How to Restore an Antique Floor Tire Pressure Gauge to Its Former Glory
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If you enjoyed our recent video on how to restore an old anvil, you might be on the market for a new, more challenging, restoration project. This old pressure gauge, for example, is in much need of some tender loving care.
In this case, this old PCL floor tire pressure gauge was acquired from an old mechanic's garage. According to the previous owner, the piece worked perfectly for years but was mothballed after they changed to a more modern system.
The previous owner even recalled how the unit has been calibrated by PCL engineers who said it might not work again after years of heavy-duty use and neglect. The restorer of the piece wanted to prove them wrong -- as well he did as you are about to find out.
Let's go through the process of restoring it to its former glory.
Like any project of this nature, you'll first need some stuff to get you started.
Tools and equipment needed
- Old tire pressure gauge (in this case a PCL model)
- Rust remover
- Dental tools
- Toothbrushes and sponges
- Metal filler
- Dishwashing liquid
- Paint stripper
- Metal files
- Orbital sander
- Dremel rotary tool and various bits
- Masking tape
- Heat gun
- 3D printer
- CAD program
With all your gear and materials in hand, it is now time to restore this venerable piece of equipment.
Step 1: Disassemble the old gauge
The first with any project of this nature is to test if the device actually works in its current state. Connect it up and give it a trial run on something like an old tire. You can test any readings it provides with a newer working digital or analog pressure gauge.
Once we are happy it does actually work, we can then get on with its restoration.
A word of warning before we begin, however. Many older items could contain some form of asbestos. Old washers, cloth or rope seals, old bakelite, wiring sheathing, mastics, etc, have been made using asbestos in the past. So, be very careful when handling anything that may contain asbestos fibers. It is suggested you wear PPE and carry out such work in a well-ventilated space.
Take the gauge and begin to carefully and systematically dismantle it. Depending on the design of the gauge, use a mixture of ratchets and screwdrivers to do so.
Remove any clamps and rubber hosing using your ratchet and be careful not to unduly damage the original parts. Of course, there will be instances where this is unavoidable, but we want to keep the piece as original as possible.
For stubborn parts, like the rubber hose nipples (most likely) spray the parts with a lubricant or something like WD40 to help loosen up the part. Then remove the bits as needed.
Use other tools like spanners for any bolts to the gauge casing. In this case, it has a vertical arm piece with two bolts holding it to the rear. You may also need to lubricate these pieces first. If the bolts are really stuck, consider using a hammer driver to loosen and remove them.
Obviously, be careful when doing this to not damage any of the more delicate components like glass or internal parts. The arm of this piece also has a large rubber ball to the end. To remove this, hold the arm in a vise and pull it off by hand.
With the arm still secure, remove any pot rivets using a power drill. Sadly it won't be possible to salvage these intact.
Depending on the age and design of the piece, you may also need to drill out lead plugs in certain places over screws. The chunks of lead should come out freely in one deformed piece once you've drilled it. This will then expose the underlying screws for you to undo as per normal.
The base of this piece is pretty beaten up so try to remove it as intact as possible. Since we will already need to beat it back into shape, you can remove the bottom bar by bending the bottom closer plate to free it.
Keep working on the piece by removing external knobs, and internal tubing, etc, using spanners and your ratchet where needed.
As you dismantle the piece, you may want to take some reference photos, or keep records, of where which goes where when we come to rebuilding it. Ideally, you can find some reference documents to help you.
Unless that is you happen to have a photographic memory. Watch for exposed springs and washers and ensure they ping off only to be lost forever.
Just take your time and be thorough.
Keep on keeping on and make sure you fully dismantle the main piece and its component pieces as needed. Keep all the bits safe so you don't lose any.
The pressure gauge plate itself should come out as one piece, but you will need to dismantle it into its constituent parts for a full restoration.
Be especially careful when you come to any glazed portions of the device. Obviously, these parts can shatter very easily.
You can also use smaller tools like dental tools and tweezers to remove fiddly pieces like small springs and rubber washers, etc.
Step 2: Begin the restoration of the main casing/housing
Let's start with the main housing piece first. Mix up some soapy water and place the piece in the water. Then using a mixture of a sponge and brushes, begin to remove any dirt and grime from the piece. Pay particular attention to the nooks and crannies of it as they have likely built up decades of dust and debris.
Dry the piece once complete, and rub the paint stripper over the entire exposed surfaces of the main housing. Use a paintbrush to work the stripper over the piece as needed.
