Filbert Pump Maintenance and Repair Instructions


Filbert Pump Base Repair Instructions.

This repair is easy, but please read the instructions before attempting the repair. I know this advice is contrary to all good judgement, commopn sense, and human instinct. However, if you don't want to make a mess of something, read the instructions first. The instructions are purposly made short for those of us, myself included, who know everything, and wouldn't admit it even if we didn't, but we do. Alright, at least read the next line...

Caution: The tube is lubricated with silicone grease. To keep the tube clean, leave the bag on the tube until you are ready to insert the piston.

Replacing the pump tube and base:

1. Remove the three screws under the handle and remove the top half of the pump from the large tube. Put the screws in a safe place because you will re-install them shortly.

2. With a tissue, wipe off the loose dirt and grime from the piston assembly. The piston assembly does not have to be spotless but do remove the big chunks of caked dust. If you remove the rubber seal be sure to replace it in the same orientation, which is with the open side toward the bottom of the pump.DO NOT WASH THE SEAL WITH SOAP AND WATER, it will remove the silicone lubricant and adversely affect the operation of your pump. Simply use a tissue or paper towel to wipe off the excess crud.

3. Insert the piston in the new tube:


Look at the picture and note the location of the large hole.

When you put the piston in the new tube insert the piston at an angle and push it in as far as it will go while keeping it at an angle. The orientation of the piston relative to the large hole is important, and will prevent the piston lip from turning over when the piston is straightened.

When the piston cannot be pushed in any farther tip the piston while pulling it out ever so slightly. When the tube is straight pull it out just a little bit more, but not past the large hole, to make sure the piston lip is not turned over.

Next push the piston in the tube about 6 inches and pull it out about 4 inches. This will further serve to straighten the piston lip in the event is turned over.

Now, you can push the piston in all the way, align the four holes in the large tube and re-install the screws. Do not make the screws too tight otherwise, the threads will pull out of the plastic.

Your pump should now be ready to inflate those balloons.

If you have, any questions give us a call at 518-765-4585.

If the screw holes do not line up, fear not, the repair is now more complicated, but still simple. The reason the screw holes do not line up is that some of the first pumps of the new design, yours is one of them, had the screw holes drilled by eye. This is because the jig to drill all holes the same was not completed at the time your pump was built. In fact, you do not need any screws at all to use the pump with the new base, the handle will not come off in use. It might come off when you carry it, although that is not very likely, but it will not come off in use, so if you are short of time you can put the new base on your pump and do your gigs with confidence. If you do not get this repair completed before your next gig put the pump together with the new base, line up the big holes, and do your gigs, then finish the repair in your leisure time.

Here is how to solve the problem.

Gather your tools. You will need a drill, a 5/32 drill bit and an 11/64 drill bit, and you will need a Phillips screw driver, a #2 Phillips fits the screws best.

First put the new base on the pump and push the piston part way in and stop. Now take three or four paper towels and stuff them into the pump around the push rod. This will keep plastic chips out of the pump when you drill the new holes.
Now put the handle on the large tube and line up the large holes in the tube and the handle. Next find the screw hole that is the closest to being in line and line those holes up. Now look to see how much of the large hole is covered. As long as at least half of the large hole is open the pump will function properly with no noticeable difference because it was designed with the breather hole larger than necessary just in case it became covered or partially plugged. In fact, the pump will operate with the breather hole completely plugged, and the only noticeable effect will be that it will be slightly more difficult to lift the piston.

The next thing to do is to put a screw in to anchor the tube and handle together so they won't move.
At each of the other two screw holes in the handle, and using each of those holes to guide the drill, drill a hole in the tube with the 5/32 drill. Now there should be three hole in the tube that line up with each of the screw holes in the handle. With a pencil put an X mark on the tube under each of the holes you just drilled and an "O" mark under the hole with the screw in place. Three holes, three marks.

