Brake flushing/bleeding procedure
Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
Brake flushing/bleeding procedure
Hey guys, i Just finished the c5 brake upgrade on my 93. I replaced all the lines with SS and also put in the DRM bias spring.
I have some questions regarding the filling of the hydraulic system and bleeding the air. The whole is dry due to the new bias spring. The master went dry and the flex lines as well.
In the FSM it states that the prime pipe must be bled in the rear storage compartment at the ABS modulator unit. This is not a big deal, however i'm confused by the next part in the FSM. How is the master cylinder bleeding done? Is it completely necessary in my case?
It seems like the brake hose needs to be removed at the master to purge air but i'm not 100% sure. Can someone help?
Sorry I dont have the FSM handy so I cant post the exact procedure. I can do so later.
I have some questions regarding the filling of the hydraulic system and bleeding the air. The whole is dry due to the new bias spring. The master went dry and the flex lines as well.
In the FSM it states that the prime pipe must be bled in the rear storage compartment at the ABS modulator unit. This is not a big deal, however i'm confused by the next part in the FSM. How is the master cylinder bleeding done? Is it completely necessary in my case?
It seems like the brake hose needs to be removed at the master to purge air but i'm not 100% sure. Can someone help?
Sorry I dont have the FSM handy so I cant post the exact procedure. I can do so later.
Team Owner
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Did you fill up and bled the master cylinder before you re-install it back on the booster?
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
You need to bleed the master before you start to bleed the entire system. You can do this while its still mounted to the booster. This proceedure will remove any air trapped in the M/C bore that can't be bleed out thru the 4 calipers.
Instructor
Joined: Mar 2012
Posts: 170
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From: NH
[QUOTE=dubin4life;1580818362]
It seems like the brake hose needs to be removed at the master to purge air but i'm not 100% sure. Can someone help?
QUOTE]
I dont have my FSM or vette handy either, but yes you need to bleed the M/C. IIRC, this is supposed to be done outside the vehicle. I have not done this on a vette, but when I did this on my truck after doing all new brakes and lines, I would loosen the nut on the line into the cylinder, have someone push the pedal in, tighten the nut, let the pedal out, and repeat. Very similar to the two man method for bleeding at the calipers, the only bad thing is that unlike with calipers you cant really put a clear tube on the nipple to see for sure that there are no air bubbles, I just put a rag down and repeated many times to be sure. Been driving the truck for over a year now with no issue.
It seems like the brake hose needs to be removed at the master to purge air but i'm not 100% sure. Can someone help?
QUOTE]
I dont have my FSM or vette handy either, but yes you need to bleed the M/C. IIRC, this is supposed to be done outside the vehicle. I have not done this on a vette, but when I did this on my truck after doing all new brakes and lines, I would loosen the nut on the line into the cylinder, have someone push the pedal in, tighten the nut, let the pedal out, and repeat. Very similar to the two man method for bleeding at the calipers, the only bad thing is that unlike with calipers you cant really put a clear tube on the nipple to see for sure that there are no air bubbles, I just put a rag down and repeated many times to be sure. Been driving the truck for over a year now with no issue.
Le Mans Master
Joined: Mar 2001
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St. Jude Donor '12
Level by raisng the car, fill the resevoir up with fluid, pump the brake pedal - a lot.
put something under the plastic parts to collect the brake fluid and one at a time quickly take them off and put yout hard lines back on.
Bleed normally from there.
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Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
Thanks for the help, looks like I'll need to get a master cylinder bleed kit. So the question is, will it be as easy on the car or should I just remove it? Sounds like it may be hard not to spill fluid all over of I bleed it on the car...
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
it would be easier with a helper but solo just make sure the lines from the bleed kit are well inside the MC's res clip them in if you can rig it. Be aware that it is possible with the booster to push so fast that you shoot the little plastic fittings out of the holes so easy does it.
Safety Car
Joined: Apr 2011
Posts: 3,660
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Its a matter of protecting the paint more than anything else...brake fluid etches paint on contact due to the high acid content of the fluid. A good reason to have a coat of wax on the car...
Brake fluid is hard on some rubber as well. Line the work area with plastic bags and have soapy water and rags handy for immediate wipe up if something gets splattered...
Taking the unit off and doing a "bench-bleed" means transporting it back and forth with fluid in it...just another means of dripping on something. Harder to hold and operate off the car too.
I found some self bleeding caliper screws that make the lower end a bit easier...stick the clear hose on the screw and into a coke bottle, crack the screw open and pump the pedal or turn on the bleeder pump (apply pressure) and the bleed screws have a built in check valve that lets fluid out, but no air back in. Tighten bleed screw when done.
Comes in handy.
Brake fluid is hard on some rubber as well. Line the work area with plastic bags and have soapy water and rags handy for immediate wipe up if something gets splattered...
Taking the unit off and doing a "bench-bleed" means transporting it back and forth with fluid in it...just another means of dripping on something. Harder to hold and operate off the car too.
I found some self bleeding caliper screws that make the lower end a bit easier...stick the clear hose on the screw and into a coke bottle, crack the screw open and pump the pedal or turn on the bleeder pump (apply pressure) and the bleed screws have a built in check valve that lets fluid out, but no air back in. Tighten bleed screw when done.
Comes in handy.
