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Username Post: 97 K1500 4 wheel ABS spongy brakes        (Topic#360904)
Bowtie_Guy 
"9th Year" Gold Supporting Member
Posts: 279
Bowtie_Guy
Loc: Ohio in the "rust belt"
Reg: 09-04-04
05-10-20 05:09 PM - Post#2793422    

I've searched the forum and can't seem to find a good lead on this issue. I replaced three rusted brake lines that were all just after the ABS module under the hood and after bleeding the system (including the module bleeder valve) repeatedly I still have a very spongy brake. If I pump the brake with engine off it builds up nicely and is firm, but of course after the engine runs the booster takes over and it goes most of the way with the "woosh" sound and barely has enough brake. In the recent past I have replaced both rear wheel cylinders, both calipers and countless rusted brake lines all around, and of course the master cylinder once all within the last three years. I haven't readjusted the rear drum brakes lately, but I wouldn't think that would jump out all at once as this seems to be a sudden loss. What could I be missing? Is it possible the ABS module could have gone out? I will admit I just recently discovered the bleeder valve on it and it did have some air in it, but that only got rid of the low brake level light on the dash. I only use the truck as a work truck now so putting huge bucks into the brakes at a mechanic seems over the top as I usually do all my own work once I understand what to look for. Anyone have an idea where to look now?

67' Chevelle SS California car needs much
97' K1500 4X4
72' Nova 350 A/C car (survivor garage kept)
2012 Silverado 4X4 LTZ


 
Shepherd 
Frequent Contributor
Posts: 2081

Loc: Lake George, NY
Reg: 11-11-15
05-10-20 05:25 PM - Post#2793424    
    In response to Bowtie_Guy

You may have to thoroughly bleed the abs unit, best way is with a high line scanner that controls the internal valves to allow s thorough bleed.



 
55 Shaker 
Member
Posts: 1548

Age: 70
Loc: north central IL.
Reg: 03-13-06
05-10-20 05:43 PM - Post#2793427    
    In response to Bowtie_Guy

It still wouldn't hurt to check the rear brake adjustment.

The older I get, the more dangerous, I am !!!!


 
Bowtie_Guy 
"9th Year" Gold Supporting Member
Posts: 279
Bowtie_Guy
Loc: Ohio in the "rust belt"
Reg: 09-04-04
05-10-20 06:10 PM - Post#2793433    
    In response to Shepherd

I'm guessing you are referring to doing the "auto bleed" of the ABS module. I'm not familiar with the high line scanner, but I have seen videos of scanners that are consumer quality that can perform that function. I will look into that as I can't imagine what a dealer would charge, and since I have another newer truck I could use diagnostic equipment for the future. Thanks

67' Chevelle SS California car needs much
97' K1500 4X4
72' Nova 350 A/C car (survivor garage kept)
2012 Silverado 4X4 LTZ


 
Bowtie_Guy 
"9th Year" Gold Supporting Member
Posts: 279
Bowtie_Guy
Loc: Ohio in the "rust belt"
Reg: 09-04-04
05-10-20 06:12 PM - Post#2793435    
    In response to 55 Shaker

No, it wouldn't hurt to check again just for piece of mind. I don't know how many more pieces I can afford to lose!

67' Chevelle SS California car needs much
97' K1500 4X4
72' Nova 350 A/C car (survivor garage kept)
2012 Silverado 4X4 LTZ


 
Tony 
Founder & Grand PoohBah
Posts: 18387
Tony
Age: 63
Loc: Orange County CA.
Reg: 03-15-99
05-10-20 06:24 PM - Post#2793437    
    In response to Bowtie_Guy

  • Quote:
I've searched the forum and can't seem to find a good lead on this issue.



Pro Tip on searching this forum.


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CowboyTrukr 
"9th Year" Silver Supporting Member
Posts: 4432
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
05-10-20 11:52 PM - Post#2793470    
    In response to Tony

Can you activate the ABS at all?

Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD
‘87 GMC S15 SCLB 4.3 Auto - SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
Bowtie_Guy 
"9th Year" Gold Supporting Member
Posts: 279
Bowtie_Guy
Loc: Ohio in the "rust belt"
Reg: 09-04-04
05-11-20 04:03 AM - Post#2793477    
    In response to CowboyTrukr

  • CowboyTrukr Said:
Can you activate the ABS at all?


When you say "activate", as in does it kick in yes it kicks in. If it's slippery, or I'm on gravel and stomp it I feel the feedback through the ABS occasionally, but not as much pedal as I should have.

67' Chevelle SS California car needs much
97' K1500 4X4
72' Nova 350 A/C car (survivor garage kept)
2012 Silverado 4X4 LTZ


 
junky 
Valued Contributor
Posts: 3434

Loc: Northeast CT
Reg: 06-27-10
05-13-20 07:40 AM - Post#2793680    
    In response to Bowtie_Guy

A friend had the same problem, and was unable to resolve it, until he found someone that had a pressure bleeder, and bled the system using that. I have no idea why it took a pressure bleeder to resolve the issue, vs. manual bleeding.

Never argue with an idiot. He'll drag you down to his level, then beat you with experience.


 
Bowtie_Guy 
"9th Year" Gold Supporting Member
Posts: 279
Bowtie_Guy
Loc: Ohio in the "rust belt"
Reg: 09-04-04
05-13-20 11:36 AM - Post#2793692    
    In response to junky

  • junky Said:
A friend had the same problem, and was unable to resolve it, until he found someone that had a pressure bleeder, and bled the system using that. I have no idea why it took a pressure bleeder to resolve the issue, vs. manual bleeding.


Well, it seems it is all about the distribution block and the ABS module. The block and module can get air trapped in the valves and block, so sometimes the power bleed system can purge the brake system better than having someone pump and bleed the brakes. It also makes it a one man job. I have opted to get an Autel Maxicheck scanner to also go through the "Auto bleed" ABS module purge part of this whole project. For what I would pay for the dealership to do this I'll have my scanner for other vehicles, and I am also looking at the power bleed from Motive Products with the flat adapter to fit these GM rectangular master cylinders. I keep throwing money at it I'll figure it out sooner or later. I had to have something to use my stimulus for.

67' Chevelle SS California car needs much
97' K1500 4X4
72' Nova 350 A/C car (survivor garage kept)
2012 Silverado 4X4 LTZ


 
streetjust 
Chatroom Supporter
Posts: 13
streetjust
Loc: Georgia
Reg: 05-14-04
06-29-20 06:27 AM - Post#2797427    
    In response to Bowtie_Guy

I use a bleeder ball from gearwrench to bleed my brakes. I ordered a couple of adapters hoping to find one that fit these master cylinders, but none did. Then I found Power Probe adapter (BA14). It's perfect for these master cylinders! It doesn't seal off the top of the reservoir like we're used to. It has 2 legs that extend through the reservoir down to the master cylinder. I've been using it for a couple of years on both of my '97 K1500 and really like it. It's adjustable so should be able to use it on other vehicles too. Mine is blue anodized so looks pretty nice in addition to being very useful. Hope this helps.

'97 Chevy K1500 & '70 Nova


Edited by streetjust on 06-29-20 06:48 AM. Reason for edit: No reason given.

 
alpinecrick 
Newbie
Posts: 19

Loc: Western Slope of Colorado
Reg: 07-11-17
07-01-20 09:56 PM - Post#2797690    
    In response to Bowtie_Guy


When my 96 K1500 brakes went "whoosh" it was the brake booster leaking.......



 
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