Separate the isolation.
Connect the body fixings.
A connected thin cradle and hollow crossmember replace the former solid support cues. Each rubber has separate metal faces and opposing stud envelopes. Shared base and tunnel-side reference holes expose the body attachment roles. Paired extension pad comparisons now receive the inner stud axes. Fitted engagement and loaded support remain unverified.
Inspect the support chain
Factory and supplier evidence
Factory parts PDF p. 72 separates CHA266 rear bracket, two rear rubbers and the base/side fixing roles. It lists 122689 before CHA615 at GAN6-176236, with a note to use CHA615 in pairs. Neither branch is identified as fitted. Front CHA280/CHA565 and North American restraint/cable/tie-bar roles remain separate comparisons.
The factory calls the two side screws “bracket to gearbox cover”; the MGOC catalogue and Rimmer catalogue describe the corresponding bracket-to-gearbox-tunnel-side role. This supports the displayed body-cover comparison, without verifying this car’s attachment map. Supplier BH606281 dimensions provide an 88.9 mm under-head long-bolt comparison; actual hardware, thread engagement, locking and torque remain unknown.
Existing IMG_7041 gives visible front filter-side mount context, IMG_6919 front underbody context and IMG_6341 cabin context. These remain owner evidence; they do not calibrate the rear bracket, hidden joints or loaded rubber condition. Existing records were reconciled before using construction estimates. No new direct owner rear-support dimensions are applied.
Evidence for the missing gearbox-side connection
The RW Auto Classics donor listing has opposing side views showing a compact mounting bracket, two inclined rubbers and integral rear-extension pads. These are unscaled architecture references, not fitted-car identification or dimensions. The prior rubbers atX±169.3333 mm were too far outboard to meet the modeled tail. RevisedX±80 mm centers and pad/cradle profiles make the drawing relationship explicit while retaining its uncertain installation.
Material geometry changes
Cradle and body-cover fixings
A narrower connected338.6667 mm-wide,3 mm-gauge cradle now has inclined rubber faces, moved outer webs, provisional return bridges and retained tunnel-side ears. Two base holes match the hollow crossmember; two side holes match the retained tunnel shell. Every gauge, contour, station and bore is estimated. This is not a drilling, repair or attachment template.
Isolation and studs
The old continuous rod through each rubber becomes two separate opposing stud envelopes. Rubber centers move fromX±169.3333 to estimatedX±80 mm under retained localY/Z stations. Inclines and outside radius stay drawing choices. Metal end plates now meet the two rubber faces instead of penetrating the rubber; this construction contact does not model bonding or compression. Bonded metal faces, cradle nuts and washers are separate. Roots, rubber bond, compression and load transfer are not simulated.
Crossmember and floor returns
The former slab becomes a hollow section with open raised end channels. Top floor returns rise 2.7333 mm from the prior drawing to the existing floor underside. The thin cradle face meets the revised metal end-face plane under shared construction datums. Both are declared construction changes, not measured packing, fitted seating or support strength.
Paired extension pads
Factory and donor views show angled cast pads receiving the inner mount studs. Native extension geometry now includes64×68 mm pad-face comparisons and plain4.5 mm-radius bores at the revised rubber axes. Profile, root depth, coordinates and bore sizes are estimates; threads, fitted rubber variant and loaded engagement are unresolved. Crossmember, base/tunnel body fixings, engine and exhaust references remain unchanged.
Source contacts stay visible
The limited static sample compares the support parts with retained cabin, transmission and underfloor-exhaust sources. Positive volumes below are reconstruction discrepancies or overlapping source divisions, not fitted-car interference findings. They do not prove loaded gearbox clearance or a supported installation.
| Source comparison | Positive contact mm³ |
|---|---|
| rear power hollow crossmember and open floor returns / underfloor cross car main pipe reference | 5613.5616 |
| rear power connected folded cradle inclined faces and tunnel ears / cabin hollow tapered tunnel with declared lever mouth reference | 1689.0322 |
| rear power connected folded cradle inclined faces and tunnel ears / cabin left floor with retained seat bores reference | 7.8287 |
| rear power connected folded cradle inclined faces and tunnel ears / cabin right floor with retained seat bores reference | 7.8287 |
| rear power connected folded cradle inclined faces and tunnel ears / underfloor cross car main pipe reference | 4482.5865 |
| rear power two tunnel side washer envelopes / cabin hollow tapered tunnel with declared lever mouth reference | 6.5549 |
Workshop boundary
The existing front-mount study cites UK factory operations 12.45.01/03, PDF p. 9 / printed p. 82. Those operations concern front mounts and do not establish an applicable North American rear-support replacement sequence. The complete fitted rear procedure, lifting/support method and tightening values remain unresolved.
The cradle and body crossmember stay fixed while small parts separate for visibility. Those choices do not establish removal ownership/order, a release vector, safe support or lifting height. The crossmember is not identified as a jack point or detachable extraction opening. No restraint installation, loaded mount travel, tunnel/exhaust operating clearance or verified replacement/removal path is supplied.
Native exports and validation
Source checks cover positive valid solids and STEP volume/count round-trip, a connected cradle/extension, shared base/tunnel/rubber/pad passages, separated rubber/end plates and nonintersection with the exported extension. These construction checks preserve the recorded cabin/exhaust conflicts. Viewer checks cover metric placement/picking, bore and material witnesses, stud separation, isolation and declared inspection movement. These validate source construction rather than fitted strength, compression or service clearance.