Power Vacuum Bleeding

cargs · 11-13-2007, 12:57 PM

I just thought of a weird way of bleeding your brakes. How about using you engine vacuum to bleed the brakes instead of a hand operated vacuum pump? you would still need to have a bottle in place to catch the fluid.

Caliper Bleeder---> Vacuum Bottle/Reservoir---> Intake Manifold.

So the procedure would be fill up the master cylinder with fluid, attach all the hoses, start the engine and begin bleeding at the wheel...

it seems like a cheap alternative to a power bleeder setup, and turns brake bleeding into a one man operation. the only thing i can think of is if the engine makes enough vacuum to suck out the fluid. Or possibly the other extreme, if the engine makes too much vacuum and sucks out the fluid too fast.

Anyone done this before?

**MAKG** · 11-13-2007, 01:08 PM

What will that save you?

30 milliseconds?

You don't need anywhere near that strong a vacuum source to attempt a vacuum bleed. You can't make any more than 30 inches or so of vacuum. Whether you do that with an engine or a hand pump is a matter of speed only.

Use an engine and the technique will just drain your master cylinder and fail to actually bleed much more quickly.

The reason vacuum bleeding fails has nothing to do with the speed of pumping. It's that an OPEN bleed screw doesn't hold vacuum off, and neither do the seals.

Pressure bleeding actually works -- the leaky stuff is on the opposite end as the "business end." So does old-fashioned (pumping with the foot pedal) bleeding. Vacuum bleeding doesn't.

cargs · 11-13-2007, 05:28 PM

haha.. thanks for the reply. it was just a daydream i had at work, wondering if anyone had done that before.

11-13-2007, 12:57 PM	#1
cargs Member Join Date: Aug 2007 Year: 1993 Make: FORD Model: RANGER Engine: 3.0L Class: 4x4 Used For: Daily Driver Posts: 189 Rep Power: 12 iTrader: (0)	Power Vacuum Bleeding I just thought of a weird way of bleeding your brakes. How about using you engine vacuum to bleed the brakes instead of a hand operated vacuum pump? you would still need to have a bottle in place to catch the fluid. Caliper Bleeder---> Vacuum Bottle/Reservoir---> Intake Manifold. So the procedure would be fill up the master cylinder with fluid, attach all the hoses, start the engine and begin bleeding at the wheel... it seems like a cheap alternative to a power bleeder setup, and turns brake bleeding into a one man operation. the only thing i can think of is if the engine makes enough vacuum to suck out the fluid. Or possibly the other extreme, if the engine makes too much vacuum and sucks out the fluid too fast. Anyone done this before? __________________ 93 Ranger, 3.0L, 5spd, manual t-case swap, MSD ignition, 31x10.5 BFG AT's, 2006 ranger bucket seats, rancho RS500 shocks, Warn 37780 "Jeep" hubs, 2007 Glasstite Raven Canopy. http://www.cardomain.com/ride/2327329/1
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11-13-2007, 01:08 PM	#2
MAKG RBV Technical Advisor Join Date: Aug 2007 Location: California central coast Year: 1991 Make: Ford Model: Explorer Engine: 4.0L Class: 4x4 Posts: 4,643 Rep Power: 21 iTrader: (0)	What will that save you? 30 milliseconds? You don't need anywhere near that strong a vacuum source to attempt a vacuum bleed. You can't make any more than 30 inches or so of vacuum. Whether you do that with an engine or a hand pump is a matter of speed only. Use an engine and the technique will just drain your master cylinder and fail to actually bleed much more quickly. The reason vacuum bleeding fails has nothing to do with the speed of pumping. It's that an OPEN bleed screw doesn't hold vacuum off, and neither do the seals. Pressure bleeding actually works -- the leaky stuff is on the opposite end as the "business end." So does old-fashioned (pumping with the foot pedal) bleeding. Vacuum bleeding doesn't. __________________ 1990 VW Jetta GL, 1.8L 8V gasoline engine, manual transmission, painted in oxidized red paint and ponderosa pine sap, unknown mileage. 1991 Exploder, 4.0L, M5OD-R1 manual transmission, electronic BW1354 transfer case, 3.54 gears, 31 inch tires, icky two-tone blue paint with little clear coat, 230K miles. 1972 Chevy C-10, 250 I-6, SM465 (2WD) four-on-the-floor, 3.73 gears in a GM 12-bolt, puke green with a white cab. The "4 wheeled trash can," with x70K miles. x is probably 2.
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11-13-2007, 05:28 PM	#3
cargs Member Join Date: Aug 2007 Year: 1993 Make: FORD Model: RANGER Engine: 3.0L Class: 4x4 Used For: Daily Driver Posts: 189 Rep Power: 12 iTrader: (0)	haha.. thanks for the reply. it was just a daydream i had at work, wondering if anyone had done that before. __________________ 93 Ranger, 3.0L, 5spd, manual t-case swap, MSD ignition, 31x10.5 BFG AT's, 2006 ranger bucket seats, rancho RS500 shocks, Warn 37780 "Jeep" hubs, 2007 Glasstite Raven Canopy. http://www.cardomain.com/ride/2327329/1
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