Scotty, I have been in your position a few years ago as I own 2 airlift
doors from 1996. I have successfully rebuilt both of my glides after numerous people and the airlift company telling me they have proprietary parts within it and cannot be fixed unless sent back to Airlift. The answer is, be nice to your local hydraulic shop. A hydraulic shop builds rams and repairs them on a daily basis for heavy construction equipment. After letting them inspect the carriage and sealed pipe, they were not phased by repairing it and told me there isn't anything within this pipe we will find we cant have made or make ourselves. The first one I paid for an expedited repair by them where everything was overnighted and was ready for me the following day in the middle of February. $500 for parts and labor, $300 to jump to the front of the line. $800 total bill for the broken one, the other I had repaired voluntarily in the summer and gave them time, that was $450 to have done. I have had no issues what-so-ever.
Tip* if you must get those
doors to work while the weather gets cold, pour transmission fluid into the air line going into the sealed pipe. The fluid will compenstate for the bad seal. The
door will open and close for aehile before all the fluid passes to the other side of the glide and will stop working again. Its a very temporary fix however it does work very well. No damage other than having to drain the excess fluid as it comes out the other other airline and goes to the airlift box. The residue of the fluid left in the line after the rebuild ensures the seals are lubricated lightly.
Good luck
-SG