1925 & Earlier Buick Water Pump Rebuilding Procedure

[Hubert_25-25]

Attached is a Buick water pump rebuilding procedure.  A few spots plagiarized from friends on this forum in an effort to save time in putting it together as this is quite involved.  This is also a conversion to a lip seal instead of using packing, and no modifications to the pump housing for this.  You can still stay with packing if you desire.  These are quite complicated to rebuild.  This is applicable to all water pumps which have a packing seal on each end.  Even those with a single seal, this procedure will generate some thoughts if you are tackling this yourself.  

I can't post a word document, so this is 15 snapshots.  This is a replacement document of the original rebuilding document.  I did have a pump seal failure just before the 100 mile mark.   You will see postings after this document about that failure.  I made several changes and I have updated this original document.   No issues after the corrections.    Hugh

 

Edited June 4, 2020 by Hubert_25-25 (see edit history)

[Mark Shaw]

This would make for a good article in The Bugle and/or Dean Tryon's newsletter.

Good job!

[Terry Wiegand]

Hugh,

Mark is right - this would make a great technical article for Dean Tryon's Newsletter.  I was cryin' the whole time I was machining those packing nuts for my '16.  After reading about what you and Larry DiBarry went through with your water pump shafts, I am now ashamed of myself for thinking that I had it bad.  My late model 1922 and slightly older 1920 model has the same single piece shaft as the '16 does.  Seeing what you guys are doing with what you have on your cars makes mine look downright antique.  Here is a photo of the shaft for the '16 D-45.  The impellor will be staked to the shaft and the Starter/Generator coupling will be taper-pinned when things go together for the final assembly.  I think I am a little biased with my thinking that because the water pump on this engine bolts solid to the crankcase, it appears to me that this configuration lends itself to an easier assembly.  I guess I'll find out when things go back together.

 

Terry Wiegand

South Hutchinson, Kansas

[Hubert_25-25]

Mark and Terry, 

   I will get a copy of this over to the Bugle, and Dean.  I also cleaned this up and I deleted a page.  At the same time, I added the Master water pump shaft and impellor dimensions, so for those looking, they are substituted in the article above. 

     Most importantly is giving credit to the others that helped me with this article - Larry Schramm, Larry DiBarry, Kyle Sliger, and Brian Heil,       Hugh

 

 

 

Edited February 19, 2019 by Hubert_25-25 (see edit history)

[Terry Wiegand]

Hugh,

Since you are including the earlier pumps on this, I will go ahead and send you the other photos that I have of my pump assembly so that there is some reference to go by.  When it comes time to assemble everything I think that I have it figured out.  Take my time, be extremely careful and think again before any move is made.  I do have a plan for this and I have been through a thousand times in my mind and if it is done precisely in order, then there is no reason why it should not come out perfect.  Here is the first of the photos for you.  The brass packing nuts have been polished out and waxed with several coats.

 

Terry Wiegand

South Hutchinson, Kansas

[Terry Wiegand]

Here is another photo for you.

 

Terry Wiegand

South Hutchinson, Kansas

[Terry Wiegand]

Here is the last photo that I took.  I like the high resolution for the photos so that they can be enlarged to see the details better.

 

Terry Wiegand

South Hutchinson, Kansas

[Mark Kikta]

Very nice article.  Thanks to Hugh and all who helped him.  This will help us all a lot.

[Hubert_25-25]

Mark, 

     Some updates on the attached drawings and specs at the top of the thread.  Larry DiBarry assembled his water pump as shown above.  This uses the seals specified by Larry Schramm.  Larry D started the pump.  No leaks, and it ran for a while but Larry noticed that it was getting very warm at the packing nuts.  I made a misjudgement on the blue washers used.  The ID of 3/4" matches the shaft size and has them pressing against the rotating shaft.  These blue washers need to be  7/8 ID and 1 5/16 OD.  This way when you tighten the packing nut against them, you have not extruded the rubber onto the shaft.  Another option is to not use the blue washers, but instead use 3 of the black O rings.  These will hold the lip seal without getting near the shaft.  

In Larry D's searching for seal information he did find out a couple of things. 

1) Reeves Auto does put lip seals in pumps they rebuild, and they use a less expensive lip seal.  They also undercut the bronze bushing so that the seal is a press fit into the bronze bushing. 

2) When Larry Schramm did his installation, he also undercut the bronze bushing.

