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View Full Version : Rejuvenating gas springs on a camper shell??



winchman
01-02-2009, 11:11 AM
Is there any way to rejuvenate the gas springs on the back glass of my camper shell? There's no play in any of the mechanism, but they won't hold the glass open in cold weather. They're only eight years old.

I was thinking about putting them in a piece of pipe, sealing the ends, and pressurizing it with argon. Would it work? How much pressure would it take to get them back to "new" performance?

Roger

Ian B
01-02-2009, 11:15 AM
Not sure what size & load you need, but would these do:

http://www.surpluscenter.com/item.asp?UID=2009010209122849&item=1-2869&catname=misc

At $3.95 each, it hardly seems worth trying to repressurise the old ones....

Ian

Circlip
01-02-2009, 11:27 AM
A question like this was posed for another reason somewhere and a gas strut manufacturer came back that if you could give them the basic dimensions and application it is usually cheaper to buy direct from them. Cuts out the 20,000% mark up, worth a try.

Regards Ian.

barts
01-02-2009, 02:30 PM
Mine went out after about 10 years; I swung by the place from which I'd bought the shell and they got me the closest match they had in stock - rather stronger, but they work. Price was reasonable IIRC (less than $20 for both).

- Bart

Thruthefence
01-04-2009, 04:54 PM
I tried this years ago, just as you described, black pipe & nitrogen gas @ 500 psig. sat overnight under pressure, & I could not tell any difference after opening it up. Maybe if it sat all week? Probably was lucky it didn't kill me.

saltmine
01-04-2009, 05:14 PM
Gas "lift struts" are common on many cars and trucks today. My own car has them to open the hood and trunk.
It's true, they're pressurized with nitrogen gas, but they are also filled with a form of hydrualic oil. This lubricates the bushings and seals. Unfortunately, as the gas bleeds off, so does the oil. Once a strut gets worn enough to start leaking it's gas and oil, I'd say it was unsalvageable...at least for a reasonable sum of money. As most have mentioned, struts are fairly cheap to replace, so why bother....?

wierdscience
01-04-2009, 06:55 PM
There is nothing in there to fix.Sad,but true,now if you get new ones the chrome rod material and the cylinder tubes are handy stock.Careful relieveing what pressure is left before you cut them though.

The local Autozone has a rack full of new replacements starting at $18 and going up according to length.

Bill736
01-05-2009, 12:01 AM
It's possible that installing a long compression spring or springs over the rod and perhaps over part of the cylinder as well would work. That's more bother than just buying new struts, but it might work in cases where an odd length strut was used, or where a strut with special compression characteristics was needed.

Thruthefence
01-05-2009, 03:39 PM
The strut I attempted to 're-pressurize' was from an aircraft nose baggage door,and very short, maybe 10" fully extended. I had already installed the new one on the aircraft, and had hoped to recycle the old one into a toy box for my daughter, and as I said, failed miserably. My lead man later asked why I had not ordered R/H AND L/H supports, his logic being the other side is probably close to failure..............Well, have any of y'all ever worked for a guy, that always takes the opposite tact from what you have done? I would have gotten the opposing critique, had I ordered both in the first place. ( "that's a waste of money!!! ect") Anyway (sorry about the long post) I was able to fish the other "bad" tho operating strut from the trash, and did indeed add it to the toy box. That was 30 years ago, and now my granddaughter is using the toy box, and the strut is still hanging in there.

winchman
01-05-2009, 05:11 PM
Oh, well. I won't spend time on that, then.

Maybe this will work when the weather is cold:

http://img.photobucket.com/albums/1003/winchman/campershell001.jpg

The price was right. :D

Roger

Duffy
01-05-2009, 06:11 PM
How did you mill the little wooden bits?

Doozer
01-05-2009, 09:42 PM
The company I work for makes gas charged lift struts. New builds are crimped and charged with nitrogen while in the crimping dies. Charge as per application specification. They are filled with either Mobil delvac, Propoline glycol (pink), or food grade hydraulic (taco) oil. The amount also per application spec. Units for stock to be charged at the time of sale are charged in a pressure chamber. The highest pressure is 3200 psi nitrogen. We have a Dewer that evaporates liquid nitrogen, and then we compress the gas nitrogen in a air intensifier compressor and feed a tank farm. I sometimes recharge units from employees cars. It is a 50/50 gamble if a warn unit will take a charge or blow its guts out. We also make GSRs, which are gas spring replacements for aircraft applications. They are 3 times the price, last 5 times as long, and are lighter than a gas spring. They use a coil spring and a hydraulic rate control. No getting away from markup. Units that cost us $2 to make, we sell for $20.

--Doozer

winchman
01-06-2009, 05:12 AM
They're standard wooden clothespins with rubber bands from the newspapers to add clamping force. I did use the bandsaw to make the ends a little narrower to clear the cylinder as it closes.

I use the clothespins for clamps when building model planes. Sometimes I rearrange the parts to get a longer grip.
http://img.photobucket.com/albums/1003/winchman/campershell-1-1.jpg
I also put spacers under the coil of the spring to get a wider grip.

Roger

GKman
01-06-2009, 09:25 AM
Surplus center:
http://www.surpluscenter.com/sort.asp?UID=2009010607211781&catname=&byKeyword=yes&search=gas%20spring

has 4 sizes from $2.00 to $5.00/each.