Adding Schock Absorbers - Sunline SR model

[JohnB]

Today it warmed up to 58! Last week it was 15…. So I took advantage of the opportunity to get a long awaited mod on the camper. Well 1/2 of it anyway. It is to add shocks to the camper. On this long camper the frame oscillation after a bump is something that just does not sit well with me seeing it in the rear view mirror.

The shocks are Monroe Magum gas shocks. Monroe Gas-Magnum Provides Mid to Full Size Pick-up Trucks and Vans with Firm Control Without a Harsh Ride These are a step up from the normal RV shocks. Monroe also seems to have stopped making the TT mounting kits so I ended up making my own.

So here it is in pics.

Here is where this started now almost 2 years ago… This was how and where to mount them. I have enclosed tanks and that creates an opportunity on the front axle....

This is one mocked up on the inside of the frame


And this is one mocked up on the outside of the frame between tire and frame.




For the rear axle is was pretty clear the shock would go on the inside of the frame. I made the lower brackets when I was installing new axles back in March of 09. A piece of pipe welded on the lower spring clamp plate. Since I had them all apart then I did that part at the same time.






Now to the top brackets I just made. Here they are with a fit up check before welding the parts together.




A check on the TT to make sure it would fit right. And yes it worked like I had planed


Here is the rear axle now all mounted. The shock on the bracket




The first easy side. The door side








Now the slide side. Here I had to contend with the square drive shaft that works the slide rack and pinion extensions. This was still easier then dealing with the tire side of the frame.






And here is all you see from the tire side. Just the nuts of the mounting bolts.


So that is the rear axle. My plan on how I was going to do this on the front axle ran into a snafu. These longer shocks would have to go between the tire and the frame as the tank compartment creates even more issues mounting them on the inside. This just is not going to work the way I had originally planned it. The lower part of the shock “might” hit the frame if the suspension ever rose up real high like going over a large object to lift the camper by one tire or the rear tire falling in a pot hole only hanging by the front. So I studied it some more and now need to order 2 shorter shocks for the front axle. I still have plenty of working stroke on the shock as the rear ones are really long just to get them to mount up high.

So this is all for now. Be back once I get the front axle done. For any one without enclosed tanks this would be a lot more straight forward on the front axle just like I did on the rear.

Hope this helps someone contemplating this on a slide camper or even non slide camper.

John

[EMD_Driver]

Nice write-up and awesome design John!

If you think it might help, I can snap some pics of how our shocks came from the factory. We also have enclosed tanks, on the 311SR...

[JohnB]

Hi Gary

Thanks for the kind comments

Pic's of your Sunline. YES!!! We like pics.... See if Sunline did it any different.

Here are some pics of other brands I took during my research. Both of these brands have enclosed tanks

This is Aritic Fox. They have more room between frame and tire




And this brand. I forgot which brand this it. I looked at so many....






As you can see they mount them at somewhat of an extreme angle and almost tucked in the well of the tire. I really do not know what that extreme angle means. I called Monroe and asked about which way the shocks should point. Mount in the center by the Equalizer or on the outer ends by the end spring hanger. Well he said they both work. I asked which is better if I had to choose. He said the outer spring hanger. Monroe shows them mounting more vertical. Like on a car or truck.

Sort of like this off of the Shockwarehouse site





My intuition tells me more straight up is better but most TT's or 5ers I have seen are on that extreme angle. So it must work.

Thanks

John

[EMD_Driver]

Originally Posted by JohnB

My intuition tells me more straight up is better but most TT's or 5ers I have seen are on that extreme angle. So it must work.

Thanks

John

I know ours are on an angle, but it's nowhere near as extreme as the ones you pictured.



You can almost make out the angle of the rear slide-side shock in this pic. Sorry, but it's all I have right now.. Stay tuned!

[ihsolutions]

One thing I can tell you, is that I would mount them closer to vertical than horizontal where possible. Heartland, the mfr of my SOB, mounts them at an extreme horizontal which is effectively useless and causes the bottom of the piston to bend when you hit a bump. Replacing the shocks yields the same result after you've taken it down the road a bit. To be fair, this is a Lippert issue, not a Heartland issue, but it annoys the same, regardless.

John, it looks like you've chosen a good angle to work with and I do not expect you will have the same problems I have based on the pictures you've provided.