- Undercutting the bronze bushing means creating a narrower bronze wear surface.  The undercut is at least 1/4" deep.  I do not know if the undercut is only on the bushing or into the housing as well.

- regarding the 2 undercut styles, I do not know what else was done in the area between the seal and the packing nut.  I have no details on this.

 One of your packing nuts looks different than the style used on our pumps.  You may have to address this one differently, so I am curious to see how you address this.  

Attached is a photo of one lip seal assembly held with the 2 blue washers and 1 black O ring in the center.  As stated the ID needs to be enlarged on these blue washers so that they do not drag on the shaft.  The second photo is using 3 black O rings.  When you order these O rings from McMaster Carr, they come in a bag of 50.  I have extras if you want me to send you some of these.  

Hugh

 

[Hubert_25-25]

Terry,   

     That looks really nice.  What are your plans for sealing the pump.     Hugh

[Terry Wiegand]

Hugh,

I am going to use graphite impregnated round cord or heavy string.  That was what was used back in the day that these cars were new.  I have used that on my 1920 and 1922 and the pumps have not leaked a drop.  The inside of the packing nuts is perpendicular to the shaft and the threaded boss of the pump body is angled to accept the packing material.  The secret is to use plenty of the packing material and squeeze it into conformity between the nut and the pump body.  Nothing to it.  Works perfectly.

 

Terry Wiegand

South Hutchinson, Kansas

[Larry Schramm]

Here is a diagram of what you need to do.  There should not be anything in the gland nuts.  They are there just for decoration after you install the new seals.

 

I did not under cut the bushing because it would have less load capability.   What I am showing is exactly what I did.  The seals need to be press fitted into the housing.  You need to remove the tapered part to have a space for the seals.  Two seals fit fine in that space,  at least on my truck pump.

 

On the suction side of the pump the open side of the seal goes to the atmosphere so the seals will not leak air into the cooling system.

 

The seal that I used for my truck because of the dimensions I was working with from McMaster-Carr is 13125K92.  It was about $35.00 each and I used 4 seals.

Edited March 4, 2019 by Larry Schramm (see edit history)

[Hubert_25-25]

Larry, 

     Thank you for the drawing.  The total length of the bronze bushing is 1 3/16", and then the bevel starts.  The bevel is about the thickness of one seal, so if you cut back the bushing by the depth of the 2 seals, you really only loose the bevel and .133 for the inner seal, so still 1" of bushing width which is sufficient.  My water pump bore is .937 and the seal pushes in easily.  

One difference in the 1925 pump is that one side of the pump is  a .749 shaft, and the other side is .755, so a little tighter shaft fit on one side.  

Hugh 

    

[dibarlaw]

I just got off the phone with Larry Schramm as we have gone over this. My first thought on rebuilding the pump with lip seals would entail boring out the tapered face of our 1925 pump housings to press fit the seals. And yes that would entail boring into that end of the bronze bearing. Larry's C-4 truck pump is somewhat different than ours more like what Terry had shown from his 1916. A note on Terry's statement about the graphite cord style packing which I have also used. The problem is when the shaft/bushings are very worn as was the pump in my 1925.  It was nearly impossible to keep it from leaking. Of course I did not know how worn the pump was until last week when I disassembled it. More than .040 play between the bushings and shaft! 

 I have had reference to another thread where the fellow has rebuilt dozens of pumps like ours for others. New shaft and new bushings. In over 20 years he has not had one fail and he indicated that they all still use the original style packing. Not the pipe fitter graphite rope but the formed graphite collar with a diagonal split as they were fitted with originally. He did indicate that they were still available.

  One advantage with the press fitted modern lip seal adaptation, that if it were to ever begin to leak one could just install the original style packing in the gland nut again.

 

[Terry Wiegand]

Larry,

Thank you for the more detailed explanation of what I did with my pump assembly.  I apologize for not being more explicit.  Please let me explain what I did in more detail here.  I started with the new shaft for this project first.  My shaft had the advantage of being finished up on an O. D. Grinder.  I did not check the finish, but, I will think it is somewhere around a 10rms.  For all practical purposes it looks like it has been plated and then polished.  I then pressed out the old bushings from the pump housing and the housing end cover.  I machined new brass bushings for the body and cover leaving them undersize on the inside diameter to be bored to finish size after being installed.  I did this several years ago and if my memory is correct, there is .0025" clearance in the bushings to accept the shaft.  Putting the end cover back into the housing and installing the shaft through the bushings (as shown in the photos) things lined up perfectly.  I really am not concerned about any coolant seepage once everything is all back together.  If I hadn't gone to all of the work described, then, yes, I probably would have a reason to expect leakage.  For me, it just seemed easier to start with the finished shaft O. D. and work from that going forward.  The fact also that this engine has a non-pressurized cooling system is going to be a big help in keeping things from seeping.  Well, that's my story for now.  When this engine gets all back together and the coolant gets poured into it for the first time and it is started for the first time in almost 50 years, if there are no leaks, you will hear some serious shouting coming from out Doo Dah way!

