Front Brake Problems

[Anonymous]

Great site guys, been reading for a few months, and I have a question that I can't seem to answer. I have a 1979 GS 850 GN. My front brakes locked, so off I went and had calipers rebuilt. Kinda worked, but then they would drag a little. Sooo, rebuilt the front master cylinder. Everything has been cleaned, return hole included, and lines flushed several times, no air. Now, every once in awhile, they start to drag a little, not alot, but enough to heat up front discs. My guess is the rubber hoses, but they look good and I cant figure what would cause the brakes to drag only a little -- the line expanding?? Any help would be great. I really hate to order steel lines if I dont need them right now, just want to make it thru the season. If it is lines, I can only seem to find them at performance paragon, but really dont want to shell out $150 if the lines will be overkill....

[IanFrancisco]

My factory manual calls for silicon grease on the caliper pins (not to mention FOUR different types of Loc-tite). A lot of guys have successfully used regular moly wheel bearing grease, myself included. I guess the silicon stuff is hi-temp. I didn't keep a close eye on the pads and wore the inner one down to metal in 3000 miles (single disc GS450). Big surprise! The outer was only about 50% worn. Greased those pins up and am keeping a much closer eye on those pads these days...

[KW]

Braided lines should cost you no more than around $70 (and they are worth every penny). Keep looking!

[Clone]

I would pull the front caliper again and check the motion of the pistons to see if they bind or return freely. also remove the boot and rotate the pistons in the bore to see if there is a point of interference. If all is ok there, then put the caliper back on the bike after cleaning and lubing the contact points to see if the caliper will move freely. Hook up the lines put in oil and try it again.

[rphillips]

I can't think of any way the lines could cause this problem, but I've seen strange things before. I would double check everything else first.

[Anonymous]

Front Brake Problems

Well, surprise, I pulled the calipers to discover that the "rebuild" I paid for was never really done. I pulled it apart myself, cleaned everything and thought it would be good, but WRONG. Caliper never wants to pull all the way back. I'm ready to unload this bike, a whole season messing with a sticky brake....

[Clone]

For a couple of hours of conscientious work your problems will be over and you can ride in confidence and comfort. Never trust anyone to do the work correctly on your bike, do it yourself if you have any mechanical skills.
Pull the caliper again, take everything that acts as a slide and inspect them for rust there will probably be a lot. Hone the bore, if you can't get a small enough hone, use 1500 or 2000 grit sandpaper and wd40 to polish the piston and the bore. Polish the slide pins and the slide contact areas, roll the sandpaper into a tube and polish the inside of the slide bushings.
Lube them all and put them back together.
All should be copacetic. 8)