Adjusting the PH springs

[van.on.the.run]

I just made this modification myself and it was pretty straightforward. Thanks for the tips here!

One thing of note, however. There weren't any "helper" springs. At least not where I expected to find them. I thought I would find them in the channel towards the back between the sliding, pinned scissoring frame end and the back of the channel. Instead there was just empty space with a ~2-2.5" hole at the back of the channel. It made it very easy to hook a come-along up to it, but I'm wondering why I don't have helper springs? This was the same condition on both sides.

My van is a 2015 MB Sportsmobile. Installed by SMB Austin, TX. Is this something that they mistakenly left out?

Is there a spring spec for something I could buy to install myself before I screw the upholstery back into place?

Thanks in advance!

[86Scotty]

I would call them! Weird that it's a newish van without them unless they've changed the design. Funny, I've never heard anyone here speak of such. Is the top REALLY hard to start when raising it? That's where the name comes from. I can't find a pic of any right now.

[van.on.the.run]

Well, I'm not sure what "really hard" would mean. I would say I have to apply about 100# of force to push it up. Is that normal? I'll send them an email, thanks for the opinion!

[van.on.the.run]

I used a scale to estimate the force I'm applying to lift the roof. It's about 150 lbs.

That's after shortening the spring tension by two links on each side. In addition to the penthouse, I have a small 53"x 58" rack made from 80/20 aluminum and two Grape Solar 180w panels. If I remember correctly the rack weighs about 18 pounds and the two panels weigh about 50 pounds together.

I contacted sportsmobile TX and they said that they have "found success without having to install helper springs in sprinter van manual penthouses"..... I don't know what that means, it seems like there's room for a spring... why not help a brotha out?

So I'm going to make a helper spring system of my own while everything is still exposed.

If anybody has any dimensions, specs on their helper springs as a starting point, I'd appreciate if they share. Thanks!

[campIV]

Originally Posted by larrie

In preparation for installing two solar panels I adjusted the penthouse springs. Here is the proceedure I used --> http://vimeo.com/61317178

Thank you for the clear, concise video. It makes what I thought a daunting project much more straightforward.

I've added two 100 watt Renogy solar panels totalling about 38 pounds including the mounting hardware and wiring. The top is definitely harder to raise and won't stay fully up after. I made corner braces from 3/4" emt conduit with white rubber table leg caps on each end to support the roof in the raised position. While these work great once the roof is up, they obviously don't help get it to that position.

I'll be tackling this soon and will report back once I'm done. Thanks again!

[boywonder]

I've been developing a gas spring alternative for the helper springs to get the manual top to raise and lower easier.


There are lots of gory details but we'll start out simple. The first attempt was to just throw a 40 lb gas spring inside the helper springs to give more "assist"....


This resulted in an additional 80 lbs (extra 40 lb gas spring per side) of force when you begin lowering the top.....that was a lot.....and at the end of the travel when the roof is almost down the extra 80+ lbs of force didn't do much.


My helper springs are about 23" long and have a spring rate of 12 lbs/in which I measured with a bathroom scale and a tape measure.


...and the crossbar slides around 10" in the track from full up to full down. My actual travel is more like 9".


I don't have any pics of the first attempt; the next attempt was to use two gas springs in series..... a long 7" travel 15 lb spring and a short 3" travel 80 lb spring inside the helper springs.
















Keeping the math simple this should start off around 15 lbs when the top is up and end about 80+120 lbs =200 lbs when the top is down. This worked better, but not what I was hoping for. The extra 15 lbs each side when the top is up is fine but 200 lbs or so when the top is down is still not nearly enough.


The stainless thumb nuts and the coupling nut were all purchased from McMaster-carr as well as the delrin tubing.

[BUFFALO]

Great idea! Thanks for sharing it and the results.
My helper springs are sooo much shorter. May have to try something similar.

[BUFFALO]

How far does your top need to be pushed up until the main springs take over?

[BroncoHauler]

Awesome effort BoyWonder.


Herb

[boywonder]

Originally Posted by BUFFALO

My helper springs are sooo much shorter

If your helper springs are shorter, that means that they have a higher spring rate than mine, which is a good thing. A higher spring rate means that the spring load will be higher at the end of the crossbar travel.


Try putting spacer blocks behind the springs to move them closer to the crossbars. Two caveats here:

If your crossbars are not sleeved, not sure how much spring load you can add before they start to bend.

If the springs bottom before the roof comes all the way down, you'll know it, and will have to shorten your blocks.

Originally Posted by BUFFALO

How far does your top need to be pushed up until the main springs take over?

The main extension springs are always acting on the crossbars. In my case, I've gone 4 chain links shorter on them. They have a spring rate of around 10 lbs/inch and in my setup they are putting about 400lbs on the crossbar when the roof is down and about 300lbs when it's up (based on 10" of crossbar travel).

Originally Posted by BroncoHauler

Awesome effort BoyWonder.
Herb

Thanks Herb...more to come.