Front Brake Problem on 1980 KZ440 LTD A

I moved my bike across the country in a covered trailer about 5 months ago. It spent 5 days strapped down in the trailer, and when I went to take it out of the trailer I noticed that the bike had shifted. The right side of the handle bars were pressed up against the wall, and the front brake lever was compressed all the way, and it was obvious that some brake fluid had leaked out onto the lever. I took off my straps, rolled the bike out of the trailer and the front brake did not work. I could compress it all the way with 0 ability to stop the bike. I have had no time to work on the bike since then, I have had to move the bike once or twice since then, and still no front brake ability. Yesterday I finally get to work on the bike, and the brake works! I didn't test it much, but just pushing it around to start working on it, but the brake seems to be working just like before. The brake fluid is low, but the reservoir still has a sizable amount in there.

So I have a couple of questions
1. Is there an obvious reason for what happened here?
2. My manual says that I shouldn't just add brake fluid, that I should change the fluid. The reservoir looks a little nasty, there's some yellow precipitate in there. How should i go about cleaning it before I change the fluid.
3. Might be answered w question 1 but, could there be a bigger problem here? Am i being a dumb ass by thinking that I can just get the fluid level back up and everything will be fine?

Thanks!

The front brake is probably the most important system on the motorcycle. I would refurbish it. new caliper kit, new master cyl piston assy & new ss brake lines w new gaskets. maybe a new caliper piston if it's pitted. I did mine several years ago except for the mc which I refurbished last year. The mc piston seemed fine & wasn't leaking, so I didn't replace it, but it's now leaking. Also, worth mentioning, old rubber brake lines can burst.

Fr br caliper painted w Duplicolor caliper paint then baked in the oven.
K&L piston & rebuild kit. others have had issues w K&L, but I've never had a problem with their parts. made in Japan.


The mc piston bore had some minor pitting at the bottom.
I honed the bore with brass wool wrapped around a nylon bristle brush.

...

On brake systems where refurbishing isn't necessary, "changing the fluid" also known as "flushing" can be done as a repetitive bleeding process whereby new fluid is continuously added to the reservoir while old fluid is allowed to escape from the bleeder screw, until eventually new fluid gets to and escapes from the bleeder screw, whereby new fluid completely replaces the old fluid.

Perhaps a rubber ball syringe could be used to suck out any crud from inside the reservoir, prior to flushing.

When flushing the brake system in the above manner, or sucking crud from the reservoir, be sure to never allow the reservoir to get empty (as getting empty allows air to be sucked into the line).

Good Fortune!

martin_csr wrote: The front brake is probably the most important system on the motorcycle.

+1 ! Ed