brakes wont work

bike had a blown piston seal in the master cylinder so i rebuilt it with a kit off ebay. today i went to fill the system and bleed it and i cant get the fluid thru the system fast enough, it barly comes throu the clear tube. i tried gravity method and the system is finally full of fluid but the master still wont pressurize everyting. removed the master and nothing will drain out of it untill you remove the cover then it slowily flows out. i removed the innards of the cylinder and everyting looks good. i went to bench bleed the thing and nothing comes out of the port when you push on the cylinder, its as if there is nothing in the resivor but its full. what do you guys know about this? with vigorous pumping i can manage a tiny bit of pressure and the lever and the brakes will grab, but as soon as i let off the lever its gone. some more info, i had the entire system removed off the bike for about a month and rebuilt the calipers.

 

Did you clean the master housing real good, paying close attention to the little bleed holes in the bottom of the resovior? It won't punp fluid if it can't get into the piston.

 

blew throu them with carb cleaner, both the small hole and the big hole both were clear when spraying cleaner throu them.

 

Hi,
It sounds like you may still have a lot of air in the line, which is very compressible.

Try pumping the brake a few times until you feel a bit of resistance, even giving it a second between letting it off and applying again and then with the lever depressed open the bleeder.
If you have a BUNCH of air in the line it will help with this method but its still a fairly long winded affair from a dry system back to a functional, air free, system.

If you're using the speed bleeders, its a bit more difficult if you have a BUNCH of air in the lines as they need a certain amount of pressure to open the little valves... not so much fun with a dry system and if you look at the paint on my forks, sometime, you'll see where a lot of my brake fluid ended up when I took the speed bleeders out to get some flow first... I went through nearly two bottles of brake fluid before everything was solid, all said and told!

 

ill try to fill the lines again tomorrow but i did the gravity method to make sure fluid got down into the lines. ill try again tomorow thanks for the tip. im not using speed bleeders or anying. tried your method today as well and i never got anywhere with it. but shouldnt i be able to bench bleed the master? i tried it with the cap off i added brake fluid to the res then actuated the lever and i couldnt get any fluid to come out of the line. i know you can bench bleed car masters so why should this one be diff?

 

You should be able to bench bleed ust like a car master. I would not remount it until you can punp some fluid throught it. Are you sure the piston cups and spring are in the right position and order?

http://www.bikebandit.com/houseofmotorc ... #sch224536

Look at this pic to check and see.

 

Hi,
In my personal experience, so far, I've bled the brakes from dry twice so far... the thing is, the first time I did it I went around and around in circles trying to work out why it wouldn't pressurise and eventually, in my case, it came down to the old, slow and steady concept.
I was sure there was a fault somewhere but as I bled and bled and bled and ... I found that right up until that last miniscule air bubble came through I was doubting the integrity of the MC/distribution block/lines. The last time I did it, I put some time aside to do it.
The speedbleeders made the end part easy but going from dry to having the speedbleeders have enough pressure do their job was still a bit longwinded.

Just thought I'd mention... and only in my experience, of course.

 

this got me riding again...

Read SLKIDs post to me.

http://xjbikes.com/Forums/viewtopic/t=28542.html

 

Bleeding brakes from dry is a pain. I have a vacuum pump to help pull the fluid through. It makes the job much easie and faster.

 

It's still a pain, it takes for bloody ever to get the system full again and bubble-free once it's been dry, the vacuum pump does help a lot but it's still a pain.

That being said, are you sure it's the right rebuild kit? eBay sellers aren't the most reliable source of correct parts.

 

mlew i thank you for the pic its really nice of you to get that for me, mad props. i took some time earlier in the day to google the kits as well as how it is installed and everything appears to match, but big fitz, im as certain as i can be that it is the correct kit i compared it to the old one. i have a vacuum pump at work ill go get tomorrow, sence i have to go in, (that just sucks) and try to force the fluid thou. ill fill you all in on the details. i have rubber band over the lever right now so lets see if i get lucky. also i read the post billb sent but am not sur of the directions. im supposed to remove the caliper bolts and let it rest on the rotor then start pumping again till the caliper moves? how will that make a difference? sorry just ignorant. hey cds, i also just decided to bleed the old fashiond long winded way and after al long while i finally got fluid down to the calipers and i can get them to grab but only after alot of hellatous pumpin. but why cant i get the master cylinder to bench bleed? that has me puzzled cause that seems to be the big problem right there doesnt it guys?

