brake bleeding, how much fluid did you use?
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
brake bleeding, how much fluid did you use?
on my 72 with power brakes, new master and booster, rebuilt the rear calipers with a kit from VB&P, using the motive power bleeder I have gone through a lot of brake fluid. 3 large bottles and 4 small bottles of the prestone DOT3 brake fluid and I still have a soft pedal. Just how much fluid have you guys gone through on these bleeds? I am not reusing any of the fluid even though it is practically new and just being pushed through the system. I am even using a rubber mallet and taping the calipers while going through the correct sequence of bleeding all six points. 4 on the rear and 2 on the front. Just curious as to how much brake fluid is typical.
thanks in advance,
Sully
thanks in advance,
Sully
Melting Slicks
Joined: Sep 2011
Posts: 3,372
Likes: 215
From: Peoria Arizona
That's a lot of fluid to use up. Are you still getting air out of the bleeders? I had a good friend of mine who is a long time brake shop owner help me and I think we used about one large bottle. He wanted to get all of the old fluid out of the system. We replaced the master cylinder, power booster and all 4 calipers and he used a power bleeder (the only way to get all of air out of a Corvette according to him). Brake pedal is very solid feeling, zero side to side pull and will just about put you through the windshield when you really hammer on them.
Sounds like your sucking air in somewhere. From what he told me it's a common problem with these cars to suck in air at the caliper seals. Are you experiencing any leaks at the pistons?
Adam
Sounds like your sucking air in somewhere. From what he told me it's a common problem with these cars to suck in air at the caliper seals. Are you experiencing any leaks at the pistons?
Adam
Last edited by AdamMeh; Jun 20, 2012 at 10:07 AM.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,444
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
forget the power bleeder for now and do the final the old fashion way. Have a buddy pump the pedal up and hold it down hard and then you crack the bleeder just a hair.
If you have clean fluid in all the lines, it shouldn't take but an OZ to bleed all four wheels
If you have clean fluid in all the lines, it shouldn't take but an OZ to bleed all four wheels
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
there's no fluid leaking out at any of the pistons from what I can see. I bleed through the whole system 3 times and the last I was getting no air bubbles at all. On the rear I changed the pistons, lip seals to O-ring style, and new dust seals then new pads all the way around and painted the calipers. I should note that when I changed the master and vac booster I jacked up the front of the car and then routed plastic tubes back into the reservoir and pump and pumped the brake pedal till no air was coming out. I then hooked the brake lines back up, jacked the rear up even with the front and then began the bleeding of the system with the motive bleeder.
Sully
Sully
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
The most fluid you should NEED to use is the volume of fluid in the brake lines and calipers. To go through so much fluid, you must still have one, or more, air leaks. You should start the bleeding process with the wheel closest to the master cylinder and work toward the one farthest away (LF, RF, LR, RR). If you cannot get clear liquid, without bubbles at the LF wheel, you will not be able to succeed in your task. Either there is a leak at the LF wheel [and you will see that effect during bleeding with ALL of the wheels], or you have a leak somewhere in the bleeding equipment or how it is installed to the calipers.
If you are able to get air-free bleed at the LF, continue the bleeding sequence until you locate a wheel that cannot eliminate the air. THAT is the section of brake system with the leak (between that wheel's caliper and back to the preceeding caliper that sealed OK).
If you are able to get air-free bleed at the LF, continue the bleeding sequence until you locate a wheel that cannot eliminate the air. THAT is the section of brake system with the leak (between that wheel's caliper and back to the preceeding caliper that sealed OK).
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
i thought it was the farthest also: right rear outer then inner, left rear outer then inner, right front and then finally left front. I admit with the pressure bleeder I purposefully let a lot of fluid through to clear the lines of old fluid.
Sully
Sully
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
Melting Slicks
Joined: Sep 2011
Posts: 3,372
Likes: 215
From: Peoria Arizona
Not to state the obvious, but did you bench bleed the master before you put it on? It is possible you still have air inside it which is not coming out during the line and caliper bleed process.
Adam
Adam
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
there's no fluid leaking out at any of the pistons from what I can see. I bleed through the whole system 3 times and the last I was getting no air bubbles at all. On the rear I changed the pistons, lip seals to O-ring style, and new dust seals then new pads all the way around and painted the calipers. I should note that when I changed the master and vac booster I jacked up the front of the car and then routed plastic tubes back into the reservoir and pump and pumped the brake pedal till no air was coming out. I then hooked the brake lines back up, jacked the rear up even with the front and then began the bleeding of the system with the motive bleeder.
Sully
Sully
funny thing is: even when the rear calipers were corroded and nasty with all kinds of crud and dirt behind the piston seals I still had a better pedal feel!
Sully
Race Director
Joined: Aug 1999
Posts: 18,126
Likes: 174
From: WI
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
i did this bc i was told when bench bleeding the master you elevate the front at a 45 degree angle or so. The master was already mated to the booster when I got them from VB&P so I installed it on the car and elevated the front of the car to replicate the procedure I was told. the rear was elevated level with the front once the master was bled and the brake lines re-installed so I could begin the brake system bleeding procedure.
Sully
Sully
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,334
From: North of Toronto - Ontario
Definitely seems something is wrong
I did pretty much the same thing two years ago (4 calipers & master) and only needed a couple of bottles to get clean and full pedal.
