QuestionI own a 1976 GL 1000 with about 90k miles. I live way out in the Rocky Mountains and only get to ride about 3 months a year. So for the past 9 months, my bike has been sitting under a cover, and under 4 feet of snow. I dug it out recently and it fired right up. But I noticed the front wheel seemed to be dragging. I found that the front calipers had pressure on the rotor. When I would squeeze the left caliper, the right would get tighter. The brake fluid looks clean. I don't know where to start the repair. Rebuild the master cylinder? Is there a valve somewhere that might be stuck to prevent the fluid from flowing back to the master cylinder? I would appreciate any advice you can offer. I've found most bike mechanics as basically scared of working on my bike...and it's 50 miles to any shop.
AnswerGeorge, this is a really common problem with older Hondas with single piston brakes. Corrosion gets built up in the groove for the O-ring in the caliper and swells the ring up against the piston, causing drag. Use the master cylinder fluid pressure to slowly push both pistons out towards the edge of the caliper and then just pull them out over a big pan to catch the fluid spill. Clean out the calipers with brake cleaner, scrub the pistons with a bit of steel wool or a brass brush, get a small scribe tip to get under the edge of the seal and pull it out. A 90 degree scribe tip works good to get into the groove and get all the crud out of the seal slot. Clean it all nice and reinstall the seal, if it looks okay. I have reused them on the past, with no problems if they aren't distorted too badly. Reassemble with clean brake fluid on the seal/piston, open the bleeder nuts and push the pistons back in. Do the other side, then you get to tackle the hard part... getting them bled again! A Mity-Vac is a good tool for sucking fluid back through the system and getting the air out. You can also put a tube on the bleeder valve, curl it into a single loop with the end down inside a half full bottle of brake fluid and then try pumping the fluid from the master cylinder into the bottle. The line submerged in the bottle will prevent air being sucked back into the system. You may have to crack the fittings at the brake junctions at the fork and then at the master cylinder to get all the air out. Takes patience.....
There is a small bleeder port in the floor of the master cylinder that can prevent the fluid from flowing back to the reservior, so be sure that it is clear and clean. You will see two holes in the bottom, the smaller forward one towards the line connection is where you need to check.
Hopefully, your master cylinder isn't leaking or bypassing due to old seals. There are kits for them, but the bores need to be undamaged from moisture sitting in there during storage.
Obviously, a bike sitting under snow isn't an ideal condition of storage and the excess moisture will be absorbed by the brake fluid and the water goes straight down to the bottom of the calipers. You will need some small 90 degree snap ring pliers or long tipped ones to get the snap ring out of the master cylinder, in case of an overhaul. Honda makes some special ones, but they are expensive.
PS Better check the rear caliper too!
Bill Silver
