XJ550 Seca front brake issue

So, formerly mine and now my wife's Seca is having an issue.

Braking requires a significant amount of force and brakes feel weak(long stopping distance). This isn't the spongy feel of air in the lines - it's the opposite. Lever is stiff.

Bike rolls just fine, brakes aren't dragging. Master cylinder is original. Hose is braided steel (came from previous owner that way)

I'm familiar with splooge hole blockage causing brakes not to release, but I haven't seen them not apply.

What might this be?

 

probally time to rebuild caliper and master cylinder.
could be the mc piston is freezing up or 1 of the 2 orings has broken and plugging the end

or the caliper seals are hardened and the piston is binding up.

could be clogged lines or the union on the forks from crap and o ring bits.

glazed caliper?

I think i have covered most things to check for.
you could open the bleeder or hose at the caliper and see if fluid is flowing then work up to mc.
or start at mc and work down.

I know len sells a bolt for testing the mc but I am unsure what you are testing I think it is the splooge hole

 

When was the brake fluid last changed?
What you describe very closely resembles what happens when the water content in the fluid gets too high.

 

try getting a can of brake parts cleaner and hit the rotor real good and get some between the rotor and pad. might just have some oil or wax on something

 

No idea when it was changed. That sounds like a good possibility.

Tried that. Didn't seem to make a difference.

 

drain and change your brake fluid it will show if you have a bad mc or clogged brake line
if your rotor is glazed you will have to sand it to clean it or have it turned if you can find someone with the proper equipment

 

Opened up the brake reservoir - fluid was clean and clear. Bled it through with fresh fluid anyway. What came out of the caliper was a little browner, but not terrible. Master cylinder moves freely when the bleeder is open.

It got better, but not by much.

So, I took off the caliper and took out the pads. Piston moves back and forth freely. I pushed it out about a half inch, cleaned it off, pushed back in. No binding that I can detect.

Pads looked a little shiny. I sanded off the shine, going to go try it now.

 

Well, same thing, really. If there is improvement, it's tiny.

Could, of course, be something about the brake rotor. Finding a shop to grind it would be interesting...

 

most places do not have the proper equipment for the offset hardened steel, possibly a dealership or used one 8mm is the thinness spec
you could try sanding it if you think it is .
manual says every 2 years for the seals, I do not know if that applies to the mc seals, and 3 years on the hoses
try trading MC from your bike to hers could be you just need to rebuild it. or the caliper. that's the nice part about having the same bike

 

We don't have the same bike. I used to ride this 550, now she has it. I have an FJ1200 now.

Speaking of which, I swapped FJ master cylinders to FJR masters, and now my clutch hand doesn't hurt and I can stop with 2 fingers. FJR has smaller MC bores. Maybe I should look for a different MC? I'd love to fit dual discs to this bike.

I haven't really tried any other 550 for comparison, so I don't know what the normal braking effort should be.

 

so you do not even know if you really have a problem?
does it feel different then when you rode it?

is the rear brake properly adjusted?

 

I have a larger hand and a stronger grip than she does. It does feel stiffer than all my other bikes, but, like I said, my current one I purposely modified to be lighter.

Rear brake is fine.

 

So what pads are on the bike? I've got the same bike (82 550 seca) and when I picked it up the PO had purchased new pads and put them on the bike. Not sure of the brand (no markings) but the front brake was not very good to say the least. I've done all the right stuff, MC kit, bled, caliper kit, new lines and still nothing. Got a set of Ferodo (sp?) racing pads off flea bay and wow big difference. Check the pads...

 

Racing pads are made from a much more aggressive material. They will eat your rotors up quick-like.

 

Hmm... I'm still thinking about the stiff lever... no binding going on there? No rust on the bolt, the rubber cover isn't interfering with the lever's movement? The adjuster screw and locknut aren't binding on the perch? Brake light switch works normally?

 

Standard pads.

Thing is, I also have standard pads on my FJ, which is a 110hp, 600-pound beast. Stops real easy.

I am starting to think the US 550 brakes were a tad inadequate.

 

Are you taking advantage of engine braking?

 

move the mc over a little and it will give a little more leverage on the lever