Bleeding Front Brakes Roadking
Thread Starter
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Tourer
Joined: Feb 2008
Posts: 251
Likes: 4
From: Philadelphia
Well guys, after a night of sitting, my master cylinder still full and I even left the banjo bolts and hose hang free from both front calipers and no fluid ran down.
Seems common culprit is upstream at master cylinder end. I loosened off banjo at MCyl and cycled brake lever and not much activity. Once holding thumb over outlet it does build pressure resistance and fluid follows. I reconnect outlet hose to MCyl and still nothing builds up or comes out. I did notice however that by loosening banjo at each caliper and cycling lever that you can hear and see spirts but no real flow and once securing banjo, cannot build any pressure or lever resistance. I know that my MCyl is good as it was operating perfect prior to the hose replacements and cracking the system open.
Think at this point I will resort to a pressure bleed or vacuum draw from bottom to force out and air and hopefully fill MCyl from bottom up. Once I get that far… I hope.. I can then finish off with a standard bleed at each caliper.
I’ve read a lot of posts and videos and I’m not alone with this.
And I don’t intend to keep pumping the lever 3000x to hopefully build pressure.
Its quite simple fluid engineering…but air is the culprit.
One would only assume that fluid would have gravity fed all night but that wasn’t the case.
Frustrating on a beautiful autumn day.
Jim
Seems common culprit is upstream at master cylinder end. I loosened off banjo at MCyl and cycled brake lever and not much activity. Once holding thumb over outlet it does build pressure resistance and fluid follows. I reconnect outlet hose to MCyl and still nothing builds up or comes out. I did notice however that by loosening banjo at each caliper and cycling lever that you can hear and see spirts but no real flow and once securing banjo, cannot build any pressure or lever resistance. I know that my MCyl is good as it was operating perfect prior to the hose replacements and cracking the system open.
Think at this point I will resort to a pressure bleed or vacuum draw from bottom to force out and air and hopefully fill MCyl from bottom up. Once I get that far… I hope.. I can then finish off with a standard bleed at each caliper.
I’ve read a lot of posts and videos and I’m not alone with this.
And I don’t intend to keep pumping the lever 3000x to hopefully build pressure.
Its quite simple fluid engineering…but air is the culprit.
One would only assume that fluid would have gravity fed all night but that wasn’t the case.
Frustrating on a beautiful autumn day.
Jim
HDF Community Team
Joined: Nov 2012
Posts: 6,186
Likes: 2,412
From: USA
Thread Starter
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Tourer
Joined: Feb 2008
Posts: 251
Likes: 4
From: Philadelphia
Thanks but that was a misread.
i won’t be drawing vacuum to suck fluid down, but will charge the fluid from caliper bleed and force upwards into Mcyl….is what I meant to say. And finish off any residual bleed the conventional way once I have full fluid in calipers and hoses.
Grateful and thanks
Jim
i won’t be drawing vacuum to suck fluid down, but will charge the fluid from caliper bleed and force upwards into Mcyl….is what I meant to say. And finish off any residual bleed the conventional way once I have full fluid in calipers and hoses.
Grateful and thanks
Jim
Tourer
Joined: Oct 2014
Posts: 412
Likes: 113
From: Nebraska
^ THAT worked for me. Just zip tie your front brake lever compressed with the system closed up. Leave it sit and see what happens after a day or so.
Road Master
Joined: Feb 2021
Posts: 1,067
Likes: 469
From: Phoenix Arizona
Howdy,
I recently did a brake bleed on my front brakes on my 2002. NO ABS.
Tried a vacuum bleeder. Close bleed screw, pump up, get 15# vacuum, crack the bleed screw, and then air bubbles get sucked into the line. FAIL.
did old fashion method.
I would pump up brake, wrap strap around handle, crack the bleed screw ( hose into small bottle with brake fluid). out comes fluid, tighten, repeat. Did that several times to change out enough fluid on both front calipers. Started with front left caliper since it is slightly longer hose.
Pleased with results.
I recently did a brake bleed on my front brakes on my 2002. NO ABS.
Tried a vacuum bleeder. Close bleed screw, pump up, get 15# vacuum, crack the bleed screw, and then air bubbles get sucked into the line. FAIL.
did old fashion method.
I would pump up brake, wrap strap around handle, crack the bleed screw ( hose into small bottle with brake fluid). out comes fluid, tighten, repeat. Did that several times to change out enough fluid on both front calipers. Started with front left caliper since it is slightly longer hose.
Pleased with results.
Thread Starter
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Tourer
Joined: Feb 2008
Posts: 251
Likes: 4
From: Philadelphia
Your old fashioned method sounds so easy and realistic, yet just unable to build any pressure by pumping lever…or tying lever and feeding as you state. Congrats your end!
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Seasoned HDF Member
Joined: Jan 2011
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From: Michigan 15 Minutes East Of Hell
I didn't read all the replies ... Sometimes a brake bleed can be very frustrating ... I know you said your master was operating BEFORE you did your service ... Is it possible that you bottomed the master ( plunger) ? ... It has happened before ... Be careful of the mess ... Disconnect the line coming out of the master ... Hold a finer over the outlet port ... Are you sensing any pressure when you depress the lever ?
@jim70
@jim70
Thread Starter
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Tourer
Joined: Feb 2008
Posts: 251
Likes: 4
From: Philadelphia
Uncle Larry,
Yes..lots of pressure almost immediately.
Yet it won’t pump the fluid down the lines. There is indeed some minimal fluid that seeps out of both caliper bleed screws but nothing significant.
oh well
Yes..lots of pressure almost immediately.
Yet it won’t pump the fluid down the lines. There is indeed some minimal fluid that seeps out of both caliper bleed screws but nothing significant.
oh well