Car sills are one of the most vulnerable parts of the body, which is the first to take the blow from road salt, gravel and mechanical damage. Over time, even neat cars develop pockets of corrosion, dents or through holes that require urgent repairs. Replacing thresholds at a car service costs 15-40 thousand rubles (depending on the model), but with the tools and patience you can do the job yourself.

In this article we will analyze the entire process - from diagnosing the condition of the thresholds to the final painting, taking into account the nuances for different types of bodies (sedan, hatchback, SUV). You will learn how to properly cut off old thresholds, fit new ones, avoid body distortions and protect the metal from repeated corrosion. We will pay special attention hidden problemsthat beginners often miss: for example, why you can’t weld thresholds “by eye” without control measurements or how to check the condition of the amplifiers inside the body.

The material will be useful to both owners of budget VAZ and Renault, and for those who repair premium foreign cars. We will not limit ourselves to the general theory - we will give specific examples for popular models, compare prices for spare parts and tools, and also tell you how to save money without losing quality.

When threshold replacement is required: signs and diagnosis

Many car owners are confused threshold repair (filling holes, putty) with complete replacement. The latter is necessary in three cases:

  • 🔧 Through corrosion more than 30% of the threshold area - when the metal crumbles when pressed, and the holes cannot be patched without losing the rigidity of the body.
  • 🚗 Deformation after an accident, if the threshold is bent inward or outward, and the geometry of the body is broken (checked on the slipway).
  • 🔥 Amplifiers rotting - internal elements that are not visible from the outside, but hold the entire structure. Their destruction leads to the “floating” geometry of the doors and roof.

To check the condition of the thresholds, take flat blade screwdriver and tap the threshold from bottom to top. The sound should be clear - a dull knock or failure of the instrument indicates rust. Please note:

  • 🔍 Joints with spars — moisture often accumulates here.
  • 🔍 Areas under plastic covers (if they exist).
  • 🔍 Mounting points for jacks - they rust first due to loads.
⚠️ Attention: If, when you press the threshold, the body “plays” (the doors do not close well, cracks appear), this is a sign of destruction of the amplifiers. In this case you will need complete dismantling of the interior lining and replacement of not only the outer panel, but also the power structure.
📊 What experience do you have in body repair?
Never tried
Minor repairs (putty, straightening)
I welded the parts myself
Professional bodyworker

Choice of thresholds: original vs. analogues, prices and nuances

Depends on the quality of the spare part up to 70% repair success — cheap thresholds may not match in geometry, have thin metal or poor galvanization. Let's consider the options:

Threshold type Benefits Disadvantages Average price (per 1 piece)
Original (OEM) Perfect fit, factory galvanized, manufacturer's warranty Dears, the wait is long (especially for foreign cars) 8 000–25 000 ₽
Analogs (for example, Febi, Meyle) Good quality, often better than the original for the price May require minor improvements 4 000–12 000 ₽
Budget (for example, Kungfu, Track) Low price, fast delivery Thin metal, poor anti-corrosion treatment, fasteners often do not match 1 500–5 000 ₽
Universal (metal sheet + template) Can be adjusted to any car, minimum cost Requires highly qualified welder and straightener 500–2 000 ₽

For most cars the best choice is high-quality analogues. For example, for Toyota Corolla or Hyundai Solaris thresholds from Hans Pries or JP Group. For domestic cars (VAZ 2110, Lada Granta) can be considered AvtoVAZ (original) or BelMag (analog).

When purchasing, pay attention to:

  • 📏 Metal thickness - at least 0.8 mm (originals usually have 1–1.2 mm).
  • 🔩 Completeness: Ideally, the threshold should come with an amplifier and technological holes for welding.
  • 🛡️ Factory processing: galvanization or primer (if you don’t have it, you’ll have to spend time on anti-corrosion yourself).
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Before buying a threshold, remove the old part and compare it with the new one in terms of fastenings. Often, even original spare parts have “surprises” - for example, there is no hole for a parking sensor.

