Applicable machines: cranes / excavators / aerial work platforms (AWPs) and other telescopic-boom equipment
Applicable parts: boom wear pads / slide pads / wear strips

Key takeaways (1-minute read)

If a telescopic boom jerks at low speed (“stick—move—stick”), with chatter or squealing noise, the cause is often not the hydraulic system itself. A very common root cause is an unstable friction condition called stick-slip (adhere → suddenly slide → adhere again) at the boom’s guide/support interfaces.

Using nylon wear pads made from MC cast nylon (PA6G) (e.g., MC901 / MC907) can often help by:

• Lower and more stable friction: reduces friction fluctuation and lowers stick-slip risk
  
• Wear resistance: slows clearance change, reducing uneven wear and repeat service
  
• Damping: reduces sharp metal-to-metal noise and vibration amplification
  

To get truly smooth motion, you must also control: retention/fixing method, shims (clearance), contact surface condition (Ra surface roughness), and dust/sand protection. For safety-critical repairs, always follow the OEM service manual and site safety procedures.

Contents

• Why booms creep/chatter/squeal: 3 common root causes
  
• Why MC cast nylon wear pads can run smoother
  
• 1-minute quick diagnosis table
  
• Service workflow: tighten → clean → adjust shims → verify
  
• Contact surface roughness (Ra): practical principles
  
• Dust/sand conditions: protection, cleaning, inspection, replacement decisions
  
• FAQ for workshops / rental fleets / aftersales
  
• Get a catalog & quick quote (inquiry checklist)
  

Why telescopic booms creep, chatter, or squeal: 3 common root causes

1) Friction mechanism: stick-slip is a common driver of low-speed “creep”

Under low speed, high load, and intermittent motion, the interface can behave as “static friction > dynamic friction.”
 The boom sticks, force builds, then it slips suddenly, then sticks again—repeating in cycles. This produces low-speed jerk, vibration, and noise.

Typical field signs

• Worse at low speed; often less noticeable at higher speed
  
• More obvious under heavier load
  
• Noise often sounds like “dry squeal” rather than low-frequency hydraulic pump hum
  

2) Mechanical factors: clearance (shims) and retention faults amplify instability

Clearance too tight

• More likely to bind and squeal; low-speed jerk becomes more obvious
  
• Signs: localized polishing, scuffing, or heat marks
  

Clearance too loose

• More “knock” or looseness; uneven wear accelerates
  
• Signs: one side wears much faster than the other
  

Retention issues (retaining plates/bolts/pad seats)

• Pads can shift; contact pressure becomes uneven
  
• Noise may come and go, usually worsening over time
  
• Common findings: loose bolts, warped plates, chipped pad edges
  

3) Contamination: dust/sand accelerates recurrence

When grit enters the sliding interface:

• Particle embedment: grit presses into the pad surface and becomes hard points that scratch the boom surface
  
• Grooving/scoring: surface grooves increase friction fluctuation → easier to trigger stick-slip
  

Why MC cast nylon wear pads can run smoother: friction stability + wear life + damping

More stable friction: fewer “spikes,” lower stick-slip probability

Stick-slip is promoted by friction that changes abruptly. In many real-world conditions, MC cast nylon pads can provide a more stable friction response, which helps reduce low-speed jerk and squeal.

Wear resistance: slower clearance growth, less uneven wear

As pads wear, clearances change and guiding can become unstable—leading to chatter and uneven wear. Wear pads help keep clearance changes slower and more controllable, reducing repeat repairs.

Damping: less sharp metal-to-metal noise

Polymers add damping, so vibration is less likely to amplify into sharp noise—especially compared with metal-to-metal contact.

1-minute quick diagnosis table

Service workflow: tighten → clean → adjust shims → verify

Step 1: Tighten and inspect the structure (rule out “false faults”)

• Confirm retaining plates and fasteners are present and tight
  
• Check for warped plates or worn pad seats
  
• Tighten first, then re-test (often saves time)
  

Step 2: Clean and remove contamination (highest priority in dusty jobs)

• Remove sand, mud, and debris from pad and contact surfaces
  
• If you find grit embedment or deep grooves, replace the pad (continued use may accelerate boom-surface damage)
  
• Inspect the boom contact surface for scoring
  

Step 3: Adjust shims (critical for smoothness and pad life)

• If symptoms are binding/squeal/strong low-speed jerk → likely too tight: reduce shim thickness or reset evenly
  
• If symptoms are knock/looseness/uneven wear → likely too loose: add shims to stabilize guiding
  
• Keep clearances even (avoid adjusting only one side)
  

Step 4: Low-speed verification (must do before returning the machine)

• Fine, low-speed motion is the easiest way to reproduce stick-slip
  
• Cycle extension/retraction 5–10 times and watch whether it “gets hotter/louder” with cycles
  

Pass criteria (practical)

• Low-speed motion is more linear; jerk is clearly reduced
  
• Noise shifts from sharp dry squeal to normal running sound
  
• No obvious knock or looseness
  

Contact surface roughness (Ra): practical principles

For web content, it’s better to state principles rather than a single Ra number (optimal Ra varies by design and pairing).

