Dumb but true question: How do I use Mightvac to bleed brakes? My reason is i want to flush them. For years my daughter would push the pedal but now she is grown up and gone (sob sob....)

Its not too hard at all.

First, make sure you've got a bleeding container. Many mityvac kits come with one. It looks like a clear canister with two hose connections, one of which has a dip tube inside that extends to the bottom of the canister. If you don't have one, you can make one by taking a soda bottle, drilling two holes in the top, attaching a hose nipple to one hole, and then passing another tube all the way through the hole, down to the bottom of the bottle. The one that extends to the bottom connects to the bleed nipple, the other connects to your mityvac.

Anyway, connect your bleed container as I said, dip-tube side to the bleed nipple, and mityvac to the other. Remove the lid to the fluid reservoir, and have fresh fluid on hand. Put your bleed nipple wrench over the nipple, then seal the tube over the nipple. Use the mityvac to pull about 10psi of vacuum. If it quickly goes away, you have a leak in your tubing, it should hold pretty steady.

Then, being to unscrew the bleed nipple a bit. You should see fluid and air bubbles coming through the line. When you stop seeing bubbles, close the nipple. Also, close the nipple when your vac gets down to about 5psi, and then crank it back up to 10 and continue.

When you are done with that wheel, check the fluid level, top up if necessary, and move to the next wheel.

The reason you have a helper push on the pedal is to prevent air from coming back up into the system when the nipple is open. The vac does the same thing, it keeps suction on it, so air can't retreat up the nipple, and it can freely suck fluid through the lines.

EDIT: Saw you want to flush, instead of just bleed. Do the same thing, but keep closing the nipple and topping up the reservoir until you see clean fluid coming out of the lines, then close the nipple, top up the reservoir, and move to the next wheel. Just make sure you don't suck an air bubble in from the top by letting the reservoir go empty. I've done it on my motorcycles (their reservoirs hold like 30ml), and its a pain in the butt, have to start all over.

Hope this helps,

peace,
sam

__________________
"That f***in' biodiesel is makin' me hungry."

1982 300TD Astral Silver w/ 250k (BIO BNZ)
2001 Aprilia SR50 Corsa Red w/ 5.5k (>100 MPG)

You need a container for the fluid. Hose goes from bleed screw to the container. The container should have another hose connection for the Mityvac. Provide suction to the container via the Mityvac and open the bleed screw. Make sure there is plenty of fresh brake fluid in the reservoir.

http://www.************************/productpage.aspx?pid=104170&name=Mityvac+Brake+Bleeder+Kit&type=10&referer=1469


The other way is to pressure bleed it from above, the method I prefer.
You have to be careful about dripping brake fluid on the paint, but it can be done quickly this way.

http://www.trackhaus.com/motive_products_power_bleeder_4_ctg.htm

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

When you loosen the brake bleeder screw take it all the way out and put grease or and anti-sieze compound on the threads. It will help you next time and it will keep you from sucking air around the threads as you try to bleed the brakes.

Thanks For Your Help

Is that my problem? I'm installing new front pads in my wife's '87 and flushing at the same time. When I suck with the Mitymousevac I get bubbles; if I have wife push gently on the brake pedal I do not get bubbles. I figured air had to be getting in somewhere but didn't even think about the fitting. I'll try putting grease around it.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

A pressure bleeder is a good investment, much easier and quicker than the Mity Vac.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

There's a thread here somewhere from a member who built his own pressure bleeder from a garden sprayer. I had considered doing that but got the Mityvac to work on my vacuum system and figured it would bleed brakes, too. Now it seems I'll build the pressure bleeder after all.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I've used the MiteyVac to change/renew brake fluid on a couple of vehicles....done the grease around the bleeder screw......biggest thing to remember is to top up fluid reservoir often....

MiteyVac works just fine, so I don't see the need for building or purchasing a pressure bleed system......I would only use it a couple of times a year (annual brake fluid change each vehicle), and then it would be moved around the shop looking for a place to hide, gathering dust.......until the next year.....

SB

FWIW: I noticed that someone in this thread mentioned "psi vacuum" there is no such term.....vacuum is measured in "inches of mercury" ("hg).....

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Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

Dang SB, what you doing on here so early? Can't sleep?

I too find the Mity-Vac perfectly adequate for my annual brake fluid replacements.

The extra work helps keep me young!

__________________
2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)

I guess its a matter of haveing something that will "do" or the right tool for the job, up too you Chief

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

If all goes well, and the creek don't rise, and the economy doesn't tank, I will build a 3 car garage (2 bays and a shop) this summer!!! Then I can get more tools and stuff, because I will have more space available.......

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

Oh yah, you gota have a shop now that your retired. Mines a "two car", Half for cars and half for "farm repair/woodworking and a small office with wood stove

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"