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Discussion Starter · #1 ·
hello. I was trying to bleed the brakes on my 85 el camino as well as rebuild the drum breaks and replace the wheel cylinders when the rear brake line snapped. I ordered new stainless steel brake lines and since ill be waiting for those I also ordered a new master cylinder and brake booster because mine were on their way out. so I will now be flushing the system and replacing the brake lines, wheel cylinders, master cylinder, and brake booster and my question is should I bleed the brakes before or after installing the new components? my fluid is very dirty and full of dirt and I dont want it running through my new parts, so I would like to bleed all the old fluid first, then remove all the old parts, install the new parts, and then refill the fluid. however I dont know if this idea will work because on the vidoes ive seen about bleeding brakes, they mention you cannot let the fluid run completely dry or the pump will be dry and you will get air in the system. so is it possible for me to flush the system prior to removing all the old components, replace the components and then refill the fluid without getting air in the system or is there a different order I should do this in? Want to make sure I do it right and dont mess up my all new brake system. thank you
 

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1987 GMC Caballero, 350, Holley Sniper EFI, 200-4R
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Buy plenty of brake fluid. Ensure you bench bleed your master cylinder before installing it.
Be very careful about getting brake fluid on painted surfaces. I purchased a 1 person bleeding kit at NAPA, cheap. I was skeptical at first, but found it works very well.
My system was full of old cruddy fluid also, that I wasn't willing to trust my life to. I replaced master cylinder, booster, proportioning valve, both front steel lines, both front flex lines, the flex line running to the rear axle, front calipers and did a rear disc conversion with all new parts. Like you, I wanted to flush all of the old cruddy fluid out, but it had to be controlled.
After installing your new master cylinder bleed from the passenger rear, to drivers rear, to passenger front and finally drivers front. I kept working that right rear bleeder until I got clear, clean fluid out. I continued the process on both rear sides until I was satisfied. I couldn't figure out another way to control where the fluid would go. In my case only the line from the proportioning valve to the rear flex line had old fluid in it.
 

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I bought the Motive brake bleeder, it looks like a small garden sprayer but works well. I replaced every component from the master cylinder, lines caliper's and wheel cylinders.
A lot of people will say it ain't so but I didn't bench bleed the master cylinder,, I pumped it up to 10psi and once I got the reservoir to stop leaking which was the biggest hassle, bleed off the pressure and added brake fluid pumped back to 10psi and started to bleed the system. Like Joe said start farthest away and once the air bubbles were out. Did it again. Went through two quarts but that brake pedal was the best pedal I every got on a A/G body.
Matty man
 

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87 Caballero Amarillo, original 305/200-4R, QJ
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You are changing parts on a sealed system. It's a guarantee you'll get some air in there somewhere, so don't stress over that, it's going to happen.
Me, I use an old, large Mason jar with 2 holes drilled in the top. One hole left open, the other stuffed with several feet of clear gas line hanging out, the tip just above the bottom of the jar. Fill the jar about 1/3rd with brake fluid, put the other end of the line over the nipple, crack it open, and start pumping. The jar is bigger than a bottle of brake fluid, so as it fills I just refill the used bottles. Watch the line for clarity and air.

Just don't let the MC run dry when pumping, or you'll be starting all over as air will go through the proportioning valve and contaminate all the lines.
 

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You DO want to flush out the entire system before disassembly. If not, when you install the new hydraulic components and bleed, you will have pushed all that rusty fluid through your brand-new parts and contaminated it.
So yes, you want to bleed first.
Make sure you buy a lot of fluid. Four large bottles should do it. Once the seal is broken on a bottle of brake fluid it's either use it or throw it away. Never use brake fluid that's been opened and used more than a few months old. As soon as that airtight seal is broken, the brake fluid starts attracting moisture.
Always use new fluid.
When I do a brake job, I buy one big bottle and four small bottles.
 