Three principles

1. Avoid extreme mirror finishes: ultra-smooth surfaces are not always best and can increase stick-slip in some pairings
   
2. Aim for consistency: avoid “polished bands” next to rough zones
   
3. Verify by results: low-speed linearity and noise behavior are the final judges
   

When the contact surface must be addressed

• Deep grooves/scoring
  
• Localized “mirror bands” (often indicates uneven pressure)
  
• Early recurrence soon after pad replacement
  

Minor issues may be cleaned/deburred; severe damage should be handled per repair standard or part replacement.

Dust/sand conditions: protection, cleaning, inspection, replacement decisions

1) Protection first (keep grit out of the interface)

• Inspect wipers/guards/baffles for damage or missing parts
  
• Close off exposed guiding areas where possible
  
• During cleaning, avoid forcing grit into sliding surfaces
  

2) Cleaning strategy: light but frequent

Dusty sites benefit from shorter inspection/cleaning intervals. Dried mud can behave like abrasive particles and increases scoring risk.

3) Inspection checklist (6 items)

1. Pad surface: embedment, grooves
   
2. Uneven wear
   
3. Retaining plates/bolts: looseness, missing parts
   
4. Shims: missing pieces, crushed shims
   
5. Boom contact surface: scoring, localized mirror bands
   
6. Low-speed test: linearity, jerk, squeal
   

4) When to replace pads (condition-based)

• Visible embedment that can’t be cleaned out
  
• Severe grooves and unstable friction behavior
  
• Chipping/crushing/deformation
  
• Abnormal uneven wear (continued use may damage the boom surface)
  

FAQ (workshops / rental fleets / aftersales)

Q1: How do I tell a wear-pad issue from a hydraulic issue?
 If it’s worse at low speed and improves at higher speed, with dry squeal and signs of embedment/uneven wear/looseness, it’s often friction/clearance/contamination. If it’s weak at all speeds with slow response system-wide, hydraulic supply/valving becomes more likely.

Q2: Why can the issue remain after replacing pads?
 Because retention, shim clearance, contact surface condition, or dust protection was not addressed. Pad replacement alone is only part of the fix.

Q3: Is tighter clearance always better?
 No. Too tight causes binding and low-speed jerk; too loose causes knock and uneven wear. Aim for stable, controllable, even clearance—verified by low-speed testing.

Q4: What’s the most important prevention in dusty conditions?
 Protection (wipers/guards/baffles) first, then frequent inspection. If you see embedment or grooves, address it early to avoid boom-surface damage.

Q5: Should I polish the contact surface to a mirror finish?
 Not necessarily. Uniformity and damage-free surfaces matter more. Extreme mirror finishes can increase stick-slip in some pairings.

Q6: How do I choose between MC901 (blue) and MC907 (natural)?
 Choose based on operating conditions (dust level, load, frequency) and design constraints (retention, shim space). If unsure, share your conditions and dimensions/drawing for a recommendation.

Q7: Can you produce pads by drawing or sample? What info do you need?
 Dimensions (L×W×T), holes/countersinks/chamfers, retention method, whether shims are used, operating conditions, quantity/lead time, and delivery location.

Q8: How do we reduce repeat repairs?
 Follow the sequence: tighten → clean → shim evenly → replace pads if needed → low-speed verify, and improve dust protection.

Get a catalog, specs, and a quick quote (Inquiry checklist)

We can provide:

• MC cast nylon boom wear pads / slide pads (PA6G: MC901 / MC907)
  
• Custom machining by drawing or sample (dimensions, holes, thickness, shape)
  
• Installation & maintenance guidance: retention method, shim clearance logic, dust/sand protection and inspection points
  
• Quality & consistency: stable dimensions and smooth surface finish; internal quality checks before shipment
  

Copy-and-paste inquiry checklist

• Machine type: crane / excavator / AWP / other: ____
  
• Location on boom: guide pad / support pad / wear strip / other: ____
  
• Symptoms: creep / chatter / noise / binding / uneven wear (multi-select)
  
• Site conditions: dust/sand level? frequent low-speed motion? ____
  
• Size or drawing: L__ × W__ × T__ (mm) / please send drawing or photos
  
• Retention method: retaining plate / bolt holes / shims used? ____
  
• Preferred material: MC901 / MC907 / need recommendation
  
• Quantity: __ pcs; spare sets needed? __
  
• Delivery country/city: ____; required lead time: ____