Sumo Rear Bump Stops

Improving the Rear Suspension 

I am very happy with the front Sumo Springs I installed so I decided to add rear Sumo Springs to my Jayco 26Y.

I got the versions that fit an E450 rear.

I got them from Etrailer:  https://www.etrailer.com/p-SSR-130-47.html

You can also get them from Amazon: https://amzn.to/3SwLFtN

This installation was done on a Jayco 26Y with HELLWIG helper springs. I was concerned that they might interfere with the springs but they do not.

All in all the installation took me about 2 hrs. With ratcheting wrenches, this would have probably taken only 1 hr.

What is in the box

The springs arrived in about 11/2 weeks packaged well in a box. The instructions can be found here: https://www.superspringsinternational.com/instructions/SSR-130-47.pdf

The instructions were simple enough but were incomplete in these ways:

• The instructions show two holes in the mounting bracket when in fact there are 4. I used the rear hole inboard of the mounting bolt.
• The ETrailer video I watched showed a left and right version. These were not marked as such and were identical.
• I was not sure whether to use the spacer or not. There are no instructions on how to tell or why to use them.

Tools

I highly advise investing in a set of ratcheting metric box wrenches. I did it with one 9/16 ratcheting box wrench (works for 14mm) and one 15mm box wrench as I have no metric ratcheting box wrenches.

The spring mounting screw is to be torqued to 20ft-lbs but I did not have a torque wrench small enough to fit in the available space so I just guessed.

I did not use the spacers and associated bolts.

Tools, removed and unused parts

Fasteners

• 15mm for the stock bump stops
• 14mm for the Sumo mounting

Preparation

One video suggested using the hydraulic lifts to jack the RV up. I decided it would be easier to use a floor jack positioned under the hydraulic jacks. Jack stands were placed as a safety measure but the RV has plenty of clearance if it were to release from the jack and I was underneath. I jacked the frame up until it took the weight off the tires. This left about a 6 1/2" clearance between the frame and the axle.

Use the Spacer or Not

Since there were no instructions on when and why to use a spacer I decided to measure the gap between the frame and the axle before lifting the RV. From this measurement, I could get an idea of how much additional pressure the spacer would create. The resting position leaves the frame about 6 1/2" above the axle. The total height of the Sumo spring was approximately 7". I decided to leave the spacers out since there would be about 1" of compression. I guessed I would not need 2" of compression. I am guessing that adding them would make an even stiffer ride. I am not trying to stiffen up the ride but reduce the rear sway. Only testing will tell if this is the right decision. If I had to add the spacers it would only require jacking up the RV and removing/replacing two bolts.

The spacer would add about 1" of additional compression.

Passenger Side Install

Remove the stock bump stop

The 15mm nut for the stock bump stop is on top of the arced section of the frame. The exhaust pipe leaves just enough room to get a box wrench onto the nut. This is where a ratcheting box wrench would speed up the installation.

15mm box wrench at 1/2 rotation per turn takes a while to remove

A smaller rachet helps but a 15mm deep socket is needed

Used this after the box wrench loosened the nut enough to get a standard socket on it.

Adding the Sumo bracket

After removing the stock stop, insert the Sumo brackets bolt up through the stock bumps hole and add the nut and washer on the top of the frame. 

Add the Sumo Spring

Insert the spring mounting bolt into the correct hole. The rear hole inboard of the frame. Then lift the spring up and mate it to the bracket. It is a little challenging to get the bolt aligned with the threaded hole in the spring and get it started. The curvature of the bracket is the same size as the perimeter of the spring when aligned. Move the spring until it is aligned with the bracket and the bolt should screw into the spring. 

Overhead view of the bracket mounting nut and spring holding bolt

Tighten the 14mm bolt on top of the spring bracket

Completing the Passenger Side Installation

Check that the bracket mounting bolt is tight.

Then torque the spring mounting bolt to 20 ft-lbs. I did not have a torque wrench that would fit into that space so I guessed. 2 grunts is about 20 lbs :). One set of instructions suggested the use of a crows foot and a small torque wrench.

Position before the jack is released.

Fully Loaded Position

Driver Side Installation

The driver-side installation uses the same steps but has easier access because there is no muffler pipe in the way. You do have to contend with a brake line bracket that is positioned under the bump stop mounting bolt. Jack up the frame and start the driver-side install.

Removing the stock bump stop with a 15 mm box wrench

Final turns with a 15 mm socket. Note the brake line bracket. 

Installing the Sumo bracket with the brake line bracket in place using a 9/16 ratchet. Don't forget the washer! 

Aligning and fastening (20 ft-lbs) the Sumo spring with the short 14mm bolt

Completed installation prior to letting down the jack

Fully loaded spring

Final Checks

• Ensure that on the passenger and driver sides, the 14 mm bracket and Sumo spring nuts and bolts are tight
• Ensure that the installation does not hamper or pinch on any wires, cable, or tubing under the RV.

While under the RV I always look for ways to better secure tubing and cables with tie-wraps.

In Conclusion

The installation was simple and easy to complete. Ratcheting box wrenches (14 & 15 mm) would have made the job a lot easier but standard tools did work. The instructions were missing some useful information regarding the mounting holes and spacer use. I will follow up this post with a report on how well the RV rides with this upgrade after the next few trips.

Enjoy and comment,

Don