front brake help

eb_xs · Posted: May 19, 2008, 1:54 pm Post subject: front brake help

hi everyone.

my front brake locked up on me one day and so i took the caliper off and rebuilt it cleaning out everything and replacing the seals and one of the pictons which was shot. everything worked great when i put it back on, but then it locked up again after sitting for a few days. i opened the bleed valve and the brake freed right up. but then a few days later i had the same problem.

so obviously, from what i've already read on this board, it's a problem with the lines or the MC. now, i'm kinda new to bikes so i was wondering if why the brake would lock up over night without me even pulling than lever. is it possible that the diaphragm in the MC resevoir is shot and allowing the fluid to just find it's way down thanks to gravity over time and fill up the caliper causing pressure? or is there another part of the MC that prevents fluid from moving that is malfunction? or do i just have too much fluid in there?

when i've bled the brake, i noticed the fluid moving forward and backward when i squeeze and release the lever so it _looks_ like the fluid is sending and returning like it should. but for whatever reason, when it sits for a while, the pressure just builds up. any suggestions?

thanks for any and all help. i'm kinda new to old bikes so please forgive my ignorance.

royfisk · Posted: May 19, 2008, 2:00 pm Post subject: Re: front brake help

brake hose's. what happens is the inner liner cracks, where you cant see it and when the fluid tries to retract the liner causes a blockage and does not allow the fluid to fully retract.

eb_xs · Posted: May 19, 2008, 3:33 pm Post subject: Re: front brake help

makes sense. thanks!

xsleo · Posted: May 23, 2008, 9:20 pm Post subject: Re: front brake help

new lines are a good idea. afterall the ones you have are 30+ years old. in the master cylinder, there is a return hole that can plug up and cause problems.

jimmythetrucker · Full Member Joined: Mar 12, 2008 Posts: 1283

Roy & Leo -- There's lotsa lines for sale out there. I see clear plastic, braided plastic, braided stainless, rubber (vinyl?) hoses -- So what's the best lines to get?

xsleo · Posted: May 23, 2008, 9:43 pm Post subject: Re: front brake help

most folks use the braided stainless. when you pull on the lever, the pressure builds up. the stock rubber lines will swell a little bit and not all the pressure goes to the caliper. with the braided lines they don't swell, so all the pressure goes to the caliper. makes the brakes firmer.

eb_xs · Posted: May 27, 2008, 2:14 pm Post subject: Re: front brake help

hey leo, i see by your signature that you have a 75 xs like i do. if you are using braided lines, where did you get them for the 75? mikesxs has them but only for the later models. thanks.

xsleo · Posted: May 30, 2008, 3:51 am Post subject: Re: front brake help

i'm in the rebuild process , collecting parts, i haven't up graded the brake lines yet. just tore the engine down for rebuild. i will have to study a bit more on the lines. i will probably use the mikes. i have a 79 front end and dual brake setup i will use. i think for the single brake they sell a one piece line that should work. i have been looking in a few catalogs at lines. i am also trying to change to a disc brake on the rear. lots of fun just thinking about what you can do with these bikes.

eb_xs · Posted: May 30, 2008, 10:26 am Post subject: Re: front brake help

i did some of my own research and found Russell Performance (Edelbrock) offers all kinds of hoses and fittings. you can basically set yourself up with hoses and fitting through them.

http://www.russellperformance.com/index_moto.shtml

good luck with the rear disc conversion. and yeah, i'm having a lot of fun playing with this bike.

xsleo · Posted: May 30, 2008, 10:08 pm Post subject: Re: front brake help

i just got the 79 front end on the bike. got the dual brakes bled out and wow what a difference. the engine is out, so i just pushed the bike around. just a light touch on the lever will slide the tire in the grass. just a little more to slide the tire on the driveway. the old single setup pulled harder and the brakes not very good. could be that the old caliper was seizing up. i'm useing a master cylinder off an 82 seca 650 turbo. when i get the engine back in then i'll work on the brake lines. don't really matter how the brakes work if it don't go.

jayel · Posted: May 31, 2008, 11:35 am Post subject: Re: front brake help

any place that make hydraulic lines or brake lines for cars should be able to make up motorcycle lines, I've seen O'reillys and some Napa stores make lines, take in your old lines so they can match fittings and even if they don't make the lines themselves they may tell you who does in your area

eb_xs · Posted: June 4, 2008, 11:18 pm Post subject: Re: front brake help

roy fisk was right. brake hoses. i just swapped them out with new braided stainless and what a difference. fantastic. thanks.

pumps · Posted: June 4, 2008, 11:53 pm Post subject: Re: front brake help

eb xs where id you get them?

eb_xs · Posted: June 5, 2008, 8:38 am Post subject: Re: front brake help

i ordered them from summit racing. i got the dot approved universal hoses by russell performance. i got a 9" for the top hose and a 12" for the bottom. i also ordered 3 AN to 10mm banjos and 3 AN to 10mm female fittings to attach to the hard lines. everything fit.

pumps · Posted: June 5, 2008, 11:55 am Post subject: Re: front brake help

Were they expensive?

eb_xs · Posted: June 5, 2008, 12:55 pm Post subject: Re: front brake help

the whole set up that i ordered - hoses, banjos, fittings - came to $84. with handling was $10 and i paid for second day air which was an extra 15 bucks so grand total was $108.82. i was trying to find a ready made kit but couldn't find anything for a 75 xs so i had to hunt and peck and do some measuring.

kinda pricey considering mikesxs has rubber ones for $22 each but he's been out of stock for awhile and i wanted to take the opportunity to upgrade anyway.

and summit gave me a free hat with my purchase. Laughing

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