| Description | Date | Identifier | |
| Gearbox synchromesh rattles by trying a second design alternative with longitudinal grooves. | 21th Jun 1934 | Box 86 \ 4 scan0097 | |
| Modifications to the reverse shaft and pinion for a special high ratio Bentley gearbox. | 7th Jul 1934 | Box 86 \ 4 scan0098 | |
| Request to fit a component to prevent synchromesh rattles when starting in second gear. | 17th Jul 1934 | Box 86 \ 4 scan0099 | |
| Solution for gearbox sleeve rattles in a Bentley. | 2nd Aug 1934 | Box 86 \ 4 scan0100 | |
| Requesting the manufacture of stronger springs for a Bentley synchromesh sleeve anti-rattle scheme. | 27th Aug 1934 | Box 86 \ 4 scan0101 | |
| Testing and potential use of magnesium parts, like gearboxes and dashboards, on Bentley cars. | 7th Sep 1934 | Box 86 \ 4 scan0102 | |
| Standardisation of a locating plunger to prevent synchromesh parts rattling in the gearbox. | 6th Sep 1934 | Box 86 \ 4 scan0103 | |
| Estimated cost and production schedule for extra jigs, tools, and equipment for the 'C' series chassis. | 3rd Sep 1934 | Box 86 \ 4 scan0104 | |
| Proposal to modify the Wraith gearbox for the Bentley by reducing the 3rd speed gear ratio from .8 to .774. | 19th Oct 1934 | Box 86 \ 4 scan0105 | |
| Letter to S. Smith & Sons regarding high oil pressure readings from an oversize oil pump on a 20/25 HP chassis. | 22th Dec 1934 | Box 86 \ 4 scan0106 | |
| Letter from S. Smith & Sons discussing the pressure testing of an oil gauge and recommending a special gauge. | 29th Dec 1934 | Box 86 \ 4 scan0107 | |
| Letter to S. Smith & Sons Ltd. regarding the risk of using a 40 lb. gauge and a request for a 60 lb. gauge for trial. | 2nd Jan 1935 | Box 86 \ 4 scan0108 | |
| Modifications to the Bentley Isolated Change Gear Lever. | 2nd Feb 1935 | Box 86 \ 4 scan0109 | |
| Requesting the manufacture of several sets of modified isolated gear levers for the 20/25 and Bentley models. | 2nd Feb 1935 | Box 86 \ 4 scan0110 | |
| Bracket, adjustments, and stiffener for an isolated gear lever on a Bentley. | 19th Feb 1935 | Box 86 \ 4 scan0111 | |
| Progress of the change speed lever mechanism for 20/25 and Bentley models. | 29th Mar 1935 | Box 86 \ 4 scan0112 | |
| Development, testing, and production of an isolated change speed lever for Bentley cars. | 29th Apr 1935 | Box 86 \ 4 scan0113 | |
| Improvement to the Isolated Change Speed Lever for Bentley. | 1st May 1935 | Box 86 \ 4 scan0114 | |
| The dispatch of a scheme for a gas tight isolated change gear housing. | 11th May 1935 | Box 86 \ 4 scan0115 | |
| Gearbox modifications for a Large Bore Bentley to address overloaded half shafts. | 15th May 1935 | Box 86 \ 4 scan0116 | |
| Higher first speed gear ratios for the Large Bore Bentley. | 31th May 1935 | Box 86 \ 4 scan0117 | |
| Requesting the fitting of altered cantilever pedals for a Bentley. | 26th Jun 1935 | Box 86 \ 4 scan0118 | |
| Customer complaints about rattling gear levers and seeking a solution. | 27th Jun 1935 | Box 86 \ 4 scan0119 | |
| Modifications to the Bentley gearbox for a higher first speed. | 2nd Jul 1935 | Box 86 \ 4 scan0120 | |
| Standardisation of an isolated change speed lever to remove rattles. | 16th Apr 1935 | Box 86 \ 4 scan0121 | |
