Brake bleeding

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Nov 17, 2002 | 08:50 AM

koshare

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Joined: Dec 2001

Posts: 82

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From: Tucson USA

Brake bleeding

hi ya:

i'm going through hell trying to get my brakes blead.

no matter what i do i can't seem to get any reasonable pedal. i have gone back around an made sure all fittings are tight.

when i started to bleed one of the wheels i had mistakingly left the cover off the master cylinder and as my wife pushed on the pedal the master cylinder acted like a fountain. not air bubbles but a stream of fluid shot all over the car. it seems to me if the master cylinder is pushing fluid back into reservior, then i might have a defective master cylinder. is this a correct assumption? this would be the second one, the first wouldn't even bench bleed. both were remanufactored units which i've read warning about using. any thoughts oh wonderful gurus?

btw i'm using a 70 dual disc/drums mastang master cylinder with a mid 80 mustang booster. booster rod is adjusted correctly for the master cylinder.

thanks,
rick

Nov 17, 2002 | 09:06 AM

GreatNorthWoods

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Joined: Apr 2002

Posts: 8,813

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From: Littleton, New Hampshire

Brake bleeding

Rick,

The fountain is normal, just keep the cover on the MC when you bleed the brakes. Also, you can minimize this by telling the wife to push the pedal down a little slower and easier when bleeding.

I guess I've had good luck with rebuilt MCs since I never ran into one that would not bench bleed.

One thing you need to do is verify that the cylinder you are using is a power brake cylinder. The bore size is often different in a power MC as opposed to a manual and you might get some unexpected results. Be sure to keep the bottom of the MC covered with fluid in both reservoirs to keep from pumping more air through the system.

Be sure that the brake rod is not too long. If it is (and this happened to me on a previous project), the piston will not come far enough out of the MC to allow the fluid to drain back to the MC when you let the pedal up causing a buildup in the cylinders.

Nov 17, 2002 | 09:25 AM

f3f350

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Joined: Oct 2002

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From: Northport, New York

Brake bleeding

Rick, I think its normal for the fluid to shoot out of the resevior if you push on the pedal down with the resevior cover off- the fluid goes in the direction with the least resistance.
Usually when you get a rebuild master cylinder they give you a little plastic hose set up used to initially get all the air out of the master cylinder. After you connect the master to your brake lines just bleed the brakes as usual- starting with the furthest brake from the master cylinder. sometimes its easier to get a piece of platic or rubber tubing that will fit over the nipple that your going to bleed & run it from the nipple into a jar or bottle of brake fluid. This way, with the master cylinder filled & closed you just crack open the brake nipple your going to bleed & pump the peddle a couple times. It will get all the air out of that line. Do this untill you dont see any bubbles in the bottle. Do this to all 4 brakes remembering to keep the resevior filled.
Do you have discs up front?
Hope this helps

Nov 17, 2002 | 09:40 AM

soso

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Joined: May 2002

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From: north of 60

Brake bleeding

I find one of the easy ways to do this is to start at the furthest wheel, losen off the bleeder screw,go have a beer,go back, fluid should be coming out of the bleeder screw.
goto the next furthest, loosen the screw,have beer, go back same senaro, do this for all four wheels they should bleed by them selfs,
no need to pump pedel just ensure resavoir stays full after four wheels you will be happy

Nov 17, 2002 | 09:54 AM

f1fordguy

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Joined: Apr 2002

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From: Austin, TX

Brake bleeding

I certainly like the soso method. Sure beats pumping the pedal although after the fourth cold beer I may not necessarily care that the pedal isn't as hard as I would normally have liked.

Anyone used speed bleeders? I am also intrigued with a $24 vacum pump sold at autozone that will bleed brakes. Same concept as soso but in theory quicker and not as much fun. Anyone used one of these pumps?

Tim

Nov 17, 2002 | 11:38 AM

koshare

Thread Starter

Junior User

Joined: Dec 2001

Posts: 82

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From: Tucson USA

Brake bleeding

>I certainly like the soso method. Sure beats pumping the
>pedal although after the fourth cold beer I may not
>necessarily care that the pedal isn't as hard as I would
>normally have liked.
>
>Anyone used speed bleeders? I am also intrigued with a $24
>vacum pump sold at autozone that will bleed brakes. Same
>concept as soso but in theory quicker and not as much fun.
>Anyone used one of these pumps?
>
>Tim
>
>

i borrowed one from a friend, but i couldn't get a good vacuum on the front disc bleed nipples. however, my friend swears by it. as far as gravity bleeding, i.e. the soso method, one may be waiting for a long time if the master is on the frame and below the wheel cylinders. but hey that just means more beer right? wife says you been drinking beer non-stop for the last week.

thanks for the help guys!

rick

Nov 18, 2002 | 07:39 AM

GreatNorthWoods

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Joined: Apr 2002

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From: Littleton, New Hampshire

Brake bleeding

One reason I've decided to go the firewall route for my master cylinder is to avoid the hassle of having the MC lower than the wheel cylinders. I went through that in a 29 Ford and it was a pain. The fluid has a tendency to drain back from the cylinders and so every time you hit the brakes, you have to pump them to get the fluid back. I did everything the brake gurus said about using 2 PSI inline residual valves to the front and 10 PSI to the rear and even included an adjustable proportioning valve, but I still had that annoying problem of excessive pedal travel until they were pumped up.