Tools and materials: complete checklist

To replace the thresholds you will need specialized tool, which is not always in the garage. Here is the minimum set:

Grinder (125 mm) with cutting and grinding wheel | Semi-automatic welding (MIG/MAG) with gas (carbon dioxide or argon/CO₂ mixture) | Chameleon protective mask and welder gloves | Jacks (2 pcs.) and stands for the body | Set of straightening tools (shovels, mallet) | Grinder with flap wheel (for cleaning seams)|Anti-corrosion materials (primer, mastic, zinc spray)|Spray gun or can of paint (according to body color)-->

If you are taking up welding for the first time, practice on unnecessary pieces of metal - the thresholds will cook spot seam in increments of 2–3 cm, not continuous. For cutting old threshold it is better to use cutting wheel for metal 1.6 mm thick — it cuts faster and does not heat the metal as much.

For consumables, prepare:

  • 🔥 Welding wire (diameter 0.8–1 mm, e.g. ESAB OK Aristorod 12.50).
  • 🧴 Degreaser (Antisilicone or acetone).
  • 🎨 Primer (epoxy or acid) and mastic (Movil, Dinitrol).
  • 🔧 Self-tapping screws and rivets (if the threshold is attached in combination).
⚠️ Attention: Do not use cheap welding wire without certificates - it may contain impurities that will make the weld brittle. For aluminum bodies (for example, Audi A8) will be required argon welding and special wire.

Step-by-step instructions: removing the old threshold

This is the most critical stage - mistakes here will lead to body distortion or problems with door geometry. Follow the algorithm:

  1. Machine preparation:
    • Remove the negative terminal from the battery.
    • Dismantle the doors (if the threshold is very rotten, they may jam after welding).
    • Remove plastic trims, seals and interior trim from the threshold side.
  • Marking of cuts:

    Step back from the junction of the threshold with the body 10–15 mm and mark the cutting line with a marker. Use angle grinder with a guide ruler to ensure an even cut. Do not cut “butt” - then it will be difficult to fit the new threshold.

  • Cutting out the old threshold:

    Start with bottom part, gradually moving upward. If the threshold is welded to the amplifier, carefully separate them with a chisel or grinder. Save all technological holes (for example, to drain water) - they will need to be repeated on a new part.

  • Cleaning and preparation:

    Remove weld residue, rust and paint until bare metal (use the petal wheel on the grinder). Check the condition of the amplifier - if it is rotten, it also needs to be replaced.

    • After removing the threshold be sure to check the body geometry. To do this:

    • 📏 Measure diagonally between reference points (for example, from the front fender to the rear pillar).
    • 🚪 Check the door gaps - they should open/close without effort.
    • 🔧 If skew is detected, use straightening stand or jacks with guy wires.
    What to do if the threshold amplifier is rotten?

    If the amplifier (internal power beam) is destroyed, it must be cut out and a new one welded. To do this:

    1. Completely remove the outer threshold and clean the amplifier area.

    2. Cut out the rotten areas, leaving healthy metal (at least 2-3 cm from the edge of the corrosion).

    3. Fit a new amplifier (usually included with the threshold) and weld it continuous seam - this is a power part, and spot welding is not enough.

    4. Before installing the external threshold, treat the amplifier zinc spray (for example, Zinc Rich Primer).

    Installation and welding of a new threshold

    Now let's move on to installation. Main rule: first fix the threshold, then cook. Procedure:

    1. Fitting and fitting:

      Place the new threshold on the installation site and check the gaps. He should fit tightly to the body without gaps. If there are discrepancies, adjust the part hammer and mallet (don't overdo it - thin metal can be deformed).