| Cost estimation for extra jigs and tools, with a cost comparison between an old and a new part. | 28th May 1935 | Box 86 \ 4 scan0122 | |
| Improvement to the gear lever reverse stop spring for all cars. | 8th Jul 1935 | Box 86 \ 4 scan0123 | |
| Cure for gear lever rattles on Bentley and 20/25 HP cars. | 17th Jul 1935 | Box 86 \ 4 scan0124 | |
| Gear lever rattles and retrofitting a standardised isolated change speed lever to Bentley and 20/25 HP cars. | 18th Jul 1935 | Box 86 \ 4 scan0125 | |
| Confirming the dispatch of a drawing showing modifications to an isolated gear lever's ball bearing mounting. | 4th Aug 1935 | Box 86 \ 4 scan0126 | |
| Issue with second gear jumping out on Bentley Chassis B.161-CW while touring in Switzerland. | 17th Sep 1935 | Box 86 \ 4 scan0127 | |
| Complaints of the second gear jumping out of mesh on 20/25 HP & Bentley models. | 31th Oct 1935 | Box 86 \ 4 scan0128 | |
| Proposal to investigate 'chunking in the drive' on a Bentley by isolating the gearbox. | 7th Nov 1935 | Box 86 \ 4 scan0129 | |
| Production and wear of Fabroil timing gears on the Bentley. | 5th Dec 1935 | Box 86 \ 4 scan0130 | |
| Testing a locked solid universal change speed mechanism to diagnose and resolve gear lever rattles. | 2nd Jul 1936 | Box 86 \ 4 scan0131 | |
| Request to manufacture stronger synchromesh anti-rattle springs for a Bentley gearbox. | 15th Jul 1936 | Box 86 \ 4 scan0132 | |
| Standardisation of parts for servo threads on synchromesh cones on drawing G.83964. | 22th Jun 1936 | Box 86 \ 4 scan0133 | |
| Cost estimate and production timeline for extra equipment for the 'J' Series Chassis. | 15th Jul 1936 | Box 86 \ 4 scan0134 | |
| Modification to a 25/30 & Bentley gearbox design to overcome lateral binding. | 14th Sep 1936 | Box 86 \ 4 scan0135 | |
| Growing complaint regarding driving dogs on the 4 1/4 litre Bentley. | 27th Oct 1936 | Box 86 \ 4 scan0136 | |
| Requesting specific Bentley gearbox parts for a cost comparison with Phantom III pieces. | 1st Dec 1936 | Box 86 \ 4 scan0137 | |
| Requesting to try a Hoffman bearing N.2583 in a Bentley rear axle. | 29th Dec 1936 | Box 86 \ 4 scan0138 | |
| The material of adjusting washers for the bevel pinion main bearing on a Bentley chassis. | 16th Apr 1937 | Box 86 \ 4 scan0139 | |
| Confirmation memo requesting a new Bentley gearbox for destruction testing on a dynamometer. | 16th Apr 1937 | Box 86 \ 4 scan0140 | |
| Instructing the despatch of five scrap Hoffman Ball Bearings to the manufacturer for examination. | 2nd Jun 1937 | Box 86 \ 4 scan0141 | |
| Letter to The Hoffman Manufacturing Co. regarding the return of five noisy bearings from a Bentley gearbox. | 2nd Jun 1937 | Box 86 \ 4 scan0142 | |
| Acknowledgment of enquiry from The Hoffmann Manufacturing Co., Ltd. | 12th Jun 1937 | Box 86 \ 4 scan0143 | |
| Report from The Hoffmann Manufacturing Co. Ltd. on the examination of failed bearings from a Bentley gearbox. | 12th Jun 1937 | Box 86 \ 4 scan0144 | |
| Failed Bentley gearbox bearing due to being fitted too tightly in the casing. | 15th Jun 1937 | Box 86 \ 4 scan0145 | |
| Requesting an update on the mock-up for the Bentley with Overdrive. | 7th Jul 1937 | Box 86 \ 4 scan0146 | |
| Development of a Bentley with Overdrive, proceeding with experimental sketches. | 8th Jul 1937 | Box 86 \ 4 scan0147 | |
| Requesting the production of one set of Bentley 1st and 3rd Motion Shaft components from two blueprints. | 9th Sep 1937 | Box 86 \ 4 scan0148 | |
| Sending blueprints for a Bentley 1st and 3rd motion shaft and requesting the production of one set. | 3rd Sep 1937 | Box 86 \ 4 scan0149 | |
| Return of a Ransome & Marles ball bearing from a Bentley Gear Box. | 22th Sep 1937 | Box 86 \ 4 scan0150 | |
| 100-hour dynamometer test of a Bentley gearbox with a magnesium casting. | 18th Nov 1937 | Box 86 \ 4 scan0151 | |
| The casting and introduction of an overdrive gearbox for the Bentley 'M' series. | 25th Nov 1937 | Box 86 \ 4 scan0152 | |
| The production schedule for the Bentley Overdrive Gearbox for the 'M' Series. | 27th Nov 1937 | Box 86 \ 4 scan0153 | |
| Instruction to slow production on parts for the 'M' Series Bentley gearbox due to a potential overdrive introduction. | 3rd Dec 1937 | Box 86 \ 4 scan0154 | |
| Requesting information on the production possibilities of the Bentley Overdrive Gearbox. | 16th Dec 1937 | Box 86 \ 4 scan0155 | |
| New layshaft drawing (PD.82) for the Bentley 50 and Wraith gearbox. | 22th Dec 1937 | Box 86 \ 4 scan0156 | |
| Outlining the introduction and associated costs for the Bentley Overdrive Gearbox. | 15th Jan 1938 | Box 86 \ 4 scan0157 | |
| Extra factory cost for the Overdrive Gearbox on a Bentley chassis. | 27th Jan 1938 | Box 86 \ 4 scan0158 | |
| Particulars of the synchromesh springs, grooves, and cam angles for the new Bentley gearbox. | 7th Feb 1938 | Box 86 \ 4 scan0159 | |
| Introduction of a new 2nd and 3rd Motion Shaft for the Bentley M Series Overdrive Gearbox. | 24th May 1938 | Box 86 \ 4 scan0160 | |
| Requesting the rebuild of a gearbox after a propeller shaft failure, with instructions for reassembly. | 8th Jul 1938 | Box 86 \ 4 scan0161 | |
| Investigation into a third-speed pinion failure in a Bentley 11 gearbox, with proposed modifications. | 20th Sep 1938 | Box 86 \ 4 scan0162 | |
| Modification to a Bentley Chassis gearbox front end cover and the dispatch of two blueprints. | 3rd Feb 1939 | Box 86 \ 4 scan0163 | |
| Suggestion for the instruction book regarding the M. Series 4 1/4 litre gearbox and gear changing. | 23th Mar 1938 | Box 86 \ 4 scan0164 | |
| Note about replacing steel bushes with brass bushes in an overdrive gearbox ahead of a trip to France. | 21th Jan 1938 | Box 86 \ 4 scan0165 | |
| Merits and issues of the Bentley overdrive gearbox. | 15th Dec 1937 | Box 86 \ 4 scan0166 | |
| Proposal to replace the third speed with an overdrive on the Bentley III Gearbox. | 20th Apr 1937 | Box 86 \ 4 scan0167 | |
| Implications of fitting an overdrive gearbox to Wraith and Bentley models, including changes to size, weight, cost and performance. | 17th Apr 1937 | Box 86 \ 4 scan0168 | |
| Performance curve comparison between a standard gearbox and a proposed overdrive for the Bentley III. | 17th Apr 1937 | Box 86 \ 4 scan0169 | |
| Modifications to the Bensport front horns (front dumb iron). | 27th Aug 1932 | Box 86 \ 4 scan0170 | |
| Scheme 3546 for the Bensport, detailing the rear engine supporting crossmember, front brake differential, and clutch pedal. | 21th Sep 1932 | Box 86 \ 4 scan0171 | |
| The dispatch of information for Bensport frame side members, specifically crossmembers. | 7th Nov 1932 | Box 86 \ 4 scan0172 | |
| The arrangement of a starting handle and front crossmembers for a Bensport (J.1) vehicle. | 7th Nov 1932 | Box 86 \ 4 scan0173 | |
| Blueprint for an experimental front end, engine suspension, and radiator support for the Bensport J.1. car. | 17th Nov 1932 | Box 86 \ 4 scan0174 | |
| Instructions and blueprints for radiator and engine suspension on the Bensport J.1. chassis. | 17th Nov 1932 | Box 86 \ 4 scan0175 | |
| Communication regarding modifications to the Bentport 3rd crossmember. | 7th Dec 1932 | Box 86 \ 4 scan0176 | |
| Design modification for the Bentley's front apron dumb iron covers after a part failed. | 6th Jul 1933 | Box 86 \ 4 scan0177 | |
| Requesting tests on chassis frame distortion for Bentley, 25-HP, and Phantom II models, with handwritten results. | 19th Jan 1934 | Box 86 \ 4 scan0178 | |
| Chassis frame distortion tests concluding that issues with doors not closing are due to the body, not the chassis. | 25th Jan 1934 | Box 86 \ 4 scan0179 | |
| Applying Terraplane frame bracing to a Bentley chassis to address frame jellying. | 1st May 1934 | Box 86 \ 4 scan0180 | |
| Modified crossmember for Bentley wings and lamps. | 31th Aug 1934 | Box 86 \ 4 scan0181 | |
| Request to investigate the vibration of the front end of a Bentley frame using a Chronograph. | 22th Sep 1934 | Box 86 \ 4 scan0182 | |
| Standardisation of parts for a dropped front cross member. | 25th Jul 1934 | Box 86 \ 4 scan0183 | |
| Cost estimate and production feasibility for extra jigs, tools, and equipment for the 'D' series chassis. | 3rd Sep 1934 | Box 86 \ 4 scan0184 | |
| Standardisation of a moved back battery cross member to increase rear seat foot room. | 23th Oct 1934 | Box 86 \ 4 scan0185 | |
| Estimated cost for extra jigs, tools, and equipment for a modification on the 'D' series. | 28th Sep 1934 | Box 86 \ 4 scan0186 | |
| Experimental department report on chassis deflection due to front braking on Bentley & Spectre models. | 18th Dec 1934 | Box 86 \ 4 scan0187 | |
| Chassis deflection tests under front braking forces for Bentley and Spectre models. | 18th Dec 1934 | Box 86 \ 4 scan0188 | |
| Frame buckling, chassis distortion, and front brake jaggering, with comparisons to other car models. | 18th Dec 1934 | Box 86 \ 4 scan0189 | |
| Modification notice for the Bentley Chassis regarding a new spherical end socket for the pedal shaft. | 22th Jan 1935 | Box 86 \ 4 scan0190 | |
| Improved fixing of the rear spring anchor bracket for a Bentley chassis. | 4th Feb 1935 | Box 86 \ 4 scan0191 | |
| Standardisation of a dropped front cross member between the head lamps to reduce headlamp movement. | 21th Jan 1935 | Box 86 \ 4 scan0192 | |
| Cost estimation for extra jigs, tools, and equipment, and a cost comparison between an old and a new part. | 8th Feb 1935 | Box 86 \ 4 scan0193 | |
| Design requirements for a cross member in the Bentley frame, considering gearbox configurations. | 26th Mar 1935 | Box 86 \ 4 scan0194 | |
| Test report on Bentley frame distortion under various loads. | 4th Apr 1935 | Box 86 \ 4 scan0195 | |
| Bentley frame distortion tests, detailing measurements at various points under different loads. | 27th Apr 1935 | Box 86 \ 4 scan0196 | |
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