company news about PTFE Coated Self lubricating DU Bushing Installation Guide, How to Avoid Common Mistakes

PVB01 Series PTFE coated self lubricating DU bushing include metal-polymer self-lubricating plain bearings composed of a steel backing, a porous bronze interlayer, and a PTFE coating sliding layer. This type of bushing is widely used across automotive, industrial machinery, and hydraulic systems.

As the performance of PTFE coated DU bushing highly relys on a thin film PTFE sliding layer for friction reduction, improper installation can degrade performance or cause premature mechanical failure. This guide outlines correct installation procedures, key technical specifications, and high-risk errors to avoid.

Technical Overview & Layer Structure

Understanding the composite structure of a DU bushing explains why careful handling is essential:

• Plating layer: Copper plating, tin plating or zinc plating

• Steel Backing: Provides structural strength and dimensional stability under press-fit loads.

• Porous Bronze Interlayer: Delivers thermal conductivity and anchors the polymer overlay.

• PTFE / Lead Sliding Layer: A low-friction surface layer (typically 0.01 mm to 0.03 mm thick) designed for dry or minimally lubricated operation.

How to Avoid Critical Installation Mistakes 

1. Hammering or Direct Impacting

• The Mistake: Using a standard hammer or soft mallet directly against the end face of the bushing.

• Why It Fails: Direct impacts will cause damage of the steel edge, peel or crack the inner PTFE lining, and distort the split joint, destroying concentricity.

• Correct Method: Always use a guided stepped tool mounted in a hydraulic or mechanical press.

2. Machining or Reaming the Inner Diameter (ID) Post-Press

• The Mistake: Attempting to ream or hone the inner diameter after pressing to achieve a looser fit.

• Why It Fails: Reaming strips away the thin PTFE self-lubricating layer. Once removed, bare bronze or steel directly rubs against the shaft, leading to rapid galling and seizure.

• Correct Method: ID dimensional closure is engineered into the press-fit calculation. Adjust housing bore tolerances (H7) or shaft tolerances (f7/h8) instead of machining the bushing lining.

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3. Ignoring Housing Chamfer and Bore Cleanliness

• The Mistake: Pressing the bushing into a sharp, unchamfered housing bore or leaving metal burrs and grit behind.

• Why It Fails: Sharp housing edges scrape the outer steel backing, creating burrs that misalign the bushing. Dirt particles trapped behind the backing create localized high spots on the inner surface.

• Correct Method: Machine a 20°+/-5° lead-in chamfer on the housing bore and thoroughly deburr and degrease before fitting.

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4. Applying Unapproved Greases or Solvents

• The Mistake: Packing the bushing with heavy grease containing solid EP additives (like MoS₂) or cleaning with aggressive chemical solvents.

• Why It Fails: Certain solvents weaken the bronze-to-PTFE bond. Heavy solid additives can clog the porous bronze matrix, preventing normal PTFE transfer film formation on the mating shaft.

• Correct Method: DU bushings operate best dry. If initial assembly lubrication is required, apply a thin film of light mineral oil or manufacturer-approved synthetic lubricant.

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5. Incorrect Split-Line Alignment

• The Mistake: Aligning the longitudinal split joint directly in the main load zone.

• Why It Fails: Placing the split in the maximum load zone causes localized deflection and accelerated wear along the seam.

• Correct Method: Position the split joint 90 ° away from the primary radial load direction.

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Step-by-Step Installation Procedure

Quick Reference: Recommended Tolerances & Tools