Power brakes LWB sedan

[frazer]

I always felt the power brake on my 1951 Suburban required to much pressure. I had the unit rebuilt a number of years ago and no difference. This united was used on other chrysler product 8 passanger sedans. Any ideas?

[De Soto Frank]

Well, if it's the same unit that's on my '50 New Yorker, it's a Kelsey-Hayes "remote" power booster that lives under the floor , just about under the driver's seat.

How long have you had this 'Burb, and what all has been done to the brakes ?

To determine whether or not there's any boost coming from the power unit, with the engine "off", apply the brake pedal firmly and release, several times( say five), then hold the pedal lightly on the 5th stroke. While holding the pedal, start the engine.

If the pedal sinks a little bit (1/2 inch to 1 inch), then stops again when the engine starts, the power booster IS working.

If the pedal response seems the same with or without the engine running, then make sure the vacuum supply to the brake booster is air-tight, and supplying vacuum; usually you'll hear the booster "gasping" a little bit through the breather filter under the seat.

If the booster seems like it's working, you might want to check-out the adjustment of the service brakes at the wheels themselves....

If the brake shoes were replaced at some point, and not set-up with one of the appropriate gauges (Miller Brake gauge or Ammco 1750), the anchor-pin adjustment (toe clearance) may be incorrect, and may create a need for excessive pedal effort to stop the car.

Also, if the braking surface inside the drum is "glazed" (very smooth and shiny), that may also create the need for excessive pedal effort... try having the drums turned.

This power brake is similar to the Hydro-Vac used on GM trucks from about 1940 into the 1970's, so the principle is fairly sound...

[Rusty_OToole]

I had the same unit on a 52 New Yorker. When it wasn't working the brakes required a heavy foot. Once I had it rebuilt the brakes were a lot easier. Not as grabby as some 50s power brakes, actually more like a modern car with power disc brakes.