Aside from the bed platform and frame, everything is replaceable on a Solidoodle. So don't give up hope.
I'm currently rehabbing an SD3 that had severe Y issues, so I am very fresh on the fixes depending on the cause. What issues are you facing?
Skipping?
Shifting?
Poor belt tension?
Grinding noise?
You do not want to replace your Y bushings for a few reasons.
1) Solidoodle glues their bushings into the carriages. This would require you to either upgrade to Lawsy's carriages (highly recommended) or buying an old carriage off another user (which I have)
2) Bushings will never perform as well as linear bearings
3) Your cause is more than likely the Y brackets wobbling, belts stretching at the holes where they mount to the carriages, Y drive belt (connected to the motor in back) has too much lash/not enough tension, pulleys along the Y drive rod (6mm) are not snug but do not overtighten the grub screws!, or gouged rods. I've seen the cause more of an issue on linear bearings than bushings though, gantry is not square, Y motor VREF needs adjustment, poor/no lubrication. For bushings, use white lithium grease, for linear bearings, use sewing machine oil.
In regards to #3, I diagnosed the issues to the aforementioned machine within 15 minutes of opening the box. If you have all required parts, it would only take about an hour to fix all problems I mentioned if all were the cause. Which, in my case, they are and I do not.
Point is, be more specific. Don't be afraid to upload pictures of what you are facing. You may want to start a new thread in the Help section of the forum for the proper attention.
Printit Mason and Printit Horizon printers
Multiple SD2s- Bulldog XL, E3D v5/v6/Lite6, Volcano, Hobb Goblin, Titan, .9 motor, Lawsy carriages, direct Y drive, fishing line...the list goes on
Filawinder and Filastruder #1870.....worth every penny!