Need help bleeding Brakes
03-21-2003, 03:19 PM
#1
Registered User
Thread Starter
Join Date: Oct 1999
Location: Tampa Florida
Posts: 1,490
Need help bleeding Brakes
Finish LS1 brakes install on my 1996 z28, think i have a air leak, need help
After spending 2 1/2 hours bleeding the system I have found that i got all the air out of my rear brakes (I didnt not change them or remove the lines). But i cant get air out of the front brakes. There is a lot of air in teh front brakes... not like air bubbles but air.
Now the master cylinder has two chambers in it right? 1 for the front and one of the back brakes. I had let the front run dry. I tried bleeding the ABS modulator but i kept getting air there to... I think it might have been a fitting on the mity vac that wasnt working properly when i was bleeding it..
But if i cant get all the air out of the front brakes would i have enough braking power from my rears to get me to a shop?
Up date- I spent an hour bleeding the front brakes and ABS... I probably went through 12 canisters on the Mity vac trying to suck out air and all im getting is air some fluid. Im gonna check for leaks with some soap and water..
Any help would be greatly greatly greatly appreciated.
After spending 2 1/2 hours bleeding the system I have found that i got all the air out of my rear brakes (I didnt not change them or remove the lines). But i cant get air out of the front brakes. There is a lot of air in teh front brakes... not like air bubbles but air.
Now the master cylinder has two chambers in it right? 1 for the front and one of the back brakes. I had let the front run dry. I tried bleeding the ABS modulator but i kept getting air there to... I think it might have been a fitting on the mity vac that wasnt working properly when i was bleeding it..
But if i cant get all the air out of the front brakes would i have enough braking power from my rears to get me to a shop?
Up date- I spent an hour bleeding the front brakes and ABS... I probably went through 12 canisters on the Mity vac trying to suck out air and all im getting is air some fluid. Im gonna check for leaks with some soap and water..
Any help would be greatly greatly greatly appreciated.
03-21-2003, 05:25 PM
#2
Registered User
Join Date: Apr 1999
Location: Texas
Posts: 1,227
Getting all the air out of the MC is tough while on the car ... the best way is to remove the MC and bench bleed it ... that is you put the MC in a vice, screw in fittings into the fluid outlets (where the brake lines hook-up), attach some clear tubing to those fittings and run them up and through the fill cap and way down into the reservoir.
Fill the reservoir with fluid, and CAREFULLY plunge the piston in the master cylinder, using a blunt object. A screwdriver will do, but be careful not to scar the face of the piston or slip and screw up a seal.
Keep plunging until there is no more air in the tubing...just solid fluid. Make sure you keep the tubing ends submerged in the brake fluid. Don't want to suck air BACK into the MC.
Once you have the MC bled, re-install it, keeping the tubes submerged in the reservoir. Reattach the brake lines removing the fittings one at a time.
Now bleed your system.
When you have an air pocket, bleed just opposite like you'd bleed to flush the system. Start at the closest point and work the air pocket to the furthest back.
As for the leak, you did use new copper seals on the banjo fittings, didn't you?
Fill the reservoir with fluid, and CAREFULLY plunge the piston in the master cylinder, using a blunt object. A screwdriver will do, but be careful not to scar the face of the piston or slip and screw up a seal.
Keep plunging until there is no more air in the tubing...just solid fluid. Make sure you keep the tubing ends submerged in the brake fluid. Don't want to suck air BACK into the MC.
Once you have the MC bled, re-install it, keeping the tubes submerged in the reservoir. Reattach the brake lines removing the fittings one at a time.
Now bleed your system.
When you have an air pocket, bleed just opposite like you'd bleed to flush the system. Start at the closest point and work the air pocket to the furthest back.
As for the leak, you did use new copper seals on the banjo fittings, didn't you?
Last edited by mitchntx; 03-21-2003 at 05:27 PM.
03-22-2003, 03:36 AM
#3
Registered User
Thread Starter
Join Date: Oct 1999
Location: Tampa Florida
Posts: 1,490
Yep copper washers were used..
Thank you very much for the bench bleeding instructions too..
Ill work on it tomorrow.. and if i cant get it then one of my buds who knows more about brakes is coming over to help me fix it.
Thank you very much for the bench bleeding instructions too..
