Part 10 - THE PRESSURE PUMP
by Dr. Bill Black
Now for the pressure pump! Restoration of the Pressure Bellows (as Wurlitzer referred to it) is one of the more difficult parts of the organ to deal with. Itıs a large piece to work with and uses large pieces of leather. Wurlitzer describes the pump in their catalog as follows:
"Our organs are so constructed that the main or Pressure Bellows can be removed in a few minutes time, if in need of repairs. Loosen the pump sticks, take out a screw here and there, remove the wedges and slip the bellows out. No need to dismantle the whole organ."
Easy to remove? Yes! Well, not so easy to repair though. If you are looking to glue a patch over a hole in the leather or replace a pin connecting a pump stick, you can do that. When you are looking to replace the leather covering on the pumpers, thatıs not so easy!
I suspect that Wurlitzer considered this pump a replaceable item rather than a repairable one. If your pump wore out, you would buy a new one from Wurlitzer and just slip in the new one. I conclude this from the way the pump is designed and assembled. You have to saw the two banks of pumpers apart. Disassembling the pump and cleaning off the old leather and glue is a rather labor intensive project.
PHOTO A shows the unrestored pump. We begin the disassembly by cutting the reservoir covering and opening up the cover. As you can see in PHOTO B, should one of the internal flap valves fail, there is no way to get at them unless you want to cut a hole in the cover to get access. In PHOTO A we see someone was faced with a flap valve problem and used this approach to get access to them.
PHOTO B shows what appears to be a large mouse nest in the reservoir when we first opened the cover. The resident probably got into the pump sometime when it was no longer in the organ and just sitting around somewhere.
PHOTO C shows evidence of another mouse assault, this time by chewing to enlarge one of the holes under a flap valve. This is likely the second time this pump has been damaged this way. There is a repair which someone did at a previous time to fix chewing damage. PHOTO C also shows something we are always looking for......old newspaper! This time we get lucky and there are two dates legible on the paper. July 31,1926 and August 1, 1926. This is the date on which the pump was assembled. Restoration of the pump will include preservation of this newspaper in the pump.
PHOTO D shows the pump after I have sawed the two banks of pumpers apart and disassembled most of it. As mentioned above, there are places when the pump is glued together rather than assembled with screws. These joints have been glued with hot glue (unless someone used white glue in a previous restoration) and the joints can be broken apart. If white glue was used, you are in big trouble and can expect to break some wood. If the pump has been sitting around for a long time where the humidity is high and hot glue was used, some of these joints may have failed and can be broken apart more easily. This was the case with this pump, but still a few pieces of the reservoir frame broke. After the disassembly, the old leather and glue remnants have to be cleaned off the wood. This takes time.
Now for the hard part. Putting it back together! My job was to take it apart and now we are off to Mikes shop. Mike makes the repairs to the wood and recovers the pumpers with new leather and reassembles it. (PHOTO E) This also takes considerable time and experience. If it is not put back together right, it will be noisy and inefficient.
PHOTO F shows the finished pump installed in the organ. The stack has been removed from the organ to make it easier to install it and to fasten the cleat on the organ case to hold it in place. Mike did a great job on the pump...it looks just gorgeous!
Dr. Bill Black is one of the nation's most knowledgeble Wurlitzer band organ experts. He has made recordings of many band organs and other mechanical music machines which are available for purchase at CarouselStores.com.