Strange sound and feeling

[ddiddle]

So I took my seven year old out for a doughnut after work today...never mind that it was 98 degrees here and as we were sitting in traffic, the monte temp gauge was touching 215. Yikes.

 

Anyway it passed that test...no steam, leaks or drips.

 

It was after we got home that things got strange. Backing up the driveway into the garage, there was a muted clunk that came from the rear of the car and a feeling like a shove to one side...like I'd tried to roll up on a curb but then fell off. I stopped, sat for a second, gave it a little throttle in reverse again and it did it a second time...and a third, then it seemed OK. The sound and the feeling like a shove sideways happened at the same time.

 

Any ideas? Could it be the brake shoes adjusting? Is that how they work on this car? I've never had the drums off.

 

 

[502ci]

Possibly a broken tooth on the gears in the differential...the piece of metal working it's way through till it settles on the bottom.

 

Hopefully that's not it and it's something simple.

[RichG]

Bad U-Joint?

[Mike 57]

What shape are your rear upper and lower control arm bushings?

I have seen old ones with a lot of slop.

[Sam (Bones)]

brakes could be grabbing, I would check the control arm bushings while you are at it, loose bushings along with the change in driveshaft direction could cause your clunk and sideways motion

[cny first gen 71]

Could also be a brake hardware part floating around in side the drumb

[Ian]

brakes could be grabbing, I would check the control arm bushings while you are at it, loose bushings along with the change in driveshaft direction could cause your clunk and sideways motion

 

Before I changed all the rear suspension mine felt like that sometimes...

[LS5]

Hey Daryl, sound like the boys have come up with a bunch of ideas that are all ligit and worth checking. My 2 cents worth, if it's kind of shoveing or grabing as it were on the one side more times than not by the sounds of things, my strong guess is a rear wheel cylinder that is giving up the ghost and is sticking....other guesses could be a broken spring inside the drum and the one pad grabs in reverse...or Worse case the axle seal is gone and diff fluid has leaked into the drum and contaminated the brake pads and they are grabing.?? check for fluid seeping out of the bottom of the drum and down the wheel onto the ground that is the dead giveaway....

Darren.

[ddiddle]

Great, guys...thanks! I'll take a look at those bushings either tonight or on Monday and we'll see what we can see. The front suspension was rebuilt, but I doubt anything was done to the rear.

 

Darren, I've never seen any fluid anywhere around the wheel/tire/ground, so I'm hopeful there, but if the bushings look good, I'll be pulling the drum. I'll let you know what I find.

[Slaman]

I have heard and felt that before too but from the front end. Mine has always been rough on the front upper control arm busings and had one throw out the rubber. When it did it made that muted metal clunk and shifted to the side a bit. But as I said that was in the front, my bet is you might have something simular with the rear arms.

 

Steve

[amsterdam84]

If you can, get someone to stand beside the car as you reverse. Maybe they can see which side is grabbing. Should look like one tire is not unlocking and pulling the rear end to that side.

[Mo's70MCs]

I'm out on a limb. My money is on, either, u-joints or maybe a loose or broken shock.

[Big Jim]

My first thoughts was brakes grabbing.

[wallaby]

My first thought was U-joints, but those usually don't have to be driven to get a clunk...you can shift from drive to reverse and often get the same clunk without the car actually moving.

I've seen worn brake shoes give that "grab & release" when they are running metal-on-metal with the brake drum (or oil soaked)... it's most noticible when lightly braking at low speeds.

 

I'm betting that you'll find your problem inside a brake drum.

[ddiddle]

Well, I checked out all the bushings and they all look good, fairly new, surprisingly.

 

Next step, take the drum off and see about binding brake shoes or something.

[ddiddle]

The only thing I could find that seemed strange was on the passenger side, the arm (in the pic, the arm in the upper left corner) that contacts the auto adjusting mechanism was looser (more loose?) than the one on the driver side. On the driver side, it was very tight back against the adjusting gear, but on the passenger side, you could pull it out very easily. It was so loose that the spring that keeps the tension on the shoe (that little spring in the upper left corner of the pic) was not compressed or under any tension, but just kind of sitting there at an angle.

 

 

 

Is there some kind of spring from the back that holds that arm against the adjuster that I can't see? And even so, would that cause such a "violent" sensation?

[cny first gen 71]

Check the return springs and the rod for the self adjuster are hooked up properly and that the springs are still good. Make sure all the parts are there and none fell out. Also check to make sure the parking brake cables are free

[cny first gen 71]

Oh yea and be carefull that dust may contain asbestos flush it with water or brake cleaner

[Big Jim]

Also please be careful with the brake cleaner. I understand it can be toxic as well.

[ddiddle]

Also please be careful with the brake cleaner. I understand it can be toxic as well.

Oh, I don't know...it tastes OK to me...

[Monte7071]

This could be a long shot but on Chevy pickups they have a similar problem. The slip yoke gets rust on it and catches we clean them up lube them and put a Isuzu spring in the yoke to keep pressure on it. Not sure that is your problem but it would be worth a shot. My dads 91 Silverado feels like the shoes are stuck and then it pops and off you go.

[ddiddle]

In the interest of full disclosure, I did finally find out what this was...believe it or not, a bad ball joint on the driver's side. It sure sounded like it was coming from the back, but the problem's gone.