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Discussion Starter #1
Folks,

I did not see this discussed here before, my apologies if I missed it.

I have a 90' FXR w PM caliper that I rebuilt last week.

When I went to bleed the system w DOT 5 though, it won't pump the brake fluid through.

When I pump the rear brake, it seems like the system is full of air and it won't suck/pull any fluid into the reservoir.

Spent a couple hours trying with miti vac kit but no luck.

Any ideas on what to do here?

Thanks
 

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If it wont vacuum bleed, you have an air leak.

Take the line loose at the master cylinder, and bleed the master cylinder. You can do it with the vacuum bleeder. Put the line back on, and bleed the caliper by pumping the brake pedal. Open bleeder, push pedal down and hold, close bleeder, slowly release pedal. Repeat. Do not repeated pump the pedal. When you get fluid at the bleeder, close it up and put some pressure on the pedal, the leak should become apparent.
 

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This is how I have bled brakes on cars motorcycles and airplanes for 50 years. Go buy a pump type oil can, the kind with little pump lever on it, get a piece of vinyl tubing that fits tight on the output of the oil can. Be sure the reservoir is not full. put your fluid in the oil can and connect the tubing to the bleeder port, crack open the bleeder port, pump the oil can as much as needed, close the port, remove the tubing, fill the reservoir. Your done.
 

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Discussion Starter #4
Okay thanks guys. I will try both of these today.

Been riding w no rear brake for a couple weeks now.
 

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been there with dot 5...wont come up....put dot 3 back in an done...i could not understand it either
 

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Discussion Starter #8
Thanks guys... I appreciate this alot.

Well, the front reservoir cap says "DOT 5 only" on it but I don't know. Some say DOT 5 is too "thick" but has the much higher boiling point(?)

Will try the reverse bleed method first, because I had no leaks before I pulled this caliper off and rebuilt it.

Then will try bleeding from the master cylinder per Thermodyne.
 

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Discussion Starter #10
This is my scoot by the way.

She's a never-ending pain in the ass, but more than worth it when all dialed in.
 

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Nice ride.

Sent from my SM-A102U using Tapatalk
 

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Thanks guys... I appreciate this alot.

Well, the front reservoir cap says "DOT 5 only" on it but I don't know. Some say DOT 5 is too "thick" but has the much higher boiling point(?)

Will try the reverse bleed method first, because I had no leaks before I pulled this caliper off and rebuilt it.

Then will try bleeding from the master cylinder per Thermodyne.
And... ensure nothing But Dot 5 been in it... other "dots" turn to Jello when mixed with Dot-5... can't bleed that!!!
 

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Thanks guys... I appreciate this alot.

Well, the front reservoir cap says "DOT 5 only" on it but I don't know. Some say DOT 5 is too "thick" but has the much higher boiling point(?)

Will try the reverse bleed method first, because I had no leaks before I pulled this caliper off and rebuilt it.

Then will try bleeding from the master cylinder per Thermodyne.
Please don’t put anything other than DOT5 in it. I spent a year getting rebuildable calipers, brakes lines and other parts because someone had put DOT3 in the bike and sat it under a tarp for 8 years. Corroded the pistons and hardened up in the lines.
 

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all harleys from around 1979 iirc,, but i know all ceom 1982 forward until abs became popular took, DOT 5 all did, not some.

many try to bleed thes zystems like they are cars,,, that does not work,, dot 5 airates when pumped it takes hours for the air bubbles to leave the fluid...

most old systems have the ports in the mc's plugged up.. these should be clenez and rebuilt at the same time as the calipers.. flush all the lines,, and do as therm says.. it will work...
 

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are u kidding after 8 years?? sitting...brake systems are crap after sitting for lot less time than that..unbeleivable!!
 

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are u kidding after 8 years?? sitting...brake systems are crap after sitting for lot less time than that..unbeleivable!!
8 years is a long Time???
Not in my World...what Exactly, do you think Aged??? The fluid?? did the pads rot?
oh... my rotors rust a little... but I don't mind, as I dislike stainless rotors..
 
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