Things go thump in the night

[jbushon2004]

We own a 2004 Monaco Diplomat with 2 slides. Every time we move and set up, for the next few weeks every once in awhile there is a thump sound and it feels like a jack adjusted or something like that. We have looked to see if we are not level before and after a few weeks and nothing appears to have changed. The only place we feel it is if we are in the front part of the coach. We have not heard or felt it in the middle of the night when we are in the bedroom.

We may get 1 to 4 or 5 of these a day and have no idea what it is.

Does anyone have any ideas?

[Robi.1014]

I heard these, primarily in the bed area ... usually when the sun is lower in the sky and the heat-of-the-day has passed. I've reasoned it to be the RV's aluminum skin popping (dragging against the RV house framing) as it is contracting. Kind of like a mini seismic shift.

[Midniteoyl]

Would have to agree.. are you setting up facing the sun?

[nutensteve]

We just experienced the same "thumps". I think the front jack looses a little hydraulic pressure and slips. It isn't much because we are still level but you sure do feel it. We haven't felt it for the last few days so not sure why the jack was slipping. We have been parked in the same spot for 3 months.

[Midniteoyl]

Are you guys on concrete pads? Could it be the expansion/contraction causing the jacks to 'slide' across the ground a little?

[HeapBigEngin]

Have experienced this. Last summer, we camped in our 40' DP for several days at a campground that had gravel/dirt pads. I leveled the coach as usual during set up, noting that the jacks on the driver side were extended somewhat more than the other side since the site was not quite level side to side and sloped to the rear just a bit. About 1:00 a.m. the next morning....boom! Half asleep, I got up, looked around....and went back to bed. About 3:00, the same thing happened, scaring us half to death. Went outside, checked the jacks, tires, wheel chucks. Nothing.

After 2 or 3 more times (now it's 7:00 a.m.), I got out the jack manual and found out several things. First, when the jacks are down and approaching their limit when "set", a VERY slight but sudden, minute pressure loss can occur. Hence, boom in a 30,000 lb MH. The manual also stated that dirty or "old" hydraulic fluid can aggravate this...and, of course, the original fluid in our coach had not been changed. The manual also suggested that certain ground conditions can contribute to this due to compaction, shifting, etc.

Since I hadn't yet acquired jack pads for the new-to-us coach, I drove the toad to a local hardware store and had a number of 2"x8"x1' wood "pads" cut. These would keep the jacks from extending as much and, hopefully, compensate for the gravel/dirt pad. I re-leveled the coach....and waited. Never heard another boom the remaining time we were there. Have since acquired quality jack pads and am much more observant of jack extension lenth and pad material....and have had no more problems since. Will change fluid this Spring. I guess it could be an internal pressure valve thing or something, but so far, so good.

Sorry for the long post, but I thougt a rather detailed account may help. I am reasonably convinced that extension length and pad material combined for one h-ll of a sleepless night. Hope this helps....and please let us know what you find out.

[nutensteve]

Sounds reasonable heapbigengin...Our front jack is extended quite a ways out. I'll get a leveling pad and see if that helps.

[radams]

Can you actually feel movement or is it more the sound? Any chance it could just be a loose awning strap blowing in the breeze and whapping the rubber donut on the end into your sidewall? I've had that happen.

[nutensteve]

Bob...You can actually feel the movement. It only move slightly but you can sure feel and hear it.

[Happycarz]

My right rear jack was doing the "bump" in the night thing too. And, the jacks were only slightly extended. After several trips with this issue, I took the front solenoid valve and swapped it with right rear solenoid valve (at the Lippert pump.) I thoroughly cleaned the pump before disassembly and and cleaned both valves before reinstalling. I wanted to see if problem transferred to front, but no more problem. Apparently, just debris of some sort not letting valve fully seat closed.

[HeapBigEngin]

Hey Happycarz....I find your post very interesting and helpful. I think when I change fluid this spring, I will consider cleaning the pump, flushing the lines, etc. I would not be surprised that I may find something in the old fluid or in the system itself. ANYTHING to keep that "boom" from happening again. Thanks!

And raadams....one can hear it AND feel it. And it ain't pretty!

[radams]

Quote:

Originally Posted by heapbigengin Hey Happycarz....I find your post very interesting and helpful. I think when I change fluid this spring, I will consider cleaning the pump, flushing the lines, etc. I would not be surprised that I may find something in the old fluid or in the system itself. ANYTHING to keep that "boom" from happening again. Thanks! And raadams....one can hear it AND feel it. And it ain't pretty!

Hey, I can well imagine how jarring that must be, particularly in the middle of the night. My experience with strange sounds is that it's never good, and the louder it is the worse it ends up. That aside, it seems to me that the leaking valve makes the most sense. I just don't see how that jack can move without a fluid change. The fluid can't compress, no apparent leaks, so it's got to be leaking past the seat of one of the valves. Good idea to change the fluid although that coach isn't that old. I wonder if it might be a good idea to carry a spare valve too, JIC.

[SpursMVP]

Quote:

Originally Posted by Robi.1014 I heard these, primarily in the bed area ... usually when the sun is lower in the sky and the heat-of-the-day has passed. I've reasoned it to be the RV's aluminum skin popping (dragging against the RV house framing) as it is contracting. Kind of like a mini seismic shift.

Yep this is the deal. Was camping in single digit weather last weekend (Ft. Davis, TX) and as soon as the sun went down the temp dropped.

As the temp dropped the occasional thump could be heard. Not to worry, although it's always a good idea to do a quick internal and external inspection to insure that it's not something mechanical.

[jbushon2004]

We are on concrete pad. And yes you can actually feel movement in the coach. I am going to put pads under the jacks and see if that changes anything. It seems after a few days it stops so, I am guess that there is a fluid problem in the jacks. I am going to change the fluid and clean the pumps this spring. Hopefully this will stop the thumping. Like I say after a few days it seems to stop.

Thanks for all your replys. I thought I was going crazy and it is nice to know I am not the only person that feels the thumps.