Questions about RABS

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Jul 17, 2017 | 11:15 PM

#16

y2kc0wb0y

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From: Washington, DC

Nice; thank you sir. Very helpful

Jul 18, 2017 | 08:53 AM

#17

krewat

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From: Long Island USA

Quote:

Originally Posted by tjc transport

i guess as they get old they fail internally and bleed off pressure.

That's correct. The dump valve leaks pressure to the accumulator and gives you that spongy feeling.

Kelsey-Hayes RWAL Antilock Brakes

Happens a lot - sometimes bleeding everything helps, but it means using some sort of diagnostic tool to exercise the dump and bypass valves while running the ABS pump. This also happens on the 3-channel ABS from Kelsey-Hayes used in later trucks like my 2001 Superduty, or my brother-in-law's 1997 Suburban (that I had a lot of experience trying to get it right - and a dealer tech we knew finally got it bled correctly with his shop equipment).

Sometimes, just taking it out on a dirt road or somewhere you can lock up the wheels can get the ABS working right again.

Jul 24, 2017 | 05:24 AM

#18

KULTULZ

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From: W (BY GOD) V

Quote:

Originally Posted by y2kc0wb0y

Hooray - first post!

Talking 1991 F250 5.8L 4X2.. trying to fix basic sinking pedal issue.

Questions about RABS....2B373 is the Ford part # in the manual, but I'm seeing a lot of OEM valves that have 2B373-x something on the end. for Example 2B373-HRM or 2B373-A. I cannot find a reference to the trailing information. Are these manufacture updates or do I need more specific information before purchasing?

Trying to decide re-man valve or OEM.

Does the forum gods recommend a re-man or do you recommend going with one of the updated OEM valves? On eBay the price is around $200/$250 depending.

First Part Numbers-

2B373 is the Basic Service PN of the part in question, in this example a RABS Valve. There is a Prefix And a Suffix attached to the Basic PN to positively ID it's application. The Prefix will give pertinent info on vehicle year/model application, while the Suffix parts super-cession and/or R or L and/or color depending on Basic PN.

RM on a FORD PN Suffix identifies the part as being re-manufactured from FORD. FORD also carries reman parts from FORD Authorized Reman Vendors and those part numbers will appear the same as FORD PN's but may vary, usually having an X in the suffix.

Now, you need that RABS/RWAL Valve as it is the only way to prevent rear wheel lock-up and it's unpleasant consequences on either panic stopping and/or wet road service. It was put there for a reason.

ALSO-

The hydraulic braking system (RABS/RABS II/ABS) is not all that difficult to diagnose. It simply requires the proper diagnostic sequence.

The MC shortcomings is described fully in a TSB released by FORD and gives the correct replacement PN's for all applications.

Jul 24, 2017 | 07:58 AM

#19

BLK79

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I agree with couple earlier posts about M/C bore being too small for solid pedal. I replaced my 92 F250 M/C with one for a 96 (1/8" bigger bore I think), made a BIG difference in pedal firmness and travel. Ignore the plug on the newer one, it is for cruise control brake switch, earlier ones are at the pedal. I unplugged my RABS module behind glovebox, no issues with it, I just don't care for anti-lock brakes for what I use this truck for.

Jul 25, 2017 | 02:48 AM

#20

KULTULZ

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From: W (BY GOD) V

Concerning MC Upgrades-

Quote:

These part numbers are from TSB's 96-25-19 and 98-5A-34, and are not normal service-stock replacement parts.

Trucks without cruise control:

F6TZ-2140-AB
F-250 Gas 4X2; F-350 DRW, SRW Gas 4X2, SRW 7.3 4X2 168" WB

F6TZ-2140-EB
F-250 4X4, 7.3 4X2; F-350 SRW 4X4, SRW 7.3 4X2 133" WB

Trucks with cruise control:

F6TZ-2140-BA

F-250 Gas 4X2; F-350 DRW, SRW Gas 4X2, SRW 7.3 4X2 168" WB

F6TZ-2140-FB

F-250 4X4, 7.3 4X2; F-350 SRW 4X4, SRW 7.3 4X2 133" WB

This is after confirming all other components are within spec.

I will post the entire TSB when I come across it.

Nov 19, 2017 | 02:38 PM

#21

y2kc0wb0y

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From: Washington, DC

Hey everyone following up on this thread. RABS success!

Did some more research on the RABS valve and it turns out the E-250/350 Vans used basically the same valve. Found a OEM part # F4UZ-2B373-A valve MFG date "07/25/96" for around $180.00 that worked out great. I had to bite the bullet and purchase it because it was getting dangerous to drive as I was getting a lot of right front bias. Sorry wasn't very interested in doing a RABS by-pass.

Lingering question
Ended up removing all the bleeders (to clean them) and notice that
left front and right front are different thread sizes. Is this normal?

Thanks for all the help
Scott

Nov 19, 2017 | 08:59 PM

#22

My4Fordtrucks

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Joined: Jun 2015

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Quote:

Originally Posted by tjc transport

they wanted to order a new RABS valve, but since everything i have ever driven before that and since until i got the 2014 in january has never had abs anyway, so it was not a big deal to have a new vehicle with working brakes.

This makes absolutely zero sense to me. It was a brand new vehicle under warranty. Make them fix it! It sounds like you didn’t want/ was scared of that “newfangled” anti-lock brake system.

My 150 had a soft/ spongy pedal (felt like a Chevy) that I couldn’t get rid of after I rebuilt the rest of the brake system from sitting for almost a decade. Replaced it (RABS module) with one out of the junkyard and it has been nice and firm ever since. Has been that way for years now.

The bleeder screws might be different because of different manufacturers and rebuilds over the years. They would have been the same from Ford.