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Discussion Starter · #1 ·
So I decided to bleed out all the reddish gooey old brake fluid from 1982 from the cx500. I figured the master cylinder has weak pressure already, so It can't get worse, right?



So I tried to follow the manual. It says to remove the bleed valve cap, then put a tube on it and then unscrew it to release the break fluid. It started to come out and into the container I had. So right in the middle of the show, my wife needs something for the baby, so I hafta leave for a second. I come back, the master cylinder is just about empty.



So then I read to keep a close eye on the master cylinder level to aviod getting air into the system. Oh crap. So I add some fluid in the cylinder, topping it off. I pump the lever, but it has no pressure catching. Uggg



So I tried to pull the lever BACK to the handlebar, and while holding it there, open the bleed valve on the caliper. I have done this dozens of times now, and each time a tiny bit of bubbles rises up from the hole in the master cylinder bottom, then I close the valve, then release the lever.



So far its not working. NO pressure. At least the brake disk isn't getting rubbed while NO brake is applied, but MAN...no pressure. Anything I can do to get pressure back? I stopepd seeing bubbles in the tube coming off the bleed valve, but still no pressure from piston

Please help!
 

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It's kind of a tricky task to bleed the left side caliper with the brake handle on the right bar. It can take a lot of cycles of pulling the handle, tie it down, open bleed valve, release handle, repeat......many times to get the air out.



Best bet is to have a helper so you can alternate the lever squeeze with the open and close of the bleeder valve. Lady of the house could do the handle, and keep an eye on the m/c, alert you when it's getting lower, re-fill, then do it more.



Eventually it will firm up. Patience and help is best.



Joel in the Couve
 

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Discussion Starter · #4 ·
Well it appears my piston isn't doing anything for some reason. I can pump it all I want, no fluid movement. I try the lever pull to handle, open bleed valve, close bleed valve, release lever from handle slowly...this isn't creating any fluid movement. I think I have air in the master cylinder piston area maybe??? Why else would the lever pump have no pressure, when the master cyliner resevoir is full of fluid?



I am stumped...I am thinking of taking a medicine syringe full of brake fluid and injecting it into the piston holes at the bottom of the master cylinder...I dunnno
 

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..I am thinking of taking a medicine syringe full of brake fluid and injecting it into the piston holes at the bottom of the master cylinder...I dunnno
This works and it works well. The air wants to go up so give it a helping hand.



Of course, your master cylinder could be shagged.
 

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Of course, your master cylinder could be shagged.


Ok, I have to ask... What's the difference between "shagged" and "knackered"?



Fib
 
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Ok, I have to ask... What's the difference between "shagged" and "knackered"?



Fib


from an english perspective,they both mean tired out.

knackered is from working and

shagged is from........
 
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Knackers I think were slaughter houses. A horse that was old and worn out was considered ready for the slaughter house, - or 'knackered'



Shagged, uh, yeah, uh, parts that have been intimate with......
 

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Well it appears my piston isn't doing anything for some reason. I can pump it all I want, no fluid movement. I try the lever pull to handle, open bleed valve, close bleed valve, release lever from handle slowly...this isn't creating any fluid movement. I think I have air in the master cylinder piston area maybe??? Why else would the lever pump have no pressure, when the master cyliner resevoir is full of fluid?



I am stumped...I am thinking of taking a medicine syringe full of brake fluid and injecting it into the piston holes at the bottom of the master cylinder...I dunnno


Spit on your hand like this,



http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=9&t=315



 

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Discussion Starter · #12 ·
I think tonight I will also remove the brake caliper from the rotor and see if the caliper pistons are extended at all. Maybe there is air all through there as well.
 

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Discussion Starter · #13 ·
Crikey....



Well I removed the banjo bolt at the master cylinder and cover the open hole up while pressing the lever, I released the air and then pressed sealing the hole as the lever returned out, which induced a vaccuum pulling the fluid into the screw hole. So it seems the piston does work, sealing up with fluid pretty well, and the lever becomes pressurized...UNTIL....



