Air Spring Install

A while ago we were really nervous that we were going to be over the weight ratings for our RV but then we found a solution. In order to meet the manufacturer’s weight ratings, we needed to have a transmission cooler and we needed to upgrade the springs. In that post I said, “If I can do all the parts (including installation) for less than $1000 I’ll be a very happy camper.” Fortunately we spent about a quarter of that amount so I’m a very, very happy camper.

First off was the transmission cooler. With that 1989 Minnie Winnie sales brochure I found recently, I learned that Daisy comes with a transmission cooler already installed from the factory and, low and behold, a close inspection of the grill did prove that it is still there! First problem solved!!!

Next was the suspension, that one wasn’t so easy. The more I poked around at the existing springs the more convinced I became that they had sagged quite a bit in addition to us needing an upgrade. So I knew we needed some pretty heavy equipment for this job but I knew next to nothing about automotive suspensions (this is the first vehicle I’ve ever even had with leaf springs). It was time to start researching.

Cue the Internet Research Montage! (heads up: language)

Ok, now what have we learned? There are apparently three different systems for after-market improvements for leaf spring suspension systems.

Option 1 – Replacement Jounce Bumpers


Jounce (my new favorite onomatopoeia) bumpers act as a bumper between the axle and the frame of your car to protect your car when you bottom out. Normally they are small and very dense and just act like the protection of last resort. A couple companies (Timbren and Sumo Springs were two I looked at) make replacement jounce bumpers that are much larger and much more squishy. They are very easy to install (undo one or two bolts, replace bumper, put bolts back in), are maintenance free and make no extra noise. Basically they just start pushing back on the axle long before the standard jounce bumper would and thus are able to spread the impact over a longer distance.

The biggest problem is that they aren’t designed to work with old suspensions that are sagging as they’ll end up under pressure all of the time. So that brings us to option 2:

Option 2 – Helper Springs

super springs

Helper springs are basically and additional strip of metal that you add to your leaf springs to make them stiffer under load (i.e. when towing) or to somewhat restore old sagging springs. They are fairly easy to install and require no maintenance. This sounds like a pretty good fit for Daisy but it turns out we can do better.

Basically, both jounce bumpers and helper springs aren’t adjustable for different loads. With the RV, our load will go up and down by close to a thousand pounds depending on how much water, waste and fuel we have on board and whether or not we’re towing the car. That’s 10-15% from one day to the next. Think about how your car handles with 5 people on board compared to just you driving it. With better jounce bumpers or helper springs we can optimize for fully loaded but then it would feel like sitting in the back of an empty school bus going over speed bumps when we’re not loaded, or we can optimize for not loaded and bottom out all the time when we are loaded. So that brings us to option 3.

Option 3 – Air Springs

Most people have seen air springs before but probably not for hauling. Those modded cars that bounce, those are air springs in action.

We installed the air springs so that you could tow things or not, not so you could throw air spring raves!

No we won’t bounce the RV (but it would be fun to try like once). Air springs are very similar to jounce bumpers in terms of placement and how they absorb bumps as you move down the road. There are a few differences though.


Air springs are constantly attached to both the frame and the axle which makes them somewhat more difficult to install. Also, they are basically inflatable balloons so you can adjust how much they compress for a given amount of weight, but routing air hoses to them makes them much more difficult to install. When you want to put more load in your vehicle (or you want it to push itself up into the air to bounce it) you add air to the bag which puts more separation between the axle and the frame.

One other side benefit of air springs is we can use them to level the RV when we park on a slant. Rather than needing to break out the blocks of wood or other crazy contraptions to get the rig level, we’ll just need to inflate one side more than the other for side to side, or both together for front to back.

So we decided to go with some massive air springs designed to help with towing. These ones in particular fit our RV nicely. Last weekend we spent all day both days figuring out, first, how to take the tires off the RV (half of the screws holding the hubcaps on were so stripped we had to drill them out, and then, of the 3 jacks that came with the RV, none of them actually worked so I had to buy a new barrel jack) and then how to install the air springs. Have some pictures, you can click on them for the bigger version with captions:

We ended up routing the lines inside the house where we’ll probably hook them up to an air compressor to make it easier to inflate. They sell automatic inflation/deflation systems that allow you to set everything with a few button presses, but that would double the cost of the system. We’ll live with it for a few months and see how it feels manually inflating and deflating.

I will admit that for this job, it was really nice that Allison is little. She was actually able to sit up under the RV where I was always laying on my back. Allison did a great job routing the air lines underneath while I finished attaching the bottom bracket to the axle.

After we got everything put back together (and I bought some new screws for the hub caps) we started playing around with using the air springs to level things out in the driveway. We were able to get around 2-3 inches of play which will definitely help us keep things level when we’re camped out away from RV parks.

Let us know if you have any questions about air springs, I’m now an internet research master!


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