NewZed Posted March 8, 2015 Share Posted March 8, 2015 Actually Miles is probably right. With air in the master cylinder you could have one side flow well and the other not, because you're unable to build pressure. Still shows an imbalance in the two sides but once all of the air is out it may not matter much. You probably still have a leak but you should be able to build some pressure. Quote Link to comment Share on other sites More sharing options...
Pac_Man Posted March 8, 2015 Author Share Posted March 8, 2015 That's basically what I was trying to confirm. I'm not the one with the magical disappearing fluid so I'm not worried about the possibility that it leaked into the booster. Quote Link to comment Share on other sites More sharing options...
Miles Posted March 8, 2015 Share Posted March 8, 2015 (edited) Pac_Man In a situation like yours I prefer to eliminate the MC as a problem first then I know for certain that the MC builds pressure and can move fluid equally to each wheel. There two issues you may have to deal with: 1. air in the MC and 2. the MC leaking internally (pedal slowly sinks to the floor). So: Check for air Check that the MC holds pressure Go to the wheel cylinder: is it leaking? If so repair it. Bleed the system. Edited March 9, 2015 by Miles Quote Link to comment Share on other sites More sharing options...
Pac_Man Posted March 8, 2015 Author Share Posted March 8, 2015 Thanks, I'm fairly sure the MC isn't leaking since the pedal doesn't sink but I suppose it's still possible to some degree. Wheel cylinder is brand new and isn't leaking. Sounds like the MC is the source of my stress so I'm going to tackle it tomorrow when I finally get some time and have some help. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 8, 2015 Share Posted March 8, 2015 That's basically what I was trying to confirm. I'm not the one with the magical disappearing fluid so I'm not worried about the possibility that it leaked into the booster. Sorry. I got misdirected. The method of running a hose from the nipple back up and in to the reservoir should work. The key for doing it on the car I think is to get a full stroke of the pistons and/or have the cylinder oriented so that the internal bleed hole is at the top where the gas bubbles are. If I was going to try it on the car, I'd jack the front end up so the front of the MC is higher than the back. Get that bubble up by the bleed hole so it can get pushed out. Quote Link to comment Share on other sites More sharing options...
Miles Posted March 8, 2015 Share Posted March 8, 2015 (edited) In order to be 100% sure all of the air is out, the piston must be pushed full stroke. On the car this can be accomplished by: Unbolt the MC from the booster, but leave the hard lines connected. Pull the MC out and away from the booster - the hard lines have enough flex to allow this. Attach clear plastic hoses to the bleeders and run into the tanks. Hold the hoses securely with clothes pins etc so they don't pop out and suck air. Open the bleeders and place a screw driver etc. up against the piston being careful not to scratch the bore. Push the piston slowly with the screw driver all the way until the piston bottoms out. Repeat until zero bubbles appear in the plastic hose. Note: sometimes air will enter around the hose where it is attached to the bleeder or around the threads of the bleeder giving the impression that there is still air in the MC and will also allow air to get sucked back into the MC. So make sure the hoses fit tight and just crack the bleeder enough to allow fluid flow. Speed bleeders insure that no air is leaking past the threads. I have been able to bleed a MC on the car with out unbolting it from the booster, but sometimes the only way to get all of the air out of the MC is to push the piston all the way until it stops as in bench bleeding. Edited March 8, 2015 by Miles Quote Link to comment Share on other sites More sharing options...
Pac_Man Posted March 9, 2015 Author Share Posted March 9, 2015 (edited) Well I tried bleeding it on the car with someone pressing the pedal so I guess maybe that's my next step since it feels exactly the same. One weird thing I did notice though was that the bleeder on the rear driver side wheel cylinder (the one I previously expressed doubt about) seems to be drawing fluid back in even after tightening it back down. I also can't get the clear line to fill with fluid when bleeding it, only go a couple inches and then it will start to retreat back up the line as if it's being sucked back in. Before I go pulling the master cylinder off the car, could this be the source of all my grief? Edited March 9, 2015 by Pac_Man Quote Link to comment Share on other sites More sharing options...
Miles Posted March 9, 2015 Share Posted March 9, 2015 Your MC is not pushing enough fluid under pressure. Take the MC off the car and bench bleed it. See post #3 in http://forums.hybridz.org/topic/109115-master-cylinder-bench-bleeding/?p=1020086 When you have the MC in a vice on the bench with the clear hose hooked up per the picture in the link above (post #3): Fill the tanks slowly so you do not create bubbles open both bleed screws. Make sure all fittings and hoses are air tight. Push the piston slowly so as not to create bubbles. If you see a lot of bubbles in the tank stop for 10 or 15 minutes and let the bubbles rise to the surface. Repeat until there are no bubbles. Be prepared to plug the output ports of the MC when you are ready to transfer the MC to the car otherwise fluid will leak out. At the car hook up the hard lines before placing the MC on the booster. Tighten the fittings finger tight. Once the MC is on the booster tighten the fittings the rest of the way. Resume bleeding the rear brakes. If there is still no fluid flowing while pumping the brake pedal then the MC is bad and you will need to replace it. Quote Link to comment Share on other sites More sharing options...
Miles Posted March 14, 2015 Share Posted March 14, 2015 Pac_Man Please post how you were able to solve the soft pedal issue. Quote Link to comment Share on other sites More sharing options...
Pac_Man Posted March 15, 2015 Author Share Posted March 15, 2015 (edited) Still working on it, unfortunately. Monday marks the beginning of finals week and it's been on the back burner. I was thinking I'd give it a shot when I get the change by removing the master cylinder from the brake booster so I can actuate the pistons the full length as was suggested earlier. Of course if that doesn't work, I'll have to remove it and try to bench bleed it. Tricky part of that is I don't even have a vice to put it in... Guess I'll cross that bridge when I get to it. Edited March 15, 2015 by Pac_Man Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted March 15, 2015 Share Posted March 15, 2015 I don't know if this has already been suggested, but get under the dash and adjust the stop screw to ensure that the pedal is returning all the way up during bleeding. I had a nightmare bleeding my clutch much like you are having and the only problem was that I wasn't getting full stroke travel during bleeding. Loosened up the travel stop and bingo! It bled really fast to a solid pedal. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted March 15, 2015 Share Posted March 15, 2015 Do well on finals (good luck)-infinitely more important. Quote Link to comment Share on other sites More sharing options...
gacksen Posted March 15, 2015 Share Posted March 15, 2015 had something similar and it was a pita to get it solved. had to remove the rear calipers as they had been maxima ones to get them bleed properly. bought easy bleeders for all the calipers and they do quite a good job. the master i bled while it was in situ with hoses back to the reservoir and it seemed to be working. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted March 19, 2015 Share Posted March 19, 2015 Did you try both at the same time? Crack both left and right rear line with a small diameter hose sitting in a reservoir of fluid. Basically the pump forces the air out of the line and bubbles into the fluid and letting off draws fluid back up the line, repeat this a few times. I actually took video of the passenger side while I leaned out and watched the driver side, and to my surprise my "bled" lines pushed a lot of air on the passenger side when both were open. Feel free to give me a shout if you can't get it, it could be something simple that's being overlooked like brake travel. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.