouldn't hurt it any.

Glad you found the issue.

 

[polara71]

Car parts are like shoes. If the left one is bad, so is the right. Same thought goes for front and rear.

 

[Yellow Galleon]

Yep replacing today. I appreciate you all's help! Will update when this boat is speeding through calm waters.. hopefully.

 

[Yellow Galleon]

Subject photo..

 

[Yellow Galleon]

Well im here to report that even at 70+mph where there was ALWAYS a slight vibration, the car is as quiet as a church mouse. Thanks to that confounded u-joint, my ears are sensitive to any onset of shaking in the car, even if its road noise.

Again, appreciate everybody's help!