 

Its so simple its confusing but, it works. Read it again, it will help you start to build some pressure.

 

If you use your vacuum pump be sure to rig some sort of resovior to pull through. You don't want to ruin a vacuum pump by sucking brake fluid in it. A strong plastic bottle with a in and out fitting will work.

 

hand held vac pump, so i should be alright.

 

I just put a long piece of vacuum tube on the nipple and suck until no bubbles.

 

spent the better part of the day mesisng with the brakes and still cant get good pressure. but on a possitive note i did get alot of pressure out of the mastercylinder. i unscrewed the bolt held my finger over it and expected to pump and get nothing but i pumped and it tried to push my finger off everytime so thats good. i do have the brakes grabing ever slightly barley enought to dip the front about an inch but its better than befor, ill just keep bleeding i guess.

 

When I changed the fluid in mine I had a real hard time getting it to feed down there.

What ended up working was half-stroking the lever quickly while holding my thumb tightly over the port on the caliper with the bleeder screw removed entirely.

It spit air, then air and fluid, and finally fluid, then it was done. Amazing how hot the fluid got just from this.

 

I don't know if anyone mentioned it, but you don't have a situation where your brake hose arches upwards from the MC then down, do you?

In that case you'd have to slide it to a high position on the bar, obviously, remove the air trap...

 

Still not desperate enough to try this one?

http://xjbikes.com/Forums/viewtopic/t=28542.html

 

saying it twice, but put a long piece of vacuum tube on the bleeder and with the top off the master cylinder suck on the hose until nothing but fluid comes through.

 

I'll probably be trying this in the spring since I don't have a pump!

 

Go to Harbor Freight, in person or online, and buy the mighty vac for $30.

 

Wizard Says to Duct tape the clear vacuum line into a shop vac hose. Start up the shop vac and pull brake fluid through until you see it coming. Thighten your bleeder screw and you got it. Let us know if that works for you.

 

That's one heck of a vacuum pump alright.

 

The information withdrawn by bobe7316

 

thanks guys. man this weather has me down for the moment, i get home and its dark and wet. i will try everones tips asap, and il let you know how it goes for me.
i dont have a high spot in the brake line next to the master.
i did try the trick bill and it didnt work for me
a mighty/shop vac sounds like a mighty good idea mr wizard.

 

ok after some more old fashoned bleeding not to mention my buddy who thinks he knows everyting about bikes gone i think i was able to get it. now it wont start so i cant really verify till i get this electrical prob sorted out!! :evil:

 

Brakes work! The problem was the screw that goes through the lever was installed wrong! The lock nut was on the wrong side. Well at least I kno I got every last bit of air out

 

brakes are better but still dont work. so if im not leaking fluid anywhere and have only a very few tiny little bubbles coming out of the clear tube , the only ting it can be is the master right? cause calipers are solid not leaking, all hoses are tight junction block is blown trough, i have been bleeding teh brakes sence i started this thread, only ting left is master itself cause i did rebuild it. what do you think?

 

can anyone post a pic of there master and hand lever along with the screw from the hand lever to the piston for me?

 

On my 82 XJ650 I also got it with no front brakes. Got bottle, put brake fluid in bottle, attached tubing from bottle to bleed screw. Opened up bleed screw and slowly squeezed. I squeezed till all air bubbles came out of master. Worked perfectly. Another problem I had later was the front brake started to slowly lock up. It turned out to be the little tiny hole in master that would not let fluid back in master.

 

Sure if need be; might take a little while though.

What are you looking for? The relationship between the adjusting screw and the lever?

It will vary from bike to bike and because of personal preference, for instance I have mine adjusted to add some free play to the lever since the rebuild.

