Brakes not working right

[Mr. Holloween]

I've read most of the treads on brakes,about all of them hanging up but mine only work about half of what they should. I check out the calpers an not all of the pistons are coming out. The lever is good its mainly the front I have to pull hard to work. Fluid ,pads are ok .Is it my lines or in the calipers

[Rocket]

I've read most of the treads on brakes,about all of them hanging up but mine only work about half of what they should. I check out the calpers an not all of the pistons are coming out. The lever is good its mainly the front I have to pull hard to work. Fluid ,pads are ok .Is it my lines or in the calipers

 

Sounds like the calipers, need to be torn apart, as pistons are sticking. At the very minimum, clean the pistons, the bores & replace seals. Also, clean any crud in the area too.

 

[dingy]

Getting the stock pistons out will be a challenge.

 

First invert caliper and drain out brake fluid.

 

What I have done on mine is to split the caliper in two pieces after you have removed them from bike. I then clamp them in a vise one half at a time. When you clamp half in, use a 1/2" thick wood backer board between vise jaws and the caliper. I put a small piece of gasket material over the bypass ports to close them off then secure in vice, clamping the gasket material. Use 'C' clamp to prevent the caliper from coming out very far at first. Put the screw portion of the 'C' clamp into the open end of the piston and the body portion of the clamp on the caliper body. Tighten the clamp up till it is a little less than snug, so as to allow the piston to move some. With an air hose, set on low pressure, put the nozzle into the brake line port on one side, with a rag over end of nozzle. Rag will help seal nozzle into inlet port. On other half of caliper, put it into the bleeder screw port, when you do other side.

 

Put some air pressure into the calipers. Watch and see if piston start to move. If it moves loosen clamp up a little and hit with air again. If it doesn't move, increase air pressure some. You need to bring the caliper out slowly. If you hit it with air without a clamp on it it will come out of caliper body like a bullet. Slowly push it out and loosen clamp till you hear it pop past seal.

 

Wear safety glasses doing this. When it pops past seal, brake fluid and debris will fly out. Also do not have your fingers in a place where piston will pinch them when it comes out.

 

If you are doing this on quad piston calipers, put a clamp on each piston, two on each half. Work them out evenly. Once you pop one out the other one will have to be worked out by hand. Hopefully, if they were brought out evenly, there will be very little left engaging seal. If you were to bring one out all the way before the other one, the remaining one will be difficult to get out.

 

I am sure others will have different methods to remove pistons, but this has worked for me.

 

Gary

[davecb]

If your brake lines are the original lines, they may have softened up and are expanding when you apply the brakes....

[Marcarl]

Take the whole system apart, clean it all, install new seals etc, add stainless lines and you'll be surprised when you hit those brakes!!!!! You'll also be surprised at all the crystals you'll find in the system, you'll wonder that you manged to stop at all. Do everything, front and rear, and don't forget the stainless lines. Takes a little time, but boy the results are awesome. And oh ya,, put in the stainless lines.

[Mr. Holloween]

Thanks all, I'll tear it down an see what happens.I think the lines have not been repaced

Dave:witch_brew: