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1933 Buick water pump question


Chuck S
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Hi all, hoping someone can help. I picked up another '33 model 57 that is somewhat dismantled. This included the generator / distributor / water pump assemblies. All are being freed up, cleaned and inspected etc. 

 

On the water pump the impeller is a bit corroded and looking to replace. But my question, is this impeller just suppose to bank off the rear bearing surface? With the unit assembled I can pull the shaft in and out quite a bit. I can see where the lovejoy type coupling at the generator limits it's forward travel. I also see where the retaining clamp for the water pump neck is set, dictates how much play there is between the impeller and rear bearing surface. However it doesn't seem right that the impeller is just bouncing off the back of the water pump. 

 

It would seem that any clearance would cause the coupling at the generator to disengage at some point. Conversely if it's too tight then it could bind or cause teeth to break on the impeller.

 

Am I missing something? Is my unit worn more than I realize? Or is this just a setup and adjust with finesse situation? Thanks, Chuck

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That is what we call a tractor mechanic fix........end play should be set up using the rear cover support. It needs a new shaft, and it should ride in the cover. Often times there is a shim between the impeller and the cover to adjust end play. Your impeller has seen better days.......

 

PS- Cast iron is brittle, be very careful. 

Edited by edinmass (see edit history)
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6 hours ago, edinmass said:

 

That is what we call a tractor mechanic fix........end play should be set up using the rear cover support. It needs a new shaft, and it should ride in the cover. Often times there is a shim between the impeller and the cover to adjust end play. Your impeller has seen better days.......

 

PS- Cast iron is brittle, be very careful. 

Thanks for the reply, it is very worn. The car has been cold since the '60's. I want to see if it will run before I set it aside, but everything is gunked up and needs cleanup badly. It will all have to come back apart and be done properly.

 

The shaft does not extend through the impeller. The shaft ends about 1/16 before the impellers face. And that bushing on the rear cover of the water pump is a larger size than the shaft diameter, it does not seem as if the shaft is intended to enter that final bearing. So no shims can be place there. The way it appears is that the impellers face just kisses that end bushing.

 

 

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Chuck, the shaft was stepped down, and the bushing is to support the shaft. The impeller would be interference fit to the step and pinned to control end play. Currently it’s unsupported and has no end play control Buick didn’t build half assed water pumps thirty years into production. It’s a old half assed replacement shaft done poorly with some drill rod and no machining. I have been at this forty years and done countless water pump builds. You can repack the pump with a bad shaft, but it will tear itself up quickly, and without the rear bushing support it will oscillate and fail ten times faster.

Edited by edinmass (see edit history)
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Definitely consider Bobs - https://bobsautomobilia.com/product-category/cooling-system/page/5/?per_page=24

There are a few pics and options for impeller/shaft or entire rebuild kit for reasonable cost and effort...its worth your time to do this vs the risk of not doing this.

Your impeller appears to be flush with the shaft, which doesn't seem correct, and is likely heading to toward the eve of serious and expensive failure.

My understanding is that the shaft should seat into the bushing in the cover to carry axial and transverse loading.

Thankfully this topic is not pursuing unobtanium, and Bobs might even have a bonus stainless steel shaft which will help introduce more longevity into your efforts.

 

P.S. don't over-tighten the water pump packing nut, it can destroy the cam gear which I can attest is a lot of work and cost to replace.  A leaking packing nut is not ideal, but its ok vs the alternative!

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1 hour ago, edinmass said:


Chuck, the shaft was stepped down, and the bushing is to support the shaft. The impeller would be interference fit to the step and pinned to control end play. Currently it’s unsupported and has no end play control Buick didn’t build half assed water pumps thirty years into production. It’s a old half assed replacement shaft done poorly with some drill rod and no machining. I have been at this forty years and done countless water pump builds. You can repack the pump with a bad shaft, but it will tear itself up quickly, and without the rear bushing support it will oscillate and fail ten times faster.

Ah thanks now I follow! I couldn't wrap my head around how such a system wouldn't fail, so it being a cob job makes more sense. Much thanks!

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1 hour ago, 32buick67 said:

Definitely consider Bobs - https://bobsautomobilia.com/product-category/cooling-system/page/5/?per_page=24

There are a few pics and options for impeller/shaft or entire rebuild kit for reasonable cost and effort...its worth your time to do this vs the risk of not doing this.

Your impeller appears to be flush with the shaft, which doesn't seem correct, and is likely heading to toward the eve of serious and expensive failure.

My understanding is that the shaft should seat into the bushing in the cover to carry axial and transverse loading.

Thankfully this topic is not pursuing unobtanium, and Bobs might even have a bonus stainless steel shaft which will help introduce more longevity into your efforts.

 

P.S. don't over-tighten the water pump packing nut, it can destroy the cam gear which I can attest is a lot of work and cost to replace.  A leaking packing nut is not ideal, but its ok vs the alternative!

Thanks for the reply! I did call Bob's the other day and unfortunately he doesn't carry one that fits a 50 series. I won't be running it in this state as there's a whole lot that could go wrong of that pump binds. Thanks!

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Chuck, making a new shaft isn’t hard......but without the original to work from, it makes the possibility to to work yourself into a corner with end play and over all length issues. You need an old fashioned machinist who knows what he is doing......and they are getting hard to find. Having to work from scratch, it could get very expensive. Copying a part is ten times cheaper than engineering it and making it work. If the shaft is too tight and not enough end play you could tear up the pump.......or what ever is driving it......like the generator, timing chain and gears, ect. It isn’t rocket science but you need to know what you are doing. If at all possible find a old shaft or take a good pump apart to use as a guide, good luck. Ed.

