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Old 01-31-2011, 08:13 PM   #1
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Spring Hanger Stiffening Upgrade (lots of pic's)

Hi Fellow Sunliner’s

Just passing this along in case someone has this same issue and here is one way to get out of the problem. In my case the problem stems from 2 different issues.

1. Bent spring hangers. This is partly due to having 5” long spring hangers and the way they are mounted to the TT. The other part deals with a heavy camper, ~ 9,200# when loaded including fresh water, and doing large turns on hard surfaces. My driveway is one of those situations. When the weather is soggy out I cannot back onto my lawn to turn around without almost guaranteeing of getting the camper stuck. Ask me how I know this..... So I end up having to do a 180 degree turn on my concrete pad.

2. Reduced tire to fender clearance due to upgrading to 6,000# axles, an adjustable axle seat and using a Dexter EX flex in place of an Alko rigid equalizer.

So this upgrade may not apply to too many folks however I’ll pass it along in case someone can find use from it. So let’s look at the bent hangers.

You can see here the hanger is bent inwards. This comes from the high force in turns hanging down so far on standard spring hangers. While I have a TT, when you go 5th wheel (usually heavier weights then TT’s) these same type of hangers often have a reinforcing rib welded inside and they can be mounted to a piece of square tubing and then mounted to the frame. This makes the hanger shorter and spreads the load out on the frame more. What you see here on my Sunline is very common in the RV industry on TT’s. It is just the way they do running gear. Light duty.



Part of the issue is the I beam flange is unsupported. If you grab the hanger with no spring attached by hand you can flex the I beam lower flange. This made me concerned on top of my turning issues. If the hanger bent then the lower I beam flange is taking a high stress as well.

Due to time, (never enough of it) I did a staged approach to the correction. First was to stiffen up the lower I beam flange to stop the twisting. Sunline already did this correction on the main equalizer hanger they just did not do it on the end hangers. You basically install a reinforcing rib between the lower flange and the I beam web. Like this.


Then stitch weld it in place. Enough to hold it but not over heat the flange. This really strengthens up the lower flange and spreads the hanger load out more even. That is 1/4 x 2” wide flat bar, about 18 inches long.


You can see here during my axle replacement Sunline had that rib in the center equalizer area.


So that now helps the lower flange. Next is the hanger itself. By installing a piece of 2” sch 40 pipe between the hanger side plates it creates a more rigid hanger. In effect it makes it a shorter hanger and the ends shorter that hang down to the axle bolt unsupported.


You can weld that pipe in or place a piece of flat bar between the 2 sides of the hanger. In my case this was a progression correction and I needed the bolt hole for a 2nd stage fix of the hangers. The combo of strengthening the lower I beam flange and the hanger inside support made a large improvement in hanger stability. And as such I ran for almost 1 1/2 years this way until I could get to last stage fix.

See here on this older Jayco Designer 5th wheel. It has the hangers attached to a tube and a piece of flat bar over the tube to the hanger to create this similar stiffening. This is now a shorter hanger.




And here compliments of Kitty and EMD_Driver is their Sunline 5er. See the plate inside the hanger. And they too have the tube to mount the hanger to like Jayco did


Here is another brand I cannot remember which brand…. And they have the gusset on the lower flange and a short hanger. Also note the spring pack is on top of the axle. Sunlines have many low rider TT’s and most have the spring pack on the bottom of the axle needing a longer hanger to get to the spring.


So this is a hanger fix that is not that complex to do. The next upgrade takes the hanger stiffening to the next level. To connect the 2 sides of the camper at the hanger for increased rigidity and in may case, TT lift. Mor Ryde makes an aftermarket bolt on kit to help this problem MOR/ryde - Products - Aftermarket - TV Mounts

In doing some research folks who do a lot of off road camping (Toy Haulers also) have hanger twist as well going up and over large uneven surfaces. Researching what some have done they weld in channel iron between the left and right side of the camper at the hangers. In my case I used 2” sch 40 black iron pipe and flange plates.

Here is the pile of plates for the front and rear axles. This is an exercise in being about to layout and drill accurate hole spacing as the clearance hole is size to size with the bolt.




