Brakes issue

[Guest]

Hello All,
Bought a 1981 GS450L last week, with the known problems that it was lacking a front break caliper, as well as a severe oil leak. I took the crankcase off, and am doing alright on that. My problem lies with the brakes. I bought a new caliper and installed it with no issues, but when I attempt to use them the brakes are unresponsive. There is little brake fluid, and I can't start the bike to get anything pumping. Would this be the issue? I would think that there would be some response by using the front brakes, yet there is none.

[tkent02]

There's no telling what's wrong if the bike has sat a while. Brake fluid solidifies, rust particles get everywhere in there, who knows what else is wrong. The only safe thing to do is disassemble all of it, the caliper, master cylinder, lines, clean everything and replace whatever needs replacing, including the lines. Starting the bike has nothing to do with the brakes.

It's not that hard to do.

[SVGS650]

It reads like you simply bolted the calliper on and are expecting it to work without any other input. The bike does in no way need to run in order to pump brake fluid through the system. It is an entirely independent system that merely is attached to the same vehicle.

What does need to happen is all about you. You should probably pull the master cylinder and caliper off, disassemble and clean them, because they will be full of hardened residue globs from old fluid, like tkent mentioned.

Then you need to buy some DOT3 brake fluid to fill the reservoir with once it is back on the bike.

After that you'll have to bleed the system, so have an 8mm wrench for the bleeder screws and a 14mm for the banjo bolts. You'll want to pump the lever, then hold it in while loosening the bleeder and/or one of the banjo bolts ever so slightly so as to not get fluid on anything painted, also to conserve waste.

Opening the banjos helps push trapped air out and replace the void with fluid.

Repeat this until you get some feel at the lever. This means that the system is getting close to full, with little air left. Do not stop until the lever is very solid feeling and you're sure there is no air left. Once you are confident that you've got the air out, you're probably done.

[chuck hahn]

Its just like bleeding car brakes. And another trick to get the air out of the master so the fluid will start to push is to ever so slightly wiggle the lever back and forth and watch bubbles come out the return port.

But the very best way, which I always suggest is done first, is to see if the auto parts store has a loaner program and a mighty vac for loan. If the front has 2 discs the manual specifies which you do first..just cant recall it right now..but its there.

For the rear one, you do the inner most ( closest to the hub ) bleeder first then the outer one.