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NorwegianRivRoy

Vacuum Routing on the 425cid Nailhead

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RivNut    953

Here's what I can tell you after running into the same situation.

There's a tee on the back of the carb that supplies vacuum to the pcv valve on the passenger side and to the power brakes on the driver's side. A line comes from the base of the carb on the right rear that goes to the vacuum modulator on the transmission and the port on the front of the carb goes to the vacuum advance.

The port coming off the back of the intake manifold goes to the heater controls.

Figure 11-80 on page 11-79 shows a schematic for the vacuum circuit for the heater / air conditioner.

Hope this helps.

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Bill Stoneberg    371

There also is a small line on the drivers side of the manifold that will go to the cruise control power unit if you have this option.

The larger hose on the cruise control unit goes through the firewall and to a switch under the dash.

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On 5/12/2007 at 10:45 PM, RivNut said:

Here's what I can tell you after running into the same situation.

There's a tee on the back of the carb that supplies vacuum to the pcv valve on the passenger side and to the power brakes on the driver's side. A line comes from the base of the carb on the right rear that goes to the vacuum modulator on the transmission and the port on the front of the carb goes to the vacuum advance.

The port coming off the back of the intake manifold goes to the heater controls.

Figure 11-80 on page 11-79 shows a schematic for the vacuum circuit for the heater / air conditioner.

Hope this helps.

Ed, I"m gathering all the info I can to bone up on rebuilding the vacuum system with new hoses, leak elimination, and getting the vent doors to open like they are suppose to ope.

thanks again for the information

RRB

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RivNut    953

RRB

The info I provided above is for a 64.  The 63 is WAAAAAAY different.  On a 63,  the vacuum for the power brakes comes from a port on the front of the intake manifold.  There's a brass Tee in that port. One side of the Tee goes to the power brakes. The other side of the Tee is the vacuum check valve for the HVAC. ALL of the first gen Rivieras have some kind of difference in the HVAC systems. Always make sure you identify exactly which year is being described and inquire if yours is the same.

 

Ed

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