I also needed to create the wet bolt feature so I can grease the bushings. After I made these I found out they sell extra long wet bolts for heavy duty 1/2" thick hangers used on heavy equipment trailers. Start with a 9/16 grade 8 bolt and drill and tap for a grease fitting along with a grease hole cross drill.


Then you tack weld the parts together and you make a hanger stiffener and TT lift kit.




You custom drill each location to be size to size with the bolts. You also reuse the old spring bolt hole.


There is a 1/2" sch 40 pipe spacer that goes in the old spring bolt hole and the 2” hanger pipe goes on the top hole.


You need to weld a 1/2 – 13 full nut on the inside of the hanger plates as you will not be able to get to that nut later on.


Here we are drilled and the spring lowered to the new location.


Install all the hanger plates and measure exactly between the hangers. Cut a length of 2” pipe to fit between, tap in place and tack weld the pipe in place. I used a sheet metal shield so the weld flash would not melt the camper plastic in the area. Then remove the pipe and end flanges and full weld it out.


And here it is on the camper


The front axle


The rear axle


And from a while ago the equalizer center hanger.








So now my suspension upgrade is complete. In my case, I plan on keeping this camper a real long time so the upgrade is worth it for me. Plus being able to do the work myself helps offset the costs and is very therapeutic at the same time.

Hope this helps someone in the future

John
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Old 02-01-2011, 03:14 AM   #2
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John,

Great write-up, as always. I think everyone with a TT that is up there in weight should be looking at this very closely. I suspect there are a lot of bent hangers out there. I will be checking ours when we can get to it. (It's in covered storage with several feet of hard packed snow & ice blocking a very long driveway.)

I did notice something in one of the pics that I wanted to ask about. (Not trying to hijack the thread, but curiosity knocks... ) What is the galv pipe and wood thingie bolted to the frame? I can not figure out what it does.

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Old 02-01-2011, 10:23 AM   #3
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Quote:
Originally Posted by Steve Collins View Post

I did notice something in one of the pics that I wanted to ask about. (Not trying to hijack the thread, but curiosity knocks... ) What is the galv pipe and wood thingie bolted to the frame? I can not figure out what it does.

Steve, Thanks for the good words on the hangers.

OK I'll help settle your curiosity.... We all take “something” away from pics!

I have enclosed tanks. Most TT manufactures that have enclosed underbellies use what is called Coroplast or something just like it. http://www.coroplast.com/ It is basically plastic cardboard. It can handle the wet, is light in weight and most of all for the RV world, cheap…. They screw it on as the bottom underbelly cover over the tanks. When new it looks nice and is pretty stiff and flat across the bottom of the TT. In time and if you take the cover off a few time it tends to turn limp and sags in the middle. Then it starts yanking on the sheet metal screws.

So an option to offset the sag is to put left to right supports across to hold it up. As I was walking the halls of Lowes trying to find the right shape and did not cost an arm and a leg I came up with.

1/2" x 1 1/4” wide clear pressure treated wood strips 8 feet long. This creates a wide foot print to support the Coroplast. These stripes where surprisingly cheap. I think ~ $3.50. I did have to sort thru the pile to find straight ones…. But that is SOP at the lumber yard now a days.

3/4 EMT conduit 10 feet long. It is galvanized, light in weight and strong enough to hold what I wanted it to do. And it was cheap. Like ~ $2.00 a stick.

Then I used stainless steel hose clamps, 3 of them, to hold the flat and tube shape together and then using 1/4" bolts on each end, bolted it across the frame.

This summer I have planned to de-rust the entire TT frame and paint it before the rust gets any worse. I’m already 2 years over due where I wanted to be on the paint job. I will then paint those strips so they do not look so bad.

The sag fix is not as elegant as I wanted but it was as cheap as I could get from the local Big Box stores. Ideally I would of had a small piece of 1” or 1 1/2” thin channel iron but getting to the other side of town to order and buy it from one of our local fab shops takes time plus the gas to go get it.

So that’s what they are.

John
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Prior Sunlines: 2004 T2499 - Fern Blue
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Old 02-01-2011, 07:37 PM   #4
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Thanks! I had a suspicion that it might have been to support the enclosure, but thought to myself, "Nah, has to be something more than that." Nicely done, and inexpensive, too.
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