Seized joints: a challenge during disassembly

A bolt, nut or splined joint can make maintenance difficult. Rather than assuming that more force is the answer, assess the condition of the components and choose a suitable disassembly method. The technical data sheet for PN 200 4 — a penetrating lubricant with molybdenum disulphide (MoS₂) lists loosening seized threaded, splined and keyed joints.

The documentation describes penetrating, lubricating and rust-release properties. This does not guarantee that every damaged or corroded assembly can be separated. Product selection must take account of the material, component condition and equipment instructions.

The lubricating film and reducing seizure

The technical data sheet states that the molybdenum disulphide lubricates mating components and that the product leaves a lubricating film. This matters when separating or assembling parts whose surfaces are in contact.

However, the properties of MoS₂ alone must not be treated as the temperature range, load capacity or service life of the complete formulation. The supplied materials do not provide a universal permissible contact pressure or protection period for every joint.

Assembling fitted components: consider the design

The PN 200 4 TDS lists the assembly of fitted components. Use must be checked against the documentation for the specific assembly. The term “close-fitting” does not mean that any lubricant can be used on every such component.

Before selecting a product, provide the materials of both parts, the type of fit, the function of the joint and the requirements for assembly and subsequent operation. If the equipment manufacturer specifies an assembly compound or surface preparation method, do not replace those instructions with a general description of a penetrating lubricant. We do not present PN 200 4 as a universal substitute for an in-service lubricant.

Acid-free formulation, corrosion protection and contact with water

The technical data sheet confirms the absence of acids, corrosion-protection properties and insolubility in water. These are separate statements: an acid-free formulation does not guarantee that rust will never return, and insolubility alone does not prove moisture displacement.

According to practical experience reported by ENYRUN, the product helps displace moisture from joints. This is an observation from use, not a claim backed by undisclosed test results or a specified protection period. The durability of protection must be assessed under the conditions of the particular application.

Important: hot surfaces and safety

The safety data sheet classifies PN 200 4 as an extremely flammable aerosol. The container is pressurised and may burst if heated. The SDS requires keeping it away from hot surfaces and other ignition sources. Follow the current label, safety data sheet and workplace safety procedures.

The supplied technical data sheet contains statements about hot components and non-evaporation. We do not use these as a recommendation to apply the product to heated parts because they conflict with the SDS warnings. An auto-ignition temperature is not a permissible spraying temperature. This issue requires clarification from the manufacturer.

What information should you include in a product enquiry?

  • Is the task disassembly or assembly?
  • What type of joint is involved, and what are the materials of both components?
  • Is there corrosion, contamination or mechanical damage?
  • What conditions and products are permitted by the equipment instructions?
  • What are the requirements for subsequent lubrication and component protection?

See the PN 200 4 product page or describe your joint and request selection advice and a quotation. Specific information helps determine whether the penetrating lubricant meets the requirements of your task.

Sources: the supplied technical data sheet “ENYRUN PN 200 4 — Penetrant z MoS₂ (odrdzewiacz)”, without an issue date; PN 200 4 safety data sheet, version 2.4, revised 6 January 2023; ENYRUN experience reported on 20 October 2026. Before use, confirm that the documents are current for the supplied product.