Thumping/grinding sound in front end

[Fleetwood Meadow]

I have noticed for a little while on my ‘51 Dodge Meadowbrook that when I am turning while going slow, 20mph or slower, I hear a thumping or grinding sound coming from the front tire area. It makes the sound at both left and right turns. I have not noticed wear marks on the inner sidewalls. The shocks are not broken and are about 2 years old. It makes the grinding/thumping sound at that spacing similar to if you had a brake hitting a high spot on the drum but I have taken the brakes apart and that is not the issue. It also doesn’t matter if the brakes are applied or not it still makes the sound. Where should I start looking? What would generally cause this sound?

 

I have also included this question on the mopar forum site in case anyone sees this there too. 

[keiser31]

How is the front end as far as condition? How are the wheel bearings?

[Spinneyhill]

How much play in the steering? If there is any, where is it? Steering box, tie rods, drag links or what have you in that model. I don't know how it is set up but top and bottom of columnar shocks (rubber bushes shot or loose?).

 

Have you replaced any rubber bushes with red plastic things, Nolathane or similar? Those rubber bushes generally rely on crush to work and many put in the plastic bushes with insufficient crush and the bushes wear prematurely (they don't work as they are intended to work) and then there are bumping noises. Those plastic bushes rely on a lot of crush to work properly.

Edited June 25, 2019 by Spinneyhill (see edit history)

[Stude17]

I would check the inner face of the wheel rims to see if there is a fracture or a bulge near the tyre bead.  I have seen a rim split in this area causing the tyre to "bulge" and as it rotated it hit against the tie rod end.  Only saw it once a long time ago.

Or maybe you have a buckled or warped wheel rubbing on the tie rod end.  Try changing both front wheels with spares if you have them.

Edited June 25, 2019 by Stude17 (see edit history)

[Rusty_OToole]

If you have oversize tires they may be rubbing at full lock.

[Fleetwood Meadow]

I am using radial 205/75r15 which they say is the replacement for the original 7.50-15. It isn’t at full lock. It starts at around 3/4 of the full turn. 

[Fleetwood Meadow]

I see no cracks or bulges. I also see nowhere where things might be rubbing. What is the pressure the tires should be at? I know the original bias tires were somewhere around 28psi. 

[Fleetwood Meadow]

Let it also be known that I don’t feel it in the steering wheel. 

[TerryB]

It’s a bit of work but have you tried switching the front wheels to the rear and rear to the front?

[Stude17]

4 hours ago, Fleetwood Meadow said:

I see no cracks or bulges. I also see nowhere where things might be rubbing. What is the pressure the tires should be at? I know the original bias tires were somewhere around 28psi. 

Have you checked your front wheel bearings as Keiser suggests?  My only other suggestion is have a look at your universal joints as they may be dry/worn out and grinding away.  Could be noticeable on slow turns.

[misterc9]

Those grease fittings all look kind of dry. Maybe you should grease them all thoroughly. You need a lube chart or shop manual to know where they all are. Next I would examine the front wheel bearings. Take them out and clean and check them if ok then lube them up good with wheel bearing grease. Then make sure they are adjusted properly. While doing this you might find some thing else loose or wrong.

[Fleetwood Meadow]

I rode around a parking lot today and it happens between 20-25 mph. It doesn’t do it when it is slower and it doesn’t do it when it is faster. I stuck my head out of the window and it sounded like it was coming from the rear end. I will check the suspension parts and make sure there is no marking from rubbing. I am also going to have to grease the u-joints while I am down there. 

[TerryB]

Unjoints are a strong candidate for this noise.

[Stude17]

1 hour ago, Fleetwood Meadow said:

I rode around a parking lot today and it happens between 20-25 mph. It doesn’t do it when it is slower and it doesn’t do it when it is faster. I stuck my head out of the window and it sounded like it was coming from the rear end. I will check the suspension parts and make sure there is no marking from rubbing. I am also going to have to grease the u-joints while I am down there. 

 

Good to see you working through the possible issues.  My final suggestion is to check your differential. Hopefully there are no broken spider gears which could be the source of the noise.

[john hess]

Since you now believe the noise is from the rear, is a parking brake cable sticking on one side or the other?..  jack up rear and be sure both brakes are not dragging... Apply, then release parking brake and check both brakes again before moving the car...  

[Fleetwood Meadow]

The parking brake in this car is a band that goes around the drive shaft under the front seat. 

