Replacing a threshold on a car: a detailed guide with photos and tips

Rusty holes on the thresholds or traces of corrosion after winter are a signal for urgent replacement. Car thresholds They not only have a decorative function, but also protect the body from deformation during side impacts. If on VAZ 2110 or Toyota Corolla In 2005, rust ate through the metal; repairs cannot be postponed: corrosion will spread to the side members and struts, and the cost of work will increase 3-5 times. Replacing the threshold yourself will cost 5-15 thousand rubles (depending on the model), while the service will ask for 25-50 thousand for similar work.

The process requires precision, but even beginners with basic welding skills can do it. The main thing is to choose the right spare part, prepare the tool and not skip the anti-corrosion treatment stage. In this article we will look at how to change the threshold on a car without errors, what materials to choose for Nissan Almera or Ford Focus, and why you shouldn’t skimp on primer.

Signs that the threshold requires replacement

Corrosion is not always visible to the naked eye. In the early stages, rust is hidden under plastic covers or a layer of putty. Pay attention to these symptoms:

• 🔍 Blistering paint — bubbles under the paint coating signal the beginning of metal oxidation. It especially often appears at the junction of a threshold with an arch or door.
• 💧 Wet spots in the interior — if after rain water accumulates under the feet of the passenger or driver, the rust has probably eaten through the threshold.
• 🚗 Creaks when opening doors — corrosion destroys welds, which is why body panels begin to “play.”
• 🔧 Cracks in the mounting points of the jacks — a critical sign: the threshold has lost its rigidity and may break when lifting the car.

On Renault Logan and Kia Rio The rear sills often suffer - dirt from under the wheels accumulates there. U Audi A4 and BMW 3 series the front sections are vulnerable due to the complex geometry and thin metal. You can check the condition of the threshold by prying up the plastic trim with a flat screwdriver or tapping the metal with a wooden hammer handle: a dull sound will indicate rust inside.

⚠️ Attention: If the sill is rusted to holes, do not use a jack at standard lifting points. Risk of the machine collapsing! Use wide boards or special spacers.

Choosing a threshold: original, analogue or homemade?

80% of success depends on the quality of the spare part. Original thresholds from the manufacturer (OEM) guarantee a perfect fit, but their price can reach 20-30 thousand rubles for one side. Alternatives:

Threshold type	Pros	Cons	Cost (for 1 piece)
Original (OEM)	Precise geometry, factory anti-corrosion, warranty	Expensive, long wait (made to order)	15 000–35 000 ₽
Analog (Aftermarket)	Cheaper than the original, wide selection (for example, Febi, Meyle)	May require local modifications	3 000–12 000 ₽
Universal	Suitable for different models, low price	Difficult installation, often thin metal	1 500–5 000 ₽
Homemade (from a sheet)	Minimum cost, perfect size	Requires metal and welding skills	500–2,000 ₽ (materials)

For VAZ 2107 or Gazelle Often they choose universal thresholds - they are easier to adjust. For foreign cars (Hyundai Solaris, Skoda Octavia) it is better to take analogues from trusted brands. Check before purchasing catalog number threshold with the car's VIN code on sites like exist.ru or emex.ru.

If you decide to make the threshold yourself, use a galvanized sheet thick 1.5–2 mm. For UAZ Patriot or Niva Chevrolet 09G2S steel is suitable - it is resistant to corrosion and cooks well.

- The threshold itself (external panel)

- Amplifier (internal part)

- Fastening elements (if provided)

- End caps (optional)

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Tools and materials: complete list

Without the right tool, replacing the threshold will turn into torture. Here's what you'll need:

• 🔧 Welding machine (semi-automatic or inverter with a current of 120–160 A). Suitable for beginners Resanta SAI-190 or Svarog ARC 200.
• 🔨 Bulgarian (angle grinder) with cutting discs for metal (thickness 1.6–2 mm). It is advisable to have spare disks - their consumption is high.
• 🛠️ Tool set: wrenches 10, 13, 17, ratchet heads, screwdrivers (flat and Phillips), hammer, chisel.
• 🧲 Magnetic square - for precise marking of cuts. Particularly important when working with Mercedes W210 or Volvo S60, where the thresholds have a complex shape.
• 🎨 Protection materials: anti-corrosion primer (Body 930), mastic (Movil or Tektil), spray paint (to match the body color).
• 😷 Protective equipment: welder's mask, gloves, respirator (when working with an angle grinder and primer).

For Lada Granta or Kalina you can get by with a minimum set, but for premium cars (Lexus RX, Volkswagen Touareg) will also be required spotter (spot welding) for neat seams. If you plan to paint the threshold, prepare putty (Novol or 3M), sandpaper (P80–P400) and degreaser (Antisilicone).

