It's much easier just to have a repair kit handy instead of having to replace the entire pump. The Comet 5026.0084 Repair Kit comes with the following. 6 x 1210.0032 - O-Rings for Valves. 6 x 1210.0047 - Head O-Rings.
6 x 1220.0035 - Valves. 3 x 1800.0088 - Diaphragms (Buna). The item "Comet 5026.0084 Repair Kit for APS51 Diaphragm Pump" is in sale since Monday, January 25, 2016. This item is in the category "Business & Industrial\Hydraulics, Pneumatics, Pumps & Plumbing\Pumps & Pump Accessories\Pump Parts & Accessories\Other Pump Parts & Accessories".The seller is "mkrittenhouse" and is located in Niagara Falls, New York. This item can be shipped to United States, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, Ukraine, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Panama, Trinidad and tobago, Guatemala, Honduras, Jamaica, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Montserrat, Turks and caicos islands, Barbados, Bangladesh, Bermuda, Brunei darussalam, Bolivia, Ecuador, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Nicaragua, Oman, Peru, Pakistan, Paraguay, Reunion, Viet nam, Uruguay.