Carson Posted April 4 Share Posted April 4 I have a 1950 Mack A20 with an EN354 straight 6 gas engine. There is a hole in the water pump housing. I need advice on how to make a repair or locate another pump.. Thanks Chip Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/ Share on other sites More sharing options...
Geoff Weeks Posted April 4 Share Posted April 4 Which side of the seal is it on? That looks like it could be a "weep hole" to allow any coolant that gets by the face seal to drain out and not destroy the bearings, also to vent air from the bearing cavity when there are temp changes. If you have a lot of coolant leaking from it than the face seal is shot. If I am wrong and it is on the impeller side of the seal, then disassemble, clean the casting and braize shut. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-549356 Share on other sites More sharing options...
mechohaulic Posted April 4 Share Posted April 4 the "adjustable " grease fitting should be on top making the hole on lower driver side, which would make sense it's location. however it does appear to be a rough cut slot or just ruff housing casting. 100 % agreement with Geoff = purpose of the hole. what we are NOT told is whether it is leaking or just noticed the hole, by picture it could be clean from leaking or washed for photo session. if it had bad bearings on pump shaft to carve that channel; there should have been some serious noise at pump. take belts off and check wobble of pump shaft for quick diagnostic 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-549360 Share on other sites More sharing options...
mechohaulic Posted April 4 Share Posted April 4 small piece left side of vent hole is the challenge. could be the work of an impeller; but hole is to clear cut. BMT " doctors "require more specific info please. is it leaking / does it wobble, and thanks for picture does help a lot. the brazing part ?????🙄 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-549362 Share on other sites More sharing options...
mowerman Posted April 6 Share Posted April 6 Yes, I was thinking the same thing back in the day they all had a weep hole that’s what it looks like. There’s lots of places around. I would check Google search. For your area It’s just a bearing and a seal. Good luck.bob Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-549507 Share on other sites More sharing options...
Carson Posted April 18 Author Share Posted April 18 The weep hole is on the bottom side of the water pump, I think, but I don't really know. In the attached pic with yellow arrow is the (weep hole?). The damaged or cut area has blue circle. No noise or wobble from the water pump. The damaged area looks like it's on the shaft side and not the impeller side. Thoughts? Thanks for your help. Chip Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-550157 Share on other sites More sharing options...
mowerman Posted April 20 Share Posted April 20 I’m not an authority on those. I can’t say but there’s lots of used parts. You might wind up buying a used pump somewhere could take some searching but as I said, there’s lots of those engines around especially with fire apparatus good luck… bob Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-550238 Share on other sites More sharing options...
Geoff Weeks Posted April 20 Share Posted April 20 My thoughts are: If it isn't leaking why worry? If it is, I would note how far the pulley flange and impeller are pressed on the shaft, then disassemble. with the shaft and bearings out of the housing you can assess the housing, and what went wrong. New bearings and seal and any repairs needed. Really only way forward on something like that. Waterpumps are fairly simple devices. The only caveat is to be careful not to damage the impeller, housing or shaft when taking apart. Make a puller to pull the pulley flange off, look at the impeller for puller holes, if there are none, the likely the shaft and impeller can be pressed out the back together and separated on the bench if you even need too. Going together make sure to press the flange back to the same depth while supporting the impeller end, the depth is what puts the preload on the shaft seal. NO HAMMERING. Did my share on the British Buses when parts were not available, or at least not readily available on this side of the pond. Industrial pump seals are made in most types and sizes and it is a good bet the Mack pump uses one of them. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-550243 Share on other sites More sharing options...
mechohaulic Posted April 20 Share Posted April 20 sure I'm wrong = will blame bad eye sight this time. that yellow circled hole don't look like any weephole I remember. blue one more like it. other then the tab on the blue hole looking as though an impeller had something to do with it. no leak or wobble ? Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-550246 Share on other sites More sharing options...
Carson Posted May 5 Author Share Posted May 5 Water leaks out of the hole circled in blue, no wobble. Quote Link to comment https://www.bigmacktrucks.com/topic/74023-mack-a20-water-pump/#findComment-551119 Share on other sites More sharing options...
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