Quote:
Originally Posted by buckroseau
Ok messed around with this a bit tonight. As I said before, I can vacuum bleed the rear cylinders and get fluid to come out. But, nothing will come out the front.
I opened the line again up front where the soft line meets the hardline, right by the swing arm. I held the vacuum bleeder up against the hardline, and I could easily get fluid to pull though the vacuum bleeder. I then took my air hose and blew through the soft line while the bleeder screw was open on the wheel cylinder, air came out. So, at this point I'm thinking there is now way it can't work. Put everything back together and tried again...nothing.
Thought I would try something a little unconventional. I took the old cover off the MC and drilled a small hole in it. I then welded an air fitting to the top and hook up the air hose. I opened the air valve and pressurized the MC with the hope or thinking it would force brake fluid out the front bleeder screw. Once again, nothing. Air leaked out around the reservoir cap but nothing came out the bleeder.
As far as pumping the pedal, I tried that. It just won't build pressure so nothing I can really do with that idea.
Matt
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Matt,
several thoughts just at random. Does the style & specs of the m/c offer enough volume to operate ALL the braking capacity your brake system, as a whole, now has? [Seems I recall you swapped in a newer rear end, like a 3/4-ton, which likely used discs on front. It also may require a much-increased
volume of fluid. This should be studied carefully: "We can't very well farm 100 acres with a Shetland pony".] Did you try pumping, via mc, to see if it would pump fluid thru hard line while you had them--hard & soft lines--apart? I think this is a must at this point, just gotta be tested. Can you 'block off' rears & try bleeding just fronts? This may narrow down variables & convincingly show which end is the trouble-maker. We all tend to be blaming front for all the pain, when rears could be the source. Another test: break apart soft-&-hard line. Put a tube from soft end into jar of fluid. See if your vacuum pump will vac. fluid from jar thru soft hose & thru bleeder: I'm betting some amount it won't do it. You said and I agree
only partly, subject to enclosed, suggested, further tests, "So, at this point I'm thinking there is now way it can't work," But it defies that 'fact'. Another mentioned replacing soft hoses. I agree. That's gotta be done, imo. All other lines are static--do not move/flex/bulge when fluid flows under pressure. Soft lines are dynamic/changing, as they do all 3 things hard ones don't. They do crazy things, like even rotting inside & allowing a 'peeling piece' to act as a 1-way valve & lock up one front wheel cylinder.
Your tests so far do NOT push fluid thru soft lines, just air. Tests also do not vacuum fluid thru soft lines--either all way from master OR from where you took apart one where soft meets hard.
Sorry if my thoughts seem to wander, but your problem has become mine. And I wish to cover all possibilities. At this point, my bet is on
either (1)a m/c that is pumping barely sufficient volume to push fluid thru a least-resistance path which is the rear bleeders. (Blocking off front lines would
verify if m/c can not only flow fluid thru rear bleeders but also operate the rear brakes with good pedal--and
determine if m/c is good or bad or 'insufficient'.).......Else
(2) front flex hoses are defective.
I'm following thread and looking for a soon-discovered solution.
Sam