Check for a lead at the master, or have a real close look (flashlight) and make sure on of the pistons isn't leaking (back side where it's hard to see but it should be pouring out onto the floor at this much fluid
Mooser
I did pretty much the same thing two years ago (4 calipers & master) and only needed a couple of bottles to get clean and full pedal.
Check for a lead at the master, or have a real close look (flashlight) and make sure on of the pistons isn't leaking (back side where it's hard to see but it should be pouring out onto the floor at this much fluid
Mooser
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
no fluid on the floor... sorry if I wasn't clear on that. I bled all the fluid through the system and most of it on purpose the clear the lines and make sure no air was there. I have read everyone else's posts on here too many times to not go the extra mile and bleed them extra. I just thought after bleeding so much through that would insure I would have a good pedal but it's not and I guess I need to go back over the whole system again.
Sully
Sully
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
let's hypothesize... if I did everything correctly on the bleeding, (no air in the system elsewhere), and the problem lies with the rear caliper rebuild wouldn't there be fluid coming out there at the pistons if air was coming in at that point?
Sully
Sully
Le Mans Master
Joined: Aug 2006
Posts: 7,413
Likes: 1,552
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
You might have a bad M/C...
In the bleeder kit there are some plugs, remove the front line at the M/C and plug it, the brake pedal should be rock hard. Then replace the front line and plug the rear and see if the brake pedal is still rock hard.
If nothing is leaking what else could it be?
If nothing is leaking what else could it be?
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
thanks again,
Sully
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
Re: Bleeding sequence.
Actually, the GM Service Manual ("Brakes" Section 5-4, "Manual Bleeding", 3.)
"Note: If the main cylinder is equipped with bleeder valves, bleed these valves first, then proceed to the wheel cylinder nearest the master cylinder, then the next nearest and so on until all cylinders [calipers] have been bled and there is no evidence of air."
Their logic, I believe, is to assure that each section of the braking system is "tight" from the master cylinder to the farthest reaches of the braking system. And the best sequence for doing this is LF, RF, LR, RR. At each step you can know that each section is 'solid', before you move on to the next farthest area, and know where a leak problem exists, rather than just knowing the whole system leaks...somewhere.
If you start with the RR, you must bleed the entire system and have no air before going to another wheel. And, if there is any trapped air in another wheel's caliper, it will defeat what you have already done.
Actually, the GM Service Manual ("Brakes" Section 5-4, "Manual Bleeding", 3.)
"Note: If the main cylinder is equipped with bleeder valves, bleed these valves first, then proceed to the wheel cylinder nearest the master cylinder, then the next nearest and so on until all cylinders [calipers] have been bled and there is no evidence of air."
Their logic, I believe, is to assure that each section of the braking system is "tight" from the master cylinder to the farthest reaches of the braking system. And the best sequence for doing this is LF, RF, LR, RR. At each step you can know that each section is 'solid', before you move on to the next farthest area, and know where a leak problem exists, rather than just knowing the whole system leaks...somewhere.
If you start with the RR, you must bleed the entire system and have no air before going to another wheel. And, if there is any trapped air in another wheel's caliper, it will defeat what you have already done.
Last edited by 7T1vette; Jun 20, 2012 at 04:12 PM.
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
Re: Bleeding sequence.
Actually, the GM Service Manual ("Brakes" Section 5-4, "Manual Bleeding", 3.)
"Note: If the main cylinder is equipped with bleeder valves, bleed these valves first, then proceed to the wheel cylinder nearest the master cylinder, then the next nearest and so on until all cylinders [calipers] have been bled and there is no evidence of air."
Their logic, I believe, is to assure that each section of the braking system is "tight" from the master cylinder to the farthest reaches of the braking system. And the best sequence for doing this is LF, RF, LR, RR. At each step you can know that each section is 'solid', before you move on to the next farthest area, and know where a leak problem exists, rather than just knowing the whole system leaks...somewhere.
If you start with the RR, you must bleed the entire system and have no air before going to another wheel. And, if there is any trapped air in another wheel's caliper, it will defeat what you have already done.
Actually, the GM Service Manual ("Brakes" Section 5-4, "Manual Bleeding", 3.)
"Note: If the main cylinder is equipped with bleeder valves, bleed these valves first, then proceed to the wheel cylinder nearest the master cylinder, then the next nearest and so on until all cylinders [calipers] have been bled and there is no evidence of air."
Their logic, I believe, is to assure that each section of the braking system is "tight" from the master cylinder to the farthest reaches of the braking system. And the best sequence for doing this is LF, RF, LR, RR. At each step you can know that each section is 'solid', before you move on to the next farthest area, and know where a leak problem exists, rather than just knowing the whole system leaks...somewhere.
If you start with the RR, you must bleed the entire system and have no air before going to another wheel. And, if there is any trapped air in another wheel's caliper, it will defeat what you have already done.
gonna try plugging the master first and then will bleed it per your suggestion
Sully
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
if I can't figure it out from there I am gonna go buy two of the cheap rebuilds from advanced auto and put on the rears! Get me by until I can get a full kit for the front and back of the o-rings ones.
Sully
Sully