Cobra Trailer Gas Spring Replacement Tips Requested

[Paul Remde]

Hi,

I think this may be the perfect question for this group.

I own a share of a DG-1000S which we keep in a Cobra trailer with a fiberglass top. It's a large trailer, of course, and the fiberglass top is heavy. The gas springs (one on each side) that help lift the top have died, so I ordered replacements. They have arrived. I've never been through the process of replacing them, so I'm looking for advice.

We'll need to find a way to brace the trailer open - perhaps 2 x 2x4 boards with padding and "V"s cut in one end to keep them from coming off the top.

We'll need a way to remove the old gas springs and compress and connect the new ones.

Any tips?

Thank You in Advance,

Paul Remde

[Mark Mocho]

I've done a bunch of lift strut replacements on Cobra trailers. The absolutely best way to do it safely is to use an overhead hoist or a hangar upper door header and come-along with straps attached to the rear handles. (The handles are plenty strong enough.) Lift the top fully until you can sort of "feel" the struts at their maximum extension. Make sure the front tongue and the rear of the trailer are supported. Use the front jack and the rear side jacks to eliminate any wiggle or vertical play. Use jackstands at the rear if it doesn't have the stabilizer jacks. The protective "hoops" on the sides that prevent rubbing against the wing surfaces needs to be removed at one end. It is generally riveted at one end, while the other end has a self-tapping screw. This screw can either be a Phillips head or in newer trailers, a Torx head. Swing the "hoop" out of the way. The lower end of the gas strut has a "T" nut that holds the lower strut eye on the threaded shaft. It also has a self-tapping screw that prevents it from rotating and coming loose. It's designed for a pin spanner wrench, but a large set of channel lock pliers will do the trick. If it is hard to turn, you don't have the trailer top at the right height and there is force either in compression (top too low) or tension (top too high.) Adjust the hoist to the proper point that frees the "T" nut. Remove the nut. Keep an eye on the nut and retaining screw so you don't lose them. At the top of the lift strut, you have to peel the protective padding back so you can access the bolt that holds the top eye. Remove the bolt, washer(s) and nut. Remember the order they are in so you can reassemble correctly. Pull the strut and the telescoping square tube out of the trailer. Remove the old strut and replace with the new strut. Make sure the eye fittings on the new strut are the same size as the ones on the old strut. (Some struts don't have the right size bolt eye.) If so, swap them with the old ones. Place the new strut into the telescoping tubes and put it in place on the lower threaded shaft. Spin on the "T" nut. Align the upper end into the channel that prevents side loading and insert the upper bolt. You may need to adjust the hoist height to get things to line up. Tighten the upper bolt, washer and nut. Repeat on the other side. Don't forget to insert the self-tapping screw in the lower "T" nut. You will have to align the hole in the nut and the shaft to insert and tighten it. Reattach the padded hoop and push the upper padding in place. Remove the hoist straps and pat yourself on the back.

[Paul Remde]

Hi Mark,

Thanks!!!

Best Regards,

Paul Remde

[Charlie M. (UH & 002 owner/pilot)]

On Monday, May 2, 2022 at 8:42:06 PM UTC-4, Mark Mocho wrote:
> I've done a bunch of lift strut replacements on Cobra trailers. The absolutely best way to do it safely is to use an overhead hoist or a hangar upper door header and come-along with straps attached to the rear handles. (The handles are plenty strong enough.) Lift the top fully until you can sort of "feel" the struts at their maximum extension. Make sure the front tongue and the rear of the trailer are supported. Use the front jack and the rear side jacks to eliminate any wiggle or vertical play. Use jackstands at the rear if it doesn't have the stabilizer jacks. The protective "hoops" on the sides that prevent rubbing against the wing surfaces needs to be removed at one end. It is generally riveted at one end, while the other end has a self-tapping screw. This screw can either be a Phillips head or in newer trailers, a Torx head. Swing the "hoop" out of the way. The lower end of the gas strut has a "T" nut that holds the lower strut eye on the threaded shaft. It also has a self-tapping screw that prevents it from rotating and coming loose. It's designed for a pin spanner wrench, but a large set of channel lock pliers will do the trick. If it is hard to turn, you don't have the trailer top at the right height and there is force either in compression (top too low) or tension (top too high.) Adjust the hoist to the proper point that frees the "T" nut. Remove the nut. Keep an eye on the nut and retaining screw so you don't lose them. At the top of the lift strut, you have to peel the protective padding back so you can access the bolt that holds the top eye. Remove the bolt, washer(s) and nut. Remember the order they are in so you can reassemble correctly. Pull the strut and the telescoping square tube out of the trailer. Remove the old strut and replace with the new strut. Make sure the eye fittings on the new strut are the same size as the ones on the old strut. (Some struts don't have the right size bolt eye.) If so, swap them with the old ones. Place the new strut into the telescoping tubes and put it in place on the lower threaded shaft. Spin on the "T" nut. Align the upper end into the channel that prevents side loading and insert the upper bolt. You may need to adjust the hoist height to get things to line up. Tighten the upper bolt, washer and nut. Repeat on the other side. Don't forget to insert the self-tapping screw in the lower "T" nut. You will have to align the hole in the nut and the shaft to insert and tighten it. Reattach the padded hoop and push the upper padding in place. Remove the hoist straps and pat yourself on the back.

