1/2 4x4 brake issues - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dillon79scotts · 10-10-2011, 01:22 AM

I recently replaced my 1/2 running gear for 3/4 ton. bled the lines, and seems to not have very good brakes, pedal went to far and it steered bad.

got a new MC and bled it, then bled my lines again. will build pressure great and then you let off for about 3 seconds, and go to push it in again, and it hits the floor for like 5 pumps..

checked for leaks everywhere, replaced MC again (warranty). TRIED starting the truck, and did no difference. i figured if one of my lines were leaking i would still have brakes on either front or rear but i lose them all. so im thinking its the proportioning valve back to the MC somewhere.

has anyone ran into this problem? my flare fittings look fine also

fastwillie 696969 · 10-10-2011, 03:00 AM

i would think you got air in the system ,how are you bleeding the brakes ,pump the brakes and cracking the bleeder valve
or gravity bleeding
try bleeding with jar of brake fluid and rubber hose and see all air bubbles is out

Dillon79scotts · 10-10-2011, 11:23 AM

Quote:

Originally Posted by fastwillie 696969

i would think you got air in the system ,how are you bleeding the brakes ,pump the brakes and cracking the bleeder valve
or gravity bleeding
try bleeding with jar of brake fluid and rubber hose and see all air bubbles is out

im pumping brakes and cracking bleeder valve. i have ran over a bottle through it each time. ive got 4 bottles bled through, but thats with 3 Mc.

how long do you let the jug stay under it?

Dillon79scotts · 10-10-2011, 10:22 PM

anyone?

Dillon79scotts · 10-11-2011, 10:59 PM

Quote:

Originally Posted by Dillon79scotts

anyone?

anyone

Dillon79scotts · 10-13-2011, 01:16 AM

checked the prop valve plunger today, it was fully out, like it should be i assume?

10-10-2011, 01:22 AM	#1
Dillon79scotts Registered User Join Date: Jun 2011 Location: Kennewick, WA Posts: 115	1/2 4x4 brake issues I recently replaced my 1/2 running gear for 3/4 ton. bled the lines, and seems to not have very good brakes, pedal went to far and it steered bad. got a new MC and bled it, then bled my lines again. will build pressure great and then you let off for about 3 seconds, and go to push it in again, and it hits the floor for like 5 pumps.. checked for leaks everywhere, replaced MC again (warranty). TRIED starting the truck, and did no difference. i figured if one of my lines were leaking i would still have brakes on either front or rear but i lose them all. so im thinking its the proportioning valve back to the MC somewhere. has anyone ran into this problem? my flare fittings look fine also

10-10-2011, 03:00 AM	#2
fastwillie 696969 ~Rest In Peace~ Join Date: May 2005 Location: CALIFORNIA NOR CAL Posts: 9,707	Re: 1/2 4x4 brake issues i would think you got air in the system ,how are you bleeding the brakes ,pump the brakes and cracking the bleeder valve or gravity bleeding try bleeding with jar of brake fluid and rubber hose and see all air bubbles is out __________________ is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex

10-10-2011, 10:22 PM	#4
Dillon79scotts Registered User Join Date: Jun 2011 Location: Kennewick, WA Posts: 115	Re: 1/2 4x4 brake issues anyone?

10-13-2011, 01:16 AM	#6
Dillon79scotts Registered User Join Date: Jun 2011 Location: Kennewick, WA Posts: 115	Re: 1/2 4x4 brake issues checked the prop valve plunger today, it was fully out, like it should be i assume?



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