⚠️ Attention: Do not use cheap welding electrodes (such as ANO-4) - they produce porous seams that quickly rust. Optimal choice: OK 46.00 or LB-52U.

Where can I buy a tool cheaper?

If you don’t want to overpay, look for a tool on the secondary market:

- Avito — they often sell almost new grinders and welders after one-time work.

- Yula — there you can find sets of sockets or wrenches at a discount.

- Telegram chat "Tools for auto repair" - there sellers offer wholesale prices.

- Auctions (for example, molotok.ru) - you can win a professional instrument for 30-50% of the retail price.

Preparing the car: removing body kits and protecting the interior

Before cutting metal, the car needs to be prepared. Start by dismantling:

1. Remove the plastic covers — they are attached with clips or self-tapping screws. On Toyota Camry or Honda CR-V The overlays may be glued, so use a hair dryer to soften the glue.
2. Disconnect the wiring — wiring harnesses often pass under the thresholds (for example, to the rear lights). Carefully disconnect the connectors and insulate the exposed contacts.
3. Remove seats and mats - this will protect the interior from sparks during welding. On Volkswagen Passat B6 The center console may need to be removed.
4. Close the doors and windows cardboard or special covers. Sparks from the grinder leave indelible marks on the glass.

If the threshold is welded to the side member (as on Mitsubishi Lancer 9), first make marks with a marker - this will help to accurately install the new part. To protect the body from overheating during welding, use asbestos gaskets or wet rags.

On vehicles with electric window lifts (for example, Opel Astra H) Before working, disconnect the battery to avoid short circuit. If there are drainage holes in the threshold, clean them with wire - this will extend the life of the new metal.

Plastic covers and seals removed

Battery disconnected

Glass and interior are protected from sparks

Drainage holes checked

Photos of fastenings and wiring were taken

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Removing the old threshold: cutting and stripping

This is the most critical stage. Errors here will lead to deformation of the body or mismatch of the new part. Follow the steps:

1. Apply the markings - step back from the edge of the rust 2-3 cm towards the healthy metal. On Chevrolet Cruze or Ford Mondeo use a cardboard template to maintain the geometry.
2. Cut with a grinder old threshold. Start at the bottom edge, then move to the side seams. Do not cut the side member - this will weaken the body!
3. Remove the amplifier — there is often an additional metal plate inside the threshold. It needs to be carefully cut or knocked out with a chisel.
4. Clean up the residue a sander with a flap wheel. Remove rust to bare metal, especially in areas of future welds.

By car from galvanized body (Volkswagen Golf, Scat Octavia) be careful: zinc coating releases toxic fumes when heated. Wear a respirator and ventilate the room.

If the old threshold was attached to rivets (as in UAZ Hunter), drill them with a drill with a 5-6 mm drill bit. For precise cutting, use pneumatic cutter — it gives a neater edge than the grinder.

⚠️ Attention: After removing the threshold, check the condition of the side member! If rust has eaten through it by 30% or more, reinforcement with metal plates 3 mm thick will be required.

Installing a new threshold: welding and anticorrosive

Now let's start installation. The algorithm depends on the type of fastening:

• 🔥 Butt welding - the most reliable method. Suitable for BMW E39 or Mercedes W211where body rigidity is important. The seam must be continuous, without gaps.
• 🔩 Riveting + welding - used on cars with aluminum parts (for example, Audi A6). Rivets are placed in areas of high loads.
• 🧲 Self-tapping screws + sealant — a temporary solution for “budget” repairs. Suitable for Duster or Largus, if you don’t have a welding machine.

Step-by-step instructions for welding:

1. Try on the new threshold, adjust it in place with a grinder or metal scissors.
2. Tack the part at 3-4 points by welding, then check the gaps between the threshold and the door (should be the same along the entire length).
3. Weld the seam in a continuous line, starting from the middle and moving towards the edges. For Nissan Qashqai or Mitsubishi Outlander use 0.8 mm welding wire.
4. Sand the seams with a sander, then apply acid soil (for example, Reoflex) for protection against corrosion.
5. Coat the inside surface of the threshold mastic (for example, Dinitrol ML) using a spray gun.

For Lada Vesta or Kalina 2 You can get by with semi-automatic welding in a carbon dioxide environment - it produces less spatter. On foreign cars (Toyota Rav4, Mazda 3) it is better to use argon arc welding (TIG) for neat seams.

After welding, be sure to check body geometry. Close the doors and measure the gaps between them and the threshold. If the gap is more than 5 mm, the threshold is installed crookedly - rework will be required.