Jeff

[matti]

Great Photos John!!! I am making a list of things such as adding shocks etc. to be done as soon as it warms up here in NJ. Have a blessed New Year

[JohnB]

Jeff, thanks for passing on that info. Good to know and yes I can see that happening now that you mention it. Some where..... in my pile of pics I do have a Heartland 5'er that I was looking at how they did shocks. I'll have to go back and see if I can figure out which one that is. Part of this deals with the slide system too as you can see in this one pic who's ever brand this was they had to contend with the slide square drive.



However realizing the problem you have found there is always a way out of it especially when the camper is being built/designed. Key is know there is an issue on the way in. In my case if the frame was sucked in 1/2" I could put the shock between the wheel and frame on the front. But then again my Monroe shocks are little bigger then the standard RV shocks like shown in the pics on the other campers. The Monroe Magnum's are 1 3/8" bore piston and 2" reserve tube with the dust shield being around 2 1/8" ish. I wanted the better shock so I knew I had to deal with the larger size.

Thanks for the info. I'll keep that in mind for sure.


Gary.

If you are out there taking pics..... can you level the camper frame and then find me an angle from vertical or horizontal of what you have? Since yours is field tested I at least know that amount of angle works. A protractor square head, angle finder what ever you have. OR just give me the X and Y measurements straight up, and straight across part of the triangle the so called shock pivot points are and I can back into the angles. If I lost you in the words.... let me know I'll post a sketch.

I also see your spring hangers are made in a way that are more supportive then the standard TT hangers.

Thanks

John

[JohnB]

Originally Posted by matti

Great Photos John!!! I am making a list of things such as adding shocks etc. to be done as soon as it warms up here in NJ. Have a blessed New Year

Hi Matt

Yours should be easier due to not having the enclosed tanks, I think.... Don't know what you have to contend with as your slide drive is more centered over the axles.

Dexter makes a shock kit. See here. Dexter Axle - Trailer Axles and Running Gear Components - Shock Kit May be able to take those part numbers and search them on the web for a cheaper price but it is a starting place. They have weld on top brackets as that is the cheapest however you can make bolt on ones if you do not have access to a welder.

ClarkLDC here on the SOC, Larry put shocks on his T2499 this past summer. I peaked quick under his camper at the Western M & G. I asked, how are they? I remember him saying, 1 bounce that is it. The shocks smooth out the continued oscillations.

Good luck

Thanks

John

[Trailblazer]

As always, Great pics and a Great write up!

Looks good so far. Our trailer is off at a storage lot right now. If you want the next time I go to visit it, I can also try and snap some pictures so you can see how ours are installed.

[EMD_Driver]

Originally Posted by JohnB

Gary.

If you are out there taking pics..... can you level the camper frame and then find me an angle from vertical or horizontal of what you have? Since yours is field tested I at least know that amount of angle works. A protractor square head, angle finder what ever you have. OR just give me the X and Y measurements straight up, and straight across part of the triangle the so called shock pivot points are and I can back into the angles. If I lost you in the words.... let me know I'll post a sketch.

I also see your spring hangers are made in a way that are more supportive then the standard TT hangers.

Thanks

John

Hi John,
I took the pictures, before reading this post. It's too dark now to get your angles, not to mention the rain. If it weren't for that, I'd be happy to get you some angles. Please don't worry about "Losing me in the words" If I don't already know what you're talking about, it means I need to learn something new(To me)!

I took several pics and uploaded them to photobucket in their original size. That way, you might be able to get as much detail as you need.

Here's a pic of the slide side. You can see that the shocks are mounted on the outside of the frame. I like the way they used tie plates, for the lower shock mounts. They pretty much determine the angle, that the shocks have to be mounted at.


Front shock, slide side:


Rear shock, slide side:


The tie plates have shock mounting holes on both sides. I like the way they mounted the shocks towards each other at the top. That configuration seems as if it would work the best, with the equalizers.


When they mounted the axles to the frame, they used square steel tubing between the frame and spring hangers. The upper shock mounts are welded to that square steel. Also, there is a steel plate, welded inside all the spring hangers. The combination of the steel plates and the square steel tubes, leads me to believe that the load and various stresses are all more evenly transferred to the frame. The T-320SR and the T-299SR both had the spring hangers welded directly to the frame. The fifth wheel has one large connection to the frame on each side, instead of three small connections.