 

Terry Wiegand

South Hutchinson, Kansas

[dibarlaw]

I have had a failure with the newly installed pump! I had run the engine 4 times for about 15 minutes each. Up to this time no leaks!! The last 2 times while running my finger under the shaft to check for leaks the front input side brass gland nut was too hot to touch! On my pump that is the .755 shaft diameter side. When I pressed the new bushing in on that side I then set that part in the chuck and opened up that bushing up to .7575. I had hoped that all would be good. When I reassembled the pump with a 1/64" gasket and checked. it was tight. I disassembled and refaced one of the bushings another .005. Reassembled and tried it again. All things seemed to turn ok but with a bit of drag. I had assembled with the seals as Hugh had indicated. Just finger tight. I had the assembly on the lathe to spin the shaft lubed with pump grease and the pump held stationary on the compound rest. Things SEEMED free....

 I removed the pump again. 20 minutes from when I opened the petcock to drain the system to out the door. I am getting good at this!

 This is what I found when I tore it down again. 

The bushing seized on the shaft and was spinning the bushing in the housing.  I had used the .937 OD for the bushing + .001(.938) when I pressed these back in. The parts book specs call it .941. 

 I was thinking that the rubber washers were binding after things got warm. Again the output side seemed fine with no heat. 

 Patrick Reeve said that when they rebuild these type of pumps they use a mandrel type reamer to make sure the bushing surfaces are aligned and then a final hone to achieve a good running fit.  This is done with the pump assembled. When the bushings are pressed in they may be cocked enough to cause my problem. Hence the line ream operation. Even so, when I inspected the EXPENSIVE seals the spring side of the seal was deformed. Pushed out of shape by the rubber O ring separator. It was the same on both sides of the pump. 

 

[dibarlaw]

 Even with the O ring just tight enough to hold the seals in place it tends to push the seals outer plastic housing out of shape.

Not nice and square like the product drawing any longer.

These seals can only work if they are pressed into a bore made to accept them. 

The good news is that I was able to save my stainless shaft. A quick file at the yellow(brass) ring area and crocus cloth polish has thing back in order.

The brass ring area on the left side (.755) side is where the bushing seized. Every thing is now polished up again. Back to the drawing board.....

 

[Larry Schramm]

I am currently helping my machinist rebuild a 1922 pump like yours for Mark Kikta.  I will be posting some pictures. 

 

To dis-assemble the pump we did need to cut the shaft behind the impeller on the front engine side because the impeller was frozen on the shaft.  He then drilled out the shaft from the impeller on the lathe. 

 

After cleaning the impeller bore out, it fit perfectly on a 3/4" shaft. 

 

Waiting for the seals, new bushings, and stainless steel bar stock to make the shaft.  Glass beaded all of the pump body & impeller parts.

[Hubert_25-25]

1 hour ago, Larry Schramm said:

I am currently helping my machinist rebuild a 1922 pump like yours for Mark Kikta.  I will be posting some pictures. 

 

To dis-assemble the pump we did need to cut the shaft behind the impeller on the front engine side because the impeller was frozen on the shaft.  He then drilled out the shaft from the impeller on the lathe. 

 

After cleaning the impeller bore out, it fit perfectly on a 3/4" shaft. 

 

Waiting for the seals, new bushings, and stainless steel bar stock to make the shaft.  Glass beaded all of the pump body & impeller parts.

