NEED HELP! brake master cylinder wont pressurize/prime for the life of me.

[brady polowy]

hell all,

I am in need of some advanced help. 

I have been through all sorts of renditions of priming/pressurizing the master cylinder to bleed the brake system after installing a rebuilt caliper and brand new stainless brake line.

I have had no luck getting any lever pressure. 

it has been three messy days of brake fluid covered aggravation.

I am looking for someone to help me, "hands-on" with my CX500 front brakes.

I know most procedures for manually bleeding brakes, so i dont need obvious suggestions (i.e. vacuum pump, reverse bleed, do this, do that) to cure this problem, I need a first hand diagnosis of the problem.

If anyone has time to help, I would love the time. 

beer, food and other "incentives" are on the table for bartering of your time/labor.

thanks in advanced!!

Brady

[brady polowy]

more details:

its my 80 honda cx 500

no ABS, no hydraulic link, one caliper (rebuilt), newer universal MC, one brand new shinny stainless steel brake line. 

everything was working well before i took it apart to replace the old brake line and caliper.

the problem seems to be from the MC not wanting to prime.

[Sammy Joe Osborne]

I'm having the same issue with my CB550. Everything was fine before I added the new caliper and steel braided brake line.

I did install a new banjo bolt and brake light sensor (like this), and I'm starting to wonder if the hole in the banjo isn't lining up with the master cylinder or if the brake line sensor is somehow interfering with the flow.

Something to consider if you've got a similar setup

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[Steven Jackson]

Try bleeding from the banjo bolts

Sent from my iPhone

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[Drew Mobley]

Had the same problem with a hydraulic clutch on an older Magna. Sometimes there is one big airbubble that can get caught right where the banjo bolt connects to the MC. No matter what bleeding you do, it wont come out. The solution, that someone else brought up on here, was to crack open that banjo bolt.  Try that. Crack it, squeeze lever, tighten back up. Might be worth a try.

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From: brady polowy <bra...@gmail.com>
To: chivi...@googlegroups.com
Sent: Friday, August 2, 2013 10:00 AM
Subject: [ChiVinMoto]: Re: NEED HELP! brake master cylinder wont pressurize/prime for the life of me.

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[norman hogeveen]

What you really want is a completely vertical line from your caliper to your master cylinder to get out all the bubbles.  This is very hard to do considering any motorcycle and the way the lines are mounted/routed/coupled etc.

The culprit is usually in the master cylinder.  I have bleed many brake systems and have found the following to be very helpful.

• make sure you have bleed the caliper and that no more bubbles are coming out of it. tighten the bleed nipple.
  
• Fill up your master cylinder to recommended level with Brake fluid.
  
• Secure the cap to the master cylinder.
• detach it from your handle bars.
• while holding it in your hands move it into a slight, or beyond, vertical position and lightly tap on the unit and "flick" the lever while holding it. this should "help" the trapped bubbles rise to the point where that when you "flick" the lever they can escape into the fluid reservoir.  You can also do this with the cap off to observe the bubbles coming out and you will feel the lever "stiffen up" knowing that you have got all the bubbles out. If you do this with the cap off be careful not to drip fluid on our paint it will eat through and damage your finish, or worse.
  
• This "should" get the majority of the trapped bubbles out and/or solve your problem.

I have seen people do the "loosen the banjo bolt at the master cylinder" trick before and this might/might not work, but you will have some clean up to do for sure.  Its really up to you.

PS.  I always drape a towel over my tank when doing front brake work and keep a spray bottle of water by your side.  If you do get brake fluid on any painted surface wipe it up and quickly spray it down with water.  Brake Fluid will absorb the water and neutralize its affect on your paint.

Good luck.

norman hogeveen
mobile 312 804.4999

[Vince Strazzabosco]

Speaking of older Magnas, years ago my brother and I were trying to bleed a clutch on one, and it wasn't working. Out of curiosity, I tried some teflon tape on the bleed screw threads, and all the sudden it bled like expected. Ever since, I've always used teflon tape, or now, teflon plumber's paste on all brake and hydraulic fittings and bleeder screws on cycles, cars and trucks. Nice side benefit is that they don't seize up if left untouched and outside for years.

What Norm and others say about moving the MC and tapping it and the lines I've also found helpful, especially looking for those tiny bubbles.

vince

--------------------------------------------
On Fri, 8/2/13, Drew Mobley <moble...@yahoo.com> wrote:

Subject: Re: [ChiVinMoto]: Re: NEED HELP! brake master cylinder wont pressurize/prime for the life of me.
To: "bra...@gmail.com" <bra...@gmail.com>, "chivi...@googlegroups.com" <chivi...@googlegroups.com>
Date: Friday, August 2, 2013, 10:45 AM

Had the same problem with
a hydraulic clutch on an older Magna. Sometimes there is one
big airbubble that can get caught right where the banjo bolt
connects to the MC. No matter what bleeding you do, it wont
come out. The solution, that someone else brought up on
here, was to crack open that banjo bolt.  Try that.
Crack it, squeeze lever, tighten back up. Might be worth a
try.

[peteM]

Disconnect hose from M.C.and  hold finger tip against output hole and see what kind of pressure you are getting.

Fluid should have enough pressure to push your finger away.

I went through a couple of those $50 aftermarket master cylinders before I got a good one.

PeteM

[Sandman]

Could you please be specific on exactly which aftermarket master cylinder brand you're referring to? Would be most helpful-thanks!

[YMRacing]

Any of them.