Post Number: 23
|Posted on Friday, 15 December, 2017 - 04:43 am: |
IntroCar in the UK sent out the following email today. I am aware of adding castor oil to Dot 4 hydraulic oil, but would be interested to hear about a chemical dispersant.
"In the Rolls-Royce fraternity, nothing seems to cause more controversy than Rolls-Royce Brake Fluid: Castrol RR363 hydraulic fluid. Any mention on a forum or chat room seems to generate acres of comment, with any number of views (some very vociferous). After all, RR363 is just a glycol-based oil, very similar to DOT3 and DOT4 synthetic oils. So why all the fuss?
When the Silver Shadow series was introduced, Rolls-Royce originally recommended DOT3 brake fluid, and it’s true – you can use it without causing irrevocable damage to the complex hydraulic system of your Rolls-Royce Silver Shadow, Bentley T-Type or Corniche (take note, though, from chassis 50001 (1980) Corniche onward you must use green mineral fluid). Pretty soon after the Silver Shadow (etc.) was introduced, owners started to complain about funny knocks and squeaks, particularly from the hydraulic rear height control rams. To cure this, Rolls-Royce Motorcars Limited developed the Rolls-Royce Brake Fluid RR363 with Castrol Oils. RR363 cured the squeaks, and everyone lived happily ever after.
Except they didn’t.
Most people know that Castrol added a certain amount of castor oil to the glycol base. Well, DOT3 is cheap, and castor oil is cheap, why not mix a bit up at home? Job done.
Not quite. The problem is that the viscosity of DOT3/4 and caster oil is different. If you leave it in a jar (or in the reservoir of your Rolls-Royce or Bentley braking system) it will separate, and one oil will float on top of the other. If they’re separate, you won’t get the benefit of both parts. Castrol solved this by adding a chemical dispersant to the oil, which keeps the caster oil evenly dispersed through the base oil.
That’s why we recommend RR363 Brake Fluid, and our customers drive squeak-free Rolls-Royce motorcars…"
Regards Alan in the UK
Post Number: 1881
|Posted on Friday, 15 December, 2017 - 06:08 am: |
I have recently gone over to DOT3/castor oil mix and have not observed this at all, having left a sample overnight in a clear container.
More importantly, Brian Vogel has kept samples for years and observed no separation. He has published photos on this forum, noting the samples had been through many hot summers and cold winters. Jim Walters also took a 4 1/2 year old sample and put it in his freezer. He also observed no separation. This experimentation, carried out by people I trust, is the reason I have started using it.
A lot has been reported on this topic - it's worth reading through the previous threads.
Post Number: 124
|Posted on Friday, 15 December, 2017 - 06:10 am: |
Thanks Alan. Do you by any chance happen to know the chemical dispersant formula and the mixture ratio between DOT3, castor oil & chemical dispersant?
Post Number: 140
|Posted on Friday, 15 December, 2017 - 07:16 am: |
I have been using castor oil specifically sold for mixing with RC aircraft fuel for years. I have recommended this type for a long time as I postulated that if it is meant to mix with fuel it probably has the additives to mix with DOT 3 as well. My sample jar is still on my desk and there is no change whatsoever in what must be going on 5 or 6 years. As Geoff mentioned I placed it in a freezer for a few days and there was no separating.
Introcar is quoted as saying they won't mix because the viscosity is different. Complete bollocks. Does honey dissolve in a hot cup of tea? The correct terminology would be castor oil and DOT3 are miscible and therefore do not separate. It has nothing to do with the viscosity of the materials.
I started using the castor/DOT3 mix in the proportion of 9.25% after I found a Citroen enthusiast's website who had sent mixes of various proportions to a lab for viscosity analysis. The result was that a mix of 9.25% castor oil to a litre of DOT3 equaled the viscosity of RR363. You can round that out to 10% for easier mixing and I think it will work just fine.
SRH8505 SRC18015 SRE22493 NAC-05370
Christian S. Hansen
Post Number: 647
|Posted on Friday, 15 December, 2017 - 10:41 am: |
At $40 or so for a pint of RR363, there is financial incentive for the usual suspects to discourage use of any other fluid I suspect.
