Introduction:

This repair guide is designed to be a handy reference in the repair of flood pumps. It provides a step by step process for taking apart flood pump components, how to repair component parts, an important materials list, sizes, tolerances, and installation. This guide also provides helpful “NOTES:” that contain valuable tips to make the entire process easier.

It is assumed that the information provided in this repair guide will be performed in accordance with the latest safety regulations using the necessary safe work procedures while wearing the appropriate personal protective equipment.

NOTE: Please fully read repair guide before proceeding so you can prepare accordingly.

NOTE: By viewing this Repair Guide you agree to hold harmless and indemnify the publisher Richard Myrchak and its ownership, partners and affiliates. This guide is a generalized reference for educational purposes only. Use at own risk. 

Acknowledgement:

I would like to thank the Mechanical Maintenance working staff for their extensive knowledge and informative contributions to make this Flood Pump Repair Guide possible. 

Order of Guide:

 Introduction

 Acknowledgement 

 Material List

 Disassembly

 Component Rebuilding

 Installing Impeller on Pump Shaft and Balancing of Pump Shaft

 Recap Checklist

 Installation and Alignment

 Alignment order diagram

Material List:

Packing Seal Material: Size of packing material will vary depending on the pump size but make sure its on hand for the install.

Bearing grease: Some pumps have hanger bearings that will need grease.

Bearing Plastics for boring and bushing Bearing Hubs:

Vesconite plastic bearing material: 205mm OD x 115mm ID x 1000mm long. (These are the dimensions that is usually ordered.). Required for flood pumps with the 6.500" diameter wear sleeve. Very common size. Material for boring and bushing bearing hub that rides on the wear sleeve.

Ertalyte plastic bearing material: Solid 6" round material x various lengths. Required for flood pumps with the 4.250'’ and 3.000'’ diameter wear sleeves. Material for boring and bushing bearing hub that rides on the wear sleeve.

Flood Pump Wear Sleeve material:

660 Bronze hollow bar: 3-1/2“ OD x 2“ ID for 3.00“ size wear sleeve.

660 Bronze hollow bar: 5“ OD x 3“ ID for 4.250“ size wear sleeves

660 Bronze hollow bar: 7“ OD x 5“ ID for 6.500“ size wear sleeves

Red Epoxy : For coating impeller and in the inside of the volute with a brush. This creates a wear resistance coating to slow down the wear rate. Shown above.

Devcon Plastic Steel Putty: For filling in and smoothing out deep recesses and craters in impeller blades and in the volute using a putty knife. Then coated with red epoxy after plastic steel putty sets. Shown above. 

Flood Pump Shaft Material: 

3 sizes of shafting material that might be required if a new pump shaft has to be made:

3" round diameter 4140 HTSR

4-1/4" round diameter 4140 HTSR

6-1/2" round diameter 4140 HTSR

The need to make a new shaft may never happen, but it would make sense to have enough material in stock to make at least one of each.

If by chance a pump shaft is found to be bent or too damaged for repair then a new pump shaft will need to be machined. This pump shaft should be made from a material called 4140 Heat Treated Stress Relived shafting (HTSR). If there is a issue finding this material due to availability issues then you could also choose 4340 Heat Treated Stress Relieved material. Dimensions needed would depend on the shaft needed to replace.

Ideally, enough shafting material should be on site and made available to make at least one new flood pump shaft in case the need should arise.

Flood Pump Bearing Hub material:

7-1/2", 10" and 13-1/2" are the 3 diameters of Ductile cast iron needed to make the three different sized bearing hubs if required.

There has been a few rare instances where a new flood pump bearing housing was needed to be made new due to damage from cracking or damage when the bearing hub was removed while using the jacking screws (as shown above). If a new bearing hub is required then make it out of Ductile Cast Iron material like shown second image up. If the plan is to overhaul 3-4 flood stations a year, then it is advised to have enough material to make at least two bearing hubs. The need to make a new bearing hub may never arise again, but it’s safer to be prepared than not to be able to source out material when its needed immediately. 

Disassembly:

First, Electricians must cut power, and lock out the electric motor that powers the flood pump using the correct lock out tag out procedures. It is before or during this time, that it should be determined whether the electric motor needs to be overhauled. If so, then the electric motor will need to be sent to the determined repair facility. 

