bypassing RABS

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Jul 9, 2017 | 11:15 AM

#31

KULTULZ

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Joined: Mar 2002

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From: W (BY GOD) V

Quote:

Originally Posted by mudrat025

but it's a brand new caliper?seemed to be operating fine while bleeding it also.today is my Monday so I will recheck it and the brake line as soon as I get home.thanks

In the original thread, you posted (1st and 6th post) this is your 2nd rebuilt caliper and it is still dragging, am I correct?

You likely have (IMO) a sticking/cocked piston, brakes pads frozen (no free movement) and or incorrect line pressure.

The reference in Post #5 regarding RABS was excellent BTW. If you followed those instructions to the T, the RABS valve should not be causing this. I think it unlikely a RABS failure at the same exact time as a front brake service unless something in the hydraulics triggered it.

Jul 9, 2017 | 12:00 PM

#32

mudrat025

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Quote:

Originally Posted by KULTULZ

okay. I'm trying to get out of here early as possible to check that out. I'll let you know

Jul 9, 2017 | 07:41 PM

#33

z31freakify

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Joined: Dec 2012

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From: Las Cruces New Mexico

I'm beating it's the brake soft lines causing the problem. If you haven't replaced them now would be a good time.

Jul 10, 2017 | 06:35 AM

#34

mudrat025

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checked and bled the dragging caliper three times and no air and it is functioning properly.dropped it off at a reputable shop to diagnose.i highly doubt its the booster at this point but maybe.i have never been beat by a brake system before

.i will update with the problem or a picture of the new truck if they cant find the problem

Jul 14, 2017 | 11:27 AM

#35

mudrat025

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it was the right front caliper!!after three new ones the shop decided to rebuild it and it works fine no!i am going to replace the old soft lines with braided just to be on the safe side

Jul 24, 2017 | 06:41 AM

#36

KULTULZ

Cargo Master

Joined: Mar 2002

Posts: 3,132

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From: W (BY GOD) V

Quote:

Originally Posted by mudrat025

it was the right front caliper!!after three new ones the shop decided to rebuild it and it works fine no!i

am going to replace the old soft lines with braided just to be on the safe side

I have been MIA for the past week and just read this.

It seems the quality of rebuilt twin piston calipers is questionable no matter who the re-builder is. If the caliper piston(s) is frozen and/or the pads not lubricated properly, the there will be a hard brake pedal with little actual braking resulting. This will fool a MC test by clamping the brake hose(s), which is risky in itself (IMO).

A better MC test would be to remove the lines one at a time @ the MC and use a block-off fitting to test.

Testing the RABS Valve will be much easier with the use of a block-off fitting @ the MC rear brake line port after the MC has been found good.