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Discussion Starter · #6 ·
Buy plenty of brake fluid. Ensure you bench bleed your master cylinder before installing it.
Be very careful about getting brake fluid on painted surfaces. I purchased a 1 person bleeding kit at NAPA, cheap. I was skeptical at first, but found it works very well.
My system was full of old cruddy fluid also, that I wasn't willing to trust my life to. I replaced master cylinder, booster, proportioning valve, both front steel lines, both front flex lines, the flex line running to the rear axle, front calipers and did a rear disc conversion with all new parts. Like you, I wanted to flush all of the old cruddy fluid out, but it had to be controlled.
After installing your new master cylinder bleed from the passenger rear, to drivers rear, to passenger front and finally drivers front. I kept working that right rear bleeder until I got clear, clean fluid out. I continued the process on both rear sides until I was satisfied. I couldn't figure out another way to control where the fluid would go. In my case only the line from the proportioning valve to the rear flex line had old fluid in it.
so install the new master cylinder first and then bleed the system?
 

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Discussion Starter · #7 ·
You DO want to flush out the entire system before disassembly. If not, when you install the new hydraulic components and bleed, you will have pushed all that rusty fluid through your brand-new parts and contaminated it.
So yes, you want to bleed first.
Make sure you buy a lot of fluid. Four large bottles should do it. Once the seal is broken on a bottle of brake fluid it's either use it or throw it away. Never use brake fluid that's been opened and used more than a few months old. As soon as that airtight seal is broken, the brake fluid starts attracting moisture.
Always use new fluid.
When I do a brake job, I buy one big bottle and four small bottles.
so once ive emptied the system and installed the new parts I will have a basically empty system I assume. am I suppose to then add brake fluid to the master cylinder and bleed each wheel until the brake fluid begins to come out?
 

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Until you get clear fluid with no bubbles.

You may have to go around 2 or 3 times.
 

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Bench bleed the master cylinder BEFORE installing it. Its easier and more effective that way.

You bought stainless steel lines. So did I and regretted it. I should have stayed with mild steel because the harder stainless steel was quite difficult to get each segment connector to seal for no leaks.

I eventually gave up on the back axel and went with mild steel after the tip of the line flare at a wheel cylinder broke off. Stainless is quite brittle and less malleable than mild steel.

Rick

Sent from my SM-G965U using Tapatalk
 

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87 Caballero Amarillo, original 305/200-4R, QJ
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Bench bleed the master cylinder BEFORE installing it. Its easier and more effective that way.

You bought stainless steel lines. So did I and regretted it. I should have stayed with mild steel because the harder stainless steel was quite difficult to get each segment connector to seal for no leaks.

I eventually gave up on the back axel and went with mild steel after the tip of the line flare at a wheel cylinder broke off. Stainless is quite brittle and less malleable than mild steel.

Rick

Sent from my SM-G965U using Tapatalk
I'd bought a SS pump to carb line from summit. Had nothing but issues with getting it not to leak because there's no forgiveness at the flares, if it's off dead center by even the slightest angle or amount, buh bye seal, it's going to leak, even with just 5lbs of pressure behind it. Brakes are much higher pressure under loads.

Went back to OEM mild steel tube, not a drip since. SS only works when both sides are SS, so you can apply the right amount of torque pressure to the fittings. If one side is brass, like with a carb seat, and sitting in a pot-metal carb, it's a no-good situation. Calipers are no different.
 

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It sounds like you're replacing pretty much the entire brake system (master, hard lines, flex lines). The only thing you didn't mention was the proportioning valve which you might as well replace. The only old fluid would be whatever's left in your calipers. Which would be the first thing to leave your system when you bleed.

I did a lnlineTube stainless replacement on my 71 A-bodies (Chevelle and Elco), 87 is in queue once I get around to it. Didn't have any fitment or sealing issues outside of the pass side front of the Chevelle where it goes over the frame—the fit is just a little snug but that's prob due to extra large headers.

I'd recommend getting all your lines in place first, then replacing your booster and master.

Prior to starting, shoot some penetrant oil on the fittings and let them soak an overnight or two.

As others have mentioned bench bleed to get all the air out of your master, or as much as you can before install. If you do the prop valve, do it with the lines.