Concern:

Those few tiny bubbles mean the system isn't fully bled yet they're what you're trying to get rid of.

This takes a while. My own personal theory is that the rough machining on the inside of the caliper bore tends to trap "microbubbles" in the machining grooves, making the initial bleed a serious PIA.

But if you're still getting bubbles, you're not fully bled yet. Be sure to wrap a turn or two of teflon tape on the bleed screw (don't block the hole) to prevent air from coming from around the threads, producing "false" bubbles.

 

kwiski, i have used your method many a time. i have a one man bleeder i got from autozone which consists of a bottle filled with fluid and you squeeze close valve and repeat. is that what your refering to?
fitz, i will def try the teflon tape cause im tired of brake fluid dripping all over the place this will probably get rid of the little bubbles too. as far as the pic i just want to see where everyone is putting the lock nut.

 

Level the Master Cylinder.
Pull the Cover and Rubber Diaphragm.
Test the Master half-full.
Pull the Brake Lever. Watch for Fluid squirting-up, ... like a fountain.
If the Fluid squirts-up high, ... you need to Service the Master Cylinder.

One Man Bleeders.
A One-man Bleeder works OK for awhile.
Modify the One-man Hose to guarantee a Air-tight fit.

Add 3-Inches of Rubber Windshield Washer Hose to the Vinyl Hose of the Bleeder.
You join the two hoses with a Hose Union.

You have to work to get the Windshield Washer Hose on the Bleeder.
But the tight fit guarantees no air will re-enter the system.

 

hey rick yeah i do get the fountain but only aftersome pumping if i go and just squeeze the handle once i wont have a fountain. so is that good? also i rebuilt the master so unless i got the wrong kit which i doubt cause i compared the new with the old closely i must have a bad master casing am i right?

 

No, but you may still have a plugged port.

In the bottom of the master cylinder are what appear to be two "false drillings."

Look VERY CLOSELY at them; one of them has a teeny tiny hole in the bottom of it. That hole has to be clean clean. I use a single bristle plucked from my HD parts-cleaning brush, and grasped with a pair of hemostats to poke the little hole clean. (Don't operate the lever with the bristle down the hole, the cylinder moving will pinch it.)

One good sized speck of crud and the hole will need poking again.

Some "fountain" is normal, especially if you jam on the lever quickly. (Don't.)

You won't get good brakes until you have no more bubbles coming out the bleeder, pure and simple.

Getting these things completely bled is an exercise in frustration; I've rebuilt more motorcycle front brake systems than I could possibly count, but '80s Yamahas are the biggest PIA to bleed that I have EVER seen. I went through the same BS when I put SS lines on my SR500s, back in the day. I honestly think it's the bloody machining grooves in the caliper bores; I've NEVER had as much of a ring-tailed hassle in over 40 years bleeding brakes as I've had with these, period. Norton, Triumph, BMW, Honda-- all relatively straightforward, bing, bang, bled. Not so '80s Yammies.

Every one was a PIA.

EVENTUALLY you'll get it; I have found that once you get "decent" brakes, a few heat cycles and then a re-bleed will net you some nice fat bubbles. Put a hundred careful miles on and re-bleed; do it again after another 200-300. THEN it will feel like you're grabbing a rock, and you'll need to ADD lever play like I did.

 

A "Swell" ... is Normal.

A show that looks like a miniature "Old Faithful" indicates a problem.

The Fluid in the Cylinder needs to be pushed OUT of the Cylinder by the Front Hydraulic Seal. When that Seal is OK, ... the Brake Fluid gets Pushed and Pressurized in the Lines ... and the amount of Fluid BETWEEN the Front and Rear Seal stays constant ... some getting "Moved" into the Reservoir.

When the FRONT Seal FAILS, ...

Brake Fluid is NOT forced OUT of the Cylinder and down to the Lines.
HYDRAULIC PRESSURE increases BEHIND the Front Seal.
Brake Fluid is FORCED out the Cylinder Replenishment Orifice and "Fountains" up out of the Orifice under pressure.