Post Number: 4
|Posted on Friday, 22 December, 2017 - 06:56 am: |
I tried to post my following question on the Australian RR Forum - and it looked like it accepted my user name and password; but my post apparently did not - post - that is.
Please help me verify that part number UR 6103 is the correct "master cylinder for 1975 Shadow SRD-21809.
Post Number: 141
|Posted on Friday, 22 December, 2017 - 09:38 am: |
Steve, you're better off using a 3/4" bore one from a 70's land Rover. It will give better pedal feel and will be much easier to bleed. A lot cheaper too. Here is one example:
SRH8505 SRC18015 SRE22493 NAC-05370
Post Number: 2533
|Posted on Saturday, 23 December, 2017 - 12:58 am: |
My sample that uses pharmaceutical grade castor oil and DOT 3 still remains in my garage and remains perfectly blended, with no separation, approaching 9 years now in completely a non-temperature and humidity controlled environment (beyond what's provided by the plastic bottle and small glass jar the two samples are in).
The sample in the small glass jar has had way more water added to it than could ever be absorbed from the atmosphere and the only difference between it and the sample that has had no added water is the color. The water addition caused the mixture to turn from pale straw color to a golden color after it had resolved from the initial cloudy condition shown in my pictures on this very forum. The other looks just like the day it was first mixed, which is precisely the pale straw color of standard DOT3 brake fluid.
I am quite certain that using hobby aircraft motor grade castor oil rather than pharmaceutical grade could only be an improvement, though I do question whether it actually is an improvement based on my own "in bottle" and "in car" field testing. It certainly couldn't hurt.
Post Number: 19
|Posted on Saturday, 23 December, 2017 - 07:05 am: |
INTROCAR offers RR363 on special offer this month at a reasonable £16 Litre, so I stocked up, considering a complete change only every 3 to 4 years, doesn't break the bank.
Robert Noel Reddington
Post Number: 1649
|Posted on Tuesday, 26 December, 2017 - 12:26 am: |
I bled the system on new DOT 4 then added the castor oil, pumped the system down then started the engine which pumped the system back up thus mixing the DOT 4 and oil together.
Viscosity within limits is not a concern with this sort of hydraulic circuit
Post Number: 1972
|Posted on Tuesday, 26 December, 2017 - 06:02 am: |
Robert, you will need to bleed the rear rams to get the lubrication through them as well.
Robert Noel Reddington
Post Number: 1650
|Posted on Tuesday, 26 December, 2017 - 09:54 am: |
Paul, correct I have to bleed a bit out of the rear rams. I cleaned out both restictors and worked the fast solenoid a few times which helps.
My restrictors were very clean inside and have only been off the just this once. So thats that job done for the next 40 years
Post Number: 797
|Posted on Wednesday, 27 December, 2017 - 06:21 am: |
Perhaps the "Castor oil, ethoxylated, propoxylated" listed in the specification of RR363 is the mystery ingredient. My research at the time indicated that the purpose of ethoxylation and propoxylation is to increase the miscibility. Castor oil with these added treatments has a CAS number.
Yet to post message
Post Number: 1
|Posted on Monday, 21 May, 2018 - 11:16 pm: |
Hello! Then who speaks Russian?
I live in Ukraine. It does not sell brake fluid RR363 for Rolls-Royce Corniche2. Maybe there is some kind of replacement? Help!
Omar M. Shams
Post Number: 1523
|Posted on Tuesday, 22 May, 2018 - 12:07 am: |
Hopefully our friend Vladimir will contact you Anton.
I mix brake fluid with 15% castor oil and it works for me in Dubai.
All the best.
Post Number: 2575
|Posted on Tuesday, 22 May, 2018 - 12:55 am: |
As Omar has already pointed out, many of us are already using either what has been dubbed:
YAK363: 10% castor oil, 90% DOT3 or DOT4 brake fluid
OMAR363: 15% castor oil, 85% DOT3 or DOT4 brake fluid
Post Number: 2576
|Posted on Tuesday, 22 May, 2018 - 01:52 am: |
Also, with regard to the earlier posts regarding the miscibility issue, it is, as several have stated, non-existent.
My ongoing experiment still looks pretty much as it did when I last posted: YAK363 with water added experiment, ongoing