    2. Fixation before welding:

      Use clamps or self-tapping screws to secure the threshold in the desired position. Check:

      • 📏 Matching lines with an old cut.
      • 🚪 Door gaps - they shouldn't change.
      • 🔧 Technological holes (for example, for attaching a jack).
    3. Welding:

      Set up the welding machine:

      • 🔌 Current: 80–120 A (depending on the thickness of the metal).
      • 💨 Wire feed speed: 4–6 m/min.
      • 🔥 Gas: carbon dioxide (CO₂) or argon/CO₂ mixture (80/20).

    Brew spot seam in increments of 2–3 cm, starting from central part and moving towards the edges. This will prevent the metal from “driving.” Allow the piece to cool after each seam to avoid deformation.

  • Seam processing:

    After welding:

    • 🔨 Clean the seams petal circle (do not overheat the metal!).
    • 🧴 Degrease the surface and apply acid soil (for example, Reoflex).
    • 🛡️ Coat the inside of the threshold mastic (through technological holes).
    💡

    Never weld the threshold with a continuous seam - this will lead to deformation of the body due to uneven heating. Spot welding in 2–3 cm increments provides strength and maintains geometry.

    To check the quality of welding, knock on the threshold with a hammer - the sound should be clear, without rattling. If you hear a dull knock, it means there are uncooked areas.

    Anti-corrosion treatment and painting

    Even the highest quality threshold will rot in 2-3 years if it is not protected from corrosion. Use multilayer system:

    1. Internal processing:

      Apply through the technological holes:

      • 🛡️ Zinc spray (for example, Zinc Rich Primer) - it creates a protective layer on the metal.
      • 🧴 Mastic (Dinitrol 479 or Movil) - fills cavities and displaces moisture.

    For better distribution, tilt the machine towards the threshold being processed (use a jack).

  • External treatment:

    Sequence:

    • 🧽 Degrease the surface (Antisilicone).
    • 🎨Apply epoxy primer (2 layers).
    • 🖌️ Putty any unevenness (if any).
    • 🔴 Paint it in body color (use spray gun with nozzle 1.3–1.5 mm).
    • ☀️ Cover varnish (2 coats) and polish.

    For durability:

    • 🔥 Don't paint the threshold in a cold garage - optimal temperature for drying 20–25°C.
    • 🚿 Avoid washing your car for the first 3 days after painting.
    • 🛠️ Install plastic covers - they protect against chipping.
    ⚠️ Attention: If you spray paint the threshold, keep it at a distance 20–25 cm and apply thin layers. A thick layer of paint will crack after a few months.

    Common mistakes and how to avoid them

    Even experienced craftsmen sometimes make mistakes that lead to re-corrosion or problems with the body. Here are the most common:

    Error Consequences How to avoid
    Welding without removing rust Corrosion spreads under the threshold, the seams are coming apart Remove rust before bare metal (use sandblaster or flap wheel)
    Using a continuous seam Body deformation, door misalignment Brew pointwise in increments of 2–3 cm, let the metal cool
    Saving on anticorrosion The threshold rots from the inside within 1–2 years Process all cavities (zinc spray + mastic)
    Untested geometry after welding The doors do not close, the body “drives” Check body diagonals and door gaps after each stage
    Painting without primer The paint is peeling off and rust appears. Use acid + epoxy primer before painting

    Another common problem is color mismatch after painting. To avoid this:

    • 🎨 Order paint by VIN code car (in showrooms or at official dealers).
    • 🔍 Check the shade on hidden area (for example, under the hood) before full painting.
    • ☀️ Paint in one time of day — lighting affects the perception of color.

