| Description | Date | Identifier | |
| Letter confirming the dispatch of a set of Bentley single valve springs to a customer in France. | 30th Jul 1934 | Box 5a \ 4 04-page076 | |
| To G.W. Hancock regarding a report of valve bounce at 3450 r.p.m. on car 21-G-IV. | 30th Jul 1934 | Box 5a \ 4 04-page077 | |
| Letter from G.W.H. to H.S. regarding work on car 21 G IV and customs paperwork for re-entry into England. | 25th Jul 1934 | Box 5a \ 4 04-page078 | |
| Confirming that low rating springs are fitted to chassis 21-G-IV. | 26th Jul 1934 | Box 5a \ 4 04-page079 | |
| Modifications, including a rubber engine mounting, for a 10,000-mile test car. | 27th Jul 1934 | Box 5a \ 4 04-page080 | |
| Acceleration tests, including speedometer accuracy and performance timings. | 30th Jul 1928 | Box 5a \ 4 04-page081 | |
| Issues with valve springs, petrol pumps, and comparing radiator weights. | 30th Jul 1934 | Box 5a \ 4 04-page082 | |
| Bonnet tests measuring average temperatures of carburettor, dash, air, oil, and water at various speeds. | 31th Jul 1934 | Box 5a \ 4 04-page083 | |
| Engine speed tests, the use of Bentley valve springs instead of standard 25 HP, and a broken rocker. | 1st Aug 1934 | Box 5a \ 4 04-page084 | |
| Technical letter discussing modifications and issues with governor unit 21-G-IV, including dirt contamination and oil leaks. | 1st Aug 1934 | Box 5a \ 4 04-page085 | |
| Request to alter 25 HP chassis units to cure a leak and check governor lubrication. | 1st Aug 1934 | Box 5a \ 4 04-page086 | |
| Despatch request for a hand control valve to be sent to G.W. Hancock in France. | 2nd Aug 1934 | Box 5a \ 4 04-page087 | |
| Governor unit troubleshooting, including pressure readings and notes on oil levels. | 6th Aug 1934 | Box 5a \ 4 04-page088 | |
| Data table for 'Governor Range', correlating M.P.H. with values in lbs. | 21th Jul 1934 | Box 5a \ 4 04-page089 | |
| Confirming radiator weight figures and reporting on delayed testing due to traffic and a broken axle. | 7th Aug 1934 | Box 5a \ 4 04-page090 | |
| Testing of new American-made rubber engine mountings for the 21-G-1V model. | 10th Aug 1934 | Box 5a \ 4 04-page091 | |
| Engine failure involving bearing metal in the sump, connecting rod issues, and an investigation into valve spring breakages. | 20th Aug 1934 | Box 5a \ 4 04-page092 | |
| Short typed memo regarding a car being held up for adjustments before a run. | 21th Aug 1934 | Box 5a \ 4 04-page093 | |
| Report from France detailing tests on valve clearance, axle arrangements, and solutions for clutch jagger. | 21th Aug 1934 | Box 5a \ 4 04-page094 | |
| Technical note on clutch engagement and engine idling with hydraulic rockers for the 25 HP Series. | 23th Aug 1934 | Box 5a \ 4 04-page095 | |
| Clutch jagger issues, the Paris Trials car crash, and observations on wing movement. | 23th Aug 1934 | Box 5a \ 4 04-page096 | |
| Advising against the use of controllable dampers on the Bentley due to safety concerns. | 24th Aug 1934 | Box 5a \ 4 04-page097 | |
| Comparison of lap times at Montlhéry track for hydraulic adjustable rockers versus standard solid rockers. | 24th Aug 1934 | Box 5a \ 4 04-page098 | |
| Letter from G.W.H. to Hs/Hn regarding a conversation with W.O. Bentley and the state of various car clutches. | 25th Aug 1934 | Box 5a \ 4 04-page099 | |
| 12,000-mile test report on vehicle 41 G IV detailing issues with the engine, exhaust, pistons, and connecting rods. | 28th Aug 1934 | Box 5a \ 4 04-page100 | |
| Inspection report detailing the condition of various engine components after testing. | 28th Aug 1934 | Box 5a \ 4 04-page101 | |
| Issues with engine mounting, carburetion, clutch, and other components. | 28th Aug 1934 | Box 5a \ 4 04-page102 | |
| Condition report on the gearbox, servo, propeller shaft, axle, and brakes. | 28th Aug 1934 | Box 5a \ 4 04-page103 | |
| Inspection report detailing the condition and performance of the axle, springs, steering, and pedal assembly. | 28th Aug 1934 | Box 5a \ 4 04-page104 | |
| Performance and condition report on various vehicle components including the radiator, bonnets, and electrical systems. | 28th Aug 1934 | Box 5a \ 4 04-page105 | |
| Vehicle performance, issues with horns and bodywork, and tyre wear. | 22th Jun 1929 | Box 5a \ 4 04-page106 | |
| Telegram from Chateauroux to Derby reporting a seized dynamo drive pinion. | 22th Jun 1929 | Box 5a \ 4 04-page107 | |
| Dynamo drive rattle caused by a seized pinion and broken ball race due to lack of oil. | 28th Aug 1934 | Box 5a \ 4 04-page108 | |
| List of required modifications for car 21-G-IV upon its return from France. | 28th Aug 1934 | Box 5a \ 4 04-page109 | |
| List of proposed modifications and tests for vehicle components, page 2. | 28th Aug 1934 | Box 5a \ 4 04-page110 | |
| 5,000-mile test report listing fourteen points for investigation and action on chassis 21-G-IV. | 4th Sep 1934 | Box 5a \ 4 04-page111 | |
| Proposal to fit lead bronze bearings to unit 21-G-IV with a .002 clearance, while lending a C.10 unit to keep the car running. | 7th Sep 1934 | Box 5a \ 4 04-page112 | |
| List of twelve modifications and examinations to be carried out on car 21-G-IV. | 7th Sep 1934 | Box 5a \ 4 04-page113 | |
| Urgent testing of a La Salle steering unit for the Spectre model. | 7th Sep 1934 | Box 5a \ 4 04-page114 | |
| Requesting the results of a 15,000-mile car test, noting issues with pistons, clutch, and steering. | 7th Sep 1934 | Box 5a \ 4 04-page115 | |
| The dispatch of various car parts to Derby and another recipient. | 12th Sep 1934 | Box 5a \ 4 04-page116 | |
| Cover sheet for a 10,000-mile trial commencing in November 1934. | 1st Nov 1934 | Box 5a \ 4 04-page117 | |
| Request to make up an air silencer and fit a new front apron to chassis 21-G-IV. | 12th Sep 1934 | Box 5a \ 4 04-page118 | |
| Instruction to examine the brakes and back axle of car 21-G-IV. | 13th Sep 1934 | Box 5a \ 4 04-page119 | |
| Alternative radiator mounting options for car 21-G-IV, comparing Harrison and Marston types. | 19th Sep 1934 | Box 5a \ 4 04-page120 | |
| Requesting a 10,000-mile test for a propeller shaft damper mounting method on vehicle 21-G-IV. | 27th Sep 1934 | Box 5a \ 4 04-page121 | |
| Replacement of an Autovac with S.U. Fuel Pumps and other fuel system modifications. | 3rd Oct 1934 | Box 5a \ 4 04-page122 | |
| Request to fit Bentley-type pistons to a 20/25 unit after oil consumption tests. | 9th Oct 1934 | Box 5a \ 4 04-page123 | |
| Clarifying five specific instructions for car model 21-G-IV. | 18th Oct 1934 | Box 5a \ 4 04-page124 | |
| Instruction to standardise and fit anti-squeak brake shoes to car 21-G-IV before its dispatch to France. | 26th Oct 1934 | Box 5a \ 4 04-page125 | |
| Specification for a 10,000-mile test on a 20/25 model, detailing chassis and engine modifications. | 26th Oct 1934 | Box 5a \ 4 04-page126 | |
| List of modifications including a flywheel, clutch, and anodised pistons for a vehicle. | 26th Oct 1934 | Box 5a \ 4 04-page127 | |
| Requesting the approximate start date for a test to commence on a 20/25 car. | 29th Oct 1934 | Box 5a \ 4 04-page128 | |
| Short internal memo replying to a previous communication and anticipating the start of a test. | 30th Oct 1934 | Box 5a \ 4 04-page129 | |
| The need to fit stronger, Bentley-type springs to the Marles steering system. | 1st Nov 1934 | Box 5a \ 4 04-page130 | |
| List of five required modifications for vehicle 21-G-IV before shipment to France. | 1st Nov 1934 | Box 5a \ 4 04-page131 | |
| Alteration to the flywheel and a modification to the clutch driven member for a 21-G-IV. | 7th Nov 1934 | Box 5a \ 4 04-page132 | |
| Typed letter to G.W. Hancock in France regarding vehicle modifications, oil testing, and upcoming part shipments for testing. | 12th Nov 1934 | Box 5a \ 4 04-page133 | |
| List of modifications for car 21-G-IV before its departure to France. | 13th Nov 1934 | Box 5a \ 4 04-page134 | |
| Modifications and preparations for the 21-G-IV 10,000 miles test in France. | 14th Nov 1934 | Box 5a \ 4 04-page135 | |
| Update on the delayed shipment of car 21-G-IV to France. | 14th Nov 1934 | Box 5a \ 4 04-page136 | |
| Letter detailing road test results and performance feedback for car 21-G-IV. | 14th Nov 1934 | Box 5a \ 4 04-page137 | |
| Stock issue with Castrol XL oil, proposing Tonic XXL as a substitute, and noting upcoming roll rod tests. | 14th Nov 1934 | Box 5a \ 4 04-page138 | |
| General specification of the servo for chassis 21-G-IV. | 14th Nov 1934 | Box 5a \ 4 04-page139 | |
| Car trial, steering ratio, and the potential standardization of a stabilising bumper bar on a 20/25 model. | 14th Nov 1934 | Box 5a \ 4 04-page140 | |
| Confirming a meeting and discussing clutch and servo modifications for car 21-G-IV and the 20/25 model. | 15th Nov 1934 | Box 5a \ 4 04-page141 | |
| Customer complaint regarding the performance of a new 20/25 HP model with an updated carburetter. | 15th Nov 1934 | Box 5a \ 4 04-page142 | |
| Letter addressing a performance complaint about a new carburettor on a 20/25 HP car and sending a new bumper bar for testing. | 15th Nov 1934 | Box 5a \ 4 04-page143 | |
| Explanation of an expense claim for a 40 Franc taxi fare for four men with luggage in France. | 18th Nov 1934 | Box 5a \ 4 04-page144 | |
| Responding to feedback on the steering of car 21 G IV and comparing its steadiness to a Cadillac. | 16th Nov 1934 | Box 5a \ 4 04-page145 | |
| Letter requesting an opinion on '90' series Dunlop tyres and discussing potential issues with heavy steering and wear. | 17th Nov 1934 | Box 5a \ 4 04-page146 | |
| From France detailing the initial findings of a car trial, highlighting several distressing faults with vehicle 21 G 1V. | 18th Nov 1934 | Box 5a \ 4 04-page147 | |
| Letter discussing daily reports on hydraulic tappets, steering comparisons with Cadillac, and tyre pressures. | 19th Nov 1934 | Box 5a \ 4 04-page148 | |
| Letter to G.W. Hancock regarding an excessive 24 Franc expense claim by an employee named Rose. | 19th Nov 1934 | Box 5a \ 4 04-page149 | |
| Telegram received by telephone regarding a shortage of standard silent tread tyres for a car. | 19th Nov 1934 | Box 5a \ 4 04-page150 | |
| Urgent internal request to order specific Dunlop tyres and tubes for direct delivery to an individual in France. | 20th Nov 1934 | Box 5a \ 4 04-page151 | |
| Letter responding to a customer's note regarding car performance and previous work. | 20th Nov 1934 | Box 5a \ 4 04-page152 | |
| Confirming a request to make a set of 10/50 rear axle gears for a 20/25 chassis. | 20th Nov 1934 | Box 5a \ 4 04-page153 | |
| Specification document for '21-G-IV' detailing 15 modifications and components. | 22th Oct 1934 | Box 5a \ 4 04-page154 | |
| Numbered list of technical modifications for components including the oil pump, exhaust manifold, steering, and clutch. | 22th Oct 1934 | Box 5a \ 4 04-page155 | |
| The use of Bentley long skirt type pistons on the 20/25 HP chassis and whether to scrap unmachined stock. | 19th Nov 1934 | Box 5a \ 4 04-page156 | |
| Halting the production of 20/25 pistons pending the results of a 10,000-mile test on a new long skirt piston design. | 21th Nov 1934 | Box 5a \ 4 04-page157 | |
| Report comparing a car's performance against a 16-cylinder Cadillac, discussing engine smoothness, ride quality, and steering. | 22th Nov 1934 | Box 5a \ 4 04-page158 | |
| Letter regarding a faulty rubber washer from the joint of a pump outlet bend on chassis 21 G IV. | 23th Nov 1934 | Box 5a \ 4 04-page159 | |
| Letter discussing vehicle reports, comparing a Cadillac to a 20/25 model, and detailing issues with steering and oil consumption on car 21-G-IV. | 26th Nov 1934 | Box 5a \ 4 04-page160 | |
| Test report detailing crankshaft, connecting rod, and main bearing clearances before and after a 10,000-mile test. | 26th Oct 1934 | Box 5a \ 4 04-page161 | |
| Table of dimensions for pistons and cylinder bores measured prior to a 10,000-mile trial for a B14 unit. | 16th Jun 1937 | Box 5a \ 4 04-page162 | |
| Request for two spare headlamp pillars for chassis 21 G IV to accommodate new 'Marchal' headlamps. | 28th Feb 1934 | Box 5a \ 4 04-page163 | |
| Questioning a report that a car's steering is too high geared, when it was in fact made lower geared. | 27th Nov 1934 | Box 5a \ 4 04-page164 | |
| Steering ratios for the 20/25 model in comparison to a Cadillac and car 21-G-IV. | 28th Nov 1934 | Box 5a \ 4 04-page165 | |
| Performance issues of the 25 HP car in France and the solution of sending a higher compression cylinder head. | 19th Dec 1934 | Box 5a \ 4 04-page166 | |
| Vehicle performance tests at a French track and an update on Cadillac repairs. | 8th Dec 1934 | Box 5a \ 4 04-page167 | |
| Engine failure due to oil pressure and a performance review of '90' type tyres after 2,947 miles. | 10th Dec 1934 | Box 5a \ 4 04-page168 | |
| Letter discussing discrepancies in test report data and engine performance issues, including pulsations and torque reaction. | 10th Dec 1934 | Box 5a \ 4 04-page169 | |
| Requesting the approximate mileage of a car with its present body before the current test. | 12th Dec 1934 | Box 5a \ 4 04-page170 | |
| The mileage history of chassis 21-G-IV before a test. | 13th Dec 1934 | Box 5a \ 4 04-page171 | |
| Letter detailing engine pulsation issues, a dynamo failure, and a comparison with a Cadillac vehicle. | 13th Dec 1934 | Box 5a \ 4 04-page172 | |
| Faulty armature requiring rewinding due to a short circuit caused by carbon dust and oil. | 13th Dec 1934 | Box 5a \ 4 04-page173 | |
| Letter to G.W. Hancock in France discussing various vehicle performance issues including carburetter oil, silencer rattling, and brake thumps. | 13th Dec 1934 | Box 5a \ 4 04-page174 | |
| The excellent condition of connecting rod bearings from car 21 U 1V after a 10,000-mile test. | 13th Dec 1934 | Box 5a \ 4 04-page175 | |
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