Re: [Amc-list] 1970 brake specs? PROP VALVE INFO!!

[farna@xxxxxxx]

They don't meter Mark! The combo valves with metering are easy to spot -- they have a pin on the end rith where both front brake lines go in. There are five connections total -- two to the master cylinder, two for front brakes, one for rear. ALL the metering combo valves are like that regardless of whether they have proportioning functions or not. 

Tom has me back in the books also! One of the first books I checked was the article on disc brake conversions in AIM that I wrote back in... July 1998! No wonder I didn't remember!! In that one I didn't spell out what years used what type of combo valve, but did write this: "A proportioning or combination valve should be used on all systems. The ideal system would have both, but accepted modern practice is to have a metering valve with the proportioning valve optional. " The rest of the paragraph wasn't worded very well... have to re-write that! In a sidebar called "Balancing Act", I state that between 70 and 75 only metering without proportioning was used through the late 70s. I didn't have the resources to determine exactly when the metering/differential switch two-way was used. I have all the TSMs now. 


DISC BRAKE BALANCING

1965-67 - Bendix non-servo rear brakes, which have no "wedging" (servo) action were used on the rear, reducing rear braking power. Calipers are four piston Bendix.

1968-70 - A separate proportioning valve is mounted on the right rear chassis rail just before the rail kicks up over the axle. This is clear in the 70 TSM -- see page 10-7. Calipers are four piston Bendix.

1971-74 - A three-way combo valve (metering/warning/proportioning) is used. Kelsey-Hayes 2.75" piston calipers are used. The valve has five connections -- two in and three out (one for each front wheel).

1975-76 - Two-way combo valve (metering/warning) is used with 3.1" piston "Big Bendix" calipers. Bendix calipers slide on the anchor plate (frame), K-H calipers slide on screw-in pins. These valves also have five connections -- the same as the earlier three-way. Metering requires two outlets from the valve for the front wheels. 

1977-78 - Only early production (presumedly those made in 1976) 77 Matadors have the two-way (metering/warning) combo valve. All other cars have no brake balancing device at all -- just a junction block with pressure differential valve. Matadors (last year is 1978)continue using the Big Bendix caliper, all other cars use a 2.6" piston Bendix caliper. 

1979 - ??? I don't have a 79 TSM! I know the rotors used for 77-78 are different from 79+ -- the wheel bearings are different. Tom and I both would really appreciate someone looking this up in their 79 TSM!! 

1980-88 - 80-81 cars use 2.6" Bendix calipers, 82-88 use 2.6" GM calipers that slide on pins similar to the 71-74 K-H calipers. The brake hose thread changed -- earlier hoses will all interchange, but won't fit the 82-88 calipers. 1980 Pacer (last year) uses the same set-up as previous models - no balancing device. All others use a two way combination valve with warning/proportioning functions, no metering. These will have a T in the front line between the master cylinder and combo valve for the left front caliper. The combo valve will have only four connections -- two in and two out. Two different style valves were used, but both functioned and were plumbed the same. 




--------------
Date: Fri, 23 Feb 2007 15:00:10 -0800
From: Mark Price <markprice242@xxxxxxxxxxxx>

OK, what was on 82-83 Concords?
Is it a combo valve with metering or not?
I've got two here, no sense in even trying to install one if they don't meter.
--
Mark Price
markprice242ATadelphia.net
Morgantown, WV

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