mak
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posted on 17/8/05 at 10:40 AM |
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Correct way to fill a new braking system?
I've just finished plumbing in my brakes, it consists of 2 master cylinders with seperate remote reservoirs, one for the front and one for the
back. I am planning to basically fill the reservoirs and pump the fluid through till it leakes out of the bleed nipples on all 4 calipers. Then
tighten them up.
Is this correct practice?
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Hellfire
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| posted on 17/8/05 at 11:02 AM |
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If only it was as easy as it sounds
Right idea though...
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VinceGledhill
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| posted on 17/8/05 at 11:34 AM |
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Bleeding the brakes is an art form.
Get an easi bleed system. You'll be glad you did.
Otherwise it's a two man job. One pumps the pedal. Then holds it down. The other then opens the valve closest to the master cylinder. Then
closes it again.
Pumper pumps again with the valve locked shut. Otherwise you pull air back in on every up stroke. Air is easier to move then the fluid.
Continue like this until there is no more air coming out of the nipple.
Then move to the next wheel and so... on.
Repeat the above until the pedal is SOLID.
I repeat. Get an easi bleed. Do it yourself. Simple.
Regards
Vince Gledhill
Time Served Auto Electrician
Lucas Leeds 1979-1983
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MikeR
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| posted on 17/8/05 at 12:10 PM |
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seconded!
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pbura
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| posted on 17/8/05 at 12:47 PM |
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Replacing a master cylinder this weekend, so looked into easi bleed. $45 + shipping for a system here (called Eezibleed in the US, incidentally).
Oh, well, child labor is free if whiny  
Don't be surprised if air is still coming out after a few cycles. You're not doing it wrong, it's just the nature of the beast.
Pete
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britishtrident
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| posted on 17/8/05 at 01:18 PM |
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For the initial priming get a mate to push the pedal down with only one nipple open and hold the pedal down while you close the nipple repeat this
procedure or four times for each wheel.
Once both circuits are primed you can start by bleeding the front circuit --Girling patern cylinders are very easy to bleed. When blleding only open
the nipple enough for free passage fluid - normally this is 1/2 turn but no more than 3/4 of a turn. It is also important the the bleed tube is a
tight fit on the nipple.
Important to pump the fluid through slowly and steady so as not to aerate the fluid -- up strokes should even slower as this helps prevent air
being drawn in past the master cylinder seal. After 4 or 5 strokes get you mate to hold the pedal down while u close the nipple.
Do one wheel at a time, move on to the next wheel bleeding each wheel twice before moving on to the other hydraulic circuit.
After it is all done get your mate to hold presure on pedal down while check for leaks.
[Edited on 17/8/05 by britishtrident]
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andyd
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| posted on 17/8/05 at 01:31 PM |
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In his book "How to Build and Modify Sportscar & Kit Car Suspension
and Brakes for Road and Track", Des Hamill goes into extreme detail about how to check and bleed each master cylinder and associated brake
circuit. He advocates clamping the pipes as near to the chassis for all brakes on the circuit not being bleed in order to eliminate the braking
action of that corner. Never tried it myself though. An easi bleed would probably be far easier.
Andy
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The Shootist
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posted on 17/8/05 at 03:03 PM |
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Easiest and cheapest!!!
Get a meter or so of clear plastic hose that will fit onto the bleeder nipple.
Get a Liter bottle or jar and make a tight fitting hole that just passes the hose thru, and also make a vent hole in the lid.
Push the hose thru the hole in the lid until the hose just reaches the bottom of the container. Pour a little clean brake fluid into the container to
cover the end of the hose (this will prevent air from being drawn in on the return stroke).
Starting with the nearest wheel to the master cylinder, put the hose end on the bleeder nipple and then loosen it 1/2 turn or so.
Fill the master cylinder and pump the pedal until you stop getting bubbles thru the hose.
Keep the master full of fluid and take time to let the bubbles settle out of the fluid.
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britishtrident
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| posted on 17/8/05 at 03:09 PM |
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EeziBleed is a good solution for dealing with Teeves systems that have kown problems with seal reversal in the master cylinder but simply isn't
required for Girling systems -- even using eezibleed the mastercylinder should be pumped at some point durring the porocedure or it cannot be
guaranteed all the air will be got out the system.
If the system is properly primed by single strokes then closing the nipple after each down stroke bleeding Lucas-Girling systems is very easy.
[Edited on 17/8/05 by britishtrident]
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NS Dev
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| posted on 17/8/05 at 03:16 PM |
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Yup
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Bob C
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| posted on 17/8/05 at 03:19 PM |
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For a fresh system it's quicker to use a finger over the end of the bleeding nipple, then pump the pedal till fluid goes everywhere. Then start
doing the open/close thing with the nipple. Otherwise you'll be there forever & so will your long suffering help.
Bob
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mookaloid
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| posted on 17/8/05 at 03:52 PM |
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quote: Originally posted by Bob C
For a fresh system it's quicker to use a finger over the end of the bleeding nipple, then pump the pedal till fluid goes everywhere. Then start
doing the open/close thing with the nipple. Otherwise you'll be there forever & so will your long suffering help.
Bob
Messy individual!
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britishtrident
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| posted on 17/8/05 at 03:59 PM |
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I was going so say something about little dutch boys *****
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the_fbi
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| posted on 17/8/05 at 06:08 PM |
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Just a thought but...
Surely if he's got 2 master cylinders he'll either need to remove the pushrod from the one he's not bleeding, or bleed front/back at
the same time.
Else the pedal will just be solid on the cylinder not being bled and not pump any liquid through.
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MikeR
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| posted on 17/8/05 at 07:06 PM |
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surely the point of the twin setup is that one cylinder won't move and the other (thats being bled) will.
(although i've got a sneeky feeling that the being bled M/C won't do full travel)
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britishtrident
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| posted on 17/8/05 at 07:13 PM |
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Not really a problem either way if the system is primed but it is best to adjust the balance bar trunnion to have a bit extra side clearance and when
bleed the first circuit for the first time use a screw driver or mole grips to jampush rod to the other the other circuit.
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NS Dev
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| posted on 17/8/05 at 10:10 PM |
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yup again!
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smart51
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| posted on 18/8/05 at 12:21 PM |
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After reading this thread, I bought a "one man bleed" kit form Halfords. Less than a fiver. Bled each brake in turn 'till no more
bubbles were seen, then went round and did each one again, pumping lots of clear fluid out of each caliper to be sure, so much so that the catch
bottle overflowed. The pedal is still very soft and I can push it all the way in.
I have sierra disc brakes all round and I removed the rear calipers each time so that the bleed nipple was at the top. There are no leaks anywhere.
Where might the air be and how do I get it out?
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britishtrident
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| posted on 18/8/05 at 01:09 PM |
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The pedal really needs to be held down on the last stroke while the nipple is closed or air will be trapped.
However there is a trick for clearing trapped air in calipers, I have used it a lot on cars with broken bleed nipples.
Remove the top from the mastercylinder, then from one caliper remove the brake pads, then carefully pump the piston(s) out to about 60 to 75% travel.
Lever the pistons back and repeat 2 or 3 times for each wheel.
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pbura
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| posted on 18/8/05 at 02:08 PM |
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quote: Originally posted by smart51
After reading this thread, I bought a "one man bleed" kit form Halfords......
The pedal is still very soft and I can push it all the way in.
Never used a pump system but, reading about them the other day, learned that it's advisable to use a helper for the last pass, as the higher
pressure helps swoosh out air pockets.
Pete
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