Then full bleed. Keep your lid cracked open. Right rear, Left rear, Right front, Left front. One wheel at a time, connect the bleeder bottle and crack the bleeder valve open 1/4 to half turn enough to get the fluid flowing but not too open as you'll risk air going back in through the bleeder screw. Keep an eye on the master so you don't run dry. If it runs dry, you'll have to start over. Do it until the fluid is clear and there are no more bubbles coming through the hose. I do about 25 pumps for the RR, 20 LR, 15 RF, 10 LF.

If you can't get the rears to evacuate, the prop valve might have reset as imbalance in fluid will make the valve think there was a catastrophic failure in the circuit. On your year valve, there's a reset button that will open it up again, on earlier models you need a plastic pin.

I would suggest getting this or something like this to make bleeding easier:

It's essentially a bottle, hose with a one way check valve. They sell a chintzier version at your local auto parts establishments but this is more robust and has more capacity which you'll need doing the whole system. You can make your own with a discarded soda bottle and hose. Check YouTube for a number of videos on that. You can also get a vacuum pump but honestly i think it over complicates things plus the attachment for older cars doesn't work very well. I have a Motive one but use the bleeder bottle even with my modern cars.

And also this or equivalent for the bench bleed:

It was a little daunting for me the first time but these were the things i ran into. That bleeder bottle made it super simple. Good luck.
 

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Discussion Starter · #12 ·
[


It sounds like you're replacing pretty much the entire brake system (master, hard lines, flex lines). The only thing you didn't mention was the proportioning valve which you might as well replace. The only old fluid would be whatever's left in your calipers. Which would be the first thing to leave your system when you bleed.

I did a lnlineTube stainless replacement on my 71 A-bodies (Chevelle and Elco), 87 is in queue once I get around to it. Didn't have any fitment or sealing issues outside of the pass side front of the Chevelle where it goes over the frame—the fit is just a little snug but that's prob due to extra large headers.

I'd recommend getting all your lines in place first, then replacing your booster and master.

Prior to starting, shoot some penetrant oil on the fittings and let them soak an overnight or two.

As others have mentioned bench bleed to get all the air out of your master, or as much as you can before install. If you do the prop valve, do it with the lines.

Then full bleed. Keep your lid cracked open. Right rear, Left rear, Right front, Left front. One wheel at a time, connect the bleeder bottle and crack the bleeder valve open 1/4 to half turn enough to get the fluid flowing but not too open as you'll risk air going back in through the bleeder screw. Keep an eye on the master so you don't run dry. If it runs dry, you'll have to start over. Do it until the fluid is clear and there are no more bubbles coming through the hose. I do about 25 pumps for the RR, 20 LR, 15 RF, 10 LF.

If you can't get the rears to evacuate, the prop valve might have reset as imbalance in fluid will make the valve think there was a catastrophic failure in the circuit. On your year valve, there's a reset button that will open it up again, on earlier models you need a plastic pin.

I would suggest getting this or something like this to make bleeding easier:

It's essentially a bottle, hose with a one way check valve. They sell a chintzier version at your local auto parts establishments but this is more robust and has more capacity which you'll need doing the whole system. You can make your own with a discarded soda bottle and hose. Check YouTube for a number of videos on that. You can also get a vacuum pump but honestly i think it over complicates things plus the attachment for older cars doesn't work very well. I have a Motive one but use the bleeder bottle even with my modern cars.

And also this or equivalent for the bench bleed:

It was a little daunting for me the first time but these were the things i ran into. That bleeder bottle made it super simple. Good luck.
one question I have, the bleeder valves on my brake lines broke off, they were so rusted that the nut twisted the entire line with it and snapped it off. I can attach the brake bleeder to the end of the brake line where it broke off, but I have no control over turning the valve to open or close the flow of fluids since the valves broke off. how would I work around that?
 

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Not sure if the bleeder valve is intact and the line broke or the bleeder valve itself snapped off with part of it still in the caliper. If it's the former, just replace the bleeder valve, if the latter it may be easier to replace the entire caliper than try to it drill or work out.
 