If you would like to view the pictures not posted in this thread, HERE is a link to the photobucket album. If you need anymore information/pictures, please let me know.

Gary

.

[JohnB]

Gary

Thank you very much for doing the "pit" crawl just for me. The pics help. I'm crunching numbers right now on a method I 1/2 figured out today. Need to take one more measurement on Sunday and will report back.

Something that stands out on the Sunlines. So far I have not found one from the factory where the axle is on top of the spring pack. There may be but it does not seem common. Even the heavy campers have the spring on the bottom of the axle. I know folks like to do axle flips to gain more drag clearance however there is another up side to having the axle on the top of the spring pack. Installing shocks. By having the attach point on the bottom it is easier to not have to go up the frame as high or the angle so horizontal to get the shock in.

Look here. The Arctic Fox. Axle on top shock has to go way up the frame. Also note the shock is on the non equalizer side of the axle and pointing in towards the center??


Sunline, axle on the bottom. You can get the shock length and not have to go up the frame so high. In this case Sunline set them up to be on the equalizer side of the axle and point in towards the equalizer.


Be back soon. So far pending brand I think I have found the shocks on both sides of the axle and pointing both ways. Obviously all methods are used.

Thanks

John

[JohnB]

Originally Posted by Trailblazer

As always, Great pics and a Great write up!

Looks good so far. Our trailer is off at a storage lot right now. If you want the next time I go to visit it, I can also try and snap some pictures so you can see how ours are installed.

Thanks Bill. Out of curiosity just see if yours are mounted like Gary and Kitty's. If different then taking some pics help solve some of the curiosity.

John

[Trailblazer]

Originally Posted by JohnB

Thanks Bill. Out of curiosity just see if yours are mounted like Gary and Kitty's. If different then taking some pics help solve some of the curiosity.

John

I was at the trailer today and took a look at how the shocks were installed on our unit. Ours are mounted exactly the same as Gary and Kitty's

[JohnB]

I think I have sorted out my front shocks. With the info from Jeff and Gary I worked out a fairly easy solution to over come the obstacles. So tonight I’m ordering 2 shorter length shocks.

Here is how I came up with this. The rear shocks I ordered long on purpose. They have 7 1/2” stroke that I split equal for up and down travel. Now I know there is no way I will ever use that much but I needed the longer shock to get the mounting pin up higher out of the way. That worked good on the rear shock.

The front shocks, well with the enclosed tank compartment and not enough room between tire and frame, I’m onto plan C. .... Basically I had to figure out the total travel and back into what standard size shocks they offer and on what angle to mount it.

See here last year. This is total travel of the equalizer. This was a test to see if I had fender clearance when I went for a rigid Al-Ko equalizer to the Dexter EZ flex. The dimensions of those 2 equalizers are different so I needed to test I was not going to bottom out in the fender well. You can see the tire on the left is full up and the one on the right has air under it. This position kissed the fender well. So when I installed my new axles I lowered the equalizer 1 1/4" to gain back 5/8" fender clearance.


Now fast forward to today. I mocked up the equalizer position to see how far down the front axle will go short of having shackle flop and added some safety margin to this distance. Shackle flop occurs when you jack up the camper and the shackle goes over center and flops down. I have never seen this occur when towing. By looking at Gary’s shocks and every other factory RV shock I have seen they are short stroke shocks. And it seems they worry more about the tires lifting then dropping.



So now knowing where full up is and full down I can sort out how to mount the front shocks that will not bottom out and cover all the bases. See here for the static position of the area I have to work with.


I felt I needed to keep the same angle on the front shock as I have on the rear shocks so the shock dampening rate would be equal per inch of axle movement. This came out to be 14 degrees from vertical. See here a mocked up shock in location on the inboard side. And this way I do not have the issues Jeff reported.


It was always my intention to lower the front and rear spring pivot bolts as well by 1 1/4" to match the new center equalizer. I even have the parts all made up just never made it to mounting them. This will gain me 5/8” more tire to fender clearance to having a little over 2 1/2". And this extra 1 1/4" helped make the whole shock thing just fit to a standard size shock of the same series I have on the rear. So here it is mocked up.


If anyone sees something that may be an issue, let me know. Very open to listening. It may be a while before I can get to this with work and the weather. Maybe next weekend we can sneak out camping. Snow now all gone. Yeh!!!!

Thanks

John