S1 Chassis Info

The chassis number for these models is composed of an initial fixed letter B followed by a number from 1 to 651. Finally two letters, the first of which determines the series of the model.

Left hand drive models have an L preceding the last two letters.

The chassis number can be found on a plate attached to the engine compartment bulkhead.

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Release Date	Chassis Number	Modification Detail	introduced at Chassis:
Apr. 55 to Nov. 55	B2AN to B500AN	Increased diameter rear engine mounting bolts and modified bracket	B268AN
Sep. 55 to Feb. 56	B1AP to B501AP	Modified butterfly valve and countersunk screws, SU carburetter	B270AN
		Introduction of thick washer under fulcrum bracket bolt lock plate to compensate for distortion of lugs on front pan	B296AN
		Steering ball joint castle nuts with increased bearing surface	B340AN
		Front Spring support plate with welded on stabiliser bracket attachment	B430AN
		Modified bosses to increase strength of rear axle tube	B476AN
		Increased friction on brake shakeback stops and increased load on servo return spring	B492AN
		Improved sealing between windscreen washer and wiper mounting and body	B492AN
		Setscrews in place of studs for main bearing caps	B39AP
		Improved water and oil mist sealing on servo	B41AP
		Strengthened spring support plates on front suspension	B87AP
		Modified rear loom to cut out brake light on side on which flasher is in operation	B155AP
		Modified flanges on exhaust fittings	B257AP
		Brake wheel cylinder material changed from aluminium to cast iron	B273AP
		Filter in brake fluid supply tank	B287AP
		Stronger clamps for rear anti-roll bar	B341AP
		Provision of drag links with greater resistance to kinking under compression	B383AP
		Modified type of rear engine mounting	B411AP
Dec, 55 to Mar. 56	B2BA to B250BA	Introduction of aluminium brake master cylinder	B20BA
Feb. 56 to Apr. 56	B1BC to B251 BC	Modified push button and door handle	B158BA
		Increased number of fixing holes in rear axle tube	B198BA
		Folding arm rests in front seats	B210BA
		Steering lever with taper roller bearings in place of bushes	B51BC
		Strengthened front suspension fulcrum bracket	B109BC
		Modified shakeback stop on front and rear brake assemblies	B115BC
		Dual brake master cylinders	B245BC
Apr. 56 to Jul. 56	B2CK to B500CK	Radiator and drain tap suitable for revised frame	B60CK
Jul. 56 to Nov. 56	B1CM to B501CM	Modified sealing ring, centre steering operating lever (P.A.S.)	B178CK
		Modified dynamo and voltage regulator	B188CK
		Welded frame stiffeners on each side of jacking bracket	B218CK
		Introduction of copper petrol pipes	B326CK
		Reach nut and washer to suit new spot facing of ball and trunnion joint body, output shaft to prop. shaft	B352CK
		Uphill run pipes from twin master cylinders to supply tank	B376CK
		Revised frame (splayed ends)	B27CM
		Reversal of power cylinder mounting bolt (P.A.S.)	B262CM
Sep.56 to Nov. 56	B2DB to B350DB	Introduction of 18,7 steering ratio on left hand drive cars	B46LDB
Oct. 56 to Jan. 57	B1DE to B351DE	Increased number of fixing holes in rear axle centre casing	B122DB
		Voltage regulator with swamp resistance (H type)	B25DE
		Introduction of oil deflector plate in rear shock damper	B249DE
Jan. 57 to Jul. 57	B2EG to B650EG	Strengthened front shock damper body (introduction of sleeve in mounting bolt bore)	B170EG
Jul. 57 to Dec. 57	B1EK to B651EK	Stronger front shock damper	B316EG
		Combined inertia and starter ring modified starter drive and stiffened clutch casing	B530EG
		Stronger fulcrum pin axle yoke	B542EG
		New trim pad clips and retainers	B544EG
		Improved propeller shaft centring button	B562EG
		2:1 ratio dynamo pulley	B628EG
		Stiffened cam wheel	B41EK
		Improved type door seals	B101EK
		4-Point fixing of number plate and reversing lamp	B133EK
		Modified rear axle shaft flange	B243EK
		8:1 compression ratio engine	B257EK
		Dunlop P.AS. expansible hose, alternative t Chrysler	B375EK
Nov. 57 to Jun. 58	B2FA to B650FA	Modified stub axle yoke seal	B377EK
Jun. 58 to Mar. 59	B1FD to B651FD	Stronger drag links	B379EK
		Modified ashtray finisher	B389EK
		Strengthened door hinges	B471EK
		Introduction of shock dampers with increased size end cover studs	B555EK
		Introduction of ‘Roto’ finished pulleys	B627EK
		Introduction of strengthened adjusting sleeve, steering cam D.R.3 windscreen wiper motor	B365EK
		Stronger rear stock damper link bushes	B54FA
		Deletion of idler lever lubrication pipe	B136FA
		Modified rear silencer mounting to prevent burning mounting rubber	B338FA
		lntermediate heater and demister contols	B350FA
		Introduction of 6” drive pulley, compressor clutch ("R.R" interior cooling)	B186FA
		Improved front door ventilator sealing	B388FA
		Wire type clips on propeller shaft grease seal	B438FA
		Improved type rear brake expander wedges	B454FA
		Final type modified stub axles	B458FA
		Twin jet. centrally mounted windscreen washer	B472FA
		Improved propeller shaft seal	B352FA
		Grease lubricated track rods	B556FA
		Improved window channel guides to ease opening in adverse weather	B556FA
		Large diameter rear axle shaft splines	B590FA
		Grease lubricated centre steering	B664FA
		Enlarged shakeback stop slot In brake shoe web	B43FD
		Modified run of hand brake cable	B45FD
		Strengthened front hubs	B65FD
		C.48 dynamo	B71FD
		Introduction of plain washers at each end of pivot distance piece on braking system direct and intermediate linkage	B129FD
		Improves type of horn footswitch (optional)	B159FD
		Replacement of .250” dia. wing and valance plate bolts and screws with .3125” dia.	B359FD
		Modified door handles with button sealing	B433FD
		Sun visor with improved driver’s vision	B457FD
		Free wheeling boot lock, Deletion of check valve In brake fluid supply pipes	B513FD
		Increased capacity boot type refrigeration	B579FD
		Modified window channels to reduce winding loads under adverse weather conditions	B607FD
		Thermal conductor type water temperature gauge	B637FD
		Modified window regulator handle to prevent fouling of trim pad	B645FD
		Simplified starter relav mounting, Special battery lid for export cars	B649FD
Feb. 59 to Apr. 59	B1GD to B125GD	Seal between bearing housing and body front shock damper	B35GD
Mar. 59 to May 59	B2GC to B126GC	Modified form of front brake shoe link, extended neck on propeller shaft seal	B4GC
		Modified heater and demister connections on radiator	B24GC
		R.L. headlight unit	B22GC
		Modified clips in electric window winder fuse box	B118GC
		Introduction of purolator air filter on cars with interior cooling	B126GC
May 59 to Jun. 59	B1HB to B45HB	No recordable modifications
May 59 to Jun. 59	B2HA to B50HA