55 Vacuum pump connection

[Bob Kielar]

 I have read all the posts on vacuum line connections and I found a lot of great information. I just got my first 55 Caddy and started to replace all the vacuum lines. I looked at the firewall and saw the vacuum block with the lines going to the wipers washers and manifold but the one on the left has no line on it. When I searched the Forum I found that it goes to the vacuum pump. What I cannot find is where the vacuum pump connection is on the engine, one post said it is by the starter. I have looked by the starter but cannot see where it would connect. Since buying the car I have found out that the engine was rebuilt I hope that they did not just plug this port up. Any help would be appreciated.

[Carl Schreiber]

Bob -

I'm not certain, but I believe the setup you refer to is 57/58.  On those engines, the vacuum supply pump is an integral part of the oil pump - yes, THAT oil pump - inside the oil pan sump(!)  There is (what appears to be) a brass fitting, about 7/8" hex with a metal tube coming out of it (vertically) up the firewall to the vacuum manifold.  This fitting and tube are on the passenger side of the engine block, right above the area where the starter bolts up.  That fitting is actually a one-way check valve and it supplies vacuum to the wiper vacuum manifold on the cowl.

I'm not positive, and someone with a 55/56 can correct me, but I believe the vacuum source for those cars is built into the fuel pump - which would mean there would be no 'fitting' above the starter on the engine block.  Don't panick yet - I'm sure Forrest or the other guys with 56's (Lou if he's not in the garage!) will be able to straighten us both out!

Regards

Carl Schreiber

[J. Gomez]

Carl,

For the 1956 you are correct, and I think same applies for the 1955..!

Bob,

A few shoots of the vacuum check valve and location on the block.

Good luck

[Bob Kielar]

So it looks like it is off the oil pump even with the great picture the only thing I found was a 1/8 ? inch plug in front of the starter on the block could this be it ?  Thanks

[J. Gomez]

So it looks like it is off the oil pump even with the great picture the only thing I found was a 1/8 ? inch plug in front of the starter on the block could this be it ?  Thanks

Bob,

If the plug is in the same vicinity as shown in the first picture that will be it..! Since this piece was removed you will need to installed the check valve at that location and extend the tube up the side the engine. Also as Carl explained the vacuum pump is connected and driven by the oil pump, hopefully the previous owner left it and the connection into the block intact.

Good luck..!

[Bob Kielar]

Thanks: Do you know where I can buy one of those check valves ?

[Coupe]

If your block is a '57/'58 and the port for the auxiliary vacuum pump is plugged there should be 2 pipe plugs on that side of the block. One at the very back for the vacuum port and one about 1/3 of the way forward for draining the coolant from the right side of the block.

[cadparts58]

The vacuum check valve assembly for 1957-1958 should have a round flat shiny metal disc with four small ears on it. Also a short tension spring pressing against the small metal disc. There should also be screening in one of the brass fittings. I have two of the assemblies, but unfortunately the disc and tension spring are long gone. Hope this helps. Thanx Frank

[J. Gomez]

Thanks: Do you know where I can buy one of those check valves ?

Bob,

McMaster-Carr (www.mcmaster.com) list vacuum check valves in different sizes and pressure, however I do not know if these will work similar to the OEM type. 

[Bob Kielar]

I have great news I found the vacuum pump port on the side of the block. It is kind of hidden behind the starter solenoid linkage. The mechanic that did the work on the engine just left it open no fitting. I pulled the starter and installed a fitting with a hose going to my vacuum gauge reinstalled the starter took the Caddy off the jack stands started the engine and EUREKA 28 pounds of vacuum!!!!!!!!!!! Now all I have to do is find the check valve and correct fittings. I want to thank everyone for all the responses hopefully this post will help others with a similar problem.