Clunking sound

[Bill Sprague]

My coach is Monterey with 85,000 miles on it.

I’ve been chasing a metallic clunking sound for months.  It is most noticeable at about 25 mph and seems to disappear at freeway speeds.  On smooth pavement it is not there.  Expansion joints, pavement cracks and filled potholes are the cause.  A dip in the road that causes a typical porpoise movement does not cause the noise.  In other words, short excursions of the suspension create the noise but larger excursions do not.  

This week I asked two friends, Marty and Jay (who post here) to ride with me.  We all agree that it seems like the sound comes from the area behind the right front wheel.  

I found a loose panel on the kitchen slide and repaired it.  There was a loose trim piece under the slide that I repaired.  The genset panel was chafing against the front cap.  I repaired that.  The license plate bracket is no longer loose.  I secured the step to the door handle with bungees and that didn’t fix it.  

It seems like it should be a shock absorber or bushing except that there is no noise with extreme suspension travel at highway speeds.  All the shocks have been looked at by both me and a truck mechanic.

Yesterday I had an experienced technician from Holiday Motorhomes (an ex Beaver dealer) ride with me.  He heard the noise but could not identify it.  I have an appointment for next week where he “will find it, no matter what”.  That could be expensive!

Rather than throw dollars at trouble shooting, are there members here that have had a similar noise or suggestions of things I could look at myself?

[Richard And Babs Ames]

We had a clunking sound in our 1997 at about 100,000 miles  and it turned out to be failed rubber bushings in the suspension control arms. The front has a total of six. An upper and lower on each side and two that are crossways. We replaced them all at a cost of approximately $1800 and have not had a clunk since. The LP tank blocked a couple of bolts from being removed so had to be lossened toget them out.

I do not think there was any chance of a failure that would cause a loss of steering or abnormal tire wear. Our new arms came from before Navistar Monaco. We used a frame and axle shop.

[Bill Sprague]

.... We replaced them all at a cost of approximately $1800 and have not had a clunk since....

  I didn't want to hear that!  Ouch! I need to save money for $5 fuel!

[Jim Nichols]

 We had same clunk under driver seat under the same conditions when we had 11,000 miles. I found it myself at least on ours under the steps. Hard to see up there but steps were close to frame box at trailing arms. Was able to get a grinder between step side wall and frame. That 1/8 gap made peace with my bride. Let us know when you solve it.....Jim Nichols

[Richard And Babs Ames]

  I didn't want to hear that!  Ouch! I need to save money for $5 fuel!

I fully understand, but I would let a good Frame and Axle shop make the call.  $1800 was several years ago, also hope the arms do not have to be custom made, I would also just fix the bad one(s) in hindsight.

[Jim Nichols]

My bride reminded me that it was the air bag mounting that to close to the step wall. Not the trailing arms.

[George Harwell]

Probably not what you are hearing but the Hydro Hot exhaust pipe heat shield cracked on my 03 Monterey. May take a look at it just for grins.

[Bill Sprague]

I think we found it!

It was raining yesterday, but I talked Marty into loaning me his driveway and ramps, to get the front end up.  I wanted to take a better look at all the bushings and bolts.  Before I could get my coveralls on, Marty was under there and inspecting everything.  We found nothing in the suspension and steering system that was wrong.

I found a sheet metal panel that is the front of the Hydro Hot box that could be buckling so I shimmed it to stop that.  

Marty found a rattle in the slide out timing bar.  It is the square tube with gears on it that keep the both ends of the hydraulic slide out moving evenly.  We took it apart, added some grease and electrical tape to one end.  I shoved some tooth picks (normally used for martini olives) into the tubing joint.  

On the drive back to storage it seemed that the sound changed significantly. It was not entirely gone, but it didn't have the metallic clank as before.   However, it was raining so hard that the road noise may have dulled my ability to hear the clunking.

The best part is that I am not worried about a safety issue with the running gear.  

Thank you Marty!  

[Richard And Babs Ames]

Thanks for the update and happy your suspension is sound. Happy you are not spending a bunch of money for a might fix. Shame to waste anything use specific though like the martini tootpicks.