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Alan Scard
Experienced User
Username: alanscard

Post Number: 23
Registered: 7-2015
Posted on Friday, 15 December, 2017 - 04:43 am:   Edit PostDelete PostView Post/Check IP

To all,
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?

Deep breath.

When the Silver Shadow series was introduced, Rolls-Royce originally recommended DOT3 brake fluid, and itís true Ė 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 didnít.

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 theyíre separate, you wonít 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.

Thatís why we recommend RR363 Brake Fluid, and our customers drive squeak-free Rolls-Royce motorcarsÖ"
Regards Alan in the UK
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1881
Registered: 5-2012
Posted on Friday, 15 December, 2017 - 06:08 am:   Edit PostDelete PostView Post/Check IP

Hi Alan

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.

Geoff
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Larry Kavanagh
Prolific User
Username: shadow_11

Post Number: 124
Registered: 5-2016
Posted on Friday, 15 December, 2017 - 06:10 am:   Edit PostDelete PostView Post/Check IP

Thanks Alan. Do you by any chance happen to know the chemical dispersant formula and the mixture ratio between DOT3, castor oil & chemical dispersant?
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Jim Walters
Prolific User
Username: jim_walters

Post Number: 140
Registered: 1-2014
Posted on Friday, 15 December, 2017 - 07:16 am:   Edit PostDelete PostView Post/Check IP

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
www.bristolmotors.com
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Christian S. Hansen
Grand Master
Username: enquiring_mind

Post Number: 647
Registered: 4-2015
Posted on Friday, 15 December, 2017 - 10:41 am:   Edit PostDelete PostView Post/Check IP

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.
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Steve Janosik
New User
Username: catullus

Post Number: 4
Registered: 8-2017
Posted on Friday, 22 December, 2017 - 06:56 am:   Edit PostDelete PostView Post/Check IP

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.
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Jim Walters
Prolific User
Username: jim_walters

Post Number: 141
Registered: 1-2014
Posted on Friday, 22 December, 2017 - 09:38 am:   Edit PostDelete PostView Post/Check IP

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:

https://www.ebay.com/itm/LAND-ROVER-SERIES-2A-SWB-BRAKE-MASTER-CYLINDER-CV-TYPE-90569126/182000064408?epid=1155292154&hash=item2a600c9798:g:Y28AAOSwoydWouZ3&vxp=mtr

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2533
Registered: 6-2009
Posted on Saturday, 23 December, 2017 - 12:58 am:   Edit PostDelete PostView Post/Check IP

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.

Brian
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felipe heuser
Experienced User
Username: felipe

Post Number: 19
Registered: 7-2017
Posted on Saturday, 23 December, 2017 - 07:05 am:   Edit PostDelete PostView Post/Check IP

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.
Happy motoring
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 1649
Registered: 5-2015
Posted on Tuesday, 26 December, 2017 - 12:26 am:   Edit PostDelete PostView Post/Check IP

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
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1972
Registered: 6-2006
Posted on Tuesday, 26 December, 2017 - 06:02 am:   Edit PostDelete PostView Post/Check IP

Robert, you will need to bleed the rear rams to get the lubrication through them as well.
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 1650
Registered: 5-2015
Posted on Tuesday, 26 December, 2017 - 09:54 am:   Edit PostDelete PostView Post/Check IP

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
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Randy Roberson
Grand Master
Username: wascator

Post Number: 797
Registