strange "clunk" below floor

[Jim McGarvie]

For the past few hundred miles we have had a new and unusual "clunk" sound when going over bumps, or even rocking back and forth, which appears to be coming from the vicinity of the front slide (which is behind the driver's seat). The owner of our local RV shop and a technician took turns driving it and even riding in the basement compartment nearest the apparent source, and they could not pin it down. They extended and closely examined the slideout. They think it may be coming from some suspension component in the front left area of the chassis, but looked and did not find anything obvious.

I have looked also, and tried to shake components but was unable to detect any slop in anything. My next step will be to jack up the front end (and block it with stands, of course), and see if I can find any looseness with weight off the front wheels.

Anybody have any suggestions regarding a possible source?

Thanks.

[96 EVO]

I would probably start with shocks / shock mounts.

[Dr4Film]

If you happen to be anywhere near Orlando FL sometime in the future and no one can pin down the source of your 'clunk", I am positive that Barry (shop manager) from Josam's will know exactly where it is emanated from if it has anything to do with any chassis component.

They have a special machine where they can get below the chassis in a pit while the coach sits on special shaker pads to observe and identify any loose components.

[Jim McGarvie]

9 minutes ago, 96 EVO said:

I would probably start with shocks / shock mounts.

I will. Thanks.

 

8 minutes ago, Dr4Film said:

If you happen to be anywhere near Orlando FL sometime in the future and no one can pin down the source of your 'clunk", I am positive that Barry (shop manager) from Josam's will know exactly where it is emanated from if it has anything to do with any chassis component.

They have a special machine where they can get below the chassis in a pit while the coach sits on special shaker pads to observe and identify any loose components.

Thanks Richard. That sounds wonderful, but we won't be heading to Florida in the foreseeable future.

[timaz996]

"My next step will be to jack up the front end (and block it with stands, of course), and see if I can find any looseness with weight off the front wheels."

I would do this. You should be able to find it with the weight off.

[Robert92867]

I had a similar clunk.

[Jim McGarvie]

7 minutes ago, Robert92867 said:

I had a similar clunk.

Good tip, Bob. Thanks.

[cbr046]

Sometimes I get a clunk also.  The front left side panel around the wheel and fuel door panel aren't secured all that well and it may be wind hitting it just right.  It's very infrequent in my case. 

- bob

[Jim McGarvie]

Just now, cbr046 said:

Sometimes I get a clunk also.  The front left side panel around the wheel and fuel door panel aren't secured all that well and it may be wind hitting it just right.  It's very infrequent in my case. 

- bob

That doesn't appear to be my issue, Bob. And ours is VERY frequent.

[Brian J]

I have used a go -pro camera mounted in the area, they have magnetic base and different clamps available. You are able to watch on a phone or tablet real time or record it..

I have used this method many times to track down an issue.

[Jim McGarvie]

1 hour ago, Brian J said:

I have used a go -pro camera mounted in the area, they have magnetic base and different clamps available. You are able to watch on a phone or tablet real time or record it..

I have used this method many times to track down an issue.

Thanks for that idea, Brian. I just happen to have one of those. If I don't find it crawling around underneath I will give that a try.

[Ivan K]

5 hours ago, 96 EVO said:

I would probably start with shocks / shock mounts.

I had a top shock eye open up on those old bilsteins and beating into the floor when we got the coach. The new ones were made much stronger. Worth checking as Ben suggested.

[Jim McGarvie]

12 minutes ago, Ivan K said:

I had a top shock eye open up on those old bilsteins and beating into the floor when we got the coach. The new ones were made much stronger. Worth checking as Ben suggested.

Our Bilsteins are only four years old, but even though stuff can happen.

 

[Bob Keating]

My driver's side slide makes a clunking noise that appears in the center of the floor just behind the driver and co-pilot seats. You can verify this by running the slide all the way in, and then back out just a bit. if the clunk goes away, that is probably your issue. Mine appeared after putting on slide plates. It changed the geometry just enough to cause the steel wheel on the slide channel to bounce off of the top the the channel with the slide fully in. I was able to verify this by opening the passenger side fuel door and shining a light on the wheel. I could replicate the noise by pushing on the steel wheel with the slide fully in. I am sure, in my case, a proper alignment of the slide will fix it.

