SuzukiSavage.com /cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Brake Master Cylinder No Workie /cgi-bin/YaBB.pl?num=1506801453 Message started by slywuf on 09/30/17 at 12:57:32

Title: Brake Master Cylinder No Workie Post by slywuf on 09/30/17 at 12:57:32 OK - so I picked up this 96 Savage recently that has been neglected over the past decade and am going thru it end to end to put back in good shape.  The front brake was not working at all - only crud in the master cylinder bowl and no fluid.  I took the slave cylinder all apart, cleaned, new pads.  Cleaned and flushed the brake line.  Took the master cylinder apart (isn't that C clip a pain in the a$$?) cleaned it up real nice.  The seals on the master cylinder piston "looked" good, so put it all back together to test it out.  First, I put the master cylinder in the bench vice and put brake fluid in the reservoir.  Pumped the handle a few times and got nada... no juice out the outlet at all.  Discovered that if I hold my finger tight over the outlet, it would pump fluid out fairly well.  OK - thought maybe once the master cylinder was back on the bike and line and slave were full of fluid it might pump.  Nope - no such luck.  I was able to put brake fluid in a clean oil can and pump it from the bleed valve on the slave all the way up to the master and see the level rising in the reservoir.  Tried operating the master cylinder again and still totally dead.  Is this just the sign of needing a master rebuild kit with new seals, or am I missing something else?

Title: Re: Brake Master Cylinder No Workie Post by Ruttly on 09/30/17 at 16:11:43 Get m/cyl as level as possible fill res. leave top off and try to get bleeder valve on caliper as close to 12 o'clock postion as possible , open valve and let it gravity bleed , keep res full , till fluid is coming out of bleeder. You may need to get fluid moving by stroking lever super slow. It may take some time. I'm pretty sure it's just air in the system. If you wind up needing a caliper I have a very nice one off a 96 only 809 miles on it with new pads.

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 09/30/17 at 18:08:06 I essentially did that same thing by forcing brake fluid from the slave bleed valve all the way up to the master cylinder reservoir.  Also, your idea does not explain why the master cylinder is not outputting any fluid at all when the piston is pumped.  Just like any master cylinder, when the piston is pulled back, it draws in fluid which is then forced out of the cylinder when the piston is shoved forward.  Mine is not doing this, and all I can think is that there is not a good seal produced by those two piston seals....

Title: Re: Brake Master Cylinder No Workie Post by Ruttly on 09/30/17 at 18:31:19 Something plugged , seals installed in wrong direction, damaged bore , internally bypassing. Is the hose clear? Disassemble , clean , inspect , blow out ports with compressed air and try it again.

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 09/30/17 at 23:00:08 Been there - done that.  All clean, seals properly installed, hose good - (remember I said I can fill the master reservoir by pumping fluid from slave bleed valve?) I'll report back after I put in a master cylinder rebuild kit, which will be several days.  Thanks for your help.

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/01/17 at 09:41:28 Before you do that, open the bleeder with the top off the master cylinder and walk away. If the lever is pushing the brakes, the hole is closed, no fluid passes. It worked on the bench. What changed?

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 10/01/17 at 18:44:27 It never worked on the bench unless I held my finder tight over the outlet and then it would pump fluid.  Acts like the seals don't really seal unless there is enough back pressure.  Opening the bleed results in fluid running out when I have everything connected up  on the bike and the reservoir full.  I know the intake hole in the reservoir is open so the piston can suck fluid in, and the very small hole next to that will spurt fluid when I hold my finger over the outlet, so that small hole is not plugged.

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/01/17 at 20:20:10 Takes a few strokes to get the pads out to the disk. If you are sure no air is in the system, close the bleeder and VIGOROUSLY apply the brake. The same condition that you created on the bench should happen.

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 10/02/17 at 23:32:29 I was thinking the same thing, but the master wont build pressure with the brake line and slave hooked up.  Ran lots of fluid thru the line from the bleed valve going up to the master, and it fills the reservoir when I do that, yet it wont pump anything back down... tried doing this many times.

Title: Re: Brake Master Cylinder No Workie Post by Gary_in_NJ on 10/03/17 at 05:24:02 You need new seals, not just seals that look good.

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/03/17 at 09:12:21  I was able to put brake fluid in a clean oil can and pump it from the bleed valve on the slave all the way up to the master and see the level rising in the reservoir.   Clever problem solving. Looks like the plunger in the master cylinder is done. Whatever cleaning inside the cylinder it travels in you do, don't leave lines running the length of the cylinder. Some 800 grit wrapped on a split shaft and run in a variable speed drill would hone it.

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 10/03/17 at 21:53:55 Yup - I'm hoping the master rebuild kit that came in today will take care of this problem.  I'll put it in tomorrow.  Good advice on checking the cylinder bore to be sure that it is not damaged... I'll eyeball that close tomorrow as well.  Hopefully good news will follow soon....

