From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Complaints of knocks from rear hydraulic dampers.
| Identifier | ExFiles\Box 130\1\ scan0332 | |
| Date | 9th April 1936 | |
| Bentley Motors (1931) Ltd., DERBY....................Hd.{Mr Hayward/Mr Huddy} Copy for HS.{Lord Ernest Hives - Chair} (Sr is absent) VA.2/Crn.9.4.36. Quarterly Complaints. (Knocks from rear hydraulic dampers of the Controllable type. Upon again referring to your memo. HA/SB{Mr Bull/Mr Bannister}22/HR.3.2.36, we find that we have not given the information as requested by you, as per paragraph No 4 of your memorandum. Kindly excuse the delay. It is rather difficult for us to indicate exactly the thickness of the washer which we have fitted beneath the F.85592 valves of the hydraulic dampers on certain chassis. The thickness of the washers fitted varied according to requirements, and as a rule were from .010" to .014" thicker than the original washer, and would therefore keep the L.P. valve off its seating from .003" to .004". We would mention that we have come across cases where there has been from .003" to .004" wear on the cone of the F.85640 L.P. valves, due to hammering effect on the seat. We refaced the valves as necessary. With reference to the second paragraph of your memo., we are also inclined to think that the cause of the knocks may be due to the replenishing valves not working properly. As you are aware, these ball valves and springs are a built in job. Each time that we dismantle a damper re the complaint in question, we check the ball valves for oil tightness, etc., and on the dampers attended to we did not find, as far as it was possible to tell, anything unusual. Do you think that the F.59286 ball valve springs are on the strong side ? We shall be very pleased to receive from you at any time any information concerning the best way of curing knocks on the above type of damper, because the complaint is becoming rather prevalent. Sr/VA. | ||