I replaced left front caliper that was leaking. Have bled front brakes twice but still have low soft pedal. Before replacing caliper brake pedal engaged power brakes within 1/2 inch from the top now it goes down almost to the floor before engaging brakes. Obviously still has air somewhere in the system.

My question is, Do I have to bleed the rear brakes also to get a firm high pedal? I used a Motive Products pressure bleed system to bleed the front brakes. All components including booster, master cylinder, lines, hoses and calipers are new. The only change is the replacement caliper.

 

yes bleed them all, if the pedal is still soft you probably got air in the master cylinder and need to bleed that also.

 

I would bleed brakes manually or with vacuum bleeder. Not a fan of pressure bleeders.

 

Everybody seems to have a preferred method, since you have the Motive system, try it again and rap lightly on the caliper to set up some good vibrations to try to get the air out. You might also try a Russel self bleeder.

 

Old School works for me, my daughter pressing the pedal to the floor, me tightening the bleeder screw etc if you do it in this sequence....

Left rear inner
Left rear outer
Right rear inner
Right rear outer
Left front
Right front

 

After 20 years of road racing, I have found that a spouse/significant other/son or daughter is an invaluable part of brake bleeding. I have tried every variant of brake bleeder in the past, and have found someone pressing on the pedal gives the most consistent solid pedal. I do use a pressure type one-man bleeder to get the bulk of the bleeding done, then call in the human factor to complete this job. This way you don't wear out your welcome making them push endlessly before getting any initial results.

Marc in Indy
1957 Corvette 283/245 4 speed
1973 Honda Civic SCCA GT5 vintage race car with the VSCDA

 

128racecar has it right.
Only way I can get a full, hard pedal on my manual brake 70.

 

Vacuum bleeders suck air in around the bleeder threads - no real way to tell if the air is coming from the system or from the "leak" around the threads. Manual or Pressure bleeding is the only reliable way.

 

If I can hijack gsimon767's thread here, I am in the same position and just bled my brakes last night (a 1970 with manual brakes). I had to bleed the rears and master and then fronts to get a hard pedal.

The car has been parked a LONG time. I had some leakage from the PS front caliper, but after working the pedal and bleeding, it appears to be no longer leaking (we will watch it for a few days). I now have a hard pedal and no brake lights, etc. but you need to STAND on the brakes to stop the car. Basically all new pads and calipers within the past 500 miles (but 6-8 years ago). Could it be that I just have contamination on the PS front pads from that leak? Other components? Firm pedal and the system is holding pressure and fluid. You have to push REALLY hard to get the car to stop. I probably can't lock the brakes up if I try.

Thoughts? Clean all four with brake cleaner and put them back together?

 

And what better way to spend some daddy daughter time..

Remember to bled in this sequence


Left rear inner
Left rear outer
Right rear inner
Right rear outer
Left front
Right front

 

Just to check basics, I would jack up the car, have somebody put their foot on the brake and check each wheel individually to make sure they are locking up.

 

I always thought you were supposed to do the line farthest away form the master cylinder first and the closest line last. In most cars, that would be right rear, left rear, right front, left front. Though with dual master cylinders, it's less important if the front or rears are done first.

 

trust me on this one, as weird as it seems

 

Can anyone explain why bleeding the left rear first instead of bleeding the right rear first is the preferred method of bleeding rear brakes on our C3's?

 

47 years of doing this, the best method I have found does not include the "aid of an assistant". (I used to install Philips and Siemens medical equipment, and every time some big, heavy piece needed to be humped around, the paragraph began with "with the aid of an assistant"). Never could find hi in the crates.

Anyway, my preferred method involves the use of 4 Miller beer bottles ( emptied previously), several feet of 1/4" ID hose (I like the clear stuff you use in aquariums to pump air) , and about a quart of brake fluid.

Put the car up on jackstands, and pull the wheels (10 minutes?)

Halfway fill the (clear glass) Miller beer bottles with clean brake fluid. ( 2 minutes)

After verifying you can open the bleeder valves, attach a length of hose sufficient to go from the bleeder valves to the BOTTOM of the half filled Miller bottle. (5 minutes)

Take the top off your master cylinder and fill to the brim with brake fluid.. ( 1 minute)

walk around the car and crack open all of the bleeder valves.

continue walking around the car, observing the brake fluid and air bubbles traveling through the hose.

check the brake fluid level in the master cylinder on each lap, being careful to not let it drain fully.

After a few minutes time good old Issac Newton and his pal gravity will bleed your brakes.

Once the bubbles stop,close all the bleeder vales, then close the master cylinder.

SLOWLY depress the rake peddle ONE time, and SLOWLY let it come back up. It will probably go all the way to the floor.

Now step normally on the brake pedal. YOU SHOULD BE GOOD TO GO.

If your brake pedal is now firm, find the two remaining Miller bottles...

 

I use Busch lite cans

 

Ah, yes. But they are not transparent..

 

Why do you fill these half full of fluid if they are just being used to drain fluid into?

If I got my math right 1/2 of a 12 oz miller bottle x 4 is 24oz of new fluid just for these drain bottles leaving only 8 oz remaining in your new 32oz bottle of fluid.

Not trying to be a wiseass just want to know why the fluid in the bottle first.

 

Having the free end of the tubing submerged in the clean brake fluid prevents air from being sucked back into the caliper.
6 oz may be more fluid than needed - depending on the length of tubing used, but the concept is solid. Ideally, you should only need just a little more fluid in the bottle than volume in the tubing.

 

Because the brake line is routed on the left side of the car....so...the brake line will 'T' off and got the to right side.

Some people think that at least getting the air all the way down to that 'T' fitting and out to the caliper is better. Then...when you go to bleed the right side...you have good air-free fluid all the way to the rear of the car and all you need to worry about is the 'cross-over' brake line and the right caliper.

I pressure bleed them with the left side first and then right....BUT...I have also bled the right side first and then the left. But to be honest...I pressure bleed the brakes TWICE....so...it kinda does matter. I achieve an air free system regardless.

DUB