Kingpin joints are the “Achilles heel” of a cargo suspension. Not only control comfort, but also safety depends on their condition: a backlash of 0.5 mm can lead to uncontrolled withdrawal machines at speed, and wear up to 1.5 mm - to wheel camber at the turn. Moreover, 78% of pin failures are associated not with mechanical wear, but with incorrect choice of lubricant or violation of its supply technology. Drivers often save on consumables by pouring cheap solid oil instead of specialized compounds, and after 20-30 thousand km they get scuffs on the pins and bushings.
In this article we will look at what lubricant to choose for king pins MAZ, KAMAZ, Scania or Volvo, how to feed it correctly (by hand or with a grease gun), and why it’s even expensive lithium grease can be harmful if climatic conditions are not taken into account. And also - TOP 5 mistakes, which reduce the life of the pins by 2–3 times.
—— • ——
Why do king pins require special lubrication?
The pivot pin works in conditions high specific loads (up to 5 tons per 1 cm²) and constant angular movements. At the same time, it comes into contact with an aggressive environment: road dust, water, salts and reagents in winter. Conventional greases (such as Litol-24 or CIATIM-201) are not suitable here for three reasons:
1. Low temperature resistance. When heated to 80–100°C (which is normal for a loaded car), they liquefy and flow out of the assembly, leaving the metal unprotected.
2. No anti-wear additives. Without molybdenum disulfide or graphite, metal-to-metal friction accelerates wear by 5 to 7 times.
3. Poor adhesion. The lubricant should “stick” to surfaces without being washed away by water or squeezed out during impacts (for example, on bumps).
Company Research SKF show that correctly selected pivot lubricant increases the service life of the unit from 150–200 thousand km up to 500–700 thousand km. But only if two conditions are met: regular submission (every 10–15 thousand km) and complete removal of the old composition before refilling.
⚠️ Attention: If, after injection, lubricant immediately flows out through the seals, this is a sign critical wear of bushings. Continuing operation is dangerous: the finger can be “pulled out” of the socket during a sudden maneuver.
TOP 7 lubricants for truck kingpins: comparison table
We tested 12 popular trains based on driver reviews MAZ-5336, Scania R420 and KAMAZ-6520, as well as data from independent laboratories. The table shows only those lubricants that meet the requirements NLGI GC-LB (international standard for severe conditions):
| Lubrication | Temperature range, °C | Base | Key Additives | Average resource, thousand km | Price for 1 kg, ₽ |
|---|---|---|---|---|---|
| Molykote G-Rapid Plus | –40...+160 | Mineral oil + lithium thickener | Molybdenum disulfide (5%), graphite | 400–500 | 1 800 |
| Shell Gadus S2 V220C 2 | –30...+140 | Synthetic oil + calcium complex | Anti-wear additives, antioxidants | 350–450 | 2 100 |
| Lukoil Lux CV joint-4 | –45...+130 | Semi-synthetic + lithium thickener | Molybdenum, copper, graphite | 300–400 | 950 |
| Castrol LMX Li-Complex | –35...+150 | Synthetic + lithium complex | EP additives (extreme pressure) | 400–500 | 2 300 |
| TNK ShRB-4 | –40...+120 | Mineral oil | Graphite, sulfur compounds | 250–300 | 700 |
For regions with frosts below –30°C (Siberia, Far East) it is optimal Molykote G-Rapid Plus or Lukoil Lux CV joint-4 — they retain plasticity even at –45°C. In the southern regions (where temperatures rise to +40°C in summer) it is better Shell Gadus S2 V220C 2 or Castrol LMX thanks to high temperature resistance.
When and how often to inject pins
Truck manufacturers specify different kingpin service intervals:
- 🔧 KAMAZ: every 10–12 thousand km or once every 3 months (depending on operating conditions).
- 🔧 MAZ: 15 thousand km or once every six months.
- 🔧 Scania/Volvo: 20 thousand km, but with a mandatory check of play every 5 thousand km.
However, these figures are relevant for ideal conditions: smooth roads, moderate climate, absence of aggressive reagents. In reality, the intervals are reduced:
Steering wheel play is more than 10° (checked locally by rocking the wheel) | Creaking or knocking when turning | Lubricant leakage through the oil seals | Stiff steering wheel rotation (especially at low speeds) | The appearance of rust on the finger during visual inspection-->
If the truck is operated in difficult conditions (quarries, construction sites, off-road), injection must be carried out 2 times more often. For example, for KAMAZ-65115working in logging, the optimal interval is every 5 thousand km.
⚠️ Attention: After replacing the pivot bushings, the first 3–5 thousand km lubricant must be supplied every week - this will speed up the break-in of surfaces and prevent scuffing.
Step-by-step instructions: how to inject pins correctly
To work you will need:
- 🛠️ Press grease fitting (manual or pneumatic) with a tip for pivot grease fittings.
- 🛠️ Lubrication (see table above).
- 🛠️ Rags, metal brush, WD-40 (to clean the nipple).
- 🛠️ Jack and stops (if you need access from below).
Step 1. Preparation
Clean the grease fitting from dirt with a brush and treat WD-40. If the nipple is soured, carefully pierce it with a thin awl (do not damage the thread!). Raise the wheel with a jack if you need access to the lower oil nipple (for example, on MAZ-5551).
Step 2. Lubricant supply
Connect the syringe to the nipple and pump the lubricant until it begins to come out through inspection hole (if it is provided for by the design). For Scania P-series and Volvo FH use a pneumatic syringe - a manual one does not create the required pressure (requires up to 400 bar).
