Brake issues on my coronet. Help…

[Huicho417]

Last weekend I replaced my front brake lines with new stainless steel. The car was braking great before changing the lines. After I changed the lines I bled the system twice until I had no air coming out. When I test drove it the pedal keep going down to the floor. Only way I got it to stop was pumping the pedal way before my actual stopping point. I parked it and bled the system again for a third time and again the fluid shot out each caliper without any air. I did notice some fluid leaking out of the master cylinder caps when I was bleeding it the third time. Took the caps off and reinstalled and the leak went away. Also on my driveway when I pumped it I could build up pressure. But when I took my foot of the break pedal and tried it again it would initially sink to the floor. Any ideas as to what the issue is? A friend of my suggested bench bleeding the master cylinder. Is it possible air is stuck there and is not pushed out when bleeding at each caliper? Thanks in advance!

 

[Ron H]

You probably know ya got to be careful bleeding keeping the reservoir with ample fluid. If this is suspect, then an MC bleed would be a thing. One thing I’d check with a helper pressing on the brakes, watch those new lines for any bulging. It’s rare; but a line could be defective.

 

[Huicho417]

Well I forgot to mention that I also removed the front calipers to paint them when I replace the lines. During that time I did remove the fluid from the m.c to prevent it from leaking while I painted the calipers. Maybe during that time air entered the master cylinder.

 

[dadsbee]

Bleeders are at the top correct....

 

[Ron H]

Sounds like you should bleed the MC

 

[Ron H]

If you're careful you can do this on the car protecting all around it from any splashing/dripping. I've done this both ways - having emptied the MC (you didn't need to do this) you likely have air in it...

 

[72ls5fla]

Also- did you clean all the places the stainless lines screw into very well before installing ?
clean mating surfaces are important.

Also be aware that stainless lines going into old brass blocks is a receipt for a mess.
they never seat well and usually end up having to muscle them hard to stop leaks or sucking air back in.
if you are re using old brass blocks (ie distribution/proportioning valves under the master) best to use regular steel lines. they are softer and will seat and seal better.

1st hand experience here talking here... LOL

 

[R413]

If the MC was emptied it must be bench bled. But that doesn’t need to be on a bench to do it. It means running the output tubes back into the reservoirs and bleeding to remove all air bubbles, then connect the lines and bleed at the wheels. All 4 wheels.

 

[dadsbee]

 

[Moms68]

Did you swap the calipers driver's to passenger's side by any chance? Bleeders should be up as dadsbee stated.

 

[bm02tj]

Master cylinder needs to be level when you bleed it

 

[dadsbee]

Master cylinder needs to be level when you bleed it

Yep ! I even had to get it nose down to remove a bubble from the front end of the piston bore.

 

[1 Wild R/T]

You need a master cylinder... Here's why.. The master cylinder was fine until you bled the brakes... But it always operated in the same short range of travel... So the area where the pistons never travel builds up sludge that sticks to the bore... When you bled the brakes the piston suddenly travels into that area, in doing so it will clean most of the sludge off the bore but it also tears up the rubber seal on the front piston... Now when you step on the brakes fluid bypasses the front piston & the pedal sinks to the floor... Very common, seen it hundreds of times....

You might get away with taking the M/C apart, cleaning the bore & replace the seals...

 

[Huicho417]

Well… rookie mistake and I know better.

I installed the calipers on the wrong sides. The bleeder valves were facing down. I switched them today and the brakes feel much better. Still a little confused though. I have the CPP front disk brake conversion and all parts are labeled with L or R. I had them installed by that indication but that’s what caused the bleeder to be at the bottom. When I initially received the kit, it came as an assembled piece and I just simply had to bolt it into the lower and upper control arm. I did not take note of what letter was on the assembled pieces. If I install them on the leading side it would all work according to the letters stamped on the caliper, but I prefer the trailer side of the rotor.

 

[Moms68]

Well… rookie mistake and I know better.

I installed the calipers on the wrong sides. The bleeder valves were facing down. I switched them today and the brakes feel much better. Still a little confused though. I have the CPP front disk brake conversion and all parts are labeled with L or R. I had them installed by that indication but that’s what caused the bleeder to be at the bottom. When I initially received the kit, it came as an assembled piece and I just simply had to bolt it into the lower and upper control arm. I did not take note of what letter was on the assembled pieces. If I install them on the leading side it would all work according to the letters stamped on the caliper, but I prefer the trailer side of the rotor.

Been there, done that! Good that it wasn't something more expensive.

 

[Don Frelier]

Well… rookie mistake and I know better.

I installed the calipers on the wrong sides. The bleeder valves were facing down. I switched them today and the brakes feel much better. Still a little confused though. I have the CPP front disk brake conversion and all parts are labeled with L or R. I had them installed by that indication but that’s what caused the bleeder to be at the bottom. When I initially received the kit, it came as an assembled piece and I just simply had to bolt it into the lower and upper control arm. I did not take note of what letter was on the assembled pieces. If I install them on the leading side it would all work according to the letters stamped on the caliper, but I prefer the trailer side of the rotor.

They can be installed rear mount or front mount.
Then right and left will need to be swapped. As the caliper is facing the other way