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Bleeding rear brakes

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Old 08-03-2018, 06:02 AM
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Default Bleeding rear brakes

Hi from Normandy, I have read numerous posts regarding bleeding brake system on Blazers but would appreciate your views on my problem.

I have a 1999 RHD Blazer with 140,000 miles on the clock. Having just replaced the transfer box I have had to replace the rear brake pipes from about half way along the chassis rail. I have replaced the 3 flexible hoses and also the metal hydraulic pipes.
The brake pedal goes down about half way and then is hard. I assumed that this was because the car was braking on the front only.
I now want to bleed the rear section, QUESTION: I there an easy way or do I need to do anything to the ABS box. I have seen mention of a scanner, this could be a problem in the wilds of Normandy.

I hope that someone can resolve the problem ( I have already tried the normal bleeding method with no sign of fluid coming through perhaps I didn't do it for long enough.

Your comments would be appreciated.

Boots
 
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Old 08-04-2018, 11:04 AM
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Hi there! Normandy? Very cool. Be sure to post some pictures.

When you replaced the tubing for the rear of the vehicle, did the fluid drain out of the forward section? If so, I'm wondering of air got into the combination valve, which is down-stream of the ABS system or that air also got to the ABS system. If the front portion of the brake lines that go to the rear wheels were not drained completely, I would think that normal bleeding could work. It would be a straight-forward calculation to estimate the amount of fluid that would be needed.

When you said you did "normal" bleeding, did you use the technique in which a tube from the brake wheel cylinder is inserted into a container partially filled with brake fluid so that you can see air bubbles coming out of the tube? I ask as that would be confirmation that you were pushing the air through the system and that you perhaps need only more fluid.
 
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Old 08-05-2018, 04:03 AM
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Hello christine_208

Thanks for your response. I don't think the front section drained as I still have some pressure operating the front brakes. However, yes fluid did drain when I cut the rear pipe and, of course, everything else is new. Have a pressure bleed kit that I have used before on other vehicles but cannot get an adaptor for the Chevy master cylinder.
'Normal' bleeding means the traditional way. Looks like I have been a bit impatient and need to just keep pumping!! Will let you know how I get on.

Normandy is wonderful, moved here in 2006 and don't regret it.
 
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Old 08-05-2018, 09:07 AM
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97' Blazer here...recently fixed a leaky rear brake line, and couldn't bleed the rear brakes until I found the little valve on the ABS module. Earlier models have a separate proportioning valve that closes the leaky line and allows the good circuit to keep working so you have some brakes. The valve is inside the ABS module on the 97', and probably on your 99'. When it gets activated, it sets the brake warning light.
Are you getting fluid out the rear bleeders? If you are, it probably just needs more bleeding...if not, the valve needs to be re-set.
You can get a scanner capable of doing the ABS "autobleed" for about $170.
 
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Old 08-07-2018, 07:53 PM
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Default Scan tool

Hey! What’s the name of that scan tool? Is it good for reading OBD 1.5 as well?
 
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Old 08-10-2018, 11:53 AM
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Looks like you have a gravel drive way, so you are all set... what the tech2 scan tool does is activate the abs module with the vehicle sitting still. A compromise, if you have a safe distance in your driveway, is to SAFELY drive at a reasonable speed and hit the brakes thus activating the ABS module. This will move any trapped air inside the module to the lines and then you can continue to gravity bleed them as described elsewhere in the forum. Now don’t go crazy and end up running into or over something! Be careful of the surroundings and this method will suffice...
 
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Old 08-13-2018, 06:13 AM
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I have a pressure bleed kit. Can I just pressurise the system, or do I have to activate the ABS? Didn't want to do this in case it caused a problem with the module.

Thanks everyone for your reponses.

Boots

 
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Old 08-21-2018, 01:13 PM
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From what I have read, even pressure bleeding won’t remove all the air from the abs module. Before I had a tech2 scanner, I pressure bled the brakes, activated the abs in my gravel driveway a few times and then gravity bled the brakes. Haven’t had any issues and brakes are firm...
 
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Old 08-22-2018, 04:06 AM
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I pressure bled the brakes, activated the abs in my gravel driveway a few times and then gravity bled the brakes. Haven’t had any issues and brakes are firm...

Plan do try this method during the next few days. Will report back with result.

BooTs
 
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Old 08-22-2018, 09:55 AM
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Originally Posted by BooTs
Plan do try this method during the next few days. Will report back with result.

BooTs
Let us know how long you gravity bled them too. Thanks and good luck.
 


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