Re: Three Jeffs AMC Feedback Form Response - Combo valve question

[farna@xxxxxxx]

I found the answer in my "new" 77 TSM! It states (page 2F-23) that early production Matadors will use the five line combo valve, later with a pressure differential valve only. 78 states combo differential/proportioning used only on four cylinder Gremlins. I don't have a 79 TSM, but 80 says combo diff/prop used on all but Pacer, which used pressure differential valve only. SO I think I've answered the question, with your prompting! 79 is the only year in question -- diff/prop combo or just pressure diff? 

I didn't have all these TSMs when I first wrote the brake article 5-6 years ago and had all the questions. I just saw the valve in the Hornet and it triggered the question again! 

--
Frank Swygert
Publisher, "American Independent 
Magazine" (AIM)
For all AMC enthusiasts
http://farna.home.att.net/AIM.html
(free download available!)

 -------------- Original message ----------------------
From: "Jeff Reeves" <amcnut@xxxxxxxxxxxxxx>
> Frank:
> No, the Hornet was an original manual drum brake car. The brake system that
> was installed on it came from a 1978 Concord.
> Apparently the 1978 model year cars were an aberration in that they did NOT
> have a typical proportioning valve like you describe. I know the 79 Spirit
> AMX and the 79 Spirit Limited we parted out both had the big prop valve, and
> I saw a 76 Hornet disc car at the Pull A Part with the big valve. The 77 TSM
> shows a prop valve, but the 78 TSM (page 2F-1) says "Four-cylinder Gremlins
> are equipped with a combination pressure differential/rear brake
> proportioning valve. Pacer, Gremlin, Concord, AMX and Matador models use a
> pressure differential valve only." Strange, huh?
> Being the driver with the most seat time in the Hornet since its completion,
> I can honestly say that it works just great and there haven't been any
> issues. The good part is that using the 78 system allowed us to reuse the
> car's existing mounting point and original front-rear brake line.
> 
> Jeff R.
>