I can't claim to be familiar with the Carter Super Shade Mark IV awning system that you have, but I had similar experiences with the A & E Travel Awn 5,000 that was on my Overlander when I purchased it nearly 8 years ago. I was determined to maintain the original equipment awning on the trailer since it had been there ever since I first met the trailer in 1964
. After spending more than 1/2 the price of a new Zip Dee awning in repairs on the Travel Awn 5,000, I finally gave up and replaced the awninng with a new Zip Dee - - ended up splurging on window awnings for the bedroom and bathroom of my coach as well. The Zip Dee operates more smoothly and is much more attractive in its closed position than the A & E. The choice was even easier when the A & E rep told me that the only parts of my awning that would still be supported via new parts would be the roller tube assembly and awning fabric.
While it may be difficult to give up on the original equipment awning, it may be financially prudent as it doesn't take too long to invest a great deal in repairs before you know what is happening. The Zip Dee is an extremely high quality unit, and the three (main curbside, rear bathroom, and streetside bedroom) awnings were less than $2,700. installed - - my dealer called Zip Dee to get the precise instructions for measuring the awnings prior to ordering to be sure that he ordered the precise size with the proper hardware.
Good luck with your decision!