I have a 5 yr old letro legend cleaner that lately hasnt been cleaning very well. The front wheels never really make contact with the pool bottom, almost like its doing wheelies, which I think it preventing good suction. The wheels seem to be moving at the proper speed, and have plenty of torque. The water pressure also seems right, plenty of water coming out of the jets. Cant figure out why those two wheels wont come down . Any ideas?