Another word of warning here too. Older paints sometimes contain lead (which is highly toxic). Ensure you wear gloves and a mask and always wash your hands before eating. It may be more advisable to simply give the piece a new coat of paint instead.
Once complete, leave the stripper to do its magic. The paint stripper should dissolve the paint leaving a coating of a muddy sort of substance.
Remove this using more brushes and ensure you wear protection in a well-ventilated space. Dispose of the sludge as needed (please do not rinse down the sink).
Keep going until you expose the bare metal underneath the paint.
With that complete, and if desired, place the casing into a sandblaster. Run the machine for a few minutes to fully clean up the metal and restore it to its former glory.
With that complete, give the piece a visual inspection and check for any cuts and scrapes. If present, hold the casing in a vise and file smooth any damaged areas.
Once happy, finish the cleanup using some sandpaper. Rinse and repeat for any chips and small dents of the casing. Take your time, this is a labor of love after all.
For deeper cuts and marks on the piece, fill them with component filing. Leave to cure.
Next, grab your orbital sander, and remove the filler to expose the metal underneath (except for the deep scuffs and grooves obviously). Keep working the piece with sandpaper and then give the piece a polish using acetone.
Step 3: Repaint the casing
With the old paint remove and damage removed or filled, we can now begin to paint the piece. Cover any parts you don't want to be painted and add a layer of undercoat or primer to the piece.
Leave the primer to fully dry, and then spray the entire piece with water. Once complete, give the piece gentle wet sand.
Once complete, add the next layer of paint to the piece. In this case, we have gone with a light gray color.
Next, take some red paint (or whatever color you want) and repaint by hand other details on the casing. For example. the plus and minus embossed symbols on the front of the casing.
Step 4: Restore the brass pieces
With the main casing more or less now complete, we can move on to restoring some of the other components. Let's begin with the brass pieces.
Gather them all together and place them all into a sandwich bag or similar. Then mix up a paste concoction of 1 part flour to 1 part vinegar to 1 part salt.
Add the paste to the bag and cover all the brass pieces. With that complete, empty the brass and paste and begin to work the paste into the brass pieces using a toothbrush.
The paste will act as a mild abrasive to remove any dust, dirt, and rust from the pieces.
Once complete, rinse the past off using water and leave the brass pieces to dry.
Next, take each brass piece and gently run it over a piece of fine sandpaper. This should remove any oxidation from the brass surfaces.
You can also use some mechanical sanding tools to make short work of this process. Obviously, watch your fingers when doing this.
During the restoration, you may find that older washers, especially rubber ones, have probably perished over the years. Replace them as needed.
For smaller or irregular pieces, you may find it easier to use a Dremel with a polishing head to clean it up. For flat-faced pieces use your metal files to work the piece too.
Keep going until all brass sections are nice and shiny. This part is really fun so enjoy the process.
Step 5: Restore the handle and rubber knob
With the main casing and brass components now fully restored we can move on to some other parts -- like the main bar. Take it and scrub it down vigorously using some sandpaper.
Keep working on the piece to remove dust, debris, and grime. With that complete, give the piece a once over using a Dremel or rotary polisher until the metal becomes nice and shiny.
With the bar complete, we can now move on to the rubber knob. Secure it into a lathe, and polish the rubber using some fine sandpaper.
Next, take some polish and work the piece using an old, clean, rag. Keep working it until the rubber looks as good as new.
With that complete, take the other metal pieces and use a mixture of sandpaper, metal files, and mechanical sanding devices to return them to their former shiny selves.
Step 6: Fix the bottom plate
With those steps complete, we can now move on to the heavily damaged base plate. Take it, and give it once over visual to assess what, if anything, needs to be done to fix it.
This particular piece has "been through the wars", so will need some serious TLC. In this case, the plate is too badly damaged to reuse so we will have to make a new one to the same design.
First, heat up the plate using a heat gun. This will help make the metal more malleable and easier to work.
It will also enable us to remove intact, as much as reasonably practicable, the original labels on one of the faces for later reattachment.
Gently peel away the labels and ensure that you remove them in one piece. You may find using a pallet knife an easier option to prize them off.
With that complete, take a regular hammer and beat the plate as flat as possible. Constantly turn the plate when doing so, and don't hit it so hard that it leaves hammer marks -- we are just trying to tease it back to its original flat shape.
Once complete, take a note of its diameter.
