How do I prime a 1991 Harley Springer front master cylinder ?

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neilw
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How do I prime a 1991 Harley Springer front master cylinder ?

#1

Post by neilw »

I took my front forks off my 1991 softail springer several weeks ago, and first removed the front brake caliper , I drained the fluid first . Now I have re assembled everything ,but have no brake . with the chamber topped up ,and working the hand lever not a drop of fluid comes out the outlet.. Since the front brake always worked before I looked on you tube for an answer .
A video showed the same m/c as mine ,and they primed it by putting fluid in it then holding the lid in place and pouring a bit into the outlet ,and with his thumb over the outlet he worked the hand lever .. The guy said he should hear a swoshing noise . He also said he had to be carful because with the lid off he could get squirted ..
I tried that , and fluid was forced out past my thumb I had over the outlet hole . but when I put it on the bike nothing comes out the outlet..
Remember I didnt take the master cylinder apart ,it is the same as when I last rode the bike . What am I missing ??

Neil
neilw
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Re: How do I prime a 1991 Harley Springer front master cylinder ?

#2

Post by neilw »

Thanks for reading my post , but I just got it figured out .. 1000 squeezes of the hand lever ,and my brake is back to normal ..
Mongrel505558
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Re: How do I prime a 1991 Harley Springer front master cylinder ?

#3

Post by Mongrel505558 »

That's why I reverse fill disk brake systems from the bleeder up to the master cylinder. Just pump the fluid into the caliper through the loosened bleeder and it pushes the air up through the line and out the master cylinder. When the master cylinder fills with brake fluid you're done. No bleeding, priming MC, 1000 pulls on the lever, etc.

Jim
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Re: How do I prime a 1991 Harley Springer front master cylinder ?

#4

Post by RooDog »

neilw wrote: Tue May 03, 2022 6:24 am Thanks for reading my post , but I just got it figured out .. 1000 squeezes of the hand lever ,and my brake is back to normal ..
I usually fill the front MC with DOT 5, and then open the bleeder on the caliper a little until fluid drips out. Close the bleeder and then begin pumping the handle. If all is right any air will rise up and bubble back through the MC's two holes. If not, there is something amiss. The last time I tried this I had a loose fitting that was leaking fluid. and I suppose, allowing in just enough air to foul this process for me. As I said, if all is well, the fill, drip, and pump method usually works out just fine for me, and I run dual discs on my scooters.....
Also, the master cylinder must be in good, operable, condition, or it ain't gonna work no matter how much fluid one back flows up to it....
....RooDog....
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Re: How do I prime a 1991 Harley Springer front master cylinder ?

#5

Post by hd74cid »

Late to the party but...

I take every connection apart. Finger over the outlet port on the master cylinder and "bench bleed" it. Once I got pressure and I can't keep a finger seal I connect the next piece of hose. Do the same thing with a finger over the open hose until I can't hold a seal. Connect that one. Move on to the next connection. Repeat until I get to the caliper. Connect and bleed. Never had a problem since starting to do this method. I used to back bleed but found this worked as well and quicker.

kEiTh
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