1970 - 1976 Combination Brake Valve Autopsy
#1167806
01/29/12 04:28 PM
01/29/12 04:28 PM
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Posts: 32 Virginia, USA
sah62
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I just finished writing an article that describes how to disassemble the combination brake valve that was used after January 1, 1970 for vehicles equipped with front disk and rear drum brakes. Here's a link to the article: http://www.musclecarresearch.com/1970-76-mopar-combo-valve-autopsyI'd appreciate any insights, additions, or corrections to make the article more useful. I'd especially like to know if anyone has ever found a small spring at the bottom of the pressure differential portion of the valve.
Scott Hollenbeck
Administrator, Mustang 428 Cobra Jet Registry
Owner, Muscle Car Research LLC
1970 Ford Mustang Mach 1
2006 Dodge Charger SRT8
1995 Chevrolet Impala SS
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Re: 1970 - 1976 Combination Brake Valve Autopsy
[Re: 70runner]
#1167808
01/30/12 12:21 AM
01/30/12 12:21 AM
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sah62
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Yeah, that missing spring makes me wonder. Ford's pressure differential valves are designed to float, but they don't have springs on either side. A spring on only one side doesn't make sense. I know the repros include a spring. I can think of three possibilities: - There never was a spring.
- There was a spring, but it has completely rusted away.
- All three of the valves I've disassembled were opened before and the spring was lost.
I'd like to believe that maybe the spring rusted away, but even then I'd expect to find some small rusty remains.
Scott Hollenbeck
Administrator, Mustang 428 Cobra Jet Registry
Owner, Muscle Car Research LLC
1970 Ford Mustang Mach 1
2006 Dodge Charger SRT8
1995 Chevrolet Impala SS
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Re: 1970 - 1976 Combination Brake Valve Autopsy
[Re: THESHAKERPROJECT]
#1167811
03/16/12 11:14 PM
03/16/12 11:14 PM
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sah62
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I think I might have stumbled across something: could it be that this is a situation where different suppliers (Weatherhead and Kelsey-Hayes) produced interchangeable valves with slightly different internal parts? The valves I've disassembled were produced by Weatherhead. I just found some pictures of a Kelsey-Hayes valve posted by bigblock340power in another thread: https://board.moparts.org/ubbthreads/showthreaded.php?Cat=0&Number=6923491&page=0&vc=1Notice the differences in the pressure differential piston and spring assembly!
Scott Hollenbeck
Administrator, Mustang 428 Cobra Jet Registry
Owner, Muscle Car Research LLC
1970 Ford Mustang Mach 1
2006 Dodge Charger SRT8
1995 Chevrolet Impala SS
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Re: 1970 - 1976 Combination Brake Valve Autopsy
[Re: sah62]
#1167812
04/08/12 03:39 PM
04/08/12 03:39 PM
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Joined: Jul 2011
Posts: 32 Virginia, USA
sah62
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I've had a chance to examine a Kelsey-Hayes valve and can confirm that it matches the service manual drawings. Having seen both I've also been able to write an article that describes how to rebuild both valves: http://www.musclecarresearch.com/1970-76-mopar-combo-valve-rebuildI have a seal kit available that I'll post in the classifieds. Thanks to all of you that have helped by letting me take a look at your valves. I'm sure there are other cars that used this type of valve, but I don't have a parts manual that covers these years. Please clue me in if you know of other applications.
Scott Hollenbeck
Administrator, Mustang 428 Cobra Jet Registry
Owner, Muscle Car Research LLC
1970 Ford Mustang Mach 1
2006 Dodge Charger SRT8
1995 Chevrolet Impala SS
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Re: 1970 - 1976 Combination Brake Valve Autopsy
[Re: moparmike1]
#1167814
04/10/12 07:33 PM
04/10/12 07:33 PM
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Posts: 32 Virginia, USA
sah62
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Thanks for the info, Mike. My 1971 parts manual doesn't seem to include this valve at all, which seems strange if it was introduced during the 1970 model year. Do you know if there's a parts manual available that includes a description of this valve?
Scott Hollenbeck
Administrator, Mustang 428 Cobra Jet Registry
Owner, Muscle Car Research LLC
1970 Ford Mustang Mach 1
2006 Dodge Charger SRT8
1995 Chevrolet Impala SS
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