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New Water Pump leaking on 48 Desoto


MarcDeSoto

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ARe there any tricks to have a successful water pump install.   I have a brand new water pump, but it is leaking where the pump snugs up to the front of the block.  I put the gasket in with gasket sealer, but still a leak.  Could it be the bolt weren't torqued tight enough?  Or the bolts didn't have enough water proof dope on them?  

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Marc, I had a similar problem. I thought I had cleaned off all of the left over original paper gasket. It felt smooth when I ran my hand over the area where the new gasket was mounted.

 

I took the Wp off again and then I found a very small piece of gasket that was still stuck to the front of the engine block.  Sanded down this area then put lubraplate on the front of the engine block mounted the gasket and then also did the same with the grease on the fron of the gasket and then mounted a second gasket with grease again to make a thin seal on all metal matching areas.

 

This stopped the leaking. Give this a try.

 

Rich Hartung

 

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Yep....very likely a small thin piece of gasket material left on the block.

I use carb/brake cleaner and spray it on the surface  that I think is 100%  cleaned.

If any gasket material is still there it will show up as a dark almost black spot.

Also use thread sealer on the three bolts....tighten firmly.

 

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50 years ago my college second car was a 49 Special Deluxe Club Coupe ( raced my first car so I needed something reliable ).

The water pump ( the original ) started leaking so I replaced it with a modern style lubed for life pump.

I had the same leak as you describe after a little while. I had tightened the 5/8ths fan belt too tight and it pulled the pump away from the block.

The fix was to loosen the belt a little and retighten the bolts.

Maybe two years later the replacement pump started leaking.

Never throwing anything away I knew I had the old pump in the trunk, so I reinstalled it.

Once in place I spied the grease fitting on it.

I fired up the Plymouth and the old pump still leaked, not having healed itself during its rest.

Found a grease gun and gave it a couple of shots AND the leaking stopped!

Amazingly enough that old original pump never leaked again.

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I have a new pump on both the '47 and '49 and lucky no leaks. I also have two or three original pumps and I have bought a few rebuild kits for them off ebay. I also purchased the tool to ream the flats in the old pumps. One of these days I will rebuilt a couple of pumps to factory specs and yes, I have a small grease gun with water pump long fiber grease in it...

 

 

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I got a new gasket from my local Napa auto parts 2 years ago . It is still listed as Part #FPG 4267 and at the low price of $2.82 

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25 minutes ago, MarcDeSoto said:

I called NAPA today and they said the water pump gasket for a 48 DeSoto or Dodge is obsolete and they no longer carry it.  I'll try again saying I want part FPG 4267.  


That part number is still listed on the NAPA website.

Edited by Sam Buchanan
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If you cannot make it...here is another part #

Screenshot_20221223-205544_Chrome.jpg

Edited by Dodgeb4ya
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Run those numbers online...those gaskets are available some where.

"Olsen's Gaskets", Port Orchard Washington would have one or make it if you want to spend money.

But it doesn't take much to make one.

I make lots of gaskets...I love making them accurately as originals.

Using good cutting tools and hollow punches.

Parts stores generally have sheets of gasket material in a few different thicknesses and materials.

Edited by Dodgeb4ya
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18 hours ago, desoto1939 said:

Marc, I had a similar problem. I thought I had cleaned off all of the left over original paper gasket. It felt smooth when I ran my hand over the area where the new gasket was mounted.

 

I took the Wp off again and then I found a very small piece of gasket that was still stuck to the front of the engine block.  Sanded down this area then put lubraplate on the front of the engine block mounted the gasket and then also did the same with the grease on the fron of the gasket and then mounted a second gasket with grease again to make a thin seal on all metal matching areas.

 

This stopped the leaking. Give this a try.

 

Rich Hartung

 

So you use grease instead of gasket sealer on your water pump and then put two gaskets on?

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6 minutes ago, MarcDeSoto said:

how about the rubberized cork gasket material.

I use to have a real tough time with T-stat gaskets & some others.

Honestly I think I was just young & impatient. .... I would scrape the surfaces clean & smooth & usually that was fine.

When they did leak & I would have to do the job over, I usually found some leftover gasket material I missed.

Seems you can scrape & clean & the surface will be smooth & you think it is acceptable.    While there is still some gasket material left. Seems like scraping it will polish it & smooth the left over gasket .... will feel smooth but is actually darker in that area.

 

Anyways as I got older & tired of re-doing my work, I pay special attention to the surfaces, I will use a heavy 36 grit sandpaper by hand & see clean shiny metal on all mating surfaces.

I will also use a straight edge & look for light shining through showing if the surface is flat or not .... sand the surface flat if needed.

 

Paper gasket & a gasket sealer is all you need .... I use Indian head shellac made by permatex. Pay careful attention to get the surfaces clean & flat.

If the water pump mounting bolts go into water jackets .... Some pipe dope on the threads would be a good idea.

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I use a very rigid professional type scraper...have to arefully sharpen it every six months or so.

Also keep lots of single edge razor blades for tight spots.

A leak means start all over!

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Since I have the water pump out, Keith reminded me that I should check my water distribution tube.  I put a new one in, but that was 40 years ago.  Maybe I should pull it out and check it.  Just have to find the right tool to hook on to it.  I remember 40 years ago having to have a welder weld on a metal handle.  Then I had to use a come along to pull it out!  It was rusted solid.  I think this one should be in better shape.  I might paint it with POR before putting it back in.  Also any water coming out the block is very rusty. I wonder if there is a way to flush out that surface rust out the engine before putting the water pump back on.  I've heard about running white vinegar in it to flush out the rust.  

 

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Marc.........use gasket paper and make a new gasket................ do NOT use rubberised cork.....just normal gasket material.........I get it in a sheet......2 thicknesses , use the thicker of the two............clean the block and water pump back plate till they are clean enough to eat from, showing nothing but clean metal,......then use some sort of non hardening gasket goo and after cleaning the bolt threads use gasket goo on the bolt threads also...........and new spring washers if available..............andyd

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