brake pressure help

[duanes7]

I just replaced all the brake hard lines (had 2 that were rotted thru) and the master cylinder. Bled everything using both the vacuum system and then installed and bled with speedbleeders. The pedal is nice and firm now. Until I turn on the engine and then it goes to pot. Possible air in the abs? I've got great vacuum at the booster.

 

[bigblue24]

hydroboost conversion for me lol
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[great white]

adjusted brakes got the system bleed brake pedal still keeps dropping have to pump them to get a firm brake pedal

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Air or possibly the master is bypassing.

If it was working fine before the slave cylinder went and now it's not, you most likely still have air in the system somewhere...

 

[duanes7]

Bought the truck in SC and drove it here to middle GA. Brakes died just before parking it at my house. It sat for about 5 months until I could begin to work on it. The brake system was dry when I started the work and unfortunately the pedal had been pumped that way. One of the front hard lines and the rear hard line both were rotted through and I replaced them (see http://www.gmt400.com/forum/showthread.php?17339-biy-brake-lines). Then, when I went to bleed them one of the wheel cylinder bleeder screws was rotted away. Replaced the wheel cylinders and the calipers. Also put in a new master cylinder for good measure. Bled the brakes using a vacuum system and then again with speedbleeders.

Ok after the novel...

I have great pedal pressure until I start the motor then the pedal goes to mush. The brake warning light is on and the pedal is still mush even with the power plug undone on the abs module. I have good vacuum at the booster.
Is this an ABS bleed problem? Been all over the net in the last few hours and it looks like the only way to bleed the ABS module, short of buying a $500ish tech 2 scan tool, is to take it to go to the dealer.

Any other ideas?

 

[sewlow]

Bypass that damn ABS (All Bull Sh*t!) system. There's a couple of threads on here on how to do that! I'd look them up for you, but I'm on my phone, not using Wi-Fi. Cost me mucho dinero to scour the forum for those!

 

[bigblue24]

yea the guy that was working on my truck hooked it up to a scanner and it had no abs reading he put the fuse in and after i pulled off i took i right back out i hate it

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[great white]

Bought the truck in SC and drove it here to middle GA. Brakes died just before parking it at my house. It sat for about 5 months until I could begin to work on it. The brake system was dry when I started the work and unfortunately the pedal had been pumped that way. One of the front hard lines and the rear hard line both were rotted through and I replaced them (see http://www.gmt400.com/forum/showthread.php?17339-biy-brake-lines). Then, when I went to bleed them one of the wheel cylinder bleeder screws was rotted away. Replaced the wheel cylinders and the calipers. Also put in a new master cylinder for good measure. Bled the brakes using a vacuum system and then again with speedbleeders.

Ok after the novel...

I have great pedal pressure until I start the motor then the pedal goes to mush. The brake warning light is on and the pedal is still mush even with the power plug undone on the abs module. I have good vacuum at the booster.
Is this an ABS bleed problem? Been all over the net in the last few hours and it looks like the only way to bleed the ABS module, short of buying a $500ish tech 2 scan tool, is to take it to go to the dealer.

Any other ideas?

Copy your post and make a new thread in the forum.

You'll get better?more specific answers to your issue rather than burying in someone else's thread.

Not trying to be snotty, it will work better for you.

 

[duanes7]

Yeah, thought about that just after I posted here. Just started a new thread. Thanx...