How to avoid “leading” the metal when welding?

- Weld short seams (2–3 cm), allowing the metal to cool.

- Use reverse hammer for leveling deformed areas.

- Heat the metal with a construction hair dryer before welding - this will reduce internal stresses.

- For thick metal (for example, on Gazelle Next) use multilayer welding with intermediate cleaning of seams.

Final processing: putty, primer, painting

Even a perfectly welded threshold needs to be prepared for painting. The process takes 1–2 days:

1. putty - Apply in 2-3 layers with drying between them. For Hyundai Tussan or Kia Sportage use putty with aluminum powder - it is vibration-resistant.
2. Primer - first epoxy primer (for adhesion), then acrylic (for alignment). On Skoda Yeti or Volkswagen Tiguan Apply primer in 3 layers.
3. Painting - use spray paint or a spray gun. For metallic (Toyota Camry) you will need a base coat + varnish.
4. Polishing - after drying (24 hours), polish the threshold with paste 3M for shine.

Select the color according to the body code (indicated in the technical data sheet or on the plate under the hood). On Renault Duster or Nissan Beetle Matte paint is often used - it hides minor defects.

Don't forget about anti-gravel protection! Place a transparent film on the threshold (3M Scotchgard) or apply a liquid cover (Liqui Moly Unterbodenschutz). This will protect against chipping in winter.

Common mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes. Here's what can go wrong:

• 🔥 Metal overheating - leads to body deformation. Solution: weld at the minimum current (80–100 A) intermittently.
• 🧲 Geometry mismatch — the new threshold “went” to the side. Solution: use clamps for fixing before welding.
• 💧 Poor anti-corrosion — rust appeared after a year. Solution: treat internal cavities wax composition (Tectyl ML).
• 🎨 Peeling paint — putty or primer was applied to a greasy surface. Solution: degrease the metal Antisilicon before each layer.

On Opel Zafira or Ford Kuga people often forget about drainage holes — they need to be drilled into the new threshold and treated with sealant. On VAZ 2121 (Niva) it would be a mistake to ignore threshold amplifier — without it, the metal will quickly rust.

If after replacing the threshold the doors do not close well, check gaps between the door and the counter. On Mercedes C-class or BMW 5 series Hinges may need to be adjusted.

FAQ: Answers to frequently asked questions

Is it possible to replace the threshold without welding?

Yes, but this is a temporary solution. Alternatives:

- Rivets + sealant - suitable for Lada Priora or Gazelle, but the seam will be less durable.

- Self-tapping screws with press washer - only for “budget” repairs, since the fastenings become loose over time.

- Epoxy glue (for example, Poxipol) - can withstand loads, but requires ideal surface preparation.

For durability, we still recommend using welding.

How much does it cost to replace a threshold at a service?

Prices vary by model and region:

• VAZ 2106–2114: 8,000–15,000 RUR per side.
• Toyota Corolla, Honda Civic: 15 000–25 000 ₽.
• Audi A4, BMW 3 series: 30,000–50,000 ₽ (due to complex geometry).
• Mercedes S-class, Lexus LX: from 60,000 ₽.

The price usually includes labor, but not always materials (primer, paint).

Which welding machine to choose for thresholds?

Optimal options:

• For beginners: Resanta SAI-190 (semiautomatic, 190 A, price ~15,000 ₽).
• For professionals: Svarog REAL MIG 200 (200 A, price ~30,000 ₽).
• For aluminum (for example, Audi A8): Fubag IR 200 (inverter with TIG function).

For thresholds, a device with a current of 120–160 A is sufficient. Please note the presence of the function hot start — it facilitates ignition of the arc.

Do I need to paint the threshold from the inside?

Definitely! The inner surface of the threshold rusts faster due to condensation. Use:

• Mastic (Movil, Tektil) - applied with a brush or spray.
• Wax compounds (Tectyl ML) - penetrate into microcracks.
• Zinc spray (Zinc Rich Primer) - for additional protection.

On UAZ Patriot or Niva Chevrolet the inside of the threshold can be processed cannon fat - it is not washed off with water and lasts for years.

Is it possible to drive with a rusty sill?

Short term - yes, but it is dangerous:

• Rust weakens the body, which threatens safety in an accident.
• Corrosion spreads to the side members and struts, increasing the cost of repairs by 5–10 times.
• On Volkswagen Polo or Skoda Fabia A rusty threshold can cause a refusal to pass a technical inspection.

If the budget is limited, at least clean off the rust and process the threshold Tsinkarem + Movilem - this will extend the life of the metal by 1-2 years.