I just sanded my very rough piston bore smooth and am afraid the stock o-rings will be a little loose; certainly not as tight as stock. Does anyone know where I can find oversize replacement o-rings? They would only have to be a few thousandths thicker.
I would suggest a new master cylinder. Less than $40.00 on eBay. Verify it is the correct one tho. https://www.ebay.com/sch/i.html?campid=5338192028&kw=MASTER+CYLINDER+#D143162&mkcid=1&mkrid=711-53200-19255-0&toolid=20004&_sop=15
We all love ya @Tinkerer but you're completely on the wrong page here mate! A series of questions for you @mbavers - as I don't think finding a suitable pair of orings will be possible. Had the piston spun in the housing due to broken tangs? How big an area did you have to sand smooth? Usually there is just an area of between 1&2 inches across the lower section of the bore. Did you sand by hand or use a die grinder or dremel? Did you notice there was one of the axle housing mounting bolts that was shorter than all the others? Plus, I think we need to see pictures of the work area & what you decided to do to lower the transaxle to get to this stage of the repair.
--- I know I am. When I read the opening post it crossed my simple mind that he was not referring to the master cylinder At least I found a cheap master cylinder if anyone is looking for one. Pictures are invaluable to eliminate confusion ! IMHO !
Good questions ALR if he worked the damage out by hand I would just go back with standard OEM rings. It would be hard to remove a lot of material by hand enough to make i badly out of round.
I replaced both master cylinders last year. Not fun.
See reply below.
Thanks all for input. I built a base with railroad ties topped with 11/8" plywood screwed down for stability. Worked perfectly. Easy to work on as a bench would have been, without the hassle of moving the complete unit. Used addition support for the other side with long 3/4" threaded rod replacing original bolts that secure axle to chassis. I chose 3/4" rod to allow room for movement. Chose jacking point slightly forward of the axles. Let unit down slowly with jack, removing blocking and unscrewing nuts on the threaded rod as I went until I was at the height I wanted. The piston had not spun; ears all intact. The piston bore surface was very rough generally; actually looked liked the casting had never been machined. I sanded both surfaces by hand, all around, first with 150 grit emery cloth, then with 400 wet with diesel fuel. Took a long time; hard work. Got a nice shiny smooth surface. Some very slight pitting remained, but I don't think that will be a problem. With new well greased o-rings the piston seemed tight enough when installing that I don't think I removed too much material when sanding. Friend with Bobcat made cradle to support axle. We lined everything up and slid the axle off and on by hand, sliding on the greased forks. I made guide studs out of 16mm (2mm pitch) threated rod, ground to a taper on outside and slotted with a cut off wheel for installation and removal with a screwdriver. The one short bolt is easy to determine (if you forgot to mark it on removal) with a depth gauge to find the short bolt hole. Will upload pics separately following. It will be a few days before I get everything hooked up and topped off with fluids.
Sorry about multiple pics previously...don't know what happened.