young olds

i did a 4 wheel disk brake swap on my 66 idk how long ago and bled them many times. the brakes go to the floor nearly every time on the first push then pump up with consecutive pumps after, though they still feel spongy like theres air. the weirdest thing is that the parking brake doesnt work, which i just recently hooked up. ive had 3 different master cylinders, 2 different proportion valves, ive adjusted the parking brake at the caliper. need more ideas before i spend money on new calipers.

oldcutlass

If the parking brake is not adjusted properly you will have a problem similar to yours.

young olds

I believe that it is but maybe not. Idk how to "reset" the caliper so I can try again.

oldcutlass

What brand are the calipers? There should be directions on how to adjust them.

young olds

I got them second hand, it's the generic kit with 80-85 Seville calipers. I've looked up how to adjust them and pretty sure I followed the directions properly

joe_padavano

Time for my usual rant:

Rather than throwing more potentially unnecessary money at the problem, how about a little troubleshooting first? It's a simply hydraulic system. You can disconnect and plug the lines, starting at the M/C, and work your way back until you figure out where the problem is. For example, once the M/C is bench bled, put plugs in the ports and see if the pedal is firm or not. If not, fix the M/C. If it is, reconnect those lines, cap at the distribution block, and try again. Work your way through the system. Just be sure to bleed the air out every time.

oldcutlass

This is a good read it has the procedure on how to adjust the E brakes:
http://www.mpbrakes.com/docs/orig-gu...STRUCTIONS.pdf

young olds

ill try working my way down the line, if i dont find anything ill go back to the rear calipers. thanks

young olds

i clamped the softline that goees from the frame to the rear end and instantly got a nice firm pedal. which means my issues is likely the rear calipers correct?

rustyroger

Correct.
Now plug the brake line to each caliper in turn, when your pedal goes soft again you have found the culprit. Almost certainly it will have trapped air, the only other reason for a soft pedal is a leak, which would be obvious.
Sorting the e-brake is a separate matter.

Roger.

young olds

clamped off the rear calipers separately and the both gave me the same crappy pedal feel. with both cut off the pedal feels awesome. still trying to figure out why the parking brake itself doesnt work, since its mechanical, also.

oldcutlass

Off the link I posted earlier, I really think this is your issue.:
WARNING
FOR YOUR REAR BRAKES TO OPERATE
YOU MUST ADJUST THE REAR CALIPERS
When installing rear disc brakes with calipers that have an internal parking brake you must adjust or set the calipers
when installing. Failure to do so will prevent you from getting a firm pedal and you will have no rear brake function. You
must also set the parking brake every time you park to keep the calipers adjusted.
The caliper piston is adjusted outward by turning the nut on the lever or by cranking the lever. This ratchets the caliper
piston outward moving the pads closer to the rotor. If you do not do this the rear calipers will take up brake fluid but the
pads will never squeeze the rotor sending the pedal to the floor.
Only peform this adjustment with the caliper and rotor installed on the car. Start by spinning the rotor. Crank the lever
and spin the rotor again to see if there is any drag. Continue cranking the lever until there is a slight drag on the rotor.
Attach the parking brake cable. The caliper should now be adjusted. Repeat on the other side.
http://www.mpbrakes.com/docs/orig-gu...STRUCTIONS.pdf

young olds

I read that and to my understanding you just "ratchet" the parking brake lever until you take up the slack between the caliper and rotor. Other directions I've found say to replace the lever with a wrench and rotate it until it tightens up then put the lever back on. I did one method on one side and the other on the other side on a car at work, someone else finished the job and the shop manager test drove it and said it was good. On my car I did the wrench method but have ratcheted it with the parking brake since then.

oldcutlass

It can be only 1 of 2 things, ebrake out of adjustment or air. Well 3 counting bad calipers. Are the bleed screws on top?

young olds

they are on top, and i believe they are adjusted properly as well as i just bled them again the other day. i cant say for sure that ive adjusted them properly as its my first car with rear disk but from my understanding of the directions i have.

rustyroger

One more check; is the flexible hose good?. It's possible for a rubber hose to balloon under pressure and return to normal looking when pressure is released.

Roger.