Larry, 

      On the 1925 pump shaft, the rear section of the shaft is .749, and the front is .755  The break is about 1/2" before the hole for the taper pin for the impellor on the Starter Generator side .  I think they did this so the impellor could be installed with a snug fit without being forced half way down the shaft.  I would think Buick did this practice on earlier models as well, but have nothing to base this on. This makes the use of the lip seal on the .755 side a little on the snug side.  Larry DiBarry and I are very interested in how you address the lip seal on .755 side.   These seals are graphite teflon so there is not as much give as an elastomeric seal.    Hugh 

[Larry Schramm]

Hugh,

 

The shaft is .750" the whole length.  If you are measuring an old shaft, ??  The impeller is retained by the pin that goes through the impeller and shaft.  From a manufacturing standpoint, it does not make sense to have a different diameter as that adds cost and at those tolerances, a LOT of cost unless there is a specifically reason.  I do not see any reason for that around the impeller area.  Both of the bushings are for a .750" shaft. 

 

I am just a KISS guy,  keep it simple and that is how we / machinist  are refurbing the pump.

 

Larry

[Hubert_25-25]

Larry, 

    The .749 /.755 shaft is the original Buick design.  Larry DiBarry, Kyle Sliger, and I all have at least 2 shafts each and they are all made that way.  Our cars are all 1925.  The impellors are bored for the  .755 shaft, so if we were to change to .749 the entire length, we would need to bore and bush the impellor to make it useable for a .749 shaft.  We are contemplating cutting the water pump shaft to .749 just after the impellor and bushing on the .755 side.  You could slide the seal on over the .755 section.  The section that the seal rides in has to be cut a little wide in case there is wear on the bushing flanges.  The other difficulty that we run into with this original design is having to line bore the 2 bearing diameters.  

     Maybe Buick started this practice of the stepped shaft in 1925.  Not a big deal to set all of this up in this manner in a factory setting.  I would think very few in 1925 would not have a difficult time putting this together in a garage shop in their local town if an owner lost a pump bushing.   

So there are a couple ways to modify our pumps.

1) .749 OD shaft - thru.  This  requires boring and bushing the impellor.  Advantage is .750 ID on both pump bushings for line boring.  

2) .749 OD shaft section on the.755 section.   Requires a smaller OD be cut on the shaft, and the cut must be a little wider than the seals.

3) Housing undercut for seals on a .755 shaft.  Requires cutting some material out of the pump housing in the bearing area to keep from crushing the seal too much.    

.006 OD difference does not seem like much on a shaft, but these are not elastomeric seals.  They are graphite teflon so they can not handle as much change in tolerance.

Hugh        

Edited March 9, 2019 by Hubert_25-25 (see edit history)

[Mark Shaw]

On ‎3‎/‎8‎/‎2019 at 9:31 PM, Hubert_25-25 said:

So there are a couple ways to modify our pumps.

1) .749 OD shaft - thru.  This  requires boring and bushing the impellor.  Advantage is .750 ID on both pump bushings for line boring.  

2) .749 OD shaft section on the.755 section.   Requires a smaller OD be cut on the shaft, and the cut must be a little wider than the seals.

3) Housing undercut for seals on a .755 shaft.  Requires cutting some material out of the pump housing in the bearing area to keep from crushing the seal too much.    

.006 OD difference does not seem like much on a shaft, but these are not elastomeric seals.  They are graphite teflon so they can not handle as much change in tolerance.

Hugh        

Gentlemen,

    I suggest you just heat the impeller to expand the ID so it will slip onto the new shaft.  I also suggest that the original packing will still work nicely for many more years after replacing the original pitted and corroded shaft with 304 stainless.

My $0.02

Edited March 11, 2019 by Mark Shaw (see edit history)

[dibarlaw]

Thanks Mark:

 After being the test case I am now leaning in that direction. I told Hugh that the packing does not care if the shaft is .749 or .755. As long as the shaft is new and the bushings are fitted correctly we should get another 90 years of wear out of it. Considering that we be using modern coolant and pump lube additive. Also we would probably not be putting water from drainage ditches into the system along the road as they had to do 90 + years ago. 

[Jim Bourque]

This is what I did with my shaft for ease of serviceability. Repeatable runout .0015.

Original Buick gear end, keyed rigid coupler I made, 304 SS shaft.

[Hubert_25-25]

I received the water pump shaft and impeller today.  There is an error in the location of the transition of the original shaft diameters from .749 OD to .755 OD. The transition is almost an inch off toward the front of the shaft.  The impeller is already bored to .755 .  Only 1/4" of the impellor bore is sitting on the .755 shaft.

 This requires that I must put a bushing in the impeller.  

I could bore 2 ID's into the bushing.  That would fix the impeller. 

Larry DiBarry also made a small .750 cut in the .755 part of the shaft for his seal to ride in.  This is shown in the power point drawing that I made in the previous posting.   