When all other lock out tag out procedures have been implemented, and all dangers have been addressed, then the procedure of uncoupling of the drive shafts from the pump and electric motor can proceed. NOTE: All parts should be punch marked beforehand so their exact location can be determined when its time for assembly. If hanger bearings are present then they should be replaced with new ones. 

NOTE: It will be important to plan out the work so a boom truck and extra required staff can be made available to lift and remove the electric motor (only if overhaul required), drive shafts, and flood pump and volute assembly from the flood station.

Drive shafts are sent out to determine if they are straight, then straightened if required. Mounting faces and spigots are inspected and need to be free of dents and burrs that may affect a flat face mount. The drive shafts are to be balanced at 900 rpm. (If drive shafts are too damaged, then new ones are made.)

NOTE: When drive shafts are being transported, be sure to add wooden cribbing supports under the shafts where its strapped down, instead of relying on just the outer flanges, otherwise the driveshafts could bend when strapped down when transported. (This has occurred in the past.)

Flood pump and volute assembly is transported to the required repair facility where assembly is punch marked, labelled, taken apart, and rebuilt accordingly.

Remove the pump shaft with the drive hub, bearing hub, and impeller from the volute and place to the side.

Fully inspect the volute for wear holes and cracks and have the volute repaired if required. Cracks, if any should be welded up FIRST. Then excessive wear areas and small holes can be filled and built up with grey Devcon plastic steel material using a putty knife then a wear resistant hard red epoxy should be applied everywhere in the inside of the volute with a brush after the grey plastic steel material has set.

Excessive worn dips and craters can be filled up and smoothed out by applying the grey Devcon plastic steel, using a putty knife, then coating the entire outside of the impeller and nose cone and inside of the volute with a wear resistant red epoxy using a brush. 

Separate the drive coupling from the pump shaft. Be aware that there are “keepers” in the groove of the shaft to stop the drive coupling from coming off, as shown above. So remove “keepers” first then heat up and pull off drive coupling with the assistance of a power press. Inspect drive coupling for damage and repair if needed.

Slide Bearing Hub off Pump Shaft. Bearing hub should be bead blasted to make it easier to work on when it needs to be bored and plastic bushed. Mark on the flange the correct pump name and number so hubs don’t get mixed up with others.

Remove nose cone from impeller by removing the end bolt, then remove bearing nut that is holding the keeper plate cup in place. Keeper plate cup needs to brought out to expose keepers that need to be removed in order to pull the impeller off the tapered pump shaft.

NOTE: Removing keeper plate cup and keepers are not easy. Patience is key, and applying penetrating oil helps. Usually a couple of holes are drilled and tapped into the keeper plate then install threaded rods and make up a slide hammer with washers and nuts and slide the make shift hammer to pull out keeper plate.

Shown above is what the pump shaft looks like under that impeller. The tapered section of the pump shaft is where the impeller is seated on. Immediately front of the impeller, the groove is where the “keepers” are located. Those curved shaped keepers prevent the impeller from coming off the taper. Holding the keepers down in place is the keeper plate cup (not shown), then the bearing nut on the pump shaft is holding the keeper plate cup in place. 

When keepers are removed with no obstructions present, then the impeller can be pulled off the pump shaft using the powered puller press and the special puller plate (shown above) designed to be used when pulling off the impeller, otherwise there is no place to pull from. 

NOTE: The above image above shows threaded holes in the impeller. You can attempt to use these first to try and pull off impeller from the pump shaft. There has been a few instances when this method was successful. If it doesn’t work then used the power puller press method.

NOTE: Impeller needs to be heated with a tiger torch for a few minutes before a lot of pressure is used with the puller. This is not easy, impeller will be tight, so be mindful of the dangers involved in the process. Be sure to use the proper personal protective equipment at all times. The trick is to heat up the impeller hot enough and fast enough so it can be pulled off before the heat transfers to the shaft. If too much heat is applied for too long without any success, then stop heating and pulling and let everything cool down and try it again when it cooled back down to room temperature.

Component Rebuilding:

Pump Shaft: 

NOTE: If pump shaft is too damaged then use 4140 HTSR shafting as explained earlier to machine a new one. Otherwise proceed to replace old worn wear sleeve.

