97 k1500 brake issue

moon23 · 10-07-2009, 02:31 AM

Just recently acquired this truck, and have some issue to resolve the first is a brake issue.
Have just completed putting on new front cals & pads, rear brake cyl, and a master cyl. The lines are okay, all away around the truck. I have good bleed at all 4 point and have bench bled two mc and still have a soft or no pedal under power.
It pumps up fine in off position,& holds pressure, but the moment I power up pedal goes to the floor. I heard everything from p.booster, proporionate valve sticking, to a total replacement of the kelsy-hayes abs module.
I'm assuming that someone out here can help narrow this down as I've run out of ideas of what it is.
I forgot to mention, that while two man bleeding, that I notices that under power and pumping the brake, that the rear portion of the mc reservior for a lack of better words, perculates.

Thank you in advance for any info or ideas to look, as I have run out of both.

Case 7230 · 10-07-2009, 02:38 AM

You still have air in the system. If you have the RAWL system you could try bleeding it by backing off the outlet pipe nut a few turns and pumping the pedal. That system can be a real pain to get all the air out.

moon23 · 10-07-2009, 02:45 AM

Sorry Case,

Backing off the outlet pipe nut????? Exactly, where is that located????

Thanks,again

Case 7230 · 10-07-2009, 03:04 AM

If you do have the RWAL system the unit sits below the master cylinder and above the inner fender with a multi-pin plug connector to it. There is a single outlet pipe from it going to the rear axle along the frame rail. It is the nut on that outlet pipe.
May not help but worth a try.
Also read through the thread below by km1980.

leolkfrm · 10-07-2009, 05:33 AM

^^^agreed make sure there is fresh fluid at every bleeder

10-07-2009, 02:31 AM	#1
moon23 Junior Member Join Date: Oct 2009 Posts: 2	97 k1500 brake issue Just recently acquired this truck, and have some issue to resolve the first is a brake issue. Have just completed putting on new front cals & pads, rear brake cyl, and a master cyl. The lines are okay, all away around the truck. I have good bleed at all 4 point and have bench bled two mc and still have a soft or no pedal under power. It pumps up fine in off position,& holds pressure, but the moment I power up pedal goes to the floor. I heard everything from p.booster, proporionate valve sticking, to a total replacement of the kelsy-hayes abs module. I'm assuming that someone out here can help narrow this down as I've run out of ideas of what it is. I forgot to mention, that while two man bleeding, that I notices that under power and pumping the brake, that the rear portion of the mc reservior for a lack of better words, perculates. Thank you in advance for any info or ideas to look, as I have run out of both.

10-07-2009, 03:04 AM	#4
Case 7230 Senior Member Join Date: Dec 2007 Posts: 666	If you do have the RWAL system the unit sits below the master cylinder and above the inner fender with a multi-pin plug connector to it. There is a single outlet pipe from it going to the rear axle along the frame rail. It is the nut on that outlet pipe. May not help but worth a try. Also read through the thread below by km1980. Last edited by Case 7230; 10-07-2009 at 03:15 AM. Reason: new info

10-07-2009, 05:33 AM	#5
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,931	^^^agreed make sure there is fresh fluid at every bleeder __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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10-07-2009, 02:38 AM	#2
Case 7230 Senior Member Join Date: Dec 2007 Posts: 666	You still have air in the system. If you have the RAWL system you could try bleeding it by backing off the outlet pipe nut a few turns and pumping the pedal. That system can be a real pain to get all the air out.

10-07-2009, 02:45 AM	#3
moon23 Junior Member Join Date: Oct 2009 Posts: 2	Sorry Case, Backing off the outlet pipe nut????? Exactly, where is that located???? Thanks,again