Brake bleeding question
Thread Starter
Racer
Joined: May 2013
Posts: 357
Likes: 15
From: Marshville, NC
Brake bleeding question
Putting on new front calipers this weekend. The back brakes are good. When I go to bleed will it be necessary to start with the RR inner and outer,then LR inner and outer before bleeding the RF and LF since the backs will not be touched?
1978 L48.
1978 L48.
Last edited by nivensid; May 28, 2015 at 06:28 PM.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
You do not need to bleed the rear brakes if all you did was replace the front calipers....AND...you did NOT allow the master cylinder to run dry in the front reservoir. AS long as fluid remained in the master cylinder...you can bleed the fronts and that will be all you need to do.
BUT.....if in your master cylinder the fluid is really dark...and there is sludge in the bottom of it. I would bleed out your rears in order to get out that old fluid. And keep in mind...I have a pressure bleeder that allows me to pressurize my tool and force fluid through the brake system....so it is not that big of a deal for me to get all your old fluid out and get fresh brake fluid in the system.
DUB
BUT.....if in your master cylinder the fluid is really dark...and there is sludge in the bottom of it. I would bleed out your rears in order to get out that old fluid. And keep in mind...I have a pressure bleeder that allows me to pressurize my tool and force fluid through the brake system....so it is not that big of a deal for me to get all your old fluid out and get fresh brake fluid in the system.
DUB
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
I would recommend bleeding the rear brakes too just because the rear brake calipers get air in them over time from the slight "pumping action" caused by small amounts of run out in the rotors. You see, as the C3's have fixed calipers instead of "floating" calipers ANY run out will pump air into them. It only takes a few additional minutes and it helps to ensure you maintain a hard brake pedal.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
I would recommend bleeding the rear brakes too just because the rear brake calipers get air in them over time from the slight "pumping action" caused by small amounts of run out in the rotors. You see, as the C3's have fixed calipers instead of "floating" calipers ANY run out will pump air into them. It only takes a few additional minutes and it helps to ensure you maintain a hard brake pedal.
AS for 'ANY' run-out causing for air to get into the system is actually not correct. The system can have some run-out in it. Just NOT excessive run-out. Your rear wheel bearings have an acceptable amount of 'play' in them...and that causes the rotor to have 'play' in it. There is no way in getting all of the components installed and indexed so it reads zero. This is simply not required.
DUB
Thread Starter
Racer
Joined: May 2013
Posts: 357
Likes: 15
From: Marshville, NC
Thanks DUB, I am not trying to take a short cut for safety's sake. I have the old front calipers off and will install the new ones tomorrow with the pads. I will bleed the front calipers with the Mityvac keeping a close watch on the master cylinder so the fluid does not get too low and draw in air.
Then time for a test drive to check out the brakes.
Thanks again for your help....
Then time for a test drive to check out the brakes.
Thanks again for your help....
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
Keep in mind that with your new calipers....that is why I mentioned on the condition of the fluid in the front reservoir. AND yes...to all others...I am aware that even if the fluid in the front and rear portions of the master cylinder are cleaned out and new fluid in them...there is still the crud that is lingering in the piston of the master cylinder itself.
For me...when I replace calipers for my customers....and they do not want to replace the master cylinder...i try to at least get as much of the sludge and crud out of the system and still not allow air into it.
DUB
For me...when I replace calipers for my customers....and they do not want to replace the master cylinder...i try to at least get as much of the sludge and crud out of the system and still not allow air into it.
DUB
