Thermally influenced Clunking

[BHutting]

Dave, do you have more specific information on the friction reducer that you used. Manufacturer, supplier, etc. would be helpful. I would like to research this as this seems to be a universal issue. Thanks!

[Tall Tex]

Mine makes the clunking noise after being on the jacks a few days. Once it starts I simply raise the rear and front slightly by manually holding the switches for a second and it is good for a few more days. I don't think it is temperature related at all. I think it is the hydraulic system bleeding down ever so slightly. I've heard similar noise on construction equipment if the bucket, boom or blade is left up with the engine off. It is on my list for the PDI/AIR scheduled in October. Can not notice that the coach changes from level when it starts. We can hear it while sitting outside every 5 to 10 minuites.

[rbr]

Adjusting jack positions had no effect when mine was doing it unless I completely unloaded them, again in my case it was almost surely temp swing related as it only occurred during periods of rapid cooling or heating.

[dave&ginny]

Originally Posted by BHutting

Dave, do you have more specific information on the friction reducer that you used. Manufacturer, supplier, etc. would be helpful. I would like to research this as this seems to be a universal issue. Thanks!

Bob,

I went to the local Caterpillar dealership and got it. I believe they called it a friction reducer for the hydraulic systems. I'll be driving past one today and see if I can get some and post a picture

[dave&ginny]

I just found the stuff on line. The Cat part number is "1U-9891". It's corrects "stick slip". According to the write up

[Randyman1]

I believe the problem you are talking about is called stiction. I had this same problem on my 2011 Cardinal 5th wheel. Learned about the Cat additive on the Forest River forum at the time. It fixed my problem once I put the additive in and got it circulated through the system.

[Grower15]

We had a similar problem on our coach when new (2016 Anthem 44A). PJ recommended adding Marvel Mystery Oil to the hydraulic jack reservoir. We did and the clunking sound went away. Probably works like the friction reducers mentioned above.

[weirba]

About midnight last night the clunking resumed and continued through the night. Remember that yesterday afternoon I aired up the coach, removed the pads I had under he jacks and then auto leveled again. So Ron we can eliminate the idea that the pads are a part of the problem.

[rprkbr]

Originally Posted by dave&ginny

I just found the stuff on line. The Cat part number is "1U-9891". It's corrects "stick slip". According to the write up

looks like they know of the problem we are having.

https://www.lci1.com/assets/content/...heets/0295.pdf

[rprkbr]

Originally Posted by rprkbr

looks like they know of the problem we are having.

https://www.lci1.com/assets/content/...heets/0295.pdf

I know this is a different company, but it sounds like the same stuff we are dealing with. Maybe ill give it a try.

[Lault]

The marvel mystery oil helped our issue, and it is a issue with the jacks with lots of us. I have not heard it for 8 months, headed to colorado so time will tell.

[jestal]

Our classic does the same thing. i think it only takes a thousandths of an inch if the jacks move to set off the noise due to the mass of the coach so it would be hard to measure. I always assumed it was the hydraulic fluid in the system expanding with temp increase or vice versa. Have to get some Cat friction modifier and /or marvel mystery oil and try it.

[brobox]

Our Classic had the same popping the first year. The first trip was terrible, it would wake you up in the middle of the night. The noise started getting less and less and now, totally gone. I figured it was air in the system, or Equalizer put CAT fluid in when they changed the jacks. We are currently in MI where it has been 75 during the day and a couple of nights in the 40's with no more noise. Back in 2014 there was a post about bleeding the air with an alan wrench

On the last tour I took, someone asked PJ about Jacks popping and he said Marvel Mystery Oil then too.

[dave&ginny]

Originally Posted by brobox

Our Classic had the same popping the first year. The first trip was terrible, it would wake you up in the middle of the night. The noise started getting less and less and now, totally gone. I figured it was air in the system, or Equalizer put CAT fluid in when they changed the jacks. We are currently in MI where it has been 75 during the day and a couple of nights in the 40's with no more noise. Back in 2014 there was a post about bleeding the air with an alan wrench

On the last tour I took, someone asked PJ about Jacks popping and he said Marvel Mystery Oil then too.

The Marvin Mystery oil would be less expensive and easier to find. I think I'll try it. If I remember correctly, the Cat oil was around $40 a quart