Pump Shaft Wear Sleeve:

Pump shaft will need the old wear sleeve replaced. It’s not advised to just machine the old worn surface off the existing wear sleeve otherwise there will no longer be any standardization of sizing which will lead to more confusion years later when flood pumps are needed to be overhauled again.

Determine original sizing by measuring the worn sleeve surface. It will only be one of the three sizes: 3.000 inch OD, 4.250 inch OD, or 6.500 inch OD.

Setup pump shaft in lathe. If no center exists on the tapered end then you will have to set it up in the steady rest, and machine one.

Machine end to accept a center if none exists.

Looking at the image above, there is only a couple of places to run the steady. The first option is the raised area on the right of the keeper groove if not damaged. Or the small area just right of the keyway ( It's on the taper, not ideal, but it works). If neither option is available, then a steady sleeve will need to be made and placed over the first option.

After center is machined then turn shaft around and drill and tap a 3/8" nc hole approx. 1-1/2" to 2" deep in the end of the shaft for a lifting eye. If one doesn’t already exist. 

After drilling and tapping end, turn around and machine off old wear sleeve. 

NOTE: What appears to be one long bronze sleeve is actually 2 shorter sleeves. There is 2 dimensions on the shaft. This is discovered when you’re machining the OD and pretty much removed the first sleeve and you start machining steel from the shaft, that means you’re too deep and must back off your cut to just remove the bronze and not the underlining shaft material. 

After sleeves are machined off then polish shaft with emery, including taper, keeper groove, threads, so fitted areas are free of burrs, dents, and gouges.

Check if threads are damaged with the nut. Chase threads if needed. Order a new nut if it’s too damaged.

Saw cut appropriate 660 bronze material needed to make the two sleeves plus a few inches to hold onto in the lathe chuck, plus a bit of room for parting off.

Machine bronze wear sleeves to have size on size to .001" interference fit on the shaft. Machine a 1/2" to 3/4" long lead in the bore that has about .002" clearance on the shaft. This helps to slip the sleeve on straight on the shaft when it is heated then shrunk on the rest of the way.

Leave approx. .030" to .050" on the OD of the bronze sleeves to finish machine after they are shrunk on and cooled off.

NOTE: It’s easier to heat up one bronze sleeve at a time, instead of rushing with both. Mark an arrow with a felt pen so you know which end of the sleeve has the machined lead in the bore so you can slip that end of the sleeve on the shaft to make it slip on easier.

Set up an inside micrometer .004" larger than the current bore size and have it close by to check the bore when heating the sleeve. Heat up the sleeve for a while then stop and see if inside micrometer easily fits effortlessly (to the point it’s sloppy) . When it is, then heat sleeve for about 10 seconds more, then using hot gloves , carefully pickup hot sleeve and slip on the first sleeve. Then repeat the process for the second sleeve. Don’t waste too much time when slipping the sleeves on or it may cool down and get stuck before reaching its proper destination.

Following these directions exactly seems to lessen the chances of getting the sleeves stuck on the shaft before they have bottomed out.

After the shaft has cooled down, then setup pump shaft back in the lathe, and finish machine the bronze wear sleeve to the determined OD size, which will be either 3.000" , 4.250" or 6.500" depending on the size of pump shaft. Polish OD with a scotch bright pad for a nicer finish. Because these pumps use packing to seal, a finish size of .002" over or under the nominal size will be fine. When pump shaft is finished, mark the name of the pump and number if it is not already marked. It’s not good to get anything mixed up. 

Bearing Hub History:

History: Years ago these bearing hubs were using a phenolic board material that was cut into wedges and fitted into the grooves in the hub. When worn out, the old wedges would be removed and new ones put in place. The hub with the new wedges would be placed in a 5 gallon bucket full of water so the wedges would swell up and be tight. Then the hubs would be setup in the lathe and bored out with clearance to ride on the pump shaft wear sleeves.

There are still flood stations that still are running the phenolic material, and over time as the flood pumps are overhauled, the bearing hubs will have their phenolic removed and grooves opened up into a bore large enough to accept the new plastic bearing material Vesconite and Ertalyte.

The reason the phenolic material was abandoned, is because the newer phenolic material wouldn’t stop swelling, and over time this would cause the bearing hubs to seize up on the pump shaft so it couldn’t turn. Crews would go and use large pipe wrenches to try turn and free up the shaft from the bearing.

