ABS Light on 92 K5 Blazer - Page 4

MI0706 · 03-31-2009, 10:37 AM

Last bump...

crabtruck · 04-01-2009, 01:21 AM

Sorry I did not respond earlier,
there have been so many posts when I got on that I didn't see it.

That is weird, right before you said it freed up from pulling the plug,
I was thinking maybe the rubber brake lines were starting that
splitting thing inside. If they are very old it may be a good idea
to replace them as preventative maint.

Are you convinved that no one has messed with the wires at the ABS ?
I will try to see what I can come up with for ideas,
right now I'm not popping anything up.
Just when we thought it was out of the woods too.

MI0706 · 04-01-2009, 03:46 AM

crab: I thought about the brake lines as well. And, yes, eventually I will be replacing them.

As for the ABS wiring, nothing really "looks" out of place. Meaning, it has the appearance that it is the original factory wiring. From what I've seen, I have no indications that it has been tampered with. That said, it is a possibility though. I just don't think my problem lies down that path.

The brake pedal is spongy. Which is an indication of air in the lines. I think I'm going to buy a brake bleeding kit that has a vacuum pump with it.

After all of the trouble codes were cleared on the ABS, the ABS motor would run for about a second when starting to leave (like at the end of the driveway, pulling out of a parking space, etc.).

Is it possible that air in the lines and/or ABS unit is causing this problem? I still find it baffling that I don't have the parking brake light (I've unplugged both before and the parking brake light acted in place of the ABS light).

Thanks for the help.

leolkfrm · 04-01-2009, 04:42 AM

you said you bled the lines? you may need to flush the lines! the fluid gets thick like molasses, bleed the lines till there is all fresh fluid coming out, didn't notice if you changed teh hoses, if not change them as they go bad internally.

MI0706 · 04-01-2009, 10:18 AM

Yes, I bled the lines but I wonder if I bled them enough. As for changing the hoses, I assume you mean the rubber hoses on the front brakes (the rear wheel cylinders have hard tubing)?

I was also looking at a bleeding kit where it was a bottle with a hand pump that fit securely over the master cylinder. You add brake fluid to the bottle, pump up the bottle to pressurize the system, and then go to each brake and bleed them. Sounds to me like this would flush and bleed the entire system (from master cylinder, through ABS, to each brake unit). What do you guys think of this set up? Here's a link... Brake Bleeders

Thanks for the help.

crabtruck · 04-02-2009, 03:16 AM

You have two problems and one mistaken idea.

Spongy pedal, smoking brakes and three (3) hoses.

Look by the rear diff for a 3rd hose, but the ones
locking on you, if they are, are the front ones.

Blocked lines or locked up ABS servos won't make
the pedal spongy, that's air or a bad master cyl.
To do a good flush and bleed will take you at least
two quarts of new fluid IMHO. I have the habit of
syphoning out the rsvr before flushing so I can see
what's in it and not push old junk through system.
I also prefer to do it manually rather than with
pumps or vacs, odd I know, but I'm not on a shop
schedule and it gives me a better feel for things.

If after a good bleed it still feels spongy, you'd do
well to isolate the sections. Block it off at master,
block it off after ABS, see where the soft comes from.
Can take a real long time to get air out from the long
humped rear lines. Patience (I've heard) is good.

Still trying to come up with something more for the
ABS itself since you pulled those wires.

MI0706 · 05-25-2009, 03:52 AM

God... Has it really been over a month since I last replied to this thread?!? Time flies when you're doing job interviews, looking at moving to AZ, fixing **** on the house and the vehicles, etc...

Anyway, I was finally able to change the brake lines (rubber hoses) on the Blazer yesterday. The front lines were a piece of cake. However, the back line I ran into a few problems.

I broke one of the hard tubing sections the goes to the RR wheel cylinder. It took me half an hour to go the auto store, get a new one, and come home. In the mean time, the rear brake line was dripping oil. The master cylinder reservoir was never drained, so I believe no air entered in through the master cylinder. Got that replaced and finally got the rubber hose portion installed (it was a mess trying to get the old one out).

Performed a flush on the system. Siphoned out the master cylinder reservoir (like crab suggested), put in fresh fluid, and commenced the flush. Like I said previously, the front brakes were a piece of cake. The rear brakes are giving me problems.

My poor wife pumped on the brake pedal for a little over an hour (bless her heart) while I was trying to flush the RR wheel cylinder. I could only get a little spirt of oil here and there out of it (nothing that was substantial). So I decided to move over to the LR. She pumped on the the brake pedal for about half an hour (bless her heart again) but I could only get a little spirt of oil here and there out of it (nothing that was substantial).

The brake pedal builds some pressure (I think because the front brakes are in good shape) but I do have the brake / parking brake light (which I think it's telling me that I have a low pressure condition on the rear brakes).

Did I not do the flushing / bleeding long enough? Is there something wrong with the master cylinder? Is there that much air in the lines that it would take a few hours to get it all out? I'm completely at a loss on this.

I need some more help fellas.

