2001 electra glide classic rear shock length

smaller rim diameter
special made shorter springs ( have to fit shorter shocky)
talk with bike modifiers for more ideas

Yes there is fluid in the lines it's called oil. and if you're running 55psi it's too much. Let the pressure down to 25psi max you will lose a little oil. When was the last time the fork oil was changed?? If never, the rear shocks mybe garbage by now.

what pressure are you running in your rear shocks
check your manual for your psi settings depending on your weight and or passenger weight

I lowered my 06 Street Glide 1 1/4" in the rear, using a bolt on, adjustable lowering kit that I purchased on Ebay. $100.00, including shipping. Took less than 30 minutes to install, and can be returned to stock, in about the same amount of time. It lowers Touring bikes either 1 1/4", or 2 1/2". If you ride 2-up, you'll have to keep some more air pressure in the rear shocks, to prevent bottoming. The SG shocks are 12" stock. The FLHTC/U has 13" shocks stock. The brand of lowering kit is R.U.B. Excellent quality, quick delivery. Hope this helps.