Front brake master cylinder rebuild question

[Mad Dog]

So... I found a drip of brake fluid on my tank, and traced it to the master cylinder plunger thing where the lever pushes. Bought the kit and I'm ready to go. Is there anything I should be aware of before I start? Are there instructions around here - I didn't see any.

 

TIA as always

 

Mike

Edited April 21, 2015 by Mad Dog
spelling

[ragtop69gs]

I don't think there's a step by step for the master cyl. Over the years I think I've read most everything there is tech wise on the site. There's not much to it. You may need a hone to clean up the bore in the master.

[Squidley]

Make sure the bore is spotlessly clean, as well as the entire assembly. Lube all the sliding pieces with brake fluid before you install them. It's a pretty strait forward repair, if you run into issues my # is in my profile.

[BlueSky]

If you hone it with sandpaper, don't sand perpendicular to the piston. Sand around and around the cylinder. Sanding perpendicular will cause it to not be able to seal.

[Condor]

Couple of things to help. There's a circlip retainer in the end of the master cylinder that could be a problem removing. You'll need to get it out to rebuild the master. It's also hard to get to due to the piston shaft limiting the access space. So.... what you need to do is push the piston down into the cylinder and stick a small screwdriver or?? into the hole at the bottom of the reserve. This will keep the spring compressed and get more room to remove the circlip. Next you need to get a pair of sacrificial needle nosed pliers, and modify the tips to retain the circlip holes. See Pics. I imagine you might be able to buy a pair of circlip pliers, but the circlip holes are very small and cheap plier tips are too big and a waste of money. Place a towel or?? over the end of the cylinder when removing to save the circlip from launching into outer space. The second thing is before reassembling run a stripped wire twist thru the expansion hole also in the base of the reserve to make sure it's clean. You might also blow compressed air thru the brake line to remove any crystals and crud. Towel over one end, air in the other. As far as honing the inside of the cylinder, on most I don't bother. Just make sure it's super clean, and only clean with brake fluid. Hope this helps....

Edited April 21, 2015 by Condor

[Mad Dog]

Great! Thanks to all.