    How much does it cost to replace thresholds with your own hands vs. car service

    Let's calculate how much it will cost to repair it yourself and in the service for popular models:

    Car model Cost of spare parts (2 thresholds) Cost of work in the service Total in service Cost yourself
    VAZ 2110/2114 3,000–6,000 ₽ (analogues) 12 000–18 000 ₽ 15 000–24 000 ₽ 3,000–6,000 ₽ + consumables
    Toyota Corolla (E150) 12,000–20,000 ₽ (original/analogue) 25 000–35 000 ₽ 37 000–55 000 ₽ 12,000–20,000 ₽ + consumables
    Hyundai Solaris 8 000–15 000 ₽ 20 000–30 000 ₽ 28 000–45 000 ₽ 8,000–15,000 ₽ + consumables
    Ford Focus 2 10 000–18 000 ₽ 22 000–32 000 ₽ 32 000–50 000 ₽ 10,000–18,000 ₽ + consumables

    Consumables (welding wire, wheels, primer, paint) will cost 3 000–8 000 ₽ depending on quality. If you already have a tool, replacing the thresholds yourself will save 70–80% cost.

    However, keep in mind hidden costs:

    • 🔧 If you don’t have a welding machine, it’s worth renting 1,500–3,000 ₽/day.
    • 🎨 Painting in a chamber (if there are no conditions at home) - 5 000–10 000 ₽.
    • ⏱️ Time: it will take the first time 2–4 days (a professional can do it in 6–8 hours).
    💡

    Replacing thresholds yourself only pays off when repairing 2-3 cars. If you need to repair one car, it is cheaper and more reliable to contact a trusted service.

    FAQ: Answers to frequently asked questions

    Is it possible to replace the threshold without welding?

    Theoretically yes, but this temporary solution. The threshold can be riveted or screwed with self-tapping screws, but:

    • 🔧 Strength will be lower than that of a welded joint.
    • 🚿 Moisture will get into the gaps between the threshold and the body, which will accelerate corrosion.
    • 🚗 Such repairs will not restore the rigidity of the body after an accident.

    Gluing the threshold is only possible using structural adhesive (for example, 3M 08115) and in combination with spot welding in critical areas.

    Which welding machine is better to choose for thresholds?

    The best option is semi-automatic MIG/MAG with the ability to work in a carbon dioxide environment. Recommended models:

    • Resanta SAIPA-190 — a budget option for beginners (from 25,000 ₽).
    • Svarog REAL MIG 200 — optimal price/quality ratio (from 40,000 ₽).
    • ESAB Buddy Arc 200 — professional device (from 60,000 ₽).

    To weld thresholds, a machine with a current strength is sufficient 120–160 A. Be sure to check the package - there should be gas reducer and wire spool.

    What should I do if, after replacing the threshold, the doors do not close well?

    This is a sign body geometry violations. Possible causes and solutions:

    • 🔧 Threshold skew: check the gaps between the threshold and the body - they should be uniform. If necessary, trim or modify the part.
    • 🚪 Amplifier Warp: If the amplifier is bent, it needs to be straightened or replaced.
    • 📏 Changing body diagonals: measure the distance between reference points (for example, from the front fender to the rear pillar). If the difference is greater 3–5 mm, will be required straightening on a slipway.

    In most cases the problem can be solved adjusting door hinges (they often “go away” during welding). If this does not help, contact a body shop to check the geometry.

    How to protect new thresholds from corrosion for a long time?

    So that the thresholds last 10+ years, follow these guidelines:

    • 🛡️ Treat internal cavities mastic (Dinitrol, Movil) every 2 years.
    • 🚿 Wash your car in winter at least once every 2 weeks, especially in the rapids area.
    • 🔧 Install plastic covers — they protect against chipping and sandblasting.
    • 🎨 Paint the thresholds anti-gravel paint (for example, Raptor).
    • 🚗 Avoid parking on the grass - Moisture from the ground accelerates corrosion.

    If you live in a region with aggressive winter (lots of salt on the roads), treat the thresholds additionally liquid wax (Sonax, Turtle Wax).

    Is it possible to replace only part of the threshold?

    Yes, but this temporary measure. Partial repairs are justified if:

    • 🔧 Damaged only bottom part threshold (for example, after chipping).
    • 🚗 No corrosion