What's wrong with my brakes??!!!

[tweaker]

The brakes on my 300EX were not very good when I got it a few weeks ago. I ordered new pads, freed the slide bolts on the calipers up and it ended was worse. They'd barely slow the quad down. I then rebuilt the master cyclinder and both front calipers. I bled the line at the master cylinder, the t-fitting and both calipers. I'm getting no air anywhere. My brake lever still pulls all the way back and I can force the wheels around with my foot. I can see the pads clamping and letting loose, but there's just no pressure building at all. What's going on?

[400exrider707]

Lines need to be bled... let me guess. you're getting fluid out of the bleeders on the calipers correct, but still no pressure? This happened to me before when I unhooked the brakelines. The calipers themselves need to be filled with fluid. I just used a piece of plastic and folded it into a V shape. remove the bleeders, then pour some fluid right into the calipers, then repeat the bleeding process, it should take then. ;)

[TRX450RACER174]

Something else i have done is use a large type of syringe and a tube fill it full of fluid and push the fluid from the caliper to the master, or if you have a syphon bleeder it is also a lot easier that way you can pump the mstr as it is puilling the fluid through the system. Good Luck.

[tweaker]

How could my calipers have air in them? The fluid comes in from the bottom and the bleeder valve is on the top. Obviously it's an issue trying to bleed these things, evidenced by you guys having similar problems. I just don't understand why. What have some of the rest of you done?

[400exrider707]

Originally posted by tweaker
How could my calipers have air in them? The fluid comes in from the bottom and the bleeder valve is on the top. Obviously it's an issue trying to bleed these things, evidenced by you guys having similar problems. I just don't understand why. What have some of the rest of you done?

Thats exactly why, the fluid is coming in from the bottom, its only gravity fed, its not reaching up into the caliper. I'm not sure exactly why it works this way, but once you start putting fluid into the caliper, it will bleed properly, try it out and let me know if it works.

[blsnelling]

I'm getting fluid from the bleeder of both calipers, no air. I also just finished vacuum bleeding probably 16 oz of fluid through the system, occasionally pumping the master cylinder. It's no better than it was. Is it possible that my lines are just shot after 13-14 years and flexing? I can't see anything. I'm stumped.

[blsnelling]

BTW, both Tweaker and Blsnelling are me. I had problems when I originally set up my account.

[TRX450RACER174]

Is it possible you put the mstr cyl plunger in incorrect? and was it doing this before you rebuilt the cyl? those cyl are aluminum and any type of grooves can affect the plunger i would double check that just a suggestion, as far as the lines they could flex but i wouldn't think to a point that you could pull it all the way to the grip, to me that seems like it has air or the cyl is not holding pressure.

[blsnelling]

The bore of the master cylinder is smooth and shiny. No grooves or corrosion at all. Both piston seals were installed the same as factory with the cups facing into the bore. As far as holding pressure, I can hold the lever back and it never looses the pressure it does build. It doesn't seem to be leaking. Another thread suggest locking the lever all the way back over night. Pump it 10 times and lock it back again. He believed this reverse bled the system somehow. I don't know if it works, but I'm trying it tonight. Tomorrow I may try forcing fluid from one caliper to the other, and then up to the master cylinder. Thus, back bleeding it. Seems like several have suggested this.

[quad97]

i think your lines are bad. I had a set of brake lines come apart on the inside in the middle of a race. tried everyting to fix the brakes and nothing helped until I changed the lines. they were even steel braided and looked fine on the outside, so if your lines are that old and stock it is very possible they are internally comming apart.

[blsnelling]

I'm about ready to agree with you. Do Streamline lines come with two or three pieces? If I'm replacing lines, I want the one that connects directly to the master cylinder as well. I'm looking at the picture here and it looks like it replaces everything from the MC to the calipers. http://www.magicracing.com/Streamline-Front-Brake-Line-Kits_p_146-953.html#

[quad97]

I'm not sure if streamline makes a sigle line to the mastercylinder, i know that they make a dual line kit that comes with a longer banjo bolt to hook both lines up. Galfer uses a single line and block to two lines like the stockers.

[JOEX]

I have Streamline and when I got them they had the option of single line with splitter or a dual line. I opted for the single and it was a complete line replacement from the master cylindr to the calipers. That was a few years ago though.