I am now considering going with the KISS principle that Larry Schramm suggests.  I would just clean the shaft length to one diameter .749

1) I do not want to heat the impeller in order to install it.   I will never be able to get it off if I ever have to replace the front seal.   If this were a shaft with nothing on the end, I would be better with it, but I don't think I could ever remove it if I had to.  The picture below shows the parts on the shaft that will not come off until the impeller is removed.  There is 2 inches between the impeller and all the parts.  

2) Can I get away with a tight - almost a hammer fit on the impellor?

3) Would you feel comfortable with a 1/4" heavy duty stainless roll pin on the parts instead of the 1/4" taper pin?

Thank you,   Hugh

  

[Larry Schramm]

Just put a bolt through the impeller with an nylock nut on the other side.  Simple and if you ever want to remove it for any reason, simple.

[Larry Schramm]

Be glad you do not live in Colorado for the price.  Look down about 5 posts.

 

 

[dibarlaw]

Wow$1,200! Good thing I made my own.

[Hubert_25-25]

I thought we were working on stuff in the nickel plated and not the gold plated era.  

[Hubert_25-25]

The special water pump seals are now in place and working well.  I put about 10 miles on the car until other issues set me to the shoulder of the road, but that is another posting.  I saw a few drips on the water pump shortly after initially starting the car.  When I backed off the brass nut, the inlet seals started to come out of the pump.  I wanted to make something that would

a) hold the seals from coming out

b) that I could remove at a later date if the seal started to leak

c) I could throw packing in the nuts as a back up plan to keep on driving.

I first made this spacer out of PVC because it was easy to make and install and remove.  You can see the lip seals behind the PVC. 

Then I realized that it might not be able to take the heat long term.  I went to look for CPVC, but could not find sch 10 (thinner wall).   So I cut these out of copper pipe.  The split in the ring determines the ring diameter.  I put a rubber O ring in for good measure and to keep it aligned.  They are a little finicky to install, but I can remove them if needed without pulling the pump apart.  

Photo 1 shows the bronze bushing, the 2 lip seals, and the little bit of ledge that is left over after cutting back the bronze bushing for the lip seals.

Photo 2 shows the PVC spacer.

Photo 3 shows the copper spacer and the rubber O ring.  Both have a single cut to allow removal.  The copper spacer does not touch the shaft.  

 

After all that I have gone thru on my water pump, I feel that I need to completely go thru my procedure on water pump rebuilding as a lot has changed to get me to this point.  I will repost it once I get some time.  

Hugh  

[dibarlaw]

Ben:

 Yes things look more crowded on your earlier 4 cylinder than on either of my 6s. where the packing nut is concerned.

 

Plenty of room to unscrew the nuts to add packing on both my 1925s

.  With bearings and couplings pulled back prior to removal.

 My advice since you have gone this far is to remove the entire pump and have a new stainless shaft and new bushings made.

 See the thread Mark Kikta has about his 1922 water pump. This is what your pumps shaft probably looks like...

These shaft surfaces should be perfectly smooth.

 

 To get your front cover off.

 You must remove the pulley nut first and use a gear puller to remove the pulley. I had done this already on my 1925 Standard WHILE THE RADIATOR WAS STILL IN PLACE. I was able to use forked wedges to get behind the pulley to drive it off uniformly. I did this to replace the original leaking felt seal with a modern lip seal. It works great . No leaks.   Photo is from another forum posters car.

Except 6 months later the head developed an oil leak so I jumped into a full rebuild.

 I am about at the same point with my 1925 Master. (The timing gear needs replaced.) I will have to disconnect my exhaust down pipe, loosen the engine mount to the frame bolts. Then, when I disconnect the front engine mount bolts on the crank stub I can raise the engine a bit to clear the frame .

 Best Of Luck!

