| Author | Message | ||
     Brian Vogel Grand Master Username: guyslp Post Number: 1347 Registered: 6-2009 |
I could swear that I once knew: - what this little electronic bit actually is - what its purpose/role is but I can't for the life of me remember or find the information about it. Someone here will probably know the answer to both of these questions. Also, I've seen this thing on SY1 cars, too, and on the reservoir. Am I safe in assuming that it serves the same purpose on those cars? Forgive the blurriness on the picture of the connector on the underside of the reservoir. My phone is the only thing I can slip into the available space to photograph that and its focus isn't that great that close up.    Brian | ||
| Robert Noel Reddington Frequent User Username: bob_uk Post Number: 53 Registered: 5-2015 |
It looks like a capacitor. Connected between earth and the dot level magnetic reed switch. It gives a clean break at the switch? I am not sure. If so a typical RR refinement. I shall look at my SS1. Never noticed the component. Very differcult to see under the tank. You did well to get the photos as clear as you did. | ||
| Chris Browne Prolific User Username: chrisb Post Number: 213 Registered: 2-2010 |
Hello Brian, Bob is right. In the Shadow 2 workshop manual, it is described as "Resistor-brake fluid level switches". Hope this helps. Kind regards, Chris | ||
| Bob Reynolds Prolific User Username: bobreynolds Post Number: 263 Registered: 8-2012 |
How is Bob right? He said it was a capacitor, not a resistor! From the (unclear) photo it looks like a wirewound resistor. Can you tell what the writing says? | ||
| Robert Noel Reddington Frequent User Username: bob_uk Post Number: 55 Registered: 5-2015 |
Half right. I should think a resistor will do the same job. Or maybe its extra load on the warning light circuit. Kind regards The other Bob | ||
| Robert Noel Reddington Frequent User Username: bob_uk Post Number: 56 Registered: 5-2015 |
The penny has dropped. I think the resistor is in series with the reed switch earth. This will limit the amps in the circuit. when the starter is engaged the low fluid light is tested. The reed switch if closed due to low fluid could then be subject to a higher load than normal thus damaging the switch. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1348 Registered: 6-2009 |
Just got back from an early evening appointment with a tutoring client. I think that the writing on the shrink wrap on the green bit is still legible, but it will have to wait until tomorrow for me to verify that. I suspected that whatever this thing was that it was tied to the reed switches for the brake fluid level. Brian | ||
| gordon le feuvre Frequent User Username: triumph Post Number: 75 Registered: 7-2012 |
Some-how i have the feeling ? that it was put in the circuit to stop the low level light "flashing" when cornering etc. | ||
| Bob Reynolds Prolific User Username: bobreynolds Post Number: 265 Registered: 8-2012 |
I've looked at mine and it's simply a 10 ohm resistor to limit the current through the reed switches. It won't stop the lamp from flashing when cornering, but it will reduce the wear on the switches when the level is at that critical point. As for the lamp test circuit when starting, this puts an earth on all the bulbs to test them, so when this happens the reed switch is short circuited and carries no current at all whether it's open or closed. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1353 Registered: 6-2009 |
Bob, Thanks. That saves me cleaning the crud (that was visible in the picture) off of the thing hoping that I would find markings under there. At least we now have definitive answers to both of the questions I posed, for which I am grateful. Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 743 Registered: 5-2012 |
Interesting. There isn't one on my car, SRX18501, so given Bob's car is SRH21909 it must have been fitted soon after mine had been built. Else, a previous owner didn't refit it. In any case I will fit one on my car next time I am working on the reservoir/hydraulics. Great information. Geoff | ||
| Bob Reynolds Prolific User Username: bobreynolds Post Number: 267 Registered: 8-2012 |
Mine's a July 1975 build. I wouldn't go to the trouble of fitting a resistor if it's not there. Providing you keep the fluid level topped up it will never be used. RR have to cater for all sorts of users of their cars, and some people could conceivably ignore the flashing brake warning light for months, until the reed switch becomes completely eroded. An enthusiast is not likely to do this! | ||
| Robert Noel Reddington Frequent User Username: bob_uk Post Number: 70 Registered: 5-2015 |
I was half right again. It protects the reed switch. But not because of warning light test. But due to Dot level on the cusp of the switch. A another bit of knowledge about Shadow hydraulics. I didn't even think that the reed switch needed protection. Stuff like this gets the Brain working. 10 ohms is also of interest because if the ratio of the bulb ohms to swamp resistor is calculated, then this idea can be used on other electrical stuff for protection. My car 1974 17768 has no resistor that I can see. Maybe 1977 and later. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1360 Registered: 6-2009 |
Bob UK, It's earlier than that. This question was also triggered by another on rollsroyceforums.com, and the car under discussion there is a 1975 Shadow with chassis number SR?21846. I know it's a US spec car, but I can't recall what letter should replace the ? at the moment. The whole transition from SRH or SRX to SRH and SR?, where ? was a year designator for non-home-market cars, makes me cloudy on what year it was that the change took place. Brian | ||
| gordon le feuvre Frequent User Username: triumph Post Number: 77 Registered: 7-2012 |
Under the post war technical heading for the Shadow a booklet entitled "Chassis Number, Modification & Production" This lists all changes and chassis numbers that applied. There were some 2000?changes over the Shadow lifetime. It is a fascinating read . |