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Discussion Starter · #14 ·
Not sure if the bleeder valve is intact and the line broke or the bleeder valve itself snapped off with part of it still in the caliper. If it's the former, just replace the bleeder valve, if the latter it may be easier to replace the entire caliper than try to it drill or work out.
the valve broke off but I was able to remove it from the calliper pretty easily but im replacing it all anyways. i was just wondering with a broken valve can i still drain the fluid out properly? when i see videos on youtube they close off the valve after pumping the brakes every few times and then reopen the valve when they are pushing the breaks again. i will not be able to do the practice of opening and closing it while bleeding the brakes because the valve broke off so will that be an issue?
 

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You will need to replace the valve before bleeding. It will suck air back in.
 

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87 Caballero Amarillo, original 305/200-4R, QJ
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Need new nipples. They serve 3 purposes, stop air from entering the system and fluid from exiting the system and allowing for air to escape the system during a bleed process. Without them in good working order, one or more of those 3 things will not happen, and for brakes to work its a must to have all 3.
 

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Discussion Starter · #18 ·
Need new nipples. They serve 3 purposes, stop air from entering the system and fluid from exiting the system and allowing for air to escape the system during a bleed process. Without them in good working order, one or more of those 3 things will not happen, and for brakes to work its a must to have all 3.
since I am replacing everything in the entire brake system, wouldnt it not matter for the first drain if the broken valve lets air in? wouldnt I be able to just unbolt it all and let the fluid come out with the parts as I remove them since I will be installing new parts that come without any fluid in them anyways?
 

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Discussion Starter · #19 ·
Need new nipples. They serve 3 purposes, stop air from entering the system and fluid from exiting the system and allowing for air to escape the system during a bleed process. Without them in good working order, one or more of those 3 things will not happen, and for brakes to work its a must to have all 3.
dont know if i mentioned but i went back and got the few last components of the brake system i had left out so now i will be replacing literally everything in the brakes
 

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Discussion Starter · #20 ·
It sounds like you're replacing pretty much the entire brake system (master, hard lines, flex lines). The only thing you didn't mention was the proportioning valve which you might as well replace. The only old fluid would be whatever's left in your calipers. Which would be the first thing to leave your system when you bleed.

I did a lnlineTube stainless replacement on my 71 A-bodies (Chevelle and Elco), 87 is in queue once I get around to it. Didn't have any fitment or sealing issues outside of the pass side front of the Chevelle where it goes over the frame—the fit is just a little snug but that's prob due to extra large headers.

I'd recommend getting all your lines in place first, then replacing your booster and master.

Prior to starting, shoot some penetrant oil on the fittings and let them soak an overnight or two.

As others have mentioned bench bleed to get all the air out of your master, or as much as you can before install. If you do the prop valve, do it with the lines.

Then full bleed. Keep your lid cracked open. Right rear, Left rear, Right front, Left front. One wheel at a time, connect the bleeder bottle and crack the bleeder valve open 1/4 to half turn enough to get the fluid flowing but not too open as you'll risk air going back in through the bleeder screw. Keep an eye on the master so you don't run dry. If it runs dry, you'll have to start over. Do it until the fluid is clear and there are no more bubbles coming through the hose. I do about 25 pumps for the RR, 20 LR, 15 RF, 10 LF.

If you can't get the rears to evacuate, the prop valve might have reset as imbalance in fluid will make the valve think there was a catastrophic failure in the circuit. On your year valve, there's a reset button that will open it up again, on earlier models you need a plastic pin.

I would suggest getting this or something like this to make bleeding easier:

It's essentially a bottle, hose with a one way check valve. They sell a chintzier version at your local auto parts establishments but this is more robust and has more capacity which you'll need doing the whole system. You can make your own with a discarded soda bottle and hose. Check YouTube for a number of videos on that. You can also get a vacuum pump but honestly i think it over complicates things plus the attachment for older cars doesn't work very well. I have a Motive one but use the bleeder bottle even with my modern cars.

And also this or equivalent for the bench bleed:

It was a little daunting for me the first time but these were the things i ran into. That bleeder bottle made it super simple. Good luck.
prior to getting my new lines in place, do i just empty my old brake fluid and let it run completely dry since im replacing everything? i got the prop valve so im replacing it all now
 
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