Description
Bolt 6mm Steel Bushing Set for M4 AEG (M4GB20)
This is a set of 6mm steel bushings from Bolt for M4-pattern AEG gearboxes, part code M4GB20. Bushings sit in the gearbox shell and support the axles of the gears, so they are a key part of a reliable gearbox. Bolt is a Taiwanese manufacturer known for its M4-pattern replicas and parts.
Worn, cracked or loose bushings are a common cause of noisy and inefficient gearboxes. Replacing them during a service or rebuild helps keep the gears running true and the gear mesh consistent.
What bushings do
Each gear in an AEG gearbox turns on an axle that is held in the shell by a bushing or bearing on either side. If a bushing wears or comes loose, the gear can wobble, which wears the teeth, increases noise and puts extra load on the motor. A good set of bushings keeps everything aligned.
Steel bushings
Bushings are plain sleeves with no moving parts, so they are simple and tolerant of shock. Steel is a hard-wearing material for this job. Many players use bushings as a robust choice for everyday builds, while others prefer ball bearings for lower friction; both are common in M4 gearboxes.
Fitting
Bushings are fitted with the gearbox open. Clean the bushing seats, press each bushing in squarely and check that it sits flush. Many techs add a tiny drop of suitable adhesive to stop bushings spinning in the shell, being careful not to get it inside the bushing. Shim the gears afterwards so they turn freely without play.
Key features
- 6mm bushings from Bolt
- Steel construction
- Listed for M4 AEG gearboxes
- Part code M4GB20
- Supports gear axles and keeps gears aligned
- Ideal for a gearbox service or rebuild
Compatibility
Listed for M4 AEGs, which normally use a Version 2 style gearbox. 6mm is the common bushing size for these gearboxes, but some replicas differ, so check your gearbox before ordering. The number of bushings in the set is not stated in the listing.
Care and maintenance
When servicing, clean old grease out of the bushings and add a small amount of suitable lubricant. Check for play in the gears whenever the gearbox is open, and re-shim if necessary. Excess grease attracts dirt and debris, so keep it light.
Who is it for?
This bushing set suits players and techs servicing or rebuilding an M4-pattern AEG gearbox.
Please note: Gearbox and gears are not included. Check your gearbox type before ordering.
