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SP1 Brake Bleed issue

2K views 10 replies 4 participants last post by  DrewBush 
#1 · (Edited)
I want to run this by you guys for some help.

On My 2000 RC51, the brake lever was nice and firm, but the fluid was horrible. On top of that I needed to put new pads on it too. I cleaned the calliper pistons, but didn’t remove them. Pushed them back in after cleaning and installed new pads. I bled the brakes like I have many many times, never let the fluid get too low, used pressure bleed method, but the lever feels very spongy and it now also creaks and makes a noise at the master cylinder, almost like the Bell ray Super DOT4 fluid doesnt lubricate enough.

I can get it to firm up if I pump it a few times, but it goes soft again after a while.

Ive re bled 3x

No bubbles at all

Im wondering if I have shit binding the calliper pistons and they are sticking ?

Ive tied the lever back over night and its firm after I do that but goes soft again after a short while

Thoughts?
 
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#4 ·
That's the next place I would check. By cleaning the pistons and pushing them back in, that might press any air up through the lines to the highest point. Sometimes you even see the bubbles surface in the reservoir but air can get trapped at the banjo bolt. it does not take much to get a spongy lever feel.
 
#8 ·
So far its much better but not 100% (like my SP2).

not a single air bubble when I re-bled it, but seems to have helped to some degree pushing the pistons out and cleaning them again and pushing them back in.

Truth is, I think the Master and the callipers could do with a disassembly and deep cleaning all the crud out.
 
#11 ·
I just did both my front and rear calipers. I ended up using the All Balls Racing kit. The kits were half of the factory stuff. Seals are good quality and I had zero fitment issues. The only thing I wish was in the kit would be seal lube. Brake fluid just doesnt work as a lube.
 
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