So you’ve found grandma’s old soda siphon, or picked up one for a price you could not refuse on the flea market. Your desire is to make soda water in it. What next?
Well, I have good news for you. Hungarian siphons were probably made to last forever. They can usually be restored to be fully functional with some love, a thorough cleaning and replacement of a few parts. If you take good care of them, they will continue to work without problems for many years. The only difficulty may be the possible lack of spare parts in the future.
The method described on this page is based on my own experience and does not constitute as professional advice. I cannot accept any responsibility for any damage or injury that may occur during the repair or use of the siphon. You perform the steps described on this page entirely at your own risk.
You now own a household appliance that could easily have came off the production line 40-50 years ago. Needless to say, it’s worth attempting to assemble it with due respect and care. My principle is to try to keep any original part where reasonable, and only replace something when it is worn out or when aesthetics absolutely demand it.
Necessary tools
Option one: Hungarian soda siphon repair kit (sold by Szász Kft.)
There is some confusion about this product, but I will try to make it easier for you. The repair kit is available in a version having 10 parts (barcode 5997969308207) and another version with 6 parts (barcode 5997969308214). I have also come across a kit with 9 parts. Be careful not to buy the cream whipper or plastic soda siphon repair kit, as the packaging is very similar!
It’s worth buying the kit with 10 parts, because the price difference is not substantial. If you see any blue rubber parts in the package, it is the most modern version of the kit and you can safely buy it. If there is no blue rubber part inside, then it may be an older item, but you can get by with that too, it’s just a bit more complicated.
If you don’t have a spanner tool for the siphon, you should look for a package that includes it: it’s a metal wrench in the shape of a winding key, which is the largest part in the package. You’re sure to find one in the 10-piece kit that includes blue rubber parts. You can do without a wrench, but it’s less convenient.
The 6-piece set will be missing the puncture pin and will not include a spanner tool. It’s almost always worth replacing the pin, so if you can, go for the 9/10 piece kit.
The kit can be purchased in larger supermarkets in Hungary (e.g. Auchan) and specialised household stores (e.g. Vasedény), and can also be ordered online.
An alternative: LISS Retro siphon parts
Most of the parts made by Szász Kft. and parts of the “Retro” line of soda siphons manufactured by LISS Zrt. until 2018 are interchangeable. I have listed below the parts in the 10-piece repair kit and their LISS-branded counterparts:
| Szász part | LISS part |
| Valve rubber (A01) | 9107 Valve rubber |
| Puncture pin (A03) | 9002 Puncture pin |
| Neck rubber (A04) | 9103 Neck rubber |
| Pipe rubber (A13) | 9013 Pipe rubber |
| Pill rubber (A15) | 9015 Valve seal |
| O-ring (A16) | 9016 O ring (6×3 mm) |
| Valve stem (A17) | 9017 Valve stem |
| Valve needle (A48) | 9048 Valve needle |
| Spanner tool (A50) | 9050 Spanner tool |
| Siphon head screw (A05) | 9005 Siphon head screw |
LISS parts can be ordered online.
Not recommended alternative: New siphon head
It goes against my principles, but for the sake of completeness I have to mention that Szász Kft. also sells a complete siphon head (Hungarian soda siphon head, barcode: 5997969308016), which you can immediately put on the old Hungarian aluminium siphons instead of the old one. However, you probably didn’t arrive to this page because you’re searching for the royal road. If you were, you would have already ordered one of the modern soda siphons. There is little point in keeping an old aluminium flask that has been around for half a century alive with a new head when the “soul” of the old unit can be perfectly refurbished with some love. If your goal is to keep using grandma’s soda siphon, keep reading!
If you don’t have a spanner tool: a buttering knife and a large Phillips head screwdriver
You will use the knife to unscrew the siphon head screw and the Phillips head screwdriver to remove the gas inlet valve. Prepare the largest screwdriver you can find, and make sure the stem is long enough to reach into the valve without getting stuck. In other words, a short screwdriver with bits may not be adequate for the purpose.
To remove the neck rubber: tweezers
Many times you are only able to remove the neck rubber broken into pieces, but even with an intact rubber, a pair of tweezers can help.
To remove the old valve rubber: a thick crochet hook
The valve rubber is almost always hardened and brittle in well-used siphons. This component gets easily stuck inside the head when the gas inlet valve is unscrewed and is very hard to access. The best tool for pulling it out is a crochet hook of suitable thickness. The proper thickness is about 4-5 mm, if thicker than this, it will not fit inside the valve rubber.
