Topic: FIXED: Please help. New brake issues NEED HELP

[Chris Liston]

Today I replaced my badly scored original front brake rotor on my CB550.  I also replaced the highly pitted caliper piston and also installed a new seal. 

The rotor swap was straight forward with no issues.

Now onto the piston/caliper issue.  I popped ou the old piston and removed the piston seal.  Cleaned everything out good with brake kleen and put new piston seal into the caliper with alittle new fluid on the seal.  I installed the new piston and had to really give it a push to get it to go past the new seal.  The old piston/seal I usually just had to give it a gentle push and it would pop into place.  I figure the new seal/piston and no worn parts of the seal what happened with the harder push is / was normal.  I installed the caliper halves on to the older and set the stationary pad and then bled the brakes (15 min)  no air in the lines,etc.. but the new piston will not retract unless I manually remove the caliper and push it back in.  I popped it out again with compressed air to inspect and everything looks as it should.

I could really use some advise on this one.  I really don't know what to do at this moment.

Thanks
chris

[Buffo]

agreed. I would first remove the piston and reclean the caliper...I like to use a brillo pad...

[Chris Liston]

The master is good as it was working fine before the work so I guess its got to be the piston seal area.  I cleaned it out pretty good as there was some crud in there.  I'll do it again tomorrow.  I'm beat.  5 hours doing all that work. 

Any more thoughts are very helpful though.

[Chris Liston]

All new parts are Honda ordered from david silver.

I had used scotchbrite with brakekleen to make sure everything was dirt / gunk free.

I must be the seal crevase that still has dirt in it though.  Although when I wiped down there was no more dirt on the paper towel.  I did have to use some presure to push the piston in, must be a very tight seal. 

[Bob Wessner]

I must be the seal crevase that still has dirt in it though.  Although when I wiped down there was no more dirt on the paper towel.

I used a dental pick to give the corners of the seal groove a good cleaning. Corrosion and debris get in the corners and then the new seal won't sit all the way down in the groove. Seemed to work really well.

[Chris Liston]

That has to  be it then.  Everything else seems good. 

Granted, I bled the system until no bubbles were left and the lever still was very soft.  Probably becuase the seal wont allow the piston to move.   

more work for tomorrow night. 

Chris

[Chris Liston]

Well after going through a very thorough cleaning of the caliper and seal area things are looking good.  Seems that when I pushed the piston in it went alittle off center.  popped it back out and its moving in and out good now.  Braking is MUCH improved thanks to the almost new front rotor and Daido Safed HP pads.  I'm very happy the way things turned out.

Just one question.  I was doing the work at my buddies house and forgot when bringing the bike over on my trailer the little nylon/plastic washer that sits between the piston and pad.  I realized it when I got home and saw it sitting on my bench.  Question, how needed is this washer as braking is very good.  I assume its to dissapate heat between the piston and pad. 

I'm going to take the caliper off tomorrow anyway and install the washer.  I can't believe I missed it on my bench.

Much thanks to this great forum as usual.

Chris