When you see "Old Faithful" when you grab the Brake Lever.
You NEED a Master Cylinder Rebuild Kit.
All the Kings Horses and all the Kings men, ...
ain't getting you good brake pressure again, ... without the Kit.

 

He rebuilt the M/C already. Unless the bore in the M/C was corroded, pitted, or excessively worn and went unnoticed, the master should be OK.

apsolus, how carefully did you clean/examine the master cylinder when you rebuilt it? How was the bore? It might need to be honed; if you can't get pressure at all and keep getting the geyser Rick describes then you may need to pull the M/C down and look in the bore.

I still think this is simply a case of the "nearly impossible to get the bloody thing bled from empty" syndrome that a whole lot of folks have posted about; it takes a whole lot more doing than one would think.

 

You'll have to look closely at the Bore of your master Cylinder.
It helps to have a Pen Light.

The Bore should be Clean and Not Pitted or Scored.
If you find an accumulation of light-colored matter on the surface of the Bore; it needs to be removed.

Super-heated with a Pencil Flame of a Torch will disintegrate the build-up and turn it into dust.
The foreign matter can be scraped away. Don't damage the Bore.
Tiny pitting can be Honed.

Fabricate a Hone.
Duct Tape the edge of a Sheet of 800 Finishing paper to the surface of a Dowel.
TIGHTLY Roll the Sand Paper around the Dowel.
Add another Sheet if the Roll isn't a TIGHT Fit in the Bore
Be sure the ROTATION is in the Direction that will Rotate the Paper NOT Unwrap it on the Dowel.

Put a 1/2" Wrap around the Tape to keep it tight.

Use WD-40 as a wetting agent and Rotate the TIGHTLY FITTING Rolled-up Sandpaper in the Bore.
Move it In & Out creating a Cross-Hatched Pattern on the Bore until the Pitting is gone.

 

nice advice gentlemen i will def try your trick rich.
bigfitz i hear ya on the bleeding after i check the master again for any abnormalities ill get back on it, thanks again guys

 

Clean and INSPECT first; don't assume you need to hone the inside of the cylinder. You could very well have a buildup of dead dried ancient brake fluid in there that just needs to be cleaned out via Rick's method.

You hone it to remove minor pitting; major pitting/scoring means replacement.

 

here are pics of the inside bore of the master. i have a hole at the area right below the resevior and i have what appears to be major pitting directly below it on the bottom side of the bore. can any of you conferm how many holes are supposed to be in the master? those pics are the best i could get.C:\Users\Svetlana\Desktop\DSC06551.JPG
well thats the best i could do to get the pics up. sorry guys. ill have to look it up anyway this shouldnt be a problem for anyone who has had one appart before. so if you need pics ill be looking into it.

 

2 holes in the mc res.No pics showed up

 

cutlass thank you for your reply, sorry if my post was misleading but i was talking about inside the bore. yes ihave the two holes, one small and one big in the resevior, but in the bore where the piston rides i have one right under the res, which i belive is the feed from the res to the bore area and another one directly below it on the bottom of the bore, not sure if its supposed to be there or if its some mega pitting. im in the search function learing how to post pics still lol

 

here goes

 

heres another better pic wow now thats bad! let me know what you all think of that. wonder if checal sells them new?

 

Before you get too far ahead of yourself; take the MC to a Gun Shop and get a Bore Cleaning Brush and a Small Box of Patches.

Scrub the Bore and remove anything on the Bore except Bare Metal.
Soak a Patch with Brake Kleen and Clean the Bore exceptionally well.

Using a Pen Light, ... Examine the Bore for Pitting.
If your MC is OK, ... the Pen Light will reflect on the Bore and reveal imperfections and foreign matter.

If the BORE is OK, ...
Move onto the Passages.

 

rich you didnt see the pic? this master is shot. its got a huge hole in the bottom of it. thats the best i could do with the pics sorry they arent more clear.

 

I'm having a hard time with both of your photos. Is that a jagged, irregular hole, like a rusted through pipe?

 

yes it is.
hey how does one get a hold of chacal? tried pm'n him but nothing