Next, remove the screw from the handle and remove the handle, but do not pull the piston out just yet.
Next, drill each of the holes with an "X" below them using the 11/64 drill. This will make these holes slightly larger.
Now take a screw and screw it in each of the holes with an "X" beneath it. You will have to push as you turn the screw to get it started. Push as you turn the screw until the screw comes through to the inside of the tube. Then remove the screws from the tube and, while laying the pump on its side, remove the piston. The paper towels should pull all of the plastic chips from the tube as the piston is removed. Inspect the inside of the tube and remove any chips that slipped past the towels and the piston.
Notice if there are any burrs on the inside of the tube at the holes you drilled. Remove these burrs with a knife held flat against the tube inside wall, and remove any remaining chips from the inside of the tube.

Now, put the piston in the tube about half way and move it up and down a few times to be sure the piston lip is not turned over on itself, then put the piston all the way in. Now line up the screw holes in the handle with the three marks on the tube, making sure the large holes line up as they did when you drilled the holes. You should now have the three screw holes in the handle lined up with three screw holes in the tube. Put in the three screws, snug but not tight, because you are working with plastic and too tight strips the threads from plastic, and you are finished.

Wasn't that easy? If you have any problems give us a call, 518-765-4585.


Top Cap Replacement Instructions

Remove the old top cap from the top disk. This can be accomplished by inserting the edge of a table knife, or thin screw driver blade, in the crack that is in the cap. Once the knife edge, or screw driver blade, is in the crack move the knife, or screw driver, from side to side which should open the crack and loosen the cap from the the top disk. Once the cap is removed you will see remnants of glue on the mating surface of the top disk. So that the new top cap fits properly it will be necessary to remove as much of this glue as possible, without removing the mating surface. In reality it will be necessary to remove a slight bit of the mating surface, but remove as little as possible. If too much of the mating surface is removed the top cap will be too loose and will tend to come off when inflating balloons. We suggest using the flat edge of a knife and scrape the glue away from the mating surface of the top disk. Remove the big pieces of glue. The thin film that remains will most likely not interfere with the fit of the top cap.

Once the mating surface of the top disk is cleaned, remove all dust and pieces of plastic from the top disk. Place the valve disk on top of the top disk, with beveled side down, and place the top cap over the valve disk. Using the heals of both hands, one on each side of the nozzle, push down on the top cap until it seats against the top disk. This is a tight fit and requires considerable force to properly seat the top cap.

Once the top cap is in place it should stay put. If it comes off again, or if the fit is too loose, a narrow piece of paper wrapped around the mating surface of the top disk will make the fit much tighter. It may be necessary to experiment with different amounts of paper to determine the correct amount needed to keep the top disk in place. It won't take much, so start with a little bit and work up to a tight fit.

Remove the nozzle from the old cap by first wrapping it with a piece of leather, an old belt or leather glove, and then gripping the leather covered nozzle with a pair of pliers and rotate the nozzle counterclockwise to unscrew it from the old cap. The leather will protect the nozzle from getting scratched by the jaws of the pliers.

When putting the nozzle in the new cap, screw it in until it stops. Then, wrap it with a balloon and tighten it by hand as tight as you can get it. That should keep it from getting loose when using the pump.

If you have any problems please give us a call at +1 518-765-4585.


Lubricating the Filbert Pump

The squeak you may hear when you inflate a balloon with your pump comes from the pushrod moving through the hole in the handle. Put a small amount of Filbert Pump Grease on a paper towel and, with the pushrod pulled all the way up, smear it on the pushrod. A thin film is all that is needed to stop the squeak.

As a Rule of Thumb, unless you inflate more than 4000 balloons a month your new pump should not need any additional lubrication for about a year. This is one of those “Rules of Thumb” things and many things effect the outcome of a Rule of Thumb.
As the piston moves up and down inside the pump the inside of the tube dusts off and the piston seal collects that dust. When the piston gets too dusty it starts to leak. This is a very gradual thing and not a real problem.

The ruler by which you measure the performance of a Filbert Pump is the Qualatex 260. If it still inflates a Q260 in one stroke than you do not need any additional lubrication.

If it is determined that you do need to lubricate you Filbert Pump here is what to do:
Remove the three screws under the handle. Remove the handle from the large tube and remove the pushrod from the pump.

Next, remove the rubber seal from the piston and clean both the seal and the piston. If you push on the seal with two fingers, the opposite edge of the seal will move away from the piston and you will be able to grab it with your fingers and stretch it over the edge of the piston. When doing this note the orientation of the seal relative to the piston. The seal has an open side and a closed side. The open side faces away from the nozzle. DO NOT use tools to grab or stretch the rubber seal, and be careful not to bend the edged of the piston. If you do bend the edges of the piston simply bend them back so that they are flat and parallel with each other.

