Just converted our ‘55 Merc to power disc brakes. Just wondering if anyone knows if the 292 Y Blocks develop enough manifold vacuum to run the power booster? I can check it, but just thought I’d take a short cut and ask first. The manual fuel pump has a vacuum pump on top of it, but it is probably bad, as it wouldn’t develop enough vacuum to operate the wiper motor, so I did the Newport conversion to electric... Thanks in advance...
I have a 272 with power brakes/dual MC installed by the builder of the car. When I got the car the vacuum was connected to a factory port on the rear of the manifold. Lots of times I would come to a stop and find i had no****ist. Quite a surprise when it happens. I started by checking engine vacuum and found about 13". I went through the tune up of valves, timing, etc and got it to 15-16 and was much better. Then I found the rear two plugs showed a lean mixture because the vacuum was connected between the two rear cylinders. I moved the vacuum supply hose the the carb base and now can rely on the power****ist.
The vacuum pump on the fuel pump was to provide vacuum when you went close to full throttle, going uphill would kill the wipers without it. Unless your 292 has a huge cam should run the booster no problem. Have a friend with a F100 unibody with a 292 and a 2005 crown vic front suspension and booster/master combo and the brakes work very well. I have not measured the actual amount of vacuum.
Thanks for the information. No big cam, all stock. So what I’m understanding is that the fuel pump just makes up for any vacuum loss at full throttle...
Yes it provides vacuum for the wipers, I don't think it (fuel pump) has enough volume to run the brake booster. Thinking about it they had power brake boosters stock on 292 T-birds, Fairlanes, and so on in 1955 - 56 so with a stock cam you should be good to go.
The vacuum pump on the fuel pump is an****ist. It is fed from the rear of a 4 barrel carb where the vacuum****ist Bendix brake also was connected at a dual fitting. The wiper****ist teed off at the wiper motor and went to a cable operated vacuum switch that opened a valve on the intake manifold right behind the thermostat housing. This allowed hot water to flow through the heater core for the passengers when the slide lever of the mid 50’s heater was moved. This on the delux heaters.
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