Bench bleeding and/or pressure bleeding?
Thread Starter
Instructor
Joined: Jan 2005
Posts: 152
Likes: 0
Bench bleeding and/or pressure bleeding?
I’m about to bleed my entire brake system after installing 4 new Wilwood callipers with steel hoses, adding a brake vacuum booster and a new MC. After searching the forum I decided to tri and bleed the system with a pressure bleeder. I seems that all the forum members that have used such a bleeder have been very happy with it.
Now my question is can I bleed the complete brake system without first making a bench bleeding of the MC?
The new MC was delivered without the necessary fittings and pipes for such a bench bleeding and I would for sure like to avoid having brake fluid all over the car if possible.
Best regards, DK.
Now my question is can I bleed the complete brake system without first making a bench bleeding of the MC?
The new MC was delivered without the necessary fittings and pipes for such a bench bleeding and I would for sure like to avoid having brake fluid all over the car if possible.
Best regards, DK.
Thread Starter
Instructor
Joined: Jan 2005
Posts: 152
Likes: 0
Thanks Durango. I know that it works if I bench bleeds first but have you or anyone else actually tried ONLY to pressure bleed?
I would for sure like to avoid to make the bench bleeding if possible.
Best regards, DK.
I would for sure like to avoid to make the bench bleeding if possible.
Best regards, DK.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
In my Vette I tried bleeding the master in the car and I made it a lot harder of an event than it needed to be.
I used an old windshield washer tank and pump filled with brake fluid to pump fluid up from the bleeders through the system from each wheel until it reach the master.
My master has bleeders built into it so I bled it from there, then bled the system at the wheels.
WAY to complicated. Now, you can install the master and bench bleed it in the car using the pedal to actuate it, but make sure it's free of air before you connect the hard lines.
Burning Brakes
Joined: Apr 2004
Posts: 847
Likes: 0
From: Des Allemands LA
ltlevil
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
Try this. Remove the tubes from the MC. Fill the resovoir. Have someone slowly push the pedal to the floor and hold it there. Now put your fingers over the MC outlet ports while your helper slowly releases the pedal. Repeat the procedure until fluid comes out in a steady stream when the pedal is pushed. It could get a little messey because one side will bleed out quicker than the other, just keep some shop towels handy. The important thing is to have your finger(s) in the ports when the pedal is released otherwise you'll suck air back in and you'll never get it bled. Good luck, it can be done this way.
Le Mans Master
Joined: Jan 2001
Posts: 6,713
Likes: 1,372
I've done both...
..and since I already own a pressure bleeder, then if I was to replace my master cylinder today, then I would not bother to bench bleed it.
With the Pressure Bleeder it didn't seem to make any differrence the last couple of times that I replaced master cyllinders...I would not bother with bench bleeding at all.
With the Pressure Bleeder it didn't seem to make any differrence the last couple of times that I replaced master cyllinders...I would not bother with bench bleeding at all.
Racer
Joined: Nov 2000
Posts: 369
Likes: 1
From: Finland
The only snafu was with my Motive pressure bleeder, the universal mc cover that came with it wasn't big enough for the long oval shaped wilwood master cylinder, so I had to make my own cover out of steel plate, fluid fitting and some rubber gasket material.
rgds Tomi
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Thread Starter
Instructor
Joined: Jan 2005
Posts: 152
Likes: 0
Thanks all of you for you help and input.
Based on the experiences of Tomi72 and Carriljc I have decided to try not to bench bleed the MC first. I’m making my own cover for the master and use air from my compressor to force the brake fluid out to the callipers. I can take a few pics and let you know how it goes.
If it doesn’t work I guess I can always go back to the messy Bench bleeding.
Best regards, DK.
Based on the experiences of Tomi72 and Carriljc I have decided to try not to bench bleed the MC first. I’m making my own cover for the master and use air from my compressor to force the brake fluid out to the callipers. I can take a few pics and let you know how it goes.
If it doesn’t work I guess I can always go back to the messy Bench bleeding.
Best regards, DK.
Team Owner
Joined: Jul 2001
Posts: 61,413
Likes: 478
From: Here to make friends
St. Jude Donor '11, '16-'17
The main reason for bench bleeding the master cylinder is so that it's piston will be lubricated when you start pumping the brake pedal. Since pressure bleeding just forces fluid through the system without pumping the brake pedal, bench bleeding may be unnecessary.
