Rear Pop when sway or lean after CHF?

[Americanrascal]

Thanks folks- very interesting. Going to go back under and look at these some more. If it is tightening against the shank then maybe a good lock washer, and washer may be in order?

I may just observe this for a while before I do any modification to see if they are loosening. May take a few months of running as we are slow for the winter. Long run coming up in February.
Joe

[Stuart W]

[QUOTE=Americanrascal;3339940]When I bought our 2016 26,000 lb F53 in March I did the CHF Front and rear. Easy. I did the 66 ft lbs of torque on the bolts front and back.

Over the past few months a loud pop or metallic sounding thunk occurs in the rear whenever the rig shifts or leans in a turn or lane change etc.

I checked the torque again on the rear sway bar and its at 66ft lbs. I still get the pop or thunk.

Can't find it. Any ideas where to look for this anomaly? Is my torque number correct? Is it something other than the sway bar? HELP!!!!
just fixed this on mine, park on level ground, no jacks, loosen all mounting bolt( links on both ends) then remove two u shaped brackets that hold the bushings one at a time, lube bushing then reinstall, do other side( I used dielectric grease) tighten all bolts to spec and noise will be gone

[TeJay]

I believe Stuart W is talking about the SB (stabilizer bar) bushing brackets. Yes they should be lubed with POLY- lube. However even if those brackets are loose nothing will clunk. There's nothing metal to metal to cause that type of CLUNK. I believe he just got lucky.

If the U-shaped bracket is loose it's metal on rubber so unless it is so loose, along with a missing or badly worn rubber bushing, and then the SB is flapping around in a lean I don't see how that can cause a metal on metal CLUNK. But I have been wrong before and will be again.

Joe!! Did you check the shock top and bottom nuts??? They are to be torqued to 250 fl/lbs. They may seem tight because they are under some pressure but in a sway that pressure will come off some and has been know to cause the CLUNK noise that you are hearing.

Using a rubber lube like 303 will/may not quiet the CLUNK completely but if you lubed things on one side first it might change the noise some which would give an indication of the noise location (maybe).

[Americanrascal]

TeJay- Still have to do the shocks. On my to do list before any future movement of the rig. But in a rainy weather pattern here and a bit too messy around the rig right now.

My Torque wrench can do 250 but I'm not sure about the guy operating it LOL

Joe

[JIMBO34PA]

joe; just get a 1/2 electric impact on those shock bolts . front uppers do thru wheel well , raise front with leveling jacks and reach thru wheel opening put the socket on em and hammer down . dont worry about breaking those shock bolts . my 2015 had 3 trips to dealer complaining of clucking rattling no fix. finally i got underneath and tightened shocks , sway bar and links , leveling jack tie bar and fixed it .

[Americanrascal]

Here is the latest-
Got enough break in the rain to get up under the rig (Got to cut back in eating those grits---- either that or I'm going to have to raise the chassis)

Anyway I managed to get up under the rear -- so much more difficult to get to than the front shocks. Turns out my torque wrench only went to 150 ft lbs and my air impact wrench could not attach to the bolts because of clearance issues in the vicinity of the rear axle .

I did get a wrench on the bolts though and found them to be very snug and tight and they would not move even though I ate my eggs and grits this morning. I found no play in the shocks or the bolts as I did on the sway bar connections.

It still may mean they are not tight enough as there's no way I applied 250 ft lbs of torque. So regardless of my attempt they still may actually be loose and below torque spec even though I did not sense any looseness or play.

I have not been out for a test drive yet since I've tightened and checked everything. I'll report back on that in a few days when complete to see if I nailed the issue.

Guess this may mean a trip (now with a legitimate excuse) to the new Harbor Freight in town for a new torque wrench that goes to 250! See there is a Santa hidden in all this!

Joe

[TeJay]

Joe,
I'm with you on the torque. I can do it but getting into the correct position under the RV is another whole story. Getting my feet so I don't go forward when using my arms to get close to 250 ft/lbs is almost impossible. Probable using an impact air/electric is the only way to go.

Years ago I tried to change an exhaust on a car on the ground. I got the old one off in pieces (rust) but getting the new one on could not be done. It was to long and could not be fished under unless up on a lift.

[Americanrascal]

Will give the impact wrench one more shot. Could not get clearance around the shock mount and the axle with the body of the wrench to get the socket on.

