how to replace brake fluid, bike stored for years?

jordey · Nitrous Nuisance Joined: 17 Sep 2012 Karma :

okay so my tzr 125 has been dry stored for years. i tried filling the rear reservoir up with brake fluid, pressing the pedal, and opening the bleed screw to let it all come through. now though, the rear brake is very stiff, and its difficult to turn the wheel. the pads also barely move when i try and press the pedal which is also stiff. why is this?

also, i tried taking off the front reservoir lid but one of the screws is stripped, how do i go about getting it off?

flumpy7 · Could Be A Chat Bot Joined: 31 May 2008 Karma :

You should have tubing on the bleed nipple and best to have the other end submerged in brake fluid in a jar so you don't inadvertently suck in air. Open the nipple, pull/push down the lever, keep the lever pulled/pushed down, close the nipple, let go of lever. Keep doing this until clean fluid is coming through the tubing, remembering to keep the reservoir topped up so no air is sucked in that way.

An easier way is to buy a cheap one-way valve bleeder kit so you don't have to keep opening and closing the nipple.

Anyway, if you've done all this and you've still got problems, I would look at popping the piston/s out of the caliper and cleaning and rebuilding with new seals and potentially new pistons if they are knackered. The pistons could be being prevented from retracting because of built up crap around the seals.
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2012 Sinnis apache

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

Stripped screw = impact driver or if it's too far gone for that, drill the head off, take the top off the reservoir and get some mole grips on the stump.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

dansp1 · Nitrous Nuisance Joined: 07 Jan 2012 Karma :

A trick i use on the crappy master cylinder cap screws is to hit them with a pin punch so that 1, you shock the thread and
2, close up the damaged slots
then get a really good fitting screwdriver, tap the end of the screwdriver with a hammer at the same time and/ or use mole grips on the handle for a bit more leverage.
I am not a huge fan of impact drivers, i have seen too many delicate parts broken by their use.