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Old 10-31-2021, 01:55 PM   #12
REDROCKER652002
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Join Date: Nov 2018
Location: South San Francisco CA,
Posts: 436
Re: 1969 C10 rear brake adjuster

Quote:
Originally Posted by pjmoreland View Post
Your brake warning light is on because the shuttle valve in your combination valve assembly has moved due to unequal pressure in the front brakes vs. the rear brakes. I struggled with this issue multiple times in the past until I got one of these tools that holds the shuttle valve centered while bleeding the brakes. It screws in in place of the warning light switch.

https://www.amazon.com/gp/aw/d/B07BY...b_b_asin_image

Once the shuttle valve has moved, it will block flow to the rear brakes. This makes it nearly impossible to bleed the rear brakes. You will need to get the shuttle valve centered again. I have read that stomping on the brake pedal can center the valve, but I have never tried this. Bleeding one of the front brakes might allow the shuttle valve to center.

In my experience, the rear brakes are much more difficult to bleed than the front brakes. You know you are done when you get a powerful flow of fluid out of each rear brake when the pedal is being pushed and you crack open the bleeder. There should also be zero air in the fluid that comes out. If the fluid flow is lethargic, then you aren't done.
Good info, thanks. From what my son said, the fluid was coming out with no air, so, to me, that should say the rears are bled. Now, with the brake light on, I am wondering if the unequal pressure was due to an internal leak in the master cylinder? That certainly could make sense to me. I just don't understand why, if he has a leak somewhere, there is no fluid on the driveway or on the frame where the line runs. Like I said, I am trying to let him do it, but I cannot help but be somewhat involved. LOL.
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