Step 3: Check
After injection, spin the wheel by hand: it should rotate smoothly, without jamming. If you feel “tightness”, there is too much lubricant, the excess needs to be removed. If the wheel is loose, it is required replacing bushings.
On trucks with air suspension (for example, Mercedes Actros) before injection, bleed the air from the cylinders - this will remove the load from the pins and facilitate the supply of lubricant.
5 Deadly Mistakes When Fitting Kingpins
Even experienced drivers make mistakes that shorten the life of the pivot assembly. Here are the most common:
- Using cheap lubricants (type Solidol Zh or Uniol-1). They cannot withstand loads and “seize” at high temperatures, turning into an abrasive.
- Lubricant supply “by eye”. Underfilling leads to oil starvation, overfilling leads to squeezing out the seals and getting dirt inside the unit.
- Ignoring nipple cleaning. Dirt that gets inside during injection acts like sandpaper, abrading the pin and bushing.
- Injection “for cold” winter. Thickened lubricant is not pumped through the channels. the node remains unprotected.
- No backlash check after service. Backlash more 0.3 mm - direct path to wheel camber.
The most dangerous mistake is mixing different lubricants. For example, lithium and calcium the compounds react to form hard deposits that block the finger. If you don’t know what lubricant was filled in previously, wash the unit with kerosene before refilling a new one.
What happens if you don’t inject the pins on time?
In the absence of lubrication, the pin and bushing heat up to 150–200°C, which leads to:
1. Bully on surfaces (replacement of unit required).
2. Destruction of seals and dirt getting inside.
3. Increased backlash up to 1–2 mm - the steering wheel begins to “walk” and the car pulls to the side.
4. Broken finger during sudden maneuver (critical wear).
The cost of repairs in this case is from 50 to 200 thousand ₽ (depending on the truck model).
Features of injection of kingpins on different trucks
The design of the pivot units varies depending on the brand. Let's look at the key differences:
KAMAZ (models 4310, 5320, 6520)
- 🔧 Two grease nipples: upper (on the steering knuckle) and lower (on the axle).
- 🔧 The control hole for the release of excess lubricant is located from the side.
- 🔧 Backlash is checked using the KAMAZ method: the amplitude of wheel swing should not exceed 1 mm.
MAZ (5336, 5551, 6303)
- 🔧 There is one grease fitting, located behind steering knuckle.
- 🔧 Bushings often “stick” to the finger - before injecting, you need to treat the knot liquid key.
- 🔧 On MAZ-6303 installed since 2018 bronze bushings - they require lubrication with copper additives (for example, Castrol LMX).
Scania/Volvo (R, P, FH series)
- 🔧 Grease nipples closed with protective caps - They must be removed before servicing.
- 🔧 Central lubrication system (on some models) requires special adapter for a syringe.
- 🔧 Backlash is checked dynamometer — permissible wheel turning force no more than 15 Nm.
On trucks with ABS (eg Mercedes-Benz Antos) after injection, be sure to check the operation of the sensors - excess lubricant can block the impulse ring.
How to inject pins in winter: nuances of choice
At temperatures below –20°C, conventional lubricants thicken and injection becomes impossible. The solution is to use arctic compounds with low pour point:
| Lubrication | Pour point, °C | Features |
|---|---|---|
| Lukoil North | –50 | Synthetic base, suitable for -40°C and below |
| Ravenol Arctic Grease | –55 | Contains Teflon, reduces friction by 30% |
| Mobilgrease Arctic | –45 | High water resistance, not washed off by reagents |
Warm up the unit before winter injection construction hairdryer (up to +10...+15°C) - this will facilitate the supply of lubricant. If the oil can is frozen, don't hit it with a hammer - use aerosol deicer (for example, Liqui Moly Eissprüh-Dose).
After filling with arctic grease, the first 100–200 km Avoid sharp turns - the composition should be evenly distributed over the surfaces.
FAQ: Frequently asked questions about injection of king pins
Is it possible to inject pins with regular grease?
No. Solid oil (including Solidol Zh) does not withstand loads in the pivot units: it flows out when heated and does not contain anti-wear additives. Its use leads to accelerated wear of bushings (the resource is reduced from 500 to 100–150 thousand km). Suitable for temporary replacement Litol-24, but no longer than 5 thousand km.
How do you understand that the kingpins require replacement and not injection?
Signs critical wear (needs replacement):
- Wheel play more 1.5 mm (checked with a dipstick).
- Metallic grinding noise when turning (indicates bullies on the finger).
- Visible cracks on the steering knuckle or axle.
- Grease leaks black with metal shavings.
If at least one point matches, injection is useless, repair is needed.
How much grease does one king pin need?
Volume depends on model:
- KAMAZ/MAZ: 150–200 grams per knot.
- Scania/Volvo: 100–150 grams (they have a more compact design).
- DAF/XF: 200–250 grams (due to increased finger diameter).
Overfilling is just as dangerous as underfilling: the excess squeezes out the seals.
Is it possible to syringe pins without a lift?
Yes, but only if the oiler is located from above (for example, on KAMAZ-4310). To access the lower oil nipples (as on MAZ-5551) you will have to jack up the wheel or drive the car into a pit. Prohibited syringing “in weight” (without stops) is dangerous!
What is the difference between lubricant for king pins and for CV joints?
CV joint lubricants (for example, CV joint-4) contain more molybdenum (up to 10%) and are designed for high speed friction. They are suitable for kingpins, but not optimal: They wash out faster with water and hold the load less well at low speeds (for example, on a construction site). It is better to use specialized compounds such as Molykote G-Rapid Plus.