[Jim McGarvie]

13 minutes ago, Bob Keating said:

My driver's side slide makes a clunking noise that appears in the center of the floor just behind the driver and co-pilot seats. You can verify this by running the slide all the way in, and then back out just a bit. if the clunk goes away, that is probably your issue. Mine appeared after putting on slide plates. It changed the geometry just enough to cause the steel wheel on the slide channel to bounce off of the top the the channel with the slide fully in. I was able to verify this by opening the passenger side fuel door and shining a light on the wheel. I could replicate the noise by pushing on the steel wheel with the slide fully in. I am sure, in my case, a proper alignment of the slide will fix it.

Interesting, Robert. The shop guys did extensive work on the slide and failed to find the source of the noise, but your suggestion is certainly worth a try. I'm not sure our slide--relatively small--even has such a wheel, but I will check. Thanks.

[Tom Cherry]

Generally speaking....both personal experience, helping others and also reading posts for over 15 years....here is the drill.

Noises that come and go or bang or clunk under the area of the wheels are a LOOSE shock. There are TWO kinds of mounts used on Monaco's...

Some have an EYE and EYE...in that there is a ring or EYE on the top and the bottom.  Others use a STUD and EYE.  The stud uses a plate, two rubber bushings...with a steel insert and a top plate and a nut. These are NOTORIOUS for loosening.  So check the TOP mounts....if they are the STUDS....then odds are....one or more is loose. I put on new shocks in 2012.  Had the front tires replaced in 2018.  TWO of the shocks had lose nuts on the studs....  WILL DEFINITELY GO CLUNK

Next...  Look at the wire or hollow tube staves or reinforcement rods that go from the corners of the fenders to the chassis.  Sometimes they crack.  Other times the screws loosen.  Often, over the years, you have to "rebend" and drill a new screw hole to tighten up the brace 

Finally....On the FRONT fenders...the ones with the curved cutout for the wheels....at least on many...., you can see the attaching screws that screw in from the bottom and hold the fender to the main body.  These bolts will loosen...  Mine, new out of the factory, banged.  The dealer put in TWO MORE screws. These are metal roofing screws.  They are a Hex Washer head with a insulation washer (fiber). You can buy them at Lowes or such.

BE CAREFUL.  Use a 1/4" ratchet and extension and tighten the existing ones...  DO NOT OVER TORQUE...as you will warp and pull one side higher than the rest.  On mine....there is a "gap" between the fender insert or panel and the main body. Keep the spacing uniform. If you add some... I added TWO....then predrill and start the self tapping drill point screws...and then finish torquing with a hand ratchet and keep the gap uniform...

[Jim McGarvie]

1 hour ago, Tom Cherry said:

Generally speaking....both personal experience, helping others and also reading posts for over 15 years....here is the drill.

Noises that come and go or bang or clunk under the area of the wheels are a LOOSE shock. There are TWO kinds of mounts used on Monaco's...

Some have an EYE and EYE...in that there is a ring or EYE on the top and the bottom.  Others use a STUD and EYE.  The stud uses a plate, two rubber bushings...with a steel insert and a top plate and a nut. These are NOTORIOUS for loosening.  So check the TOP mounts....if they are the STUDS....then odds are....one or more is loose. I put on new shocks in 2012.  Had the front tires replaced in 2018.  TWO of the shocks had lose nuts on the studs....  WILL DEFINITELY GO CLUNK

Next...  Look at the wire or hollow tube staves or reinforcement rods that go from the corners of the fenders to the chassis.  Sometimes they crack.  Other times the screws loosen.  Often, over the years, you have to "rebend" and drill a new screw hole to tighten up the brace 

Finally....On the FRONT fenders...the ones with the curved cutout for the wheels....at least on many...., you can see the attaching screws that screw in from the bottom and hold the fender to the main body.  These bolts will loosen...  Mine, new out of the factory, banged.  The dealer put in TWO MORE screws. These are metal roofing screws.  They are a Hex Washer head with a insulation washer (fiber). You can buy them at Lowes or such.

