Troubleshooting brake problems

[Narcoleptic_Snowman]

So, about a week ago I noticed my bike was pretty hard to roll around. Then after about a a twenty minute ride, and parking it in the sun for about 4 hours I found the front wheel to be totally locked. I checked the brake lever and there was so much pressure I couldn't move it at all. So, I grabbed a 8mm wrench, bled some fluid from it, and went on my way. The next day, same thing happened. I asked my step dad (who was a car mechanic for 15 years and still does some work out of his garage) what it might be and he said that it was likely water in the brake lines. water expands with heat creating pressure. Right. So I totally flush the front brakes until it's all clean and shiny fluid coming out of both calipers. It still did the same thing the next day. So I ran half a bottle of brake fluid through it to be sure I got all the junk out. And it did come out a little dirty.

that's everything I've done thus far. Right now, it builds up pressure very slowly til it's not driveable any more. To the point where I've had to pull over to the side of the road to bleed some fluid from it. Good thing 8mm wrenches are small and pocket friendly... it's not too bothersome as my front brakes work fine and brake fluid is dirt cheap. Slowly getting more irritating though.

Anyway, if any of you have any insight as to where I should start tackling this beast, it would be much appreciated.

Thanks in advance

[tkent02]

You certainly shouldn't be riding it, a locking wheel will put you on the ground quicker than anything, tends to be a hard landing too. Ask Painter Dave.

Fluid not able to return due to clogged lines or a chunk in the tiny return port?

Is it both calipers when it is stuck?
If so the problem is likely in the master cylinder or the line where it is common to both calipers.
Actually you should ask Painter Dave what caused his to lock up, he probably knows by now.

[simon kuether]

All the Bargwahns will get up you for not saying what type/year the bike is.I've got no idea by the way.Cheers,Simon.

[tkent02]

All the Bargwahns will get up you for not saying what type/year the bike is.

Doesn't really matter, they are all pretty much the same.
What's a Bargwahn?

[Narcoleptic_Snowman]

Well it's not an instant lock up, it takes almost 100 miles of riding to get it to the point where the brakes are just barely touching, and at least I wear a helmet... lol. You're right, I probably shouldn't be riding it, but I can't afford to drive my beast of a truck... Money has to be the evilest thing ever invented. That's a story for a different day. As far as the brakes, I haven't really been able to determine if it's one or bother calipers. Now that you mention it though... it does sound like a clogged return or something relating to that, because it seems the more I use the front brake (I like the back brake more anyway) the faster it builds and keeps pressure, so that makes way too much sense. I will definitely be checking that as soon as I get home. I get off work in about 10 min. Yay.

Oh, and any tips on how to go about checking that would be helpful I can rebuild an engine with my eyes closed but ask me about brakes... lol. I could probably figure it out, but tips are good.

[chef1366]

You have dirt in the return port. Clean and rebuild the M/C.

[Zook]

And learn to like your front brakes more than the back!

Most of the braking comes from the front, not the back.
Don't rule out a sticky caliper piston, either.

[Suzuki mad]

Your front master cylinder pushes fluid to the front one/two callipers. If the master cylinder is in trouble the plunger inside will keep the pressure up keeping the brakes on instead of allowing them to relax after braking.

The front one/two callipers have pins that the body of the calliper slides one. These are prone to seizing in place. The piston of your calliper/s has two seals. An outer dust seal and an inner fluid seal. Rubish such as dirty and oxidation gets in the calliper/s and causes the pistons to seize or jam so when they are pushed out by the master cylinder the refuse to return.

Start with the calliper/s and check that the bolts and piston move freely and see if that cures the problem. If not then its the master cylinder. (Likely to be a block return or the seals failing.)

Suzuki mad

Had a rear brake seize on a GS1000 after sitting all winter due to master cylinder.

[Narcoleptic_Snowman]

thanks for all the advice everyone, when I replaced the front fluid I did notice a bit of rust in the master cylinder. Last night I took it all apart and lo and behold the ports were rusted almost completely closed... I poured some kleenstrip rust remover on it let it sit for about half an hour and cleaned it off. Then I picked out the two holes with a safety pin. put the brake system back together, bled out the bubbles, and hey! it works! took it for a 20 minute ride last night using the brak liberally (stopping quickly on an empty street) and it hasn't locked up at all. so I do believe it has been fixed.

thanks again everyone.