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Flushed & bled my front brake, still sucks.

bcgrown2011-04-07 22:23:24 +0000 #1
The bike is a 1980 Honda CB400T, and it's been sitting for about 2 years in a warm, dry underground parking space.

I replaced the battery and the engine still starts and runs great, but the front brake has practically no power.

I flushed out the old fluid with new stuff then bled the air from the system, following the instructions in my Clymer repair manual.

The brake still has hardly any stopping power though. I have to use all my hand strength on the lever just to stop at all, and it's not a very convincing stop. The lever feels about as firm as I remember, but it's been a long time.

Obviously my memory of the last ride before parking the bike is a little fuzzy, but I don't remember it being this bad.

Where should I look next?
Mechannibalism2011-04-07 22:30:07 +0000 #2
Caliper seized. Time for a rebuild!
gxr jo2011-04-07 22:37:45 +0000 #3
are the pads new ?
Mechannibalism2011-04-07 22:40:49 +0000 #4
Look at the pads do they overhang the rotor? I have seen this on cars where the pads wear down untill they press up against one another and not the rotor --No brakes!!
bcgrown2011-04-07 23:51:50 +0000 #5
The pads are old but look like they still have a lot of material left. I pulled one out for a closer look and it had some sort of liquid on it (brake fluid I assume).

Looks like you might be right that the caliper is toast. Is it likely to be just the seals, or should I start looking for a new piston as well?
Mechannibalism2011-04-08 00:06:09 +0000 #6
Just replace the seals --there easy to do just make sure everything is absolutely clean. You'll have to free up the piston first -try a C-clamp to push it in then use compressed air to pop it out.
PRSmechanic2011-04-07 23:19:52 +0000 #7
Pads can be useless, no matter how thick or new looking they are. Age hardens them.

Seized caliper is also suspect as noted above.

As you sound like you have mastered bleeding, rebuilding (clean and reseal, grease pins if it's a floating caliper) would be smart. you can just take it off the fork slider and pump the brake until it pops out.

NOTE, brake fluid is like paint remover, so watch where stuff squirts!



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