To unscrew the clamping screw: pipe wrench
The clamping screw at the top of the siphon head can be a hit or miss. Sometimes it can be easily unscrewed by hand, but sometimes it takes a lot of force to get it to move. This is where a pipe wrench comes in handy.
For pushing out the lever pin: Metal pen refill
The lever pin is usually firmly stuck in the plastic siphon head and does not come out easily. It’s not hard to knock out with a hammer and a punch, but it’s even easier to disfigure the head with a wrong move. I therefore recommend an expendable metal pen refill for the purpose. If you don’t bend it, a good quality (steel-tipped) refill will continue to work afterwards, weaker refills will be ruined by this. A metal refill is necessary because a plastic one will break and is not capable of exerting the necessary force.
For lubricating rubber parts: household silicone grease
It’s not essential that you use it, but moving parts, especially if they are made of rubber, should be lubricated. It prolongs the life of the seal and is good for the sealing ability. Remember, the material is in contact with your drink. It is worth using a product that is food safe, such as T-Silox OXETT A2.
For descaling the bottle: 20% vinegar and a bottle washing brush
If you have a peek inside an old siphon, you can often see interesting stalactite formations. Vinegar is perfect for removing scale. It also helps you to wash your siphon thoroughly, as you’ll want to do this many times after a vinegar treatment to ensure there’s no aftertaste…
May be necessary: Neck rubber
If you have bought a repair kit that does not include a blue neck rubber, you will definitely need one. The alternative is to buy a newer, shorter version of the puncture pin, which can be used with the old neck rubber.
May be necessary: Siphon pipe
Replacing the siphon pipe is necessary if you are not happy with the condition of the old pipe found in the siphon. That is, you do not wish to consume soda water that touched the pipe.
May be necessary: Level pipe and level pipe extraction tool
In many cases, the level pipe is missing from old siphons. If it is not missing, decide whether you want to continue using it or replace it based on its condition.
If you’ve made it this far and you’ve got everything on the list, that’s half the battle! The operation is not difficult, if I was able to do it, you can do it too.
Disassembly
During the disassembly process, parts must be turned counterclockwise to loosen.
1. Unscrew the siphon head from the flask. Pull out the siphon pipe.
2. If the bottle has a plastic level pipe, pull it out. You can remove the old type pipe with a level pipe extraction tool. If you have the new type, you can remove it by inserting the end of the cartridge holder in the tube, turning it clockwise and pulling it out.
3. Fill the flask up to the neck with 20% vinegar and set it aside for a day to let the vinegar descale it.
4. Unscrew the cartridge holder from the siphon head.
5. Use the wider end of the spanner tool – or the blunt end of a buttering knife if you don’t have a tool – to unscrew the siphon head screw.
6. Use tweezers to pull out the neck rubber (or, in the case of old, worn-out neck rubber, dig out the remnants), or gently pry it out with the tip of a knife.
7. Use the narrow end of the spanner tool to tilt the pin to one side or the other. You do this just to loosen it so it falls out by itself when you turn the thread downwards.
8. Using the narrow end of the spanner tool again, find the keyway in the valve needle with firm moves. You should push the wrench into the opening as far as you can. Due to the manufacturing tolerances of the plastic part, this is not always an easy task. If you do not have a spanner tool, you can use a Phillips head screwdriver to remove the valve. Unscrew the valve and then pull it out of the opening.
9. If you manage to pull out the valve needle but the valve rubber remains stuck inside the head (which it usually does…), you can remove it with a crochet hook. If it’s your first time, it will take a few tries. Don’t give up!
10. Unscrew the clamping screw at the top of the siphon head. If necessary, use anti-slip material or grip it with a pipe wrench, but be careful: the locking screw is a visible part of the siphon head and can easily be disfigured. Remove the spring under the screw from the siphon head.
11. Push the lever pin out with the tip of a metal pen refill. Once you have enough of it outside that you can grip, you can pull it out, no need to torture the pen refill any further. The less maintenance the siphon head has received, the more difficult the operation is.
12. After removing the lever pin, the lever itself can simply be pulled out of the siphon head.
13. The best tool for removing the valve stem is the push lever itself. The pointed end can be used to push the valve stem upwards out of the siphon head. When you have enough of it out to grip, grab it and pull it out by hand.
