maximus Posted June 7, 2004 Report Share Posted June 7, 2004 Just recently changed the pistons on my rear brakes. I am having a lot of trouble getting the brake fluid back into the brake line. I have tried injecting the fluid into the reservoir, but it just flows back out. Has anyone any tips or can anybody tell me the sequence of moves I have to take, to get this bleedin' fluid back into the bleedin' brakes"!!!!! Quote Link to comment Share on other sites More sharing options...
boofont Posted June 7, 2004 Report Share Posted June 7, 2004 I hope I'm not stateing the obvious, when you are attempting to fill the reservoir have you got both ends open, ie an open line from resi to the caliper? If you have the caliper end closed off then you will have an air lock and the fluid will not flow very well. Quote Link to comment Share on other sites More sharing options...
96woody Posted June 9, 2004 Report Share Posted June 9, 2004 I once had to bleed my rear brake too. I found the best way to do it is to fill the reservoir with brake oil and open up the valve on the calliper. Then continuously pump the brake until oil start to come out of the valve and if the oil level in the reservoir goes down then keep topping it up. Once oil has reached the valve, close it off. Then open the "bleed" valve, on the main valve you have just closed, but make sure you have a small piece of pipe of tube of some sort filled with brake oil on covering the valve so as not to accidentally get more air into the system. Then, like before, keep pumping the brake until it will not press all the way down (there is no air left and so the pistons are being stopped by the disc, as they should be). Once you have achieved this then close the valve, making surely it is adequately tight enough but not over tight. Then careful remove the tube filled with brake fluid and at all costs avoid getting any of your discs or pads as this will prevent them from working. You only need a small amount of brake fluid, just enough to form a small barrier to stop any air getting in whilst the bleed valve is open. This also is a good indicator as to you progress because as the air bubbles are pumped from the system you can see them rise up through the oil in the tube. Finally check the oil level in your reservoir and top it up if needs be. And there you have it a working rear brake with no air in the system. Hope this helps. Quote Link to comment Share on other sites More sharing options...
bigfoot Posted June 9, 2004 Report Share Posted June 9, 2004 I always use a syringe to push fluid from the caliper back to the master cylinder. Take the cap off the reservoir, loosen the bleed nipple on the caliper and push the fluid back the way until no air is seen arriving in the reservoir. This also helps as it pushes any dirt up and out of the system leaving only clean fluid. If there is dirt coming up in the reservoir finish off by using the syringe to suck it our and then refill with clean stuff. Never fails. Quote Link to comment Share on other sites More sharing options...
windlestone Posted June 17, 2004 Report Share Posted June 17, 2004 took me seven days to bleed rear brakes. I'm still having nightmares. The problem is the hose from rear caliper runs inside the swinging arm and air gets trapped at the bend below the master cylinder. I hung my bike by the front wheel from the garage roof. Take rear wheel out and caliper off the frame, take exhaust rear and middle boxes off .Get all brake lines as straight as you can from caliper up to reservoir. fill the system from the caliper bleed screw with a large syringe. When the reservoir is full you need to take some fluid out and keep filling system untill there is no more air bubbles. I still had no pedal after doing this. Bleed the system from the lowest point to the highest point. This is a really boring tedious job and takes ages. I found the most effective way to bleed the system was to push both calipers in at once then crack open master cylinder hose bolt. Keep pressure on calipers then tighten bolt up. Move hoses and tap on them and master cylinder every now and then just to help release bubbles. good luck it's a nightmare. Some lads have said it bled first time no problems but if you get air trapped it can take forever. Quote Link to comment Share on other sites More sharing options...
ridgrunr Posted June 22, 2004 Report Share Posted June 22, 2004 It's almost impossible to bleed the rear brakes using the brake pedal. Not enough travel in the pushrod and piston to pump out the air in the top of the master cylinder. It is easy however to bleed them, just like you would a car brake from the master cylinder to the brake. Just take off the brake lever and pull the acuator rod out of the master cylinder. Then stick a phillips screw driver up in there. Put hard pressure on the screwdirver and pump the brake up, then open the bleeder valve at the disc (make sure you have a hose on the bleeder nipple to keep the fluid off the disk). When the screw driver bottoms out in the top of the master cylinder shut off the bleed valve. Keep pressure on it till you've closed the valve. Don't let it suck air back into the system. Pump it up again with the screwdriver (just like pumping up a car brake for bleeding). Do it a few times till the air quits coming out. Make sure to keep the brake reservoir full so you won't suck in air from the top. When you are only getting fresh brake fluid and no air, tighten down the bleeder valve, remount the brake lever and actuating rod, and go riding. Works everytime and is easy. Quote Link to comment Share on other sites More sharing options...
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