Exactly....just did 1 strut on a ASH-25 trailer at the Perry contest.
We wedged a 2x3 between the trailer bottom (inside the trailer) and the rail in the top. To attach the strut, do the bottom first, install the T nut and then do the top. I kicked the 2x3 back and forth (along the length of the trailer) to align the top bolt.
As to the bottom strap, I could pull it down below the strut.
Have contact cement to reattach the carpet on the square tube.

[Dave Nadler]

I don't have a hoist, so I've used the 2x4 method. A few notes:

1) Make SURE the trailer can't move: Attach to a heavy car, rear jacks
or door jacked against ground.

2) 2x4 into top's channel works great - but square it up at top and then
clamp it to the side of the trailer so it cannot escape. You may need to
adjust the 2x4s (lift more or less) to get the gas springs to slide
off+on the bolts easily.

A helper to lift the top and position the 2x4s really helps. But perhaps
not two helpers ;-)

Have fun and report back,
See ya, Dave

[Mark Mocho]

Bracing the top open with 2x4s does work, but it is quite a bit less safe than using a hoist. If using this method, only remove one strut at a time. Remove the weak strut first and replace it with the new one before proceeding to the second one. If possible, clamp the 2x4 to the side of the trailer and try to fix it somehow to the top rail. If it slides and lets the top fall, you could torque the trailer top enough to crack a 'glass top or permanently twist an aluminum one. And there is also a possibility of crushing your own little pink body. If available, use a hoist. Also, if using the brace-the-top-open method, don't do it outside if it is windy.

[Dave Nadler]

On 5/2/2022 11:13 PM, Mark Mocho wrote:
> Bracing the top open with 2x4s does work, but it is quite a bit less safe than using a hoist. If using this method, only remove one strut at a time. Remove the weak strut first and replace it with the new one before proceeding to the second one. If possible, clamp the 2x4 to the side of the trailer and try to fix it somehow to the top rail. If it slides and lets the top fall, you could torque the trailer top enough to crack a 'glass top or permanently twist an aluminum one. And there is also a possibility of crushing your own little pink body. If available, use a hoist. Also, if using the brace-the-top-open method, don't do it outside if it is windy.

Absolutely, be careful!

[soaringjac]

I replaced mine about 8 months ago. Only one of them was dead which made it easier, but I did replace both struts anyways. I also have smaller trailer. I just propped open the top with 2 2x4s placed at a slight angle. Took the strut bolts out and put the new strut in and replaced the bolts. 30 min job. I did not have to compress the struts for install. I just made sure the top was lifted as high as needed for the new struts to fit uncompressed. Obviously trailers and situations are different, but I found it pretty easy to replace them. Good luck!

[Mark Mocho]

One other note: Make sure both the upper bolt and the lower pivot shaft are inserted through the square tubes AND the gas strut eyes. It is possible to miss the eye without realizing it, and the strut will not be properly secured to the pivots. Ask me how I know this.

[Paul Remde]

Hi Mark and Dave and everyone,

Thank you very much for the excellent tips. We did the strut replacement today. We tied the trailer top up using the rafters in the large hangar. It worked well. Once the trailer was positioned and the top tied up, the strut replacement took about 15 to 30 minutes. Since the top is 2-seat trailer's fiberglass top is quite heavy, we used nylon straps and carabiners and setup a purchase to allow the top to be raised and lowered the inch or two required to compensate for belt and rope stretch. Using boards would work but would make fine adjustment while re-inserting the bolts more difficult.

Thanks!

Paul Remde
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