Different methods were used to try and limit the swelling such as lengthening the time the bearing hub would sit in the water before machining. Then water, machine bore a bit, then water again, and again, and so on. Every time, no matter the process the phenolic would continue to swell. The manufacturing process for that phenolic must have changed over the years, because the older phenolic material would stop swelling over time, but the newer material wouldn’t.

Regardless, the new plastic materials are easier to work with, less time consuming, and it doesn’t swell up and seize on the pump shaft.

Bearing Hub:

NOTE: If bearing hub is too damaged, then use ductile cast iron as explained earlier to machine a new one. Otherwise proceed to bore and bush old bearing hub. 

Setup bearing hub and bore out. Either you’re boring out what used to contain phenolic wedges or a worn out bearing plastic bushing, in which case, the old worn bushing can simply be pressed out, and then a new plastic bushing can be made.

If you’re boring out what used to contain phenolic wedges, then you can bore it out until the bore is round, which will remove the wedges and the grooves which held the wedges. This older style will contain a end plate that would help keep the wedges from creeping out. Just machine the whole thing out, the remaining end plate will fall off when there is no more bolts left holding it in place from opening up the bore so much. An end plate is no longer required when using the plastic bushing style.

NOTE: If you use coolant while machining out the old phenolic it will keep the dust down. It does have an unpleasant odour.

NOTE: Check the OD of the plastic bearing material you are using. You may not be able to fully clean up the bore of the hub, because the OD of the plastic may not be large enough after the OD of the plastic is machined. Most of the time there are still some remnants of the grooves still left, and that is fine. There is still plenty of surface area cleaned up to hold the plastic bushing in place. If even larger plastic was used so the bore could be fully cleaned up, then the wall thickness of the bearing hub would be getting quite thin. 

After boring out the hub, record your measurement. Next, you need to find out the measurements that you need to machine the plastic pump bearing.

This information is found at vesconite.com where you can input the known measurements and then the sizes you require will be generated.

NOTE: The same site is used when also using Ertalyte plastic bearing material.

When you have accessed their homepage press the “machining calculator” button.

Then press the “pumps design a bearing” button from the imperial section.

Then input your known information:

Below is an example of results shown after inputs are given. In this example the housing was bored to 5.667". The pump shaft wear sleeve is going to be 4.250", and the bearing housing length is 7.625". The pump is oriented in the vertical position so there really isn’t weight present for mass supported area to fill in. You can fill in the RPM area to 900 rpm if you desire but there isn’t any difference in the result sizes. (Tried with rpm and no rpm and the results were the same.)

NOTE: Be aware that the ID shown is NOT the fitted inside bore size. This is the size given if the plastic bearing is made, and only pressed in later assuming it will exactly shrink to the fitted inside diameter. (Don’t do it this way).

There has been confusion around these measurements in the past. Assumptions about excess clearances were made that bores were finished to the ID size which is .018" larger than the fitted inside diameter size which already has .016" clearance for a total clearance of .034" when they were actually finished to the fitted inside diameter. This happens when the sheet is not fully or properly read.

The best way to proceed is to leave the plastic bushing bore at least .050" SMALLER than the fitted inside diameter. Machine a small lead on the OD of the plastic bushing about 3/4" long .002" under the housing diameter so you can start the bushing in the housing straight, then fully press the bushing in using a hydraulic press. Then setup the bearing hub in the lathe and finish the bore size to the FITTED INSIDE DIAMETER.

Then machine your water grooves.

Then mark the pump name and number on hub so nothing gets mixed up.

Pump Shaft Key Modifications:

There are two keys on the pump shaft, and these two keys can sometimes be difficult to remove. To make it easier in the future to remove these keys, drill and tap two 1/4" nc holes near the ends of each key, with set screws installed so the keys can be jack lifted out of the keyways next time. 

DO A DOUBLE CHECK:

Check all the sizes on the pump shaft wear sleeves and bearing hubs ensuring they are correct.

Make sure the drive shaft mounting faces and spigots are flat, smooth and dent free.

Make sure drive hubs mounting faces and spigots are flat, smooth and dent free.

Check volute and impeller to be sure everything appears to still be crack and hole free.

