I had a problem similar to that. You can go to homedepot and get some pvc end cups that come down on the racer and touch the sidewalls. It helps guide it. You do have to drill holes in the middle of those cups though. The plastic is soft enough were it won't damage your cups with more pressure. Before you do this....grab both cups and apply some light grease and put them in the freezer overnight. Then try it again. It makes a different having them shrink just a tad. If you don't want to try that...then take to the shop and let them do it right. IT's not worth the headache unless you really like to do stuff yourself.