Using a paper towel, remove all the old grease, crud, dust, food, and bits of balloons from the seal and from the piston. Once the seal is removed from the piston you will see some grease around the center hub of the piston. If you do not have any new grease save a little of this old grease to lubricate the piston once everything is clean. DO NOT WASH the seal, just wipe it clean with a paper towel. Do a good job of cleaning the piston and seal. This will directly effect the performance of your pump.

Once the seal is clean stretch it just a bit and bend the thin outer edge of the seal away from center. This will refresh it a bit and give it a better fit in the tube.

With a paper towel or rag on the end of a stick, clean the bottom of the large tube, making sure to remove whatever crud might be at the bottom of the tube.

Now put a little grease on a paper towel and rub the grease on the inside of the large tube. If your hand is small enough to reach inside the tube use your hand, otherwise use a stick to rub the grease on the inside of the large tube. A thin film of grease is all that is needed, so use the grease sparingly. If you do not have any new grease you can skip this step.

Now that you have grease on your fingers, apply a thin film of grease on the edges and flat side of the seal. Use the saved old grease from the center of the piston if you do not have any new grease. A thin film is all that is needed, so use the grease sparingly.

Now, stretch the seal over the piston with the open side facing away from the nozzle. Once on the piston the seal should be loose and move freely on the piston.
Put the piston back in the large tube by tipping it at an angle and putting one edge of the piston in the tube. Then straighten the pushrod and the other edge of the piston will tip into the tube. Be careful that the lip of the piston seal does not get folded over, as this will cause it to leak and bind in the tube. You should now be able to push the piston to the bottom of the tube.



Now place the handle over the end of the large tube and align the large holes in the handle and large tube. The three small screw holes should now be aligned. When replacing the screws only tighten them until they are just a little snug, any tighter will cause the plastic threads to strip. Be careful!
Your Filbert Pump should now be ready for another years worth of inflating balloons.

If you have any problems with this maintenance give us a call at 518-765-4585, or send us an email at, and we will sympathize with you.


Handle Replacement

First, read the complete instructions before beginning the repair. I know this is against all natural instincts, but grit your teeth and do it anyway.

The repair should be made while the pump is resting on its side. This will keep the glue from dripping on the pump handle or running down the pushrod and permanently gluing the pushrod to the handle.

What you will need to make the repair:

You will need some means of cutting the pushrod. I recommend a hacksaw with a 24-tooth blade.

You will need a small can of PVC cement marked REGULAR CLEAR. We use Oatey brand available in Home Depot, Lowes, or most hardware stores, but any brand will work.

You will need some paper towels and a tissue. You will need a thin pole or coat hanger.

Put some newspaper on your work surface and be careful with the glue. It will permanently damage most plastic surfaces.

Now to the repair:

First remove the three screws located under the handle. Put the screws in a safe place, as they will be used again.

Remove the handle and pushrod assembly from the pump base assembly, and set the base assembly out of the way.

Make a pencil mark on the pushrod at a point 3/4 inches, 19 mm, from the bottom of the top assembly.


Cut the pushrod at the pencil mark. Make the cut as square as possible. This is not critical but the squarer the better.



Remove the broken handle and set it aside.

Next, remove all the plastic chips from the cut ends of the pushrod with a knife or similar sharp instrument. Blow out the plastic chips from the top assembly.

Take a tissue and stuff it in the piston end of the pushrod. Using a long thin pole or straightened coat hanger, push the tissue until it exits the pushrod at the cut end. This will remove all of the plastic chips from the pushrod.

Now is the time to clean the piston and piston seal, following the instructions included with the provided grease.

For the next two steps you will need the new handle, the top assembly, the provided coupling, and the pushrod,




Place the new handle on the pushrod and slide it to the piston. Be sure the handle is facing in the proper direction on the pushrod. The top of the handle should face away from the piston.

NOTE, You must do the next two steps quickly as the PVC Cement dries very fast. When applying the cement, the cement thickness should be more than a thin film but not so much that it runs or drips.

