# Mainshaft front bearing to housing shim clearance (NA6 5MT)

Canonical URL: https://miatatorque.com/spec/mainshaft-front-bearing-housing-clearance-na6-5mt/

Applicability: NA 1990–1993 (B6, 5MT) — 1991–1993 inferred from 1990 factory evidence; actual-year verification is separate.

Confidence: fsm

0–0.1 mm (0–0.004 in)

Always confirm against your factory manual. Match every restriction and follow all stages and procedure notes. Disputed claims must not be automatically resolved. The complete record below preserves every printed unit, source claim and procedure.

```json
{
  "id": "mainshaft-front-bearing-housing-clearance-na6-5mt",
  "name": "Mainshaft front bearing to housing shim clearance (NA6 5MT)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NA",
      "years": [
        1990,
        1993
      ],
      "engines": [
        "B6"
      ],
      "trans": [
        "5MT"
      ],
      "note": "1991–1993 inferred from 1990 factory evidence; actual-year verification is separate."
    }
  ],
  "kind": "non-torque",
  "value_text": "0–0.1 mm (0–0.004 in)",
  "procedure": {
    "notes": "After pressing the mainshaft front bearing into the bearing housing, measure the bearing-to-housing clearance and select adjustment shims. Printed shim thicknesses: 0.1 mm (0.004 in), 0.15 mm (0.006 in), 0.3 mm (0.012 in)."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1990",
      "page": "J–30 (PDF p. 362)",
      "as_printed": "Standard clearance: 0—0.1mm (0—0.004 in)\nAdjustment shim:\n0.1mm (0.004 in), 0.15mm (0.006 in),\n0.3mm (0.012 in)",
      "verified_years": [
        1990,
        1990
      ],
      "document": {
        "id": "fsm-1990",
        "tier": 1,
        "title": "1990 Mazda MX-5 Miata Workshop Manual",
        "part_number": "1193-10-89C",
        "covers": [
          {
            "gen": "NA",
            "years": [
              1990,
              1990
            ],
            "engines": [
              "B6"
            ]
          }
        ],
        "url": "https://archive.org/details/1990-mazda-mx-5-miata-workshop-manual_202411"
      }
    }
  ],
  "jobs": [],
  "system": "transmission",
  "component": "inventory-pass-2026-10",
  "componentName": "Service measurements and fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/mainshaft-front-bearing-housing-clearance-na6-5mt/"
}
```