Then, mark out a circle of the same diameter on a new sheet of metal. Cut out the circle using your angle grinder and secure the new plate into your lathe.
Tidy up the outer edge of the cut plate using your lathe until it forms a perfect circular plate.
With that complete, lay the old plate on top of the new one, and mark out the position of any bolt or clasp points.
Cut or drill them out as needed.
Once the holes are cut, tidy them up using a variety of metal files, sandpaper, and mechanical polishing tools. Polish the edge of the plate as well.
With the new plate ready, we can now reattach the original stickers. As the original adhesive is now gone (after the heat gun treatment) we will have to cut a strip of double-sided sticky tape to stick the old stickers to the new plate.
With that complete, we can continue restoring some of the other components of the pressure gauge.
Step 7: Move on to the other components
As before, first sand the old grimy and tarnished pieces using some sandpaper. Then truly bring out their original glory using mechanical polishing tools.
For awkwardly shaped pieces, you may need to use come cylindrical metal files as well.
For the metal rim of the glass part of the gauge, hold it in a vise, and polish the piece by hand using some metal wool. Apply pressure with your fingers and run the metal wool along the length of the piece.
Keep working the rim until it is as good as new.
Next, take any rusted pieces and submerge them in liquid rust remover. Prime candidates to need this kind of treatment will be springs, bolts, screws, nuts, and other iron-rich metal parts.
Leave the rust remover to do its work for about 20 minutes or so, and then remove and rinse off the remover using water. Then, leave them to dry.
Once dry, continue to polish the pieces by hand using sandpaper and mechanical polishing tools.
For things like bolts, and other threaded pieces, you may want to use metal brushes to work the finer details of them.
To make light work of things like buts, attach them to a spare bolt in your lathe, and polish them by hand. This is usually the quickest and most effective way of restoring such pieces.
For other pieces, you can secure them in the jaws of your vise and use strips of sandpaper to polish them in a saw-like fashion. For screws, clamp a spare piece of wood in your lathe, screw the screws into the middle of the wood, and polish them by hand using metal wire or metal brushes.
Use your lathe for other pieces like old washers, and springs. For any missing pieces, like large washers, you will likely need to make replacement parts -- unless they are common pieces.
In this case, one of the larger donut button cap pieces is missing so the creator of this video had to make one by hand, To do this they took a cylinder of steel, and machined the piece to the same dimensions as the original.
Match the original piece as best you can. This will take some patience and attention to detail.
Keep polishing and work on other pieces until they look as good as the day they left the assembly line. Depending on the condition of things like bolts and nuts, you may need to rethread them too.
This will depend entirely on the condition of your pressure gauge and its constituent parts.
With main parts now restored and polished, we can start to make them look even more awesome. In this case, the restorer has opted to paint some pieces black.
You can, of course, skip this step if you'd prefer to keep the original metallic look.
Step 8: Restore any old gaskets, plastic, and glass parts
For more flexible pieces, like old tubing and gaskets, the options we have for restoration depend on their condition. In this case, the main glazing gasket is pretty beat up and perished.
Unfortunately, we will need to make a new one to the same dimensions. Take some rubber gasket rope of the same diameter as the original, mark out the length needed, and cut it down to size.
This particular pressure gauge also has some clear plastic and glass components. Take these, and remove any dust, and grime with a good soak and scrub in soapy water.
Use brushes for extra stubborn bits of grime on the glass or plastic as needed.
Step 9: Make other pieces as needed
Not to labor the point, but depending on the condition of your piece, you may find that it is missing some other major components entirely. In this case, the original piece had a narrow black plinth.
You can search the internet for these missing pieces or indeed for reference photographs of near-perfect machines. But, if you can't find the original bits that are missing, you will be forced to make your own -- as in this case.
Depending on your skill set, you either try to make one by hand or model a new piece in CAD. In this case, the creator opted for the second option.
After building the model the dimensions needed, they 3D printed the new piece in TPU filament.
Next, check other parts like rubber and plastic hosing. Depending on the condition of your piece, these may also need to be replaced.
In this case, one of the main rubber hosing pieces is punctured and in need of repair. You can either replace it with a brand new one or attempt to effect a good repair on the piece.
The original pressure gauge also lacks the original air connector to the end of the hosing. So, in this case, a new one has been sourced.
Step 10: Begin the reassembly
With all the pieces of the pressure gauge now fully restored or replaced with new alternatives, it is now time to begin the reassembly of the piece.
