Topic: Redid brakes, now dragging. Normal?

[Patrick]

I redid the front brakes on my K5 750 this weekend. New single braided steel brake line, rebuilt the cqliper, new shoes. The master was fine, so I left it alone. With the new brake shoes, there is a certain amount of binding in the front brakes now. The shoes are dragging somewhat. The wheel isn't locked or anything and I can ride it, but pushing it in or out of the garage is more challenging now. Is this normal? I pushed the piston all the way back into the caliper before I remounted everything and bled the system, so I wasn't expecting this.  Granted, the pads I took off where shot and had very little meat left, but I figured the caliper would compensate.

Is there something i was supposed to do that I haven't done?

Thanks, in advance, for any advice.

Patrick

[Patrick]

By the way, I have adjusted the caliper mount both in and out but I can't seem to find a spot without significant dragging.

[750goes]

when you rebuilt your caliper - did you grease up or clean the piston sides - or inside the caliper ??

pushing the piston all the way bacjk in can cause some stickiness with any old build up behinfd the piston - did you put in a new seal as well - did you clean the old seal itself or replace it??

try scuffing the pads and the disk a bit it may halp..

[LoopsAndLogic]

I had the same problem. So I took the caliper apart and examined it.

After replacing the piston and seal with OEM NOS parts, it still did it

So, I took 1500 wet sand paper and went inside the bore of which the piston rides on, went very slowly and took off
very little material, and it worked!

I went all the way up to 3000 grit, and there is no sticking or binding of the caliper piston. I actually looks and feels better than stock.

 Best of luck

[GammaFlat]

I'm sure this topic has been hit in other threads and at the risk of repeating things...

My '76 750 front brake decided to start dragging bad (couldn't push it at all) and my father-in-law's rear Goldwing brake started to drag about the same time.  I took them apart.  The hard part was getting the piston out and calipers off the dang rotors.  BTW - for those reading this that haven't done it yet.... don't be anxious to disconnect the brake line after removing the caliper.  You'll need to pump your brake lever to get the piston out... could be challenging. 

Once I got the piston out, I cleaned the piston(s), made sure the cylinder walls were clean too.  I scrubbed hard with a rag, finger nail and brake fluid and got everything visible off both surfaces (piston and cylinder) - black crud.  I re-used the original seals and was careful to put the pistons in as straight as possible with the help of the old (or new) pad. 

I guess I got lucky on the seals.  I have talked to guys that have removed the seal and cleaned the groove it sits in with a bent pick - I apparently didn't need to do this.  (A guy I know that fixes old Honda's for a living says you rarely need new seals but if I had it to do over again, I'd have bought new ones.) 

On a new caliper, you can go crazy trying to bleed the air out....  you have to tap (ok, maybe really rap) the caliper (or master if that's what you're replacing) between bleedings to get "stuck" air bubbles off the insides of the caliper.  For some reason it does not seem to be as much a problem with calipers that have recently bathed in brake fluid. 

Slightly off topic:
I hear the hot setup is speed bleeders. They have spring loaded ball bearings inside to allow bleeding but not reverse air back into the system.  Great for doing brakes by yourself... Once done, you tighten them up just like a regular bleeder.  I have not used them but hear they are great.  There's also noise about backing up "older" contaminated brake fluid into ABS modules (on cars obviously) being a bad thing in which case you could open your speed bleeder while you re-compress your piston (when putting new pads on) without risk of getting air in the system....  possibly "speed bleeder marketing hype" but interesting. 

[BobbyR]

I actually use a 2 cycle measuring syringe type thing from WalMart. The vinyl hose fits the bleeder nipple and it will actually push the fluid from the caliper into the master cylinder. Costs about $4.00.

[Patrick]

After reading your replies I took the caliper apart again and cleaned it again. This time I lightly abrades the inside f the cylinder with some 2000 grit sandpaper. I had previously cleaned it with a nylon bristle brush and brake fluid. It looked clean. The sandpaper, however, polished it up. When I put the piston back in it went just a bit deeper than before. Now the brake pad is flush instead of having just a bit showing.

Bottom line, the brake adjusted much better. There's still some minor dragging, but I figure all brakes drag a little. The bike rolls much better.

Thanks, guys.

Patrick