David:Your comments here raised a question about what I discovered when I recently rebuilt the pump in one of my MF-35s. Specifically, upon reassembly of my pump using aftermarket TISCO parts, I discovered that the piston assemblies interfered with the linkage for the oscillator and the pump would not rotate a full 360 degrees. I made several attempts to reorient the piston assemblies but could find no arrangement that eliminated the interference. Eventually, I relieved the corners of two of the square piston frames with a die grinder, reassembled the pump, installed it in the tractor, and everything seems to be fine. Annoyed with TISCO, I attributed the interference to an aftermarket redesign of the piston assemblies without proper verification that the redesigned parts would not interfere. The assemblies are installed such that a machined surface of each is toward either end frame of the pump. According to my I&T manual this is correct. Unfortunately, when orienting the assemblies this way, the factory relieved corners of the piston assemblies are not in proper position to provide clearence for the oscillator linkage. Orienting the piston assemblies such that the unmachined surfaces are toward the pump end frames would result in clearance for the oscillator linkage as the pistom frames are relieved in this area. Have you seen this before? Additionally, you state that the pistons are not centered symetrically on the square frames. Is this offset side to side or vertically? The original pistons appear to be symetrical and I cannot look at the new ones as they are in the tractor. I am contemplating removing my pump again to see if perhaps I missed something. Perhaps the piston assemblies are upside down causing the interference. Any advice that you may offer will be appreciated. Dean
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