Let's start with the rubber washer to the main glazing display. Take your new rubber seal, and insert it around the rim of the main display of the casing. Ensure it is fully inserted and trim down to fit if needed.
With that complete, take the glass piece, and gently place it into the hole and on top of the rubber seal. It should fit perfectly.
With that complete, take the metal ring and install it around the perimeter of the glass piece, as needed. Take care not to damage the glass underneath.
With that complete, add the bolt and metal ring restraining clamp piece to the main casing to secure the glass, rubber seal, and metal holding ring firmly into place. Again, make sure you don't overtighten the piece and damage your wonderfully restored pieces.
With that complete, we can now turn out attention to the pressure gauge's gubbins.
Turn the main casing over, and rest it on a surface that will not damage or potentially scratch the glass. Insert the larger bolts and brass valves into the casing, and secure them using their matching bolts, washers, and rubber gaskets (where applicable).
Tighten by hand, but do not overtighten. You don't want to damage the pieces and the main casing now you've spent a lot of time lovingly restoring them.
Next, take the main pressure gauge dial and insert it into place behind the glass cover piece. Make sure it is properly aligned, and then secure it to the casing using its original bolts.
Next, take the plastic cover for the plate, and thread any tubing through it, as needed. Secure it to the main casing as needed.
With that complete, take the main brass pieces from inside the pressure gauge and reassemble them as needed. Ensure that the springs and other components are used where they were originally found.
For more delicate components, you may find it easier to manipulate them using tweezers rather than your bare fingers.
With each piece assembled, and where applicable, ensure they are working as intended. If not, adjust accordingly. With that complete, attach rubber and plastic tubing the brass pieces as needed.
Again tighten all nuts by hand using a spanner, but don't overtighten.
Connect the brass pieces together as needed and ensure they are to the original design of the piece. As detailed before, refer to your original notes or photographs, or indeed manufacturer's instructions, to help you out here.
With that complete, transfer the brass pieces and tubing to the main casing, and connect the main pressure gauge plate to the assembly, as needed.
With that complete, connect the tubing to the main valves in the pressure gauge casing.
Step 11: Continue and finish the reassembly
With the main casing, pressure gauge, brass pieces, and tubing now complete, we can move on to the other key components of the pressure gauge. Take the main components for the increase and decrease pressure buttons.
Reassemble them using their matching parts and springs.
With that complete, secure them into place on the main casing as needed. These buttons should come in two main parts, so bear that in mind when reinstalling them.
As with other parts, tighten by hand but don't overdo it. Rinse and repeat for the other button of the pressure gauge as needed. With that complete, add and secure the main button caps (one of which we needed to make from scratch earlier).
Tighten them into place using a mixture of Allen keys and a spanner, as needed.
With that complete, let's turn our attention to the base closer plate of the piece. Take your newly fashioned plate, and attach the metal bar into its matching slots.
Now insert the plate into the rear of the pressure gauge casing. Take the original, now fully restored, screws and washers, and secure the plate to the casing as needed.
With that complete, place the entire pressure gauge assembly into its brand new plastic base plinth. Press it down firmly into the plinth -- it should fit perfectly and snuggly.
Now, take the main back bar and mount it to its matching mounting bolts on the rear of the pressure gauge casing. Tighten its matching nuts and washers with your ratchet to hold it firmly to the casing as needed.
With that complete, take the bar air connector resting bracket and mount it to the back bar using either new bolts and nuts or in this case, or the restored originals.
With that complete, we can now return the bar's original rubber knob into place. Add some lubricant to the end of the knob mounting point spur.
Then, take the knob and firmly push it back onto the end of the bar. Be firm, it should fit snuggly back into place. You will likely need to push and twist the rubber knob to get it back in too place, but this will depend on the design of your piece.
With that complete, take your restored pressure valve nipple pieces, and thread them into place as needed. With that complete, connect the hosing to the main air connector (original or new), and secure it tightly to the nipple.
With that, your old venerable pressure gauge has now been fully restored to, dare we say, better than its original condition. This particular piece really is a thing of beauty, so you may want to consider displaying it somewhere of prominence in your workshop or home.
Alternatively, you could put it to immediate work and check the pressure of the tires on your car. Outstanding work.
If you enjoyed this restoration project, you may want to also check out this guide on how to turn a regular old hammer into a fancy Katana-grip style version.
Why do we do it, how can we stop it, and who else is at it?