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3 hours ago, edinmass said:

Chuck, making a new shaft isn’t hard......but without the original to work from, it makes the possibility to to work yourself into a corner with end play and over all length issues. You need an old fashioned machinist who knows what he is doing......and they are getting hard to find. Having to work from scratch, it could get very expensive. Copying a part is ten times cheaper than engineering it and making it work. If the shaft is too tight and not enough end play you could tear up the pump.......or what ever is driving it......like the generator, timing chain and gears, ect. It isn’t rocket science but you need to know what you are doing. If at all possible find a old shaft or take a good pump apart to use as a guide, good luck. Ed.

Thanks Ed! The good news is that I have another car that I can borrow the shaft dimensions from. Provided that there are no surprises when I open that pump.. I have an old lathe that should get me through. I do have a good machinist but his time is hard to get, so I tend to make sure I'm backed into a corner before I bother him. I think the worry now is locating an impeller. I've got a call out to Paul R hopefully he has something. If I had a way to get brass to melting temp I'd try casting one but that's probably a last resort. 

 

Regards

Chuck

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Chuck S the above AACA thread may be of assistance to you in re-building your pump.   It appears that your pump has the proper shaft fitted and does not spigot on the rear pump cover plate.  The "bronze" insert on the cover plate is the thrust surface for the rear of the impeller. There would also be a thrust surface on the front of the impeller. If it were my pump I would set up the internal end float around  18-20 thou.  If necessary you may have to machine another another end plate thrust bearing to give you this end float. When measuring the end float make sure the gasket (or one of the same thickness) is between the end plate and the pump housing.  Good luck  and if replacing the bearings in the pump housing be careful when removing the old ones.

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In 40:years of working on pre war cars I have never seen an unsupported shaft that just runs up against the cover on a bushing with a hole in it.........the other thread shows what can happen when you handle old cast iron incorrectly.......if you look in my very first post here I warned him what could happen. I would never try and install a new bushing......I would ream the bushing and make a new custom shaft to match. We use to sell Pierce water pump rebuild kits with a shaft that was oversize but 95 percent of the hobby shop people couldn’t figure it out without damaging the pump and shaft so we discontinued selling the parts.........the water pump impeller above can be saved if you don’t want to make a new one yourself. I would expect they have been done in the past and someone may have one on a shelf if they are out of production. There are ceramic based epoxies that are made to fix the damage to the impeller and pump housing.......they are very expensive and difficult to use. Short cuts always bite you in the long run.........let’s face it, without a very good and reliable water pump, you may as well not drive the car.

Edited by edinmass (see edit history)
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Here is a water pump impeller and shaft manufactured early this year for my 1917 White touring car. Notice the shaft with a gear....all one piece. Talk about a pump project......the parts were measured and done in cad/cam by an engineer, then the impeller was 3D printed to make a pattern, then they were cast, and finally machined. Lots of effort went into this, more than you can imagine and several talented people were involved. Making “old car parts” is a difficult and time consuming process. I had this pump on and off the car no less than six times before we had the final assembly done, it doesn’t leak and has worked great. I’m guessing there is 150 man hours in the entire process.......just for a water pump rebuild.

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Edited by edinmass (see edit history)
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I don't want to start a controversy so I will only speak from my experience.  I have disassembled at least a dozen 1931 and 1932 50 series water pumps.  None of them had the shaft supported in the end coverplate.  The inner shaft bushing has a thrust face and the end plate has a thrust face.  The impellor has thrust faces on both ends. In operation, the pump is driven in line from the generator  with a coupling between the two.  There is no side force from the drive.  The only side force is from the low pressure pump inlet to the high pressure pump outlet.  The pump shaft has two line bearings about 6 inches apart to keep the shaft in alignment.  The Vane on the pump is only 7/8" wide.

 

When I replace the bushings in the pump body, I drill the old bushings rather than pressing them out.  This eliminates the chance of cracking the housing.  I make the new bushings a light press fit.  Heat the housings and chill the bushings and it takes very little force to seat them.  Because the inner bushing has a thrust face it will not move once assembled and there are no forces to move the outer line bushing.  Line ream the two inlet bushings for a good shaft running clearance. Make your thrust clearance by measuring the impellor face thrust thickness  and comparing to the plate thrust face plus the pump thrust face and include the gasket thickness.

 

When installing the pump be sure that the couplings at the pump shaft and generator shaft have a clearance so they do not put any thrust on the shafts.   

 

The biggest problem that occurs with these water pumps is setting the packing too tight.  When new let them weep when running and after a break in period make light tightening adjustment.  

 

Bob Engle

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Bob, no worries........so if I understand you correctly there are two bushings in the center of the pump spaced apart far enough to support the shaft and thus the impeller on the end of the shaft won’t need support. Interesting design. In your above paragraph it says bearing but I’m going to guess it means bushings. Bushings six inches apart would provide pleanty of stability to the shaft to let the impeller just hang off the end. Is there only one packing or is there two......one on each side of the bushings? It’s interesting that the design uses a bushing in the cover for end play and has a hole in the center. I have seen a few pumps with a flat bushing in the center of the cover.........but never one that had a hole that wasn’t supporting the shaft. I shall stand corrected. Strange design....but who am I to argue with the Buick engineers. It’s interesting that the Buick water pump is a better design than the Cadillac water pump from the same era. And easier to service and rebuild. 👍👍👍
 

 

PS- ten years ago I cast Pierce Arrow water pump covers out of gray iron. The cover had a tab on it that helped control excessive end play in the shaft.......a steel shaft contacting a cast iron surface. There is more than one way to skin a cat!

Edited by edinmass (see edit history)
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