Apply a small amount of PVC Cement around the inside of one end of the provided coupling, and, with a twisting motion, immediately push the glued end of the coupling over the short piece of pushrod extending from the bottom of the top assembly. The coupling should touch the end of the top assembly.



Is the handle in the proper position on the pushrod? The top of the handle should face away from the piston.

In a similar fashion, apply a small amount of PVC Cement around the inside of the other end of the coupling, now attached to the top assembly, and, with a twisting motion, immediately push the coupling over the end of the pushrod. Push the coupling as far on the pushrod as it will go, about 1 inch, 25.4 mm.



While the glue is drying, clean the pump tube and be sure to remove the bits and pieces of stuff from the bottom of the tube. Apply a small amount of the provided grease to a paper towel or cloth and wipe the inside of the tube with the grease. Use the grease sparingly, as a little bit goes a long way.

Put the piston in the cleaned large tube by inserting one edge of the piston in the tube at an angle while holding the pushrod at an angle to the large tube. Straighten the pushrod such that the piston tips into the tube until the pushrod is in line with the tube. This will prevent the piston seal from jamming in the tube.



Allow the glue to dry for an hour or two and your pump repair will be complete.

If you have any questions or problems contact me via email at, or by telephone at +1-518-765-4585 and I will try to help.

Re-Glue Base to Large Tube Instructions
What you will need to make the repair: A philips screw driver, a knife or putty knife or some sort of scraper, a piece of medium grit sandpaper, rubber gloves, Naphtha, paper towels, and some epoxy glue.

I would use a ten minute or fifteen minute cure time epoxy available in DIY stores such as Home Depot, Lowes, or most hardware stores. Do not use five minute epoxy because the work time is too short.

Naphtha is available at the same places that sell the epoxy.

Naphtha is inexpensive and is great for removing sticky stuff and grease or oil from things that get sticky stuff on them, such as kids and everything that kids touch. Kids are really robotic sticky stuff dispensers disguised as cute little people in cheap suits. Naphtha in small quantities doesn't harm most surfaces and dries fairly fast. Every household, particularly those harboring little people in cheap suits, should have some naphtha kicking around. Naphtha may irritate your skin, or your kid's skin, so be cautious and use common sense. Be warned, however, Naphtha is flammable, which is why it is used as lighter fluid.

We like the Ronson brand lighter fluid because it comes in a dispenser that doesn't leak and dispenses only a little bit at time.

Here is how to go about making the repair:

First, remove the three screws under the handle and remove the handle and piston assembly from the large tube and set aside out of the way.

Note, the next step should probably be done outside because of the fumes from the Naphtha you will be using to clean the parts.

Now is the time for the rubber gloves.

Using the knife and/or scraper/sandpaper, clean off any loose glue from the inside of the base and the end of the large tube. Then make a loose ball of clean paper towels and push the ball through the large tube several times to clean any loose debris from the inside of the tube. Set the large tube aside.

Now remove all the loose stuff from the inside of the base.

Next, use naphtha and some paper towels to degrease the inside of the base and the outside end of the large tube.  This will remove the silicon lubricant and allow the epoxy to make a good bond when it cures. Use enough naphtha to do a good job degreasing the parts. If there is any silicone on the parts the base will come off again. If there is no silicone on the parts the base may still come off again, however it will take a lot longer.

Wearing clean rubber gloves, not the ones worn while cleaning the parts as they may have silicone on them, mix the epoxy per instructions.  With your finger smear a thin film of epoxy on the inside sidewall of the base and a litter thicker film on the end of the large tube.   With a gentle twisting motion push the large tube in the base until it reaches the bottom of the base.  Now wipe the excess epoxy from the joint between the tube and base and you are done.  Set the base and large tube aside for at least 24 hours while the epoxy cures.  Some epoxies take 72 hours to fully cure so you might want to take a quick look at the instructions.  Let the epoxy cure fully and the repair should last a long time.  If you work the bond too early it might not last very long.

While you are waiting for the epoxy to cure clean the piston and seal of your pump.  Those instructions are on the filbertpump web site under the Maintenance button.

If you have any problems give a call or send an email and I will sympathize with you.

Good Luck,


Last Update 6-1-2016