Here is the situation:
I installed the MP Power Brakes front end kit on my 1972 Duster, so now it has disc brakes. Part of the kit had a new master cylinder and distribution block/hold-off valve/switch assembly. The rear end has been replaced with an 8-3/4" with 11x2.5 brakes. The master cylinder leaked out of the back seal and was replaced with a rebuilt '73 master cylinder.

The problem is when the brakes are stepped on hard, the brake light comes on. I understand it may be because of the difference in the piston size of the master cylinder and the fact that the rear brake cylinders are larger too.

Assume first, that brakes have been bled correctly.

How can this be remedied?

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'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
CompCams 252S, Holley 390cfm, Offy manifold
Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

Adjust the brake light switch under the dash at the brake pedal.

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Joshua

Josh, it sounds to me like he's talking about the "BRAKE" warning light on the instrument panel, not the car's stop lights out back.

BWJ, which brake light do you mean?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I mean the light that comes on when your brakes fail. (High pressure differential across valve).

bwhitejr

_________________
'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
CompCams 252S, Holley 390cfm, Offy manifold
Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

It could be as simple as the rear brakes shoes not being seated (worn in) to the drums and the shoes flexing use up enough travel to drop the pressure and illuminate the warning lamp. 11" drums are overkill on an A-body.

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Joshua

I'd bet that it has something to do with having a "reman" master on there!