ABS issues

[Tanner]

I have a 1996 chevy k1500 with the 350 vortec. My problem is the brakes. it has a new master cylinder, drums, hardware, shoes, wheel cylinders, rotors, pads, calipers, and some new lines. no matter how much I bleed it I cannot get a hard pedal. I understand these trucks dont have very good brakes to start with but I have driven several other GMT 400 trucks and the brakes were tons better than mine. I have checked that the drums were adjusted out as well.

I read this forum and tried it

http://advrider.com/…s-fixed.919964/

and I did get some pretty nasty fluid out as well as some air but it didnt seem to help the pedal much.

I took it to a shop with a tech 2 scanner to see if maybe I had air in the ABS and they said that their scanner would start the test however something wouldnt alow it to do the whole test and they didnt know why. they said they tried it 3 times and it would not do it, however the pedal does feel better than it did.

also as per erics video about working the abs i tried it on snow and the pedal felt better but then after long it goes back to how it was. I have bled the heck out of the brakes as per the manual rr,rl,fr,fl.

any ideas?? I have been reading alot but not finding many answers. I did find two more things with rubber caps on them under the proportioning valve anyone know what they are?? could it be my proportioning valve?? they fronts seem to grab pretty good and the drum brakes dont seem to be grabbing like they should. with the truck off the brakes are rock solid and the pedal wont bleed down. but soon as I start the truck the pedal goes way down. I have about 3-4 inches before the brakes start to grab and about 5-6 inches untill they are grabbing better. If I slam on the brakes it stops fairly well but still not like they should. I feel like I am about at worlds end with this does anyone have an idea??

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[Tom]

I don’t know the answer to your question, but I will commiserate with you . . . . for 6 years, I had a Honda Accord with EXACTLY the same symptoms. I replaced pretty much EVERYTHING in the braking system by the time I was done, and the pedal never got any better. Hopefully, you will have better luck with yours than I had with mine!

[Tanner]

ok. this is what I have done. we bled all 4 brakes again for good measure. we checked all the hard ware and made sure everything was tight and leak free.

it didnt change anything. I clamped the rubber lines one at a time and think there maybe something to that. I have replced the passenger side rubber line but not the driver or the rear rubber ones. with the line clamped off my wife said the pedal didnt feel any different. however I could feel the line swell. with my vice grips just touching the outer hose the driver side deffinatley swelled more than the newer passenger side. and the rear was about the same as the driver side so there is something to be said there that I would probably bennefit from replacing the lines.

also is it normal for the line to move when the brake pedal is pressed?? once again the rear and driver side moved more than the newer passenger side. just for kicks I made sure I wasnt losing vaccuum or anything at the booster. and the check valve is working as well.

the last thing I found is that if you press down on the master cylinder a little you can hear air come out is that normal?? also I am not sure if my friend spilled a little fluid when topping the mc off but where the reservoir meets the master cylinder was wet like they may have been leaking???? I really hope freakin not its new!! not rebuilt!!

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