[Hubert_25-25]

75 miles on the Buick and I took it for a long drive (10 miles) to see how it would do with a little speed and distance.  It would do 50 mph, but preferred 45 mph.  I had driven it at 45 mph for a few miles a couple of days earlier and it seemed to run well.  On the return trip I saw some spots on the windshield (my hood is not on yet).  Then I looked down across the windshield and I could see antifreeze streaming out of the rear water pump packing nut.  We pulled over.  The bright finish from the packing nut was gone, and the paint discolored at the outlet threads.  I tightened the nut a few turns. but that only slowed the leak to a smaller leak but would not stop it.  We towed it home.  I had spun the rear water pump bushing and the heat just melted the rear water pump seals.  All that was left were the springs from the 2 rear lip seals.  Upon disassembly, the front bushing was also spun as it came right out of the housing and was stuck to the shaft.   The front seals had not gone yet.  So, back to working on the water pump again.  I guess the tolerances were too tight for the heat generated so next time I make the tolerances a little more sloppy - not sure what the tolerances should be other than I can make them less tight.   There was just a little drag on the pump when you spun it.  I am also wondering about the choice of bushing material.  McMaster Carr sells several bearing materials.  The original was some bronze (not oilite).  These are SAE 660 leaded bronze.  The note also says "they are sometimes called 932 bronze bushings".  They also say "lubrication required" The oilite bearing is SAE 841 bronze.  Under lubrication it says "SAE 30 wt".  I will post my notes on getting these bearings off the shaft as well, as it was not easy.  

Hugh 

[Hubert_25-25]

Still working on how I really want to do my water pump - again.  I could go back and just increase the tolerances on the bronze pump seal bushings after reinstallation, and hope for the best.  I did purchase a different 3/4" reamer with an adjustable pilot guide which would greatly improve the chances of keeping the line boring correct on a bushed water pump.   The spacing is too far apart for just a standard adjustable reamer. They say this style is supposed to be used when doing king pins as well. 

The Ford model A folks have a lot to teach us about why so many of their cars are still on the road.  It's not just that they built so darn many, but they have been upgrading parts over the years as well to make them more reliable.  Crazy difference in their world to get these 1/2" thick catalogs of parts for model A and model T cars - most every part available, and from multiple vendors.   
  I then read this forum on model A leakless pump seals, and a couple of things struck me.  It seems almost all of them use inexpensive neoprene lip seals, and there is also a real variety of bearing designs used. 

 

https://www.fordbarn.com/forum/showthread.php?t=18945&showall=1

 

Another thing that I find strange about my Buick water pump bushings is that there are no grease connections.  I honestly think that the grease would wash away rather quickly anyway, but many other cars of this era have these.   By the way,  At max engine RPM (2800) the water pump spins at 4200 rpm.  The fan spins at 5600 rpm.    

So I plan to only reinstall the bushings to use them for maintaining the end play on the impeller.  I am also looking into doing a lip seal conversion and using ball bearings.  The following shows the layout that I am working on.  My pump has a packing nut on each side, and all this fits in the packing nuts.  

Hugh

 

[Dave39MD]

A similar problem just came up on the vcca site, might be of some help;

 

https://vccachat.org/ubbthreads.php/topics/427023/water-pump-bush.html#Post427023

 

Dave

[Hubert_25-25]

Dave,

   Thanks for the above note.  I am taking another stab at the bronze bushing again as using a ball bearing design is providing it's own challenges.  Some major changes that I will eventually incorporate into the revised rebuilding procedure.  The biggest being setting the Inside diameter for the bronze bushing.  I found this tolerances table of fits provided by South Bend.  I also decided to go with the oilite bearing from McMaster Carr rather than the solid bronze.  The oilite bearing is slightly shorter than stock, but only needed a light touch on the face to provide a little more end play, and an undercut behind the flange.  Both modifications could be done without the use of a lathe.  The bushing was .002 oversized as shipped and it pulled right into the housing.  This made the space for my lip seals a little longer, but that was an easy fix to extend the seal holder.  The difference that I am banking on is that I am also using a long piloted reamer.  This allows me to get the reaming operation straight.  I think I did a decent job of this last time, but not as uniform as the long pilot provides.  The other item is that I opened the bearing clearance to +.002 of the shaft size.  On the previous build, I reamed it until the shaft would rotate, but there was possibly a little drag on the bushings.  No wonder the bushings seized when they got a little warmer.  Given that the shaft is 3/4", +.002 for the bushing is noticable that I have allowed some room for thermal expansion.  You can see the shaft move side to side in the bushing slightly, and I could not see that before.  My micrometer can also barely catch the end of the bushing now to take the ID measurement, but there is just enough.     Hugh 

         

[Crazyfamily]

Since it’s on topic, I see Bob’s has water pump rebuild kits, anyone know if their rebuild kit has a stainless shaft?  I’ll give them a call Monday but just curious if anyone knows in the meantime?

 

i have an extra water pump that I am going to rebuild but don’t mind doing it myself if their kit is worth it.....