04-01-2009, 04:42 AM	#34
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	you said you bled the lines? you may need to flush the lines! the fluid gets thick like molasses, bleed the lines till there is all fresh fluid coming out, didn't notice if you changed teh hoses, if not change them as they go bad internally. __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
2000 Chevy Blazer dome light problem	TerrieM	Chevy Truck Forum	8	11-21-2008 11:51 AM
blazer brake indicator light prob	pbouffard	Chevy Truck Forum	12	11-08-2007 07:40 PM
k5 blazer	chevygirl91	Chevy Truck Forum	1	07-26-2007 09:43 PM
4x4 s-10 blazer	mudseeker	Truck Classifieds	0	08-27-2006 08:58 PM
Check Engine light and overdrive light on	chief	Introductions	0	02-05-2006 08:12 AM

03-31-2009, 10:37 AM	#31
MI0706 Senior Member Join Date: Dec 2007 Location: Crawfordsville, Indiana Posts: 84	Last bump...

04-01-2009, 01:21 AM	#32
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,366	Sorry I did not respond earlier, there have been so many posts when I got on that I didn't see it. That is weird, right before you said it freed up from pulling the plug, I was thinking maybe the rubber brake lines were starting that splitting thing inside. If they are very old it may be a good idea to replace them as preventative maint. Are you convinved that no one has messed with the wires at the ABS ? I will try to see what I can come up with for ideas, right now I'm not popping anything up. Just when we thought it was out of the woods too.

04-01-2009, 03:46 AM	#33
MI0706 Senior Member Join Date: Dec 2007 Location: Crawfordsville, Indiana Posts: 84	crab: I thought about the brake lines as well. And, yes, eventually I will be replacing them. As for the ABS wiring, nothing really "looks" out of place. Meaning, it has the appearance that it is the original factory wiring. From what I've seen, I have no indications that it has been tampered with. That said, it is a possibility though. I just don't think my problem lies down that path. The brake pedal is spongy. Which is an indication of air in the lines. I think I'm going to buy a brake bleeding kit that has a vacuum pump with it. After all of the trouble codes were cleared on the ABS, the ABS motor would run for about a second when starting to leave (like at the end of the driveway, pulling out of a parking space, etc.). Is it possible that air in the lines and/or ABS unit is causing this problem? I still find it baffling that I don't have the parking brake light (I've unplugged both before and the parking brake light acted in place of the ABS light). Thanks for the help.

04-01-2009, 10:18 AM	#35
MI0706 Senior Member Join Date: Dec 2007 Location: Crawfordsville, Indiana Posts: 84	Yes, I bled the lines but I wonder if I bled them enough. As for changing the hoses, I assume you mean the rubber hoses on the front brakes (the rear wheel cylinders have hard tubing)? I was also looking at a bleeding kit where it was a bottle with a hand pump that fit securely over the master cylinder. You add brake fluid to the bottle, pump up the bottle to pressurize the system, and then go to each brake and bleed them. Sounds to me like this would flush and bleed the entire system (from master cylinder, through ABS, to each brake unit). What do you guys think of this set up? Here's a link... Brake Bleeders Thanks for the help.

04-02-2009, 03:16 AM	#36
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,366	You have two problems and one mistaken idea. Spongy pedal, smoking brakes and three (3) hoses. Look by the rear diff for a 3rd hose, but the ones locking on you, if they are, are the front ones. Blocked lines or locked up ABS servos won't make the pedal spongy, that's air or a bad master cyl. To do a good flush and bleed will take you at least two quarts of new fluid IMHO. I have the habit of syphoning out the rsvr before flushing so I can see what's in it and not push old junk through system. I also prefer to do it manually rather than with pumps or vacs, odd I know, but I'm not on a shop schedule and it gives me a better feel for things. If after a good bleed it still feels spongy, you'd do well to isolate the sections. Block it off at master, block it off after ABS, see where the soft comes from. Can take a real long time to get air out from the long humped rear lines. Patience (I've heard) is good. Still trying to come up with something more for the ABS itself since you pulled those wires.

05-25-2009, 03:52 AM	#37
MI0706 Senior Member Join Date: Dec 2007 Location: Crawfordsville, Indiana Posts: 84	God... Has it really been over a month since I last replied to this thread?!? Time flies when you're doing job interviews, looking at moving to AZ, fixing **** on the house and the vehicles, etc... Anyway, I was finally able to change the brake lines (rubber hoses) on the Blazer yesterday. The front lines were a piece of cake. However, the back line I ran into a few problems. I broke one of the hard tubing sections the goes to the RR wheel cylinder. It took me half an hour to go the auto store, get a new one, and come home. In the mean time, the rear brake line was dripping oil. The master cylinder reservoir was never drained, so I believe no air entered in through the master cylinder. Got that replaced and finally got the rubber hose portion installed (it was a mess trying to get the old one out). Performed a flush on the system. Siphoned out the master cylinder reservoir (like crab suggested), put in fresh fluid, and commenced the flush. Like I said previously, the front brakes were a piece of cake. The rear brakes are giving me problems. My poor wife pumped on the brake pedal for a little over an hour (bless her heart) while I was trying to flush the RR wheel cylinder. I could only get a little spirt of oil here and there out of it (nothing that was substantial). So I decided to move over to the LR. She pumped on the the brake pedal for about half an hour (bless her heart again) but I could only get a little spirt of oil here and there out of it (nothing that was substantial). The brake pedal builds some pressure (I think because the front brakes are in good shape) but I do have the brake / parking brake light (which I think it's telling me that I have a low pressure condition on the rear brakes). Did I not do the flushing / bleeding long enough? Is there something wrong with the master cylinder? Is there that much air in the lines that it would take a few hours to get it all out? I'm completely at a loss on this. I need some more help fellas.