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/03/17 at 22:17:27 Jamming new parts into a place where they are supposed to travel and seal off requires inspection. Sounds like you've got it nailed.

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 10/04/17 at 12:20:54 Success!  Put in the master cylinder rebuild kit... new seals.  Brake is good now, but did not take right off without some coaxing.  Here is what I did: After putting new seals on the new plunger and double checking the cylinder bore to be sure it was smooth, I put the master cylinder back on the handle bars but did not hook up the brake hose to it.  I filled the reservoir with brake fluid and then pumped the brake lever a few times. Fluid did not pump out of the outlet, but I was seeing some bubbles come up in the reservoir, out of the two small holes going into the brake cylinder.  I sealed off the outlet with my finger and continued to pump the brake lever slowly.  This eventually started to build pressure and fluid would squirt from my "finger seal"  Apparently getting some pressure built up expanded the seals on the plunger, which improved the seal and thus the pumping action.  I then connected the brake line and refilled the reservoir.  I opened the bleed screw on the slave cylinder and let a couple of reservoirs worth of fluid run out.  I closed the bleed valve and started working the brake lever slowly.  Got some resistance in the lever after the brake pads seated on the rotor disc, but it was still a bit spongy.  I opened the bleed valve again and let some more fluid run out, closed the valve and added more fluid to the reservoir.  After pumping the lever a bit longer, the usual firmness returned and the brake action was working well.  Apparently the old seals had worn enough to where they could no longer make a tight enough seal to build proper pressure.

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/04/17 at 16:32:38  Apparently the old seals had worn enough to where they could no longer make a tight enough seal to build proper pressure. Correct as you may be, you're treading Alarmingly close to exposing yourself as an anti-old and decrepit kinda guy. Ageism is not nice. I feel threatened. When you get old You might be needing a few slow pumps before you can build up pressure, too.

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 10/04/17 at 22:44:38 HA! Yes indeed... By the way I AM old.  Hard to be anti-old when I am 65.  Regarding this problem with the non-performing master cylinder, it was a combination of factors that made it challenging to fix.... This Savage that I recently picked up had been abandoned in a storage unit for years and someone then bought it up that didn't know squat about motorcycles.  He and his young kids proceeded to try and get it running but succeeded in only screwing it up.  The whole front brake system was mega-sick, with only gooey crud residing where brake fluid once was.  Probably the old piston seals were dry and not as flexible as new ones, and just would not seal properly despite "looking" pretty good.  Just took some time after everything was clean and new seals in place for it to start working well again.  After I correct another 1/2 dozen problems, I think I will have a fairly decent 96 Savage to enjoy riding... its got just 14K miles on it and good shape body wise (not counting the tank that needs repainted.)  An enjoyable project.....

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/05/17 at 07:55:31 We've seen a coupla motors screwed up after sitting, oil dripping out of the cylinder, and then getting started.

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 10/05/17 at 21:47:32 This Savage that I am straightening out was a prime example of what happens when non-technical brains and fingers start playing around with something they know nothing about.  I wont bore you with the gory details.  I do have it running well now, so it should turn out pretty decent.

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/05/17 at 21:52:32 You don't have to give the entire, blow by blow, but if it's funny or educational, you can hit the high spots.. Were the exhaust flange bolts busted off? I'm waiting for Cheap Newbie to unload his...

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 10/06/17 at 22:02:36 OK - Here is a sample of what the lack of knowledge can produce.... When I got this bike, the two carb bowl vents were connected together with a tee, which then connected to the fuel tank.  Nothing was connected to the fuel inlet fitting on the carb.  Before even attempting to start the motor, I drained the oil.  Should hold about 2 quarts, and yet about 4 quarts came out... also had the smell of old gas.  That bogus connection to the fuel tank must have just dumped fuel right thru the carb, thru a valve and cylinder and then into the crankcase... or maybe something even crazier than that.  Flushed the crankcase, put on a new oil filter and put new oil back in.  After doing a major clean job on the carb, she started up and seems to be running pretty well.

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/06/17 at 22:13:33 The OEM petcock is known for drizzling gas into the crankcase. The T connection is a first. That's funny..

Title: Re: Brake Master Cylinder No Workie Post by slywuf on 10/08/17 at 08:11:01 Before buying the bike, I asked the dude who got it from an abandoned storage unit if it ran... He said that it did.  Then later on he says "it will idle all day long but poops out when you open the throttle"   Yea... right - that must have been before they tried the "lets feed gas into the bowl vents" modification.  The tank on this one no longer has the OEM petcock... apparently a previous owner had trouble with it and replaced it with a standard, non-vacuum model.

Title: Re: Brake Master Cylinder No Workie Post by justin_o_guy2 on 10/08/17 at 10:35:53 Let's  hope he didn't let it idle sitting on the sidestand all day while he scratched hizzass thinking.

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