'72 flh front disc question

Smack the caliper with a rubber malet. The puck in the caliper is stuck.

tried that, I pushed the piston back in some, it helped a little, but as soon as I "pumped it back up" it seemed like too much drag

jeff

You'll probably have to clean the bore of the calper of the break dust. Pop it apart with air presure but be carefull it will come apart like a rocket. the O ring is just sticking in the bore. Don't tear up the boot on the puck.

Ok good to go again.

I checked the mastercylinder and found it almost empty. So I topped it off and pumped up the lever. I noticed some bubbles in the resevoir so I continued to work them out. Now the wheel still was dragging so I used a screw driver to "pry" the calipers piston back in away from the disc.
"note to self: put the mastercylinder cap back on before doing this next time"
I did this a couple times and kept working the brake lever in and out, and now all seems well.
Not sure if the piston was getting sticky in the caliper and needed to be worked out or the low fluid in the m/c was sucking air and not drawing the piston back off the pads? Oh well, its fixed for now.

Hopefully the new bushings quite things down.


Jeff

Glad you got it fixed.

As far as the rattling banana caliper goes, I always put a piece of the 1" wide foam insulation with one sticky side between the leg and the caliper. It kind of cushions the caliper and quites the knocks quite a bit. They also make a spring to put tension on the caliper and keep it from rattling so bad. That works ok for a while.
Larry T

nope, no good.
1/2 way to work it started dragging again.
I got home at night and popped out the piston from the caliper and there was some nasty chunky fluid in there (But the bore look great) so I cleaned everything out and Ill try again soon.

jeff

Try useing .5 fluid. Repels water a lot better than .3 and it don't fuck with the paint. just a sugeston.

jcs64 said:

nope, no good.
1/2 way to work it started dragging again.
I got home at night and popped out the piston from the caliper and there was some nasty chunky fluid in there (But the bore look great) so I cleaned everything out and Ill try again soon.

jeff

Click to expand...

Have you cracked the bleeder when it start locking up? If it's pressured up and frees up the brake when you crack it, you might start looking at the master cylinder. I guess a collapsed brake hose could do it too, but I've never seen that on a scooter.

Anyway there is a small bleed hole in the master cylinder that lets the fluid back in the reservoir when you let off the brake. I've seen them plug up and cause the problems you're having.
Larry T

Ok, this thing is kicking my butt!
Ive disassembled the front caliper (twice) and just finished putting the mastercylinder back together. All were dirty/sludgey but I found no other problems
I put the old sloppy bushings back, thinking mabe things were binding or crooked w/ the new snugger ones. It made no difference.
Cracking the bleeder was a great idea! But It made no change.
W/ the caliper in my hand (just the 1/2 containing the piston) if you pump the lever, the piston easily moves in and out.
Put it all back together and spin the wheel and its good! Spin, tap the brake, good. I repeated that a bunch of times, spin, tap the brakes, good. Now, Spin, squeeze hard (as you would when trying to stop), and now it drags.
So light pressure is ok, but heavy pressure wont fully realease.
The piston bore has no indication that the piston is cocking in the bore and getting hung up. I see no scuff marks in the bore at all.
Now I really wish this was a manual drum front

jeff

I would start looking at the break line it's self. I've had the same headache with a bad line on a PM caliper, smoked the rotor out on the hwy, turnd out to be the line had collapsed and fluid would not return to mastercylinder.