wonderful brakes, not really

so on my bike i can bring the brake lever all the way into the bars and the rear will still be planted on the ground

there are no leaks that i can see

the lever is extremely spongy to my taste
my 85 year drum brake dirt bike has better stopping power....

will breaded or steel tubing brake lines help me with this? (steel tubing to the distribution block braided from there on out)

and can i take the piston out of the caliper with out damaging it? (will not have to get new seals) its not leaking but i would like to clean it

it has new brake fluid in it dot 3&4

pad are good and newish rotor looks fine

how far is the pivot point on the caliper supposed to move?


thanks in advance for your replies

 

The brake lever should NOT come all the way up to the bars. The spongy feel is most liekly due to air (bubbles) being trapped within the brake system, and it will need to be thoroughly bled. I advise the use of a vacuum brake bleeder system like the MITY-VAC systm that I offer, it does a great job without taking 45 minutes of hand-pumping (motorcycle brake systems are ridiculously difficult to bleed by hand).

Braided stainles steel lines will give you a much firmer and more responsive lever and brake system. However, any air in the system will still lead to that spongy feel and loss of braking system effectiveness.

The pistons can be carefully removed from the calipers without damage; however, given the minimal expense involved, I would replace the seals and hone the cylinder while you've got everything that far apart!

 

Pivot point on the caliper move? Clarify please.

Can you take the piston out without damaging it? YES, but you may discover you need new seals. They're not expensive.

Stainless steel lines will improve performance but yours has a problem. The stock brake, while not all that excellent, still should work quite well. The 550 had one of the shortest stopping distances in its class even against dual-disc rivals. You most likely need to disassemble, clean, and possibly rebuild your master cylinder, as well as clean the caliper's moving bits.

 

I just thought of something. Look at where the lever actually contacts the piston in the master cylinder. Is there a screw there with a locknut? The stock brake lever has a travel adjusting screw to adjust the lever's engagement point. If that is MISSING the lever will come WAAYYY back before it does anything.

 

the screw is in there... and the brakes start to apply when you first start squeezing the lever, but they are so spongy that when they are back to the handle they will still not lock up the wheel nor lift the rear

i have bled the brakes until clear liquid came out but i ever emptied them and refiled


how far it the pivot point(guess i should call it a slide) on the caliper supposed to move my caliper slides along the axis of the wheel but not very far, how far should it move?
i am only seeing something like 1/8-1/4" of movement

how much is a seal kit/rebuild kit for the caliper and master? and what do i need to hone it? a cylinder hone will surly not work (3-7")
and i am not sure but i don't think my auto parts store has hones that small

 

cleaned and greased all moving parts on the caliper got anti-seize graphite
the caliper moves more and it moves easier

piston got buffed and polished it has some pitting not much though
fluid seal looks o.k. but the dust seal is dieing
in the cylinder there was a little jelly, that got cleaned out

bled the brakes, you know that if you let them sit gravity will pull the fluid though...

and the lever is back where it was, maybe just a touch harder

when i pull the lever back to the bar the caliper flexes a little (very little)
as well do the brake lines


do you think that the caliper was seized and not letting the other pad touch the disk?
i have not taken it for a test ride yet due to it being dark and i have to cross my muddy yard to get it to the street

 

If it works good now I would not worry about why it did not work before.
what ever you did fixed it.

 

As was mentioned earlier, the brake lever should not pull back to the handle bar.
It is not fixed.

 

then i guess i need to take the master cylinder apart and inspect & clean her out?

is this beginning to look more like the lines?

what else would cause weak breaks/low line pressure?

 

Low line pressure is definitely a master cylinder problem, unless your brake lines are sol old and so deteriorated that they are "swelling" (almost to the point of bursting, I would think!) and absorbing all the pressure in the system (instead of passing that pressure to the caliper pistons). Of, of course, if there are any leaks in the system (bleeder screws?) that would bleed off pressure.

By the way, the levers on different model bikes have different contours. So an incorrect lever could cause "too much pullback". But the spongy feel is the real cause of concern. That's almost always a brake hose or air-in-the-fluid problem......which the "jelly in the caliper" attests to.

 

I am mostly a novice with some mechanical background. I got the master cylinder kit and mity vac chacal sells, and had the job done quickly. I recommend getting the C-clip pliers, too -- getting that c-clip out was tough enough with exactly the right tool. Bench bleeding the mc was the hardest part for me. Well, that and the crushed bleeder valve that made the mity vac not work, but that was the fault of the PO, not the equipment.

The clue for me was the squirting inside the MC -- that shouldn't happen. the rebuild made that go away and formed the brakes up considerably.

 

If you still have the original rubber lines they MUST be replaced. They were only rated for ~4years. I bought an AM MC from partsnmore.com and Len hooked me up with custom SS lines. After a caliper rebuild kit I can lock the front tire up pretty easy. Bleeding it wasn't too bad, not nearly as bad as I was led to believe. Maybe it is because I used a different MC?

 

what is this about squirting in the mc?

after i cleaned the caliper out i had very slightly more braking power

 

If you see a little "fountain" IN the MC reservoir every time you squeeze the brake lever there is still a plugged passage (or passages) in the MC. Like I said before, you need to pull the whole system APART (MC included) and go through it. Partial measures won't cut it, this is your front brake we're talking about. Everything has to work 100% all the time, your life is literally riding on it. The bike is 26+ years old and a lot of the brake components had an expected 4 or 5 year service life.