QuestionI'm usually good at these things, but this one's getting me down!
I have a SAME mercury 85 tractor [1988]. Wet brakes.
I've already ruined 3 pairs of seals trying to get the pistons in; before the last try, I read on all experts a post from Arnie Jossie explaining how to drive them in straight with a custom jig.
I oiled up the rings and piston and pulled it in with 3 bolts as he described, yet still ruined another pair of [expensive and hard to get] o rings.
Perhaps at one point the piston was out of alignment about .75mm. would that do it?
Do I need to lube with grease? would it cause any problems if I do?
piston is polished, everything looks cherry in there.
This model uses ATF for brake fluid. Straight from M. cylinder, no power assist.
Answeri normally lube seals with what ever the fluid is used in your case ATF .I've never done seals on a same.im taking it they use a couple of small pistons if I'm wrong please correct me.the trouble with some seals is that when you expand them to put them on they don't always go back to their original size.do they use an O ring type seal or is it different.what i do some times is to put the seal in hot water(not boiling hot)then fit it to the piston then wrap PVC tape (white plumbers tape) around the piston wrap it as tightly as you can so it contracts the seal on the piston then leave it in a bucket of cold water for 10 minutes.start inserting the piston as the seal is nearly in unwind the tape and hopefully the seal will go in ok.
this is just an idea for you as i haven't seen these brake seals before let me know if I'm on the wrong track and how you get on
i think it shoul be ok to use grease to lube these seals as it would definatly protect the o rings better than ATF i often use grease as long as dot 3 and dot 4 brake fluid isnt being used
