Lippert 281281 Shock Kit Install

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Actually..............I installed only the shocks that came with the kit using brackets I custom designed and fabricated for our Passport 23RB. In a previous post, I shared my disappointment with the kit and the need for custom mounting brackets: http://www.keystonerv.org/forums/sho...ock#post209633

I originally thought I would wait for the end of the season before doing the install, but I had the parts made this past week and the weather was perfect for the 11 hour install today.

The brackets that come with the kit are the two on the left, the parts I designed/fabricated (with some help from those with better welding skills than I have) are on the right. The new parts consist of a spring bracket with holes for mounting the lower shock stud, a top shock mount and a nut plate to reinforce the TT frame and mount the top shock bracket.



My frame is from BAL with a cross section shaped like a "Z" and is 11 gage (.12 inch) thick. I was not comfortable using the 3/8 self tapping screws to anchor the top shock bracket to the frame, so I made a nut plate that meant I needed to access the covered side of the underbelly. More on how I achieved access in Part 2.

The first step was to replace the factory top spring plate with a new plate that the bottom of the shock would mount to. To reduce the axle spring load, I raised the front of the trailer and replaced the spring plates on both sides of the front axle. I then lowered the front of the trailer, and replaced the spring plates on the rear axle.

Factory spring plate:



New wider spring bracket to mount the bottom of the shock:

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Part 2:

Preparation for mounting the top shock brackets consisted of loading the trailer with water and other items as if on the road. The trailer was then levelled front to back so both ends of the equalizer on the side I was working on was the same distance from the bottom of the frame. I also measured the distance from the bottom of the axles near the hub before raising the wheels to remove them. With the wheels removed on one side of the trailer, I lowered and blocked the axles to the height measured previously (as if it were on the wheels).

To gain access, I cut the underbelly material at 45 degrees in the areas I needed access and then bent the under belly material at 90 degrees to the cut. This gave me a triangular access hole that was easy to close up later with tie wraps. The curb side was more time consuming, since the propane black pipe had to be lowered.



To position the top shock bracket to the frame, I used a 1/2 inch threaded rod that extended 13 inches from the top bracket (to simulate the normal ride length of the shock) down to the shock mount hole in the new spring bracket.

The top plate was then clamped to the frame and the hole locations were marked onto the frame using a transfer punch. Then I step drilled the holes in the frame (this was the most time consuming part of the install) making sure I did not hit any wires or heating duct by using a short piece of swimming noodle foam to hold the wires and ducting away from the inside of the frame where I was drilling.

After drilling the holes in the frame , I positioned the nut plate on the inside of the frame and bolted the upper bracket to the frame/nut plate. Before torquing the mounting bolts, I adjusted the bracket so the threaded rod was aligned with the spring plate shock mount hole.



After removing the threaded rod, with the shock vertical, I cycled the shock ~5 times to purge any air before installing it onto the brackets with the supplied rubber bushings. Once the stud nut was tightened until the bushing was the same diameter as the washers, I added a second nut to act as a jam nut.



I repeated this procedure for the other three shocks.

The shocks are mounted at ~52 degrees which results in ~80% shock efficiency:

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Part 3:

With nearly 4 inches of clearance between the frame and the tire, I was able to achieve 1 inch of clearance between the shock body and the tire. Whereas I was able to achieve just under 3/4 inches of clearance between the upper shock mount bracket and the shock body.



I closed the openings with tie wraps:




If the weather cooperates next weekend, the shocks will get their first field test over some rough roads and many miles of evenly spaced concrete joints. I hope the install was worth all the effort and cost.


BTW: For those lucky enough that the supplied brackets work on their TT, here are the installation instructions from Lippert since none come with the kit: https://www.lci1.com/assets/content/...ion_Manual.pdf BUT note that IMO, 4 inches not 2.5 inches of frame to tire clearance as stated in the manual is required between the frame and tire for adequate clearance.

[jsmith948]

Nice job - thanks for the detailed and well-thought-out post. The pictures provided are spot on. Something on my list of future mods/upgrades.

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Put on about 240 miles yesterday on some very rough roads. Did the shocks make a difference? Yes they did. Was it a night and day difference? No it was not, but enough for the DW to think it was an improvement.

I was able to travel at 65 mph over evenly spaced concrete joints whereas in the past I would drop down to 55 mph to make it somewhat comfortable over the same stretch of highway. Not silky smooth, but better than before.

The biggest improvement seems to be on the larger bumps where in the past the trailer tongue would want to rise and fall a few times before settling down. We feel the bump once now with the shocks.

Was it worth the time and cost?
For us yes, since we make a cross country trip once a summer. Probably not worth it for weekend warriors who's trips are not much more than a few hundred miles on weekends.

I crawled under the trailer today with a torque wrench and checked all the u-bolt and shock mount fasteners. A few were off by a few ft-lbs. and there was no evidence of the shocks contacting the tires. So the setup should hold up with time.


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Update:

Crawled under to check the torque in all the fasteners last week. All were at the desired torque, but I did notice that the bushings on the stud mounts allowed some movement before the shocks would be loaded/move. So I tightened the mounting nuts to compress the bushings more.

Canadian Tire had a sale on shocks last week. I had no plans on buying new shocks for the TV, but could not resist the temptation. Ended up buying adjustable Rancho 9000XLs for all four corners of the TV which I had on the rear of my previous F150. Turns out that with only 15,000 miles on the TV's OEM shocks, three of the four no longer were pressurized and would not extend on their own.

After some trials on a rough stretch of highway without the TT connected, I decided on a 3 setting on the front and 5 on the rear shocks. 3 and 3 was best without the TT connected but went to 5 on the rear for towing.

Towed out to a campground last evening and the ride over the rough highway was noticeably better than any previous experience.

The TV rides much better with and without the TT now and the TT is well behaved even on the roughest stretches. So mission accomplished.

I may replace the TT rubber shock bushings with polyurethane bushings next spring.


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Another update:

I purchased urethane bushings that I will install next spring.

While researching shocks for a friend who I passed on the Lippert kit's brackets to, I came across the Monroe Magnum RV Gas shock PN 555025 which looks like a direct replacement for the Lippert shock that comes in the Lippert kit. So if anyone is installing shocks with their own fabricated brackets, you may want to consider the Monroe Magnum shocks.