Ill work on it tomorrow.. and if i cant get it then one of my buds who knows more about brakes is coming over to help me fix it.
03-22-2003, 09:42 PM
#4
Registered User
Join Date: Feb 2003
Location: New Hampshire
Posts: 51
Ummmm......
Yer using a Mity Vac, right....?
Is the problem, that you have a steady stream of bubbles coming through the hose?
If so..... you're sucking air past the bleeder screw threads.
The Mity Vac is a nice tool but this is a common problem in bleeding with it. You can try removing the bleeder screw and wrapping the threads with teflon tape (be carefull not to get the tape over the holes in the end of the screw). Use a few wraps of the tape ... make it thick. Re-install the screw & start again.
This won't last forever.... it'll start leaking again eventually.
Good Luck,
gordon
www.provenperformanceconcepts.com
Yer using a Mity Vac, right....?
Is the problem, that you have a steady stream of bubbles coming through the hose?
If so..... you're sucking air past the bleeder screw threads.
The Mity Vac is a nice tool but this is a common problem in bleeding with it. You can try removing the bleeder screw and wrapping the threads with teflon tape (be carefull not to get the tape over the holes in the end of the screw). Use a few wraps of the tape ... make it thick. Re-install the screw & start again.
This won't last forever.... it'll start leaking again eventually.
Good Luck,
gordon
www.provenperformanceconcepts.com
03-24-2003, 07:34 PM
#5
Registered User
Join Date: Nov 2002
Location: Charleston, SC
Posts: 18
Try bleeding the brakes using two people. One person to pump the brake pedal and another to open and close the bleeder screw. It helps to have the car level. I'm an engineer for an ABS manufacturer and our specifications for service work recommend doing an old fashioned two man brake bleed. It has to do with how fast fluid is pumped through the ABS unit to flush the air out of all the bores. The mighty vac does not suck the fluid fast enough. When the car is built, a powerful vacuum pump is used to completely evacuate the system and I think that dealerships use something similar. One other thing, don’t turn the ignition to the on position until you are completely done bleeding the system. Most ABS units do a self test when the key is turned on and if there is air present, it can get in places where it is almost impossible to get out.
03-24-2003, 08:08 PM
#6
Registered User
Thread Starter
Join Date: Oct 1999
Location: Tampa Florida
Posts: 1,490
Originally posted by sir_z28
One other thing, don’t turn the ignition to the on position until you are completely done bleeding the system. Most ABS units do a self test when the key is turned on and if there is air present, it can get in places where it is almost impossible to get out.
One other thing, don’t turn the ignition to the on position until you are completely done bleeding the system. Most ABS units do a self test when the key is turned on and if there is air present, it can get in places where it is almost impossible to get out.
Will that air in the ABS be sent through the brake system once the ABS activates under hard braking?
Do you think a place like Sears would beable to suck all the air out of the braking system? Or is a dealer my only option? Just the dealers around here will rape me on the charges..
03-29-2003, 08:11 AM
#7
Registered User
Join Date: Nov 2002
Location: Charleston, SC
Posts: 18
I doubt that Sears would be able to do it correctly and the dealer will rape you on ABS service since most of them do not know much about it. I would recommend doing a good hard ABS stop from about 25 to 30mph on a wet street with no one else around. The ABS should still work fine and this should flush all of the air out of the pump and accumulators. It is a good idea to do that every once in a while to exercise the ABS unit anyways. After doing the ABS stop, if the brake pedal feels okay, I would leave it alone. A little bit of air in the system will not hurt it. If the brake pedal feels too soft, try doing the two man brake bleed and push the pedal down fast with the bleeder screw open and allow it to return slowly with the bleeder screw closed. And if that does not get it, I don’t know what else to do. Good luck.
By the way, ABS service may be a pain but I wish I had it on my ’89 Camaro last week. A Ford Explorer in front of me had ABS and he was able to stop while I just slid. I had to buy the guy a new bumper but amazingly all it did was scratch the nose of my car and crack the emblem.
By the way, ABS service may be a pain but I wish I had it on my ’89 Camaro last week. A Ford Explorer in front of me had ABS and he was able to stop while I just slid. I had to buy the guy a new bumper but amazingly all it did was scratch the nose of my car and crack the emblem.
Thread
Thread Starter
Forum
Replies
Last Post