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1956 Century Riviera Power Brakes


davidyavidy

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After removing the Delco-Moraine power brake assy from vehicle and separating master cylinder (cast iron) from vacuum power cylinder (double spring model), I removed the cylinder plug in preparation to replace the soft parts of the master cylinder. According to the 1956 Buick maintenance manual, page 9-30, paragraph 12, it states: "Unscrew and remove cylinder plug from hydraulic cylinder body, using Spanner Wrench J 5794 (fig 9-23), then remove secondary cup expander, secondary cup, secondary cup support, vacuum cup retainer, and vacuum cup from cylinder plug assembly". I've underlined the portion I'm having trouble with. How in the world do you remove the vacuum cup and its retainer? Is the cylinder plug a two-piece unit and therefore comes apart? It appears as though the vacuum cup and its retainer were placed into the cavity of the non-threaded portion of the cylinder plug, then the threaded portion of the cylinder plug was pressed onto the non-threaded portion making an assembly. In another part of the manual it states that if the vacuum cup is bad, the cylinder plug must be replaced as an assembly. Any help out there would be greatly appreciated.

Dave J. :confused:

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Leif,

I have a complete 1956 Buick Service Manual on CD, as well as other documents. The exploded view shown above appears in two different documents which I have. What the manual does not provide is a step by step procedure for removing the vacuum cup and retainer from the cylinder plug after the cylinder plug has been removed from the master cylinder housing. The exploded view shows the proper orientation of the cylinder plug, the vacuum cup, and the vacuum cup retainer to each other, but does not show or describe how the vacuum cup and its retainer got installed inside of the cylinder plug in the first place, nor does it describe how to remove these items from the cylinder plug. That's my problem. The manual does not give enough information on how to do it; it just says do it. It also does not mention whether the cylinder plug assembly can even come apart or not. But thanks for the offer of help.

Dave

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Dave,

This last summer I've performed what you're doing. I dont fully understand which part your having difficulty with but if you use the diagram Leif has provided let me know which numbers you are having a tough time dissassembling.

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Pletch,

The exploded view Leif is refering to is in the 1940-1963 Buick Master Chassis Parts Book, of which I have a copy on CD. It's found on page 555, and the part I'm refering to is named "PLUG, Bearing and Seal", and is identified as part "AS". In the 1956 Buick Maintenance Manual, of which I also have a copy on CD, the R&R steps are located in Section 9-D, Power Brakes. Disassembly instructions are found on page 9-30, par 12, and references figure 9-23 (see red-lettered portion of original thread above). Assembly instructions are found on page 9-31, par 4, and does not reference any figure. Figure 9-15, page 9-26, shows the relationship of the vacuum cup (which is inside the aluminum cylinder plug) to the rest of the components in the power brake assembly.

The disassembly instructions tell you what to do (remove vacuum cup and its retainer), but not how to do it. The assembly instructions tell you what to do (install vacuum cup and its retainer), but again, not how to do it. However, the assembly instructions do mention "cup support" and "shoulder in plug", two items not mentioned in the disassembly instructions. Since no pics are referenced, I'm left to guesstimate that somehow a piece of the cylinder plug (cup support?) is removable to gain access to the vacuum cup and its retainer.

Guess I need to figure out how to download and attach pics I took with the digital camera my kids gave me last Christmas so I could show you and everyone else exactly what I'm talking about. I'm going to take a closer look at the cylinder plug tomorrow when I go down to my buddy's shop where the car is and see if I can figure out how to remove this 'cup support' thing (if it's even possible). Hope I've made myself clear as to what I'm trying to figure out here.

Dave

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Leif,

Finally figured out that this "cup support" thing (part AW in the exploded view drawing) is actually a removable flat washer. Because of years of corrosion, the washer and plug appeared to be one piece which is why I didn't realize at first that this thing called "SUPPORT, secondary cup" was simply a removable washer. It came out with a couple light taps of a small hammer and punch. Thanks for the help.

Dave

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