[Fleetwood Meadow]

I found the rear axle spindle nuts to be a little loose so I tightened them and took it for a drive. Now I not only hear it in the back but I feel it. It happens between 10-20 mph. It goes thump thump thump the whole time, not just when turning. I went to look at the u-joints but they are ball and trunnion and I don’t know how to service or lubricate them. 

[c49er]

Swap the driveshaft end to end... if the noise changes dramatically ... bad ball and trunnion joints.

[Guest]

3 hours ago, Fleetwood Meadow said:

I found the rear axle spindle nuts to be a little loose so I tightened them and took it for a drive.

?rear axle spindle nuts??   If your axle nuts were loose, (enough to make noise) you should have had the weight off the wheel when tightening them in order to seat the hub on the axle taper.  You also should pull the hubs because you may have damaged the axle keys driving with loose wheels.  BTW the nuts should be tightened to about 150 ft/lbs.

[Fleetwood Meadow]

Tinindian, they were loose but they did not clear up the sound. In fact after tightening them the sound was more apparent not only when turning but also when driving straight under 20 mph. And now I could feel it thumping inside the car.

[Stude17]

I still think universal joints and differential gears are likely suspects, however, as you now say it is a "thump, thump, thump"  you should also check the circumferences (treads) of the tyres to make sure there are no bubbles or bulges.  Sometimes they are hard to see depending on where the wheel stops.

[Curti]

Possibly the drive shaft is out of phase ?

[jrbartlett]

This is a long shot, but it did happen to me on a '64 Lincoln. Rhythmic thumping in the rear end that several mechanics thought might be the spider gears in the differential. It turns out that the rivets holding a brake lining onto a shoe had come loose, allowing the lining to slide over to one side and rub the inside vertical surface of the brake drum as it rotated. Once I found it, I pulled the shoe off and used a hammer and punch to tighten up the rivets, and the noise was gone forever.   

[keiser31]

This may sound silly, but maybe you can get someone to ride around the block in the trunk to see if the sound is coming from the center or either side of the rear end.

[c49er]

Most likely driveshaft or the rear diff... ring and pinion or spider/side gears. Easy to figure out.

[TerryB]

1 hour ago, keiser31 said:

This may sound silly, but maybe you can get someone to ride around the block in the trunk to see if the sound is coming from the center or either side of the rear end.

Hmmm, haven’t done that since the drive-in movie days.  Nothing still attached to me is able to flex that much anymore😀

[Fleetwood Meadow]

I lifted the rear end and spun the tires with my hand. I can hear the scrape scrape scrape of the driver’s side brake. There is a very slight jiggle that I can do with the passenger’s side tire. I can’t see it but I can feel it when I rock the tire grabbing the top and bottom of the tire. But I was hearing, so I thought, the thumping in the driver’s side. I may be wrong. I can also hear the spindle gear clanking as it rotates, as if it is dry. 

[Spinneyhill]

If you can move a rear wheel, there is a problem with the wheel bearings. Mine was like that. The bearing was spinning on the axle and had worn the axle a few thou'. The bearings could even be rumbling, which you might hear more inside with the soundbox effect of the body.

[Fleetwood Meadow]

21 hours ago, Spinneyhill said:

If you can move a rear wheel, there is a problem with the wheel bearings. Mine was like that. The bearing was spinning on the axle and had worn the axle a few thou'.

In the event that the axle has been worn what do I do to correct that? It doesn’t rumble or noticeably make the scraping/thumping sound when traveling over 20mph. 

[Spinneyhill]

Best would be replace the axle. I reached into my stack of spares ex swap meets and found a new unused one, but it was rusty so I put a speedy sleeve on where the inner oil seal goes. If you don't fix it, the movement will destroy the seals anyway and diff. oil will get into the brakes. Mine did.

 

If not, visit some engineering shops. There may be a tiny possibility to grind it and put a speedy sleeve on it under the bearing, but this is precision engineering. Hopefully others have better ideas based on experience, such as special welding and grinding back to size.

 

Over 20 mph other noise might be drowning it out! You certainly need to fix it. Wee story: my Triumph 2.5 1975 developed a rumble in the rear that was fairly audible at low speed. On asking around, it was clear they fail wheel bearings at low mileage (mine had 53,000 km only). "Simple" fix.

 

Any possibility the dry rumbling spindle gear is making the noise? It shouldn't rumble, even dry.

[Fleetwood Meadow]

Spinneyhill I do have a leaking gasket on the differential so I have to keep adding oil at the beginning of the season. The gears may have been ground down by the leak before I got the car. It runs great and doesn’t give me any problem I just hear the slight scraping sound. My first check will be at the rear brakes and then move inward.