[highdesert]

put in new front rotors, pads and calipers went to bleed and cant get the pedal to stay hard with it running is it hard to get the air all out i went thru quite a bit of fluid in the front but did not seem to have air in the rear at all think i could have other problems? dont know the truck well cuz i just got it and have been doing some PM work on it. thanks :thumbsup:

 

[JohnBer]

i had a heck of a time getting all the air out of mine when i upgraded the rear wheel cylinders. finally got 25' of clear tubing ran the tubing from the bleeder back to the master cylinder and in the fluid cracked the bleeder and pumped the pedal slowly (dont bottom out the brake pedal) till all the air was gone. tried just running it into a bottle 1/2 full with brake fluid in it but it didnt work for me. At first i was so sure i had a bad m/c i went and purchased a new one, it did the same thing. I'm pretty sure ya got a slug of air its just a pain to get it out sometimes.
I used the clear tubing for a couple reasons to see the air and to see dirty brake fluid. I flushed it till it was clear before i put it back in the m/c.reasoning behind back in the m/c is im not jumping out of the truck a dozen more times refilling the fluid. only cost me 4.99 for the tubing at the local hardware store think its 3/16 (looks like clear fish aquarium air tubing)

 

[highdesert]

gonna try that, thanks alot!

 

[illflem]

Make sure the calipers are installed on the correct side.
They fit perfectly upside down on the wrong side except the bleed screw will be at the bottom of the caliper.
If it's at the bottom it will be impossible to get all the air out.

 

[highdesert]

got the right and left calipers, if i cant get it to purge out i will bring it back up thanks for the help!

 

[highdesert]

ok i worked it till all the bubbles are gone, but still the pedal goes to the floor slowly but surely need a little help:S: any suggestions?

 

[JohnBer]

the line back to the m/c has always worked for me. did you by chance bottom out the m/c in the bleeding process? or run it hard to the floor holding the pedal while watching it bleed off?I have seen it kill em before. takes the internal seals out. the reason i was so sure mine was bad was i lost a rear wheel cylinder coming home from work and the pedal hit the floor a few times. it dont always take the m/c out but it does it's fair share of times.

 

[illflem]

If the pedal sinks slowly to the floor and there are no leaks or fluid loss it means you have an internal master cylinder leak.
Usually cheaper to buy a rebuilt one than to rebuild yourself if you can even find the parts.

Happens quite often when bleeding brakes by pumping the pedal.
What happens is if you push the to the floor is the master cylinder shaft travels into an area that it never travels in normal braking. Rust on the shaft tears the seals up.
If you have no other method to bleed besides pumping put a block of wood under the pedal to keep it from going further than it's normal travel.

 

[highdesert]

the pads are touching the rotors and make them pretty stiff to turn, will the master cylinder help this or do yall think this is normal? thanks again

 

[illflem]

It's normal for the pads to touch but it shouldn't be hard to spin the tire.

 

[highdesert]

pretty stiff with the rotor but maybe with the tire and wheel it'll loosen up.

 

[highdesert]

ok, replaced the master cylinder and bled the brakes real good the pedal still sinks but not to the floor and the stupid light comes on and then will go back off, i can pump it and get a little harder feeling pedal but still will sink some. the truck has a BRAKE-GUARD down stream of the M/C could this be my issue? the ABS is on but i think that is a different problem. i really appreciate you guys trying to help me thanks.