BE CAREFUL.  Use a 1/4" ratchet and extension and tighten the existing ones...  DO NOT OVER TORQUE...as you will warp and pull one side higher than the rest.  On mine....there is a "gap" between the fender insert or panel and the main body. Keep the spacing uniform. If you add some... I added TWO....then predrill and start the self tapping drill point screws...and then finish torquing with a hand ratchet and keep the gap uniform...

Great info, Tom! I hope to get under there this morning if it isn't raining (the ceiling in our hangar is too low to raise the motorhome inside), and I will check all of those things. I will let the group know what I find. I'm betting an upper shock mount, which IIRC are of the stud variety.

[Paul J A]

4 hours ago, Jim McGarvie said:

Great info, Tom! I hope to get under there this morning if it isn't raining (the ceiling in our hangar is too low to raise the motorhome inside), and I will check all of those things. I will let the group know what I find. I'm betting an upper shock mount, which IIRC are of the stud variety.

IIRC means ???

[Jim McGarvie]

4 minutes ago, Paul J A said:

IIRC means ???

Sorry, "if I recall correctly." I thought with this group acronyms were pretty familar. I still haven't figured out what the frequently-used "DW" means.... Dear Wife maybe?

[Paul J A]

5 minutes ago, Jim McGarvie said:

Sorry, "if I recall correctly." I thought with this group acronyms were pretty familar. I still haven't figured out what the frequently-used "DW" means.... Dear Wife maybe?

T y.

[6Wheels]

17 hours ago, Jim McGarvie said:

Sorry, "if I recall correctly." I thought with this group acronyms were pretty familar. I still haven't figured out what the frequently-used "DW" means.... Dear Wife maybe?

Deer wife is correct.                                                            😆

[bradyence]

It definitely could be a bad shock, bushing or maybe even an airbag.  But I did had the exact same thing happen on my 2001 Diplomat, it took me a little while to figure it out. I don’t believe we have the same chassis, mine is a rr8r and I think yours is a rr4r, but it might be something similar. My airbags are outside of the frame rails in line with the tires, and have frame sections that protrude out sideways from the rail to hold the airbag and shock. And there are stringers in between the frame rails that stabilize everything. I had several spots on my stringers that the weld had broke or the metal had bent this was causing the frame to flex more than it should. I had two of the arms protruding from the frame, actually pushing up into the floor of the motorhome. We had to jack up the frame and pull the pieces back together with chains, once we had the right place we welded it back together, and added extra gussets to strengthen it. I would recommend inspect every weld and connection point on the frame. Helpful yours it’s simpler than mine. 

[wamcneil]

On 3/18/2024 at 12:57 PM, 96 EVO said:

I would probably start with shocks / shock mounts.

My clunking was broken off upper shock mount stud. 

[Jim McGarvie]

17 hours ago, bradyence said:

It definitely could be a bad shock, bushing or maybe even an airbag.  But I did had the exact same thing happen on my 2001 Diplomat, it took me a little while to figure it out. I don’t believe we have the same chassis, mine is a rr8r and I think yours is a rr4r, but it might be something similar. My airbags are outside of the frame rails in line with the tires, and have frame sections that protrude out sideways from the rail to hold the airbag and shock. And there are stringers in between the frame rails that stabilize everything. I had several spots on my stringers that the weld had broke or the metal had bent this was causing the frame to flex more than it should. I had two of the arms protruding from the frame, actually pushing up into the floor of the motorhome. We had to jack up the frame and pull the pieces back together with chains, once we had the right place we welded it back together, and added extra gussets to strengthen it. I would recommend inspect every weld and connection point on the frame. Helpful yours it’s simpler than mine.

 

Thanks, Brady. I hope so too!

30 minutes ago, wamcneil said:

My clunking was broken off upper shock mount stud. 

Thanks Walter. I hope ours is just loose and not broken!

[rustykramermetalfab]

My previous coach, 2000 Dynasty I had a shock mount stud break off the bracket in the rear.  Basically, I made it a bolt on stud to the original bracket.  I am not sure how it lasted 90K miles with the tiny cold weld tacks it had from the factory.