Installing Impeller on Pump Shaft:

This is another step that isn’t an easy task. Impeller needs to be heated up, and seated back, high enough on the pump shaft taper to fit the keepers back in their groove. This process may take a few attempts before being successful.

Then install keeper plate cup and bearing nut, tightened up against it. Finally place the impeller nose cone back on secured with the end bolt.

NOTE: Looking at the image above, remember that the inner face of the impeller needs to be flush or slightly further up the taper in order for the keeper keys to fit in the groove. 

Shown above is the pump shaft with new machined seal sleeve with impeller and cap installed. (Bottom of the pump shaft isn’t seen because work table has a hole in it.) Red hard surface epoxy is brush coated on the impeller and nose cone. 

Balancing the Pump Shaft:

Completed pump shaft with impeller and nose cone installed (coated with red epoxy earlier) is then sent out for balancing at 900rpm. After it comes back from balancing, there maybe a few areas that will need a brush coating of the red epoxy when places on the impeller were ground away for balancing purposes. 

Recap Checklist:

At this point in the flood pump repair guide, it would be prudent to take an account of the work completed. If all the required tasks are finished, then it will be time to start planning the installation of the newly refurbished components at the flood station. 

NOTE: It also needs to be known if any other work needs to be completed on the flood station itself unrelated to the actual flood pump. This could possibly alter or delay the timeline, and hinder the installation of the completed flood pump components.

1) Electric motor overhaul or repair if required is completed and is currently in good condition and ready to be used once installation of newly refurbished components are finished.

2) Cracks and holes (if any) repaired in the impeller, volute, and impeller nose cone.

then coated with hard finish wear resistant red epoxy.

3) Drive shafts are repaired if damaged and balanced at 900rpm. Hanger bearings (if any) have been replaced and are ready for usage.

4) Drive hubs free from damage and have dent free mounting faces. Drive hub keepers are in good condition and ready for use.

5) Pump shaft is completed with new seal sleeve. Pump shaft is drilled and tapped in one end for lifting eye, plus any other repairs required.

6) Bearing hub is completed with new plastic bushing plus any other repairs required.

7) Pump shaft keys are drilled and tapped for jacking screws to make removal easier in the future.

8) Impeller keepers and the keeper plate cup and bearing nut are in good condition and ready for use.

9) Pump shaft with impeller and nose cone is balanced at 900rpm. Impeller is touched up with red epoxy in spots ground away in the balancing procedure.

Installation:

Installation will require extra planning, with the proper coordination of additional staff from different departments along with a boom truck working constructively together on the same timeline to successfully and safely lower and connect all the newly refurbished flood pump components together as they were correctly punch marked and labelled at the beginning of this project. 

Alignment:

It is not enough to simply connect all the newly refurbished pump parts together and expect it to magically run smoothly. Flood pump components must be aligned correctly starting from the bottom up. This can be a time consuming process but the result will be a smooth running worry free flood pump for years to come, without the excessive wearing of bronze wear sleeves and plastic bearing sleeved hubs, and hanger bearings prematurely. A properly aligned flood pump will turn freely and will be smooth turning with no obstructions or side loads to stop it from turning. 

NOTE: The maximum allowable tolerance for misalignment is .003".

Someone must be competent in their capabilities using laser alignment equipment 

Alignment must happen from the bottom up because the flood pump with volute can’t be moved, but hanger bearing and even the mounting of the electric motor can be moved accordingly. In fact, there has already been instances at flood stations where this has taken place.

This is probably the result of the ever so slight shifting of a pump station over the years. It must be remembered that even a slight small movement or shifting in the building can be greatly exaggerated throughout the distance of the station from where the electric motor and flood pump are located, resulting in a seemingly large misalignment.

The image shown above is an example of misalignment. Drive shafts with hanger were properly aligned, but as a result of “shifting over time” the drive shaft flange is offset from the electric motor drive coupling causing misalignment. Therefore the motor mount area was moved to align with the drive shaft flange. 

NOTE: Sometimes the mounts for the hanger bearing will need to be moved and possibly shims added for proper alignment as shown above. 

NOTE: Sometimes height is affected as well, and may require the machining of a shim plate or mount to have the shaft flange face and electric motor drive coupling mount face at the same height. 

Alignment Order Diagram: