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Gravity Bleeding

Old 08-09-2018, 01:12 PM
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Car: 1986 IROC.(RPO B4Z)
Engine: 305 TPI
Transmission: 700r4
Gravity Bleeding

Okay guys how some questions here I have an 86 IROC 305 TPI I replaced the power booster and the master cylinder bleed the master cylinder on the bench I'm trying to bleed my brakes and all I'm getting is microbubbles like crazy I don't have a second person to help me do the old style of pump pump pump hold turn closed so I'm trying to figure out how to gravity bleed I have my bottle set up I have my hose connected to the bleeder valve I'm doing the passenger side rear first here's my problem like I said I keep getting bubbles after bubbles I've got a zip tie around the bleeder tube call Dad on tight is there any way that maybe the bleeder valves or letting are being behind them when I loosen them up? Also what are the proper steps for Gravity bleeding?
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Old 08-09-2018, 01:50 PM
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Re: Gravity Bleeding

"Call Dad?"

Yeah, the threads around the bleeders usually leak like a sonuvabitch. It's almost comical how one of those MightyVac hand pumps will pull bubbles through the threads non-stop.
If the two person bleeding isn't working for you, you need to figure it out. Gravity bleeding probably won't cure the problem. Worse yet, I have never had a bit of luck gravity bleeding a thirdgen. Maybe it's because my brake lines are corroded and blocked, but it's never worked at all well for me.

With the two person method, with a full master cylinder reservoir and the bleeder/threads being the only leak, the only way anything can flow is out backed by fluid pressure. Gravity bleeding won't remove air pockets that can form, and since the system isn't under pressure air bubbles aren't being forced or kept out of the system.
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Old 08-09-2018, 10:44 PM
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Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10 bolt 4.10 Auburn Posi
Re: Gravity Bleeding

I tried the MightyVac & bottle method on my 2003 Camry. All I got was the microbubbles also.
So I just cracked each bleeder one at a time with the hose running into the bottle and let gravity do the rest.
I let them drip until I got about a cup of brake fluid from each. Afterwards I went back and double checked
with a pressure bleed. There was no air.

Speedbleeders replace your standard bleeder screws with bleeders that have an internal spring and ball bearing.
You just attach the hose and run it into a bottle, crack the bleeder and then pump the brake pedal.
I believe RockAuto even carries the Dorman version.

Last edited by NoEmissions84TA; 08-09-2018 at 10:50 PM.
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Old 08-09-2018, 11:24 PM
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Car: 86 Imponte Ruiner 450 GT
Engine: Various
Transmission: 700R4 3000 stall.
Axle/Gears: 9 Bolt Torsen 3.70
Re: Gravity Bleeding

I have gravity bled my 86 Trans Am with no difficulty. That said, pressure at the master and vacuum at the bleeders is the way to get it done quickly and efficiently.

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