Join Date: Jul 2000
Thanked 331 Times in 315 Posts
Rep Power: 21
Re: Leaking Oberdorfer water pump
Look for a teeny weep hole at the area of where the pump body casting encases the input shaft .... if there's any sign of rust or water in this weep hole .... you need to rebuild the pump to replace the seals / bearings and to make sure the input shaft isn't 'scored'/damaged.
Oberdorfer pumps, especially when rebuilding, require some quite precise 'gaps' (precision spacing) between the seals and the bearings .... especially on Oberdorfer-type (knock off/imitation) pumps on many Japanese made engines. These 'as assembled' gaps allow a calculated volume/amount of water between the spaces to provide proper 'cooling' of the seals and the shafting in the area of the seal.
Most Japanese (licensed) versions of the Oberdorfers will have these specified 'clearances' listed in their 'mechanics shop manuals'. One sets-up these spec. clearances with wire-type 'feeler gages', etc. when press-fitting the seals and bearings during their installation.
If you don't have a shop manual simply use a 'wire type' feeler gage and measure for any 'gap' before your disassembly ... and return to the correct 'gap' when you reassemble with new parts.
For actual Oberdorfer made pumps, go to the Oberdorfer website, choose the correct P/N of the pump and look up in their database for the correct 'gap' (if any).
FWIW - if your engine is Japanese made and its over about 15-17 years of age, a high probability is that the pump has become functionally obsolete ... and a new pump will be costing about $400+. Re-sealing and bearing replacement is sooooo much cheaper.
If you have the 'gap' specifications and don't have the expertise of setting up 'gaps' when press-fitting the replacement parts, any 'automotive' machine shop (every large town has one) is probably the best and most economical place to press-in the seals and bearings - about a 20-30 minute job and probably at less cost than you buying yourself a proper set of 'wire-type feeler gages'.
Last edited by RichH; 04-28-2017 at 10:02 AM.