Installed new brake master cylinder, didn't bench bleed it. How screwed am I?
05-02-11, 08:03 PM
#1
Installed new brake master cylinder, didn't bench bleed it. How screwed am I?
I installed my new master cylinder tonight, and I failed to bench bleed it. 
I installed all my lines and filled with fluid. I proceeded to pump it and expect it to stiffen up. That didn't happen, obviously. So I pumped a bunch more times and thought "wtf?" And... then like an idiot I kept pumping. After finally realizing something is wrong, I called it a night. Now I think "DUH!!!" But it's too late.
So... how bad is it now? I'm sure there is a ton of air in the system. I would rather not take it out again. I know I should hook up some lines and route them back into the reservoir. But... should I undo all the brake lines (difficult method) or can I get away with only undoing one (easy method)?
Probably the hard way at this point. Oh well, haven't driven the car in 6 months, what's another few days.
It's Monday, I'm an idiot
I installed all my lines and filled with fluid. I proceeded to pump it and expect it to stiffen up. That didn't happen, obviously. So I pumped a bunch more times and thought "wtf?" And... then like an idiot I kept pumping. After finally realizing something is wrong, I called it a night. Now I think "DUH!!!" But it's too late.
So... how bad is it now? I'm sure there is a ton of air in the system. I would rather not take it out again. I know I should hook up some lines and route them back into the reservoir. But... should I undo all the brake lines (difficult method) or can I get away with only undoing one (easy method)?
Probably the hard way at this point. Oh well, haven't driven the car in 6 months, what's another few days.
It's Monday, I'm an idiot
05-02-11, 09:02 PM
#6
talking head
are you worried now after all those reposts?
if you have a clutch or brake master that fails to pickup the fluid cause of airlock the solution is easy
you need a spare round cap off the top off a master and you tap the top for an airline fitting
( or bike pump )
you run up the compressor and then bleed it back so it has less than 5 psi in it
connect the airline to the cap and use the air pressure to assist the initial bleeding process
( as hinted you can use a bike tyre air pump )
do not use pressure higher than this as it will blow the cap or bowl off and make a big nasty mess
if you have a clutch or brake master that fails to pickup the fluid cause of airlock the solution is easy
you need a spare round cap off the top off a master and you tap the top for an airline fitting
( or bike pump )
you run up the compressor and then bleed it back so it has less than 5 psi in it
connect the airline to the cap and use the air pressure to assist the initial bleeding process
( as hinted you can use a bike tyre air pump )
do not use pressure higher than this as it will blow the cap or bowl off and make a big nasty mess
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05-02-11, 09:25 PM
#9
^^^^^ lol....i seriously was laughing out loud for 30sec straight. YOU WORRIED? do just what bumb start said. go to vatozone, Pepboys, Advanced, orillys, ect.... Get a metal valve steam.the part that goes on the inside of the rim is flat and the part that goes on the outside has a nut and the outside of the valve is threaded. Now you need another cap. Drill a hole in the cap, put the valve threw, put the nut on, put the cap back on, bicycle pump...Be done in 5min. i already have a brake&clutch caps made for this.
05-03-11, 05:58 AM
#13
No friends, perhaps a hockey stick? If it's a matter of opening a brake bleed valve and pounding away, I can handle it. I was worried about air getting "stuck" around the master and not being able to get it out.
"what have I done" was in reference to all the reposting
"what have I done" was in reference to all the reposting
05-03-11, 08:20 AM
#15
Full Member
It isn't a matter of opening a bleed valve and pounding away, it is a synchronized process of opening a bleed valve, stepping on the pedal, closing the bleed valve and releasing the pedal. Alternatively you can get a motive power bleeder or use the air compressor method described above. Bring the reservoir up to 3-5psi and open a bleed valve until nothing but brake fluid comes out, or you lose pressure (which will probably happen the first few times). Top up the reservoir with brake fluid, repressurize and repeat.
05-03-11, 08:24 AM
#16
Go to autozone and get a self bleeder bottle thing, they're like $5 and do wonders. I put a master in my old fc before I knew about bench bleeding, all I did was crack the lines open at the master cylinder and bled it there first, then proceeded to bleed it normally at the slave cylinders.
05-03-11, 11:50 AM
#17
I must rephrase my phrasing. I know how to bleed brakes, done it a dozen times on different cars. My issue was I forgot to bleed the master, and was worried about what issues it would cause, and how much extra work I was giving myself to do. I will try to hit up autozone and get a self bleeder
thanks
thanks
05-03-11, 05:13 PM
#20
Red Pill Dealer
iTrader: (10)
As said before, get a self bleeder. I've used them for years with great results.
If the master is stubborn about taking in fluid, try cracking the line fittings at the master cylinder and then pumping. Also try moving the pedal real slow at first. I seem to have better luck with a slow movement instead of a rapid one. It will eventually take fluid.
If the master is stubborn about taking in fluid, try cracking the line fittings at the master cylinder and then pumping. Also try moving the pedal real slow at first. I seem to have better luck with a slow movement instead of a rapid one. It will eventually take fluid.
05-03-11, 07:52 PM
#21
thanks for all the suggestions. I was "worked up" about the master because I forgot to bench bleed, and I was reading that this is a fairly important thing to do with a brand new one. Anyway, I took off 2 lines, and ran tubes routed back into the reservoir. It seemed to get the juices moving. After that I bled the rear wheel ONCE and the pedal stiffened up good. I called it a night early and will be picking up a self bleeder tomorrow. Time to do things right!
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