I try to removed my finger and get the banjo bolt back on quick before the fluid gets replaced by air...I screw it in as fast as humanly possible. The lever looses pressure almost as soon as I start screwing the thing in. I DO have the bleed valve on the brake caliper shut when I am doing this



So next I think I will try the suction thing from the bottom bleed valve. I have a siphon...though maybe I could hook it to the bleed valve and start pulling.



BOY...I tell you. I almost just want to get a new master cylinder from ebay, but what if pressurizing the system is still just as hard with a new one?
 

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Discussion Starter · #15 ·
Okay, thanks for all help! Got it back under pressure!



I tried a little bit of everything I read from your links and on here, and I will summarize:



With the brakeline hooked up to caliper, I couldn'tt it to pressurize even with the priming trick (removing banjo bolt at master cylinder and putting finger over hole, the pumping out air until brake fluid comes through) There must've been so much air in the brake line that the cylinder would just fill back with air after 1 pump.



So I got a rental mityvac type thing from advance auto, they let you take it, use it then get you money back once you return it. I hooked it up to the caliber bleed valve and started pumping...nothing came out!



So I yanked off the banjo bolt on the caliper, expecting fluid to drain out. Not a drop came out, so I realised the line was dry. Hmmmmmm



I pulled the banjo bolt off the top, (master cylinder) and still nothing spilled out of the line, so I reprimed the master cylinder by pumping with finger over hole, allowing the air to pressure out and pumping until brake fluid started to squeeze by, I then screwed the banjo bolt connection back on at the master cylinder (with the one at the caliper STILL off) and started pumping. I felt some pressure and SAW brake fluid slowly coming out the lower banjo bolt, so I added some fluid to the master cylinder, because as I pumped the lever and it sprayed out the bottom on the driveway, the level dropped in the master cylinder quickly. Once I had a good flow and was SURE of it, I stopped pumping. To my surprise, even with the lower banjo bolt off, the fluid doesn't spill out because of the vaccuum, so I re-hooked the caliper banjo bolt up at the bottom, then started pumping. I also cranked up the mityvac thing and opened the bleed valve.



I could see a strong flow going with the tubes for the mityvac thing, air bubbles pushing through into the collector cup thing that the vaccuum pump comes with. I cranked the vaccuum pump good, and continued pumping with the brake lever, until the flow looked like all brake fluid. I had almost filled the collector cup. I got the cap back on the master cylinder, and the brake level was as solid as my new bike. COOL



I did noticed the master cylinder is a bit 'weepy' unfortunately. The oring and plastic resevoir needs to be replaced. Probably the resevoir gasket too, but its not coming out fast or anything. Just enough to be annoying. At least I know how to recharge the fluid if I get new parts now.



Thanks for all help and advice

MW
 

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but its not coming out fast or anything. Just enough to be annoying.






mine was like that too, then one day there was NO pressure and all fluid leaked out, and that was with it not even being ridden. better do sumthin about that pretty soon
 

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I had this exact problem yesterday. I found this thread and tried the syringe trick. I forced fluid into the bleeder valve and watched gleefully as air bubbles appeared in the reservoir. when the air bubbles stopped, I tightened the bleeder valve and had good brake pressure. This was after hours of "Squeeze, Loosen, Pause, Tighten, Release, Pause, Repeat" with no resultant brake pressure. Pushing fluid in from the bottom of the system took about 7 minutes. Thanks for the idea.
 

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Knackers I think were slaughter houses. A horse that was old and worn out was considered ready for the slaughter house, - or 'knackered'



Shagged, uh, yeah, uh, parts that have been intimate with......


Sorry to interrupt. Thanks for the answers guys. I love words and knowing where those words and and/or sayings came from.



Ok, back to business...



Fib
 

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Sorry to interrupt. Thanks for the answers guys. I love words and knowing where those words and and/or sayings came from.



Ok, back to business...



Fib


"Knackers" in the UK is also slang for testicles




As in,"That was a kick in the knackers"
 
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