I really had no room to work with to get any energy into the wrench

[Stuart W]

Originally Posted by TeJay

I believe Stuart W is talking about the SB (stabilizer bar) bushing brackets. Yes they should be lubed with POLY- lube. However even if those brackets are loose nothing will clunk. There's nothing metal to metal to cause that type of CLUNK. I believe he just got lucky.

If the U-shaped bracket is loose it's metal on rubber so unless it is so loose, along with a missing or badly worn rubber bushing, and then the SB is flapping around in a lean I don't see how that can cause a metal on metal CLUNK. But I have been wrong before and will be again.

Joe!! Did you check the shock top and bottom nuts??? They are to be torqued to 250 fl/lbs. They may seem tight because they are under some pressure but in a sway that pressure will come off some and has been know to cause the CLUNK noise that you are hearing.

Using a rubber lube like 303 will/may not quiet the CLUNK completely but if you lubed things on one side first it might change the noise some which would give an indication of the noise location (maybe).

Tejay with all due respect I was not speculating, I did the rear CHF on my 26k 37 foot MH two weeks ago and after I had the same noise as described. I did exactly what I listed in previous post and the noise was gone.
(FYI just put 1900 miles on it after this correction with no noise)
I believe that when I did the CHF I only loosened the lower bolts for the links, and after the sway bar was repositioned it was in a bind, in addition the poly bushings were bound tight to the sway bar on both sides.
Take it for what it is worth, this absolutely fixed the noise for me!

[TeJay]

Stuart,

It's great that your noise is gone. I was not for one minute doubting that what you did fixed your CLUNK. I'm just not understanding what effect loosening all attaching bolts followed by torquing them all back down had on the noise. I'm just curious and trying to figure out what happened for future reference.

I do recall performing the CHF on the rear as opposed to the front. The front SB links did not bind on the frame connection but they sure did on the rear. At the time I loosened the top so the bushing would rotate and reduce any binding that might occur.

[Stuart W]

Originally Posted by TeJay

Stuart,

It's great that your noise is gone. I was not for one minute doubting that what you did fixed your CLUNK. I'm just not understanding what effect loosening all attaching bolts followed by torquing them all back down had on the noise. I'm just curious and trying to figure out what happened for future reference.

I do recall performing the CHF on the rear as opposed to the front. The front SB links did not bind on the frame connection but they sure did on the rear. At the time I loosened the top so the bushing would rotate and reduce any binding that might occur.

TeJay, that is what I was trying to say, when taking the two bar-end bolts loose I had to raise the sway-bar( move it closer to the frame) about 1/2 an inch to get the bolts back in the links to sway-bar ends. so I did not loosen up the top bolts that hold the link to the frame. in my case I believe this was my mistake and when the bar had to deflect more over large dips or hard turns the top link(s) was being moved slightly, metal to metal and the mounting point making the noise. it was a simple fix. The noise was also much louder then I would have thought prior to this fix. another thought; by not loosing the top bolts, to make the bar fit the links you have to basically twist and load the rubber link bushing.

[Americanrascal]

Stuart W:

In the next few days I'm going to test drive it again and see if its my favorite popping sound is still there. If it is I'm going to loosen, adjust and re-torque everything with loctite and see if that is the same as I have

Good info here from all

Thanks all

Joe

[Americanrascal]

I think I have this thing licked!

I took the rig out for a test drive last night. No sounds or clunk/pop/thunk-- however one wants to describe the sound that used to be there when shifting weight or rounding curves.

It appears it was the rear connecting links from the chassis to the swaybar. Those bolts at the chassis were VERY loose, and virtually to the point of the nuts almost spinning free

Thanks all for weighing in. I hope this experience will help others as a place to look when the infamous "clunk" sound rears up!

Joe

[marjoa]

Originally Posted by TeJay

Another lose part causing the same clunk type noise were loose shock bolts. They should be torqued to 250 ft/lbs. It's not easy to determine if a shock is loose. It's difficult to compress them so they seem tight.

Also on both the SB link bolts and the SB bushing bracket bolts they need to have blue or red lock tight on them so they won't come loose.

250lbs....wow that's a lot. When I switched to Koni shocks about 2 months ago, I asked this question from 3 sources, 2 koni shock dealers & a reputable mechanical shop I use all the time and they all said 125lbs. I torqued them to 125 and have had no problems or noises.