14. All removable parts are out of the siphon head at this point. The exterior should be cleaned gently, without scrubbing, using some dishwashing liquid. Unfortunately, the shiny polyamide material is easy to scratch, so care should be taken. The inside of the siphon head can be cleaned by rinsing it thoroughly with detergent several times. The push lever should also be cleaned, as it is the other visible part of the soda siphon besides the clamping screw. Modern soda siphons are made of plastic with a plastic lever, so the metal lever is one of the distinctive features of vintage Hungarian siphons.
Replacing parts
Rubber parts are meant to be replaced with every maintenance. The colour of the new part is irrelevant, I have seen red, black, white and blue rubber and silicone based seals. They perform equally well, with a possible difference in their durability. This is something worth discussing after a few decades 🙂
For rubber parts, if a part is included in the repair kit, consider replacing it even if the old one is in good condition. Safety first – it’s not worth taking any risk to save a few hundred forints. However, always save the old part if it is in good condition. Everything is easy now, as there are still replacement parts available to be bought, but that may not always be the case.
Check which of the rubber parts are due for replacement:
Replacing plastic and metal parts is not always necessary. However, the puncture pin is a very important wearing part, so consider replacing it at every maintenance.
Decide which of the plastic and metal wearing parts you wish to replace:
Prepare replacement parts, discard worn parts.
Assembly
1. Replace the O-ring and the valve seal on the valve stem. Apply a thin coat of silicone grease to the rubber parts, then push the valve stem back into the valve bore with the lever slot in the correct orientation.
2. Push the lever back in place, fiddle with it until it snaps into the slot of the valve stem and moves into its normal position.
3. Push the lever pin back into its bore by hand and carefully push it further into the siphon head using a hard surface (e.g. a table top). If necessary, nudge the lever slightly to keep it out of the way. You can push the pin back almost fully with the table top, and without damaging the siphon head. It is not essential that the pin sits exactly in the centre of the hole, but if it does bother you, you can adjust it with the tip of the pen refill you used for pushing it out. Be careful though.
4. Check that the pin and lever work as expected: if you can operate the lever, everything is placed correctly.
5. Replace the spring in the spring housing and then screw back the clamping screw into its place. If necessary, use the pipe wrench to tighten it.
6. Check the lever again, the spring should now work as usual. Be amazed at how easily and smoothly you will be able to dispense soda water thanks to the new parts and silicone grease! (A little backlash of the lever is acceptable.)
7. Remove the old valve rubber from the valve needle, then apply a thin coat of silicone grease on the surface of the needle where the valve rubber will fit. Slide the new valve rubber onto the needle until the end is flush with the end of the valve needle and the wide collar sits correctly on the valve. Also apply a thin coat of silicone grease to the outside of the new rubber, especially on the collar.
8. Push the valve needle in its place, then use the spanning tool or a Phillips head screwdriver to screw it in firmly, but do not over-tighten it.
9. Pick up the new puncture pin and put it in its place. It is important that the base of the needle sits in the right position, firmly in its place. If it is crooked or you can easily tilt it with your fingernail without any resistance, it is not in place! Use the narrow end of the spanner tool or a screwdriver to adjust the round base of the pin until it snaps into its place. If you can’t easily move it out of position with your fingernail and it’s not misaligned, the installation is correct.
10. Apply a thin coat of silicone grease to the rimless end of the new neck rubber. Then press the rubber firmly into place with the rimless side facing inwards.
11. Use the spanner tool or the blunt side of a knife to turn the siphon head screw into place. Make sure that the rubber is still straight at the end of this operation and that it is not wrinkled.
12. Replace the pipe rubber on the siphon pipe, or if necessary you can also replace the pipe. Cut the pipe to be long enough to reach the bottom of the siphon. You can test the exact length by cutting it slightly longer than necessary, then putting it in place and threading the head onto the siphon. The “excess” will extend over the top of the pipe rubber. If you are installing a new pipe in the siphon, cut the bottom of the pipe in a V shape on both sides, as it is standard practice.
13. After soaking for a day, wash the siphon flask thoroughly with drinking water using a bottle washing brush. When you are satisfied with its cleanliness, place the rinsed level pipe into it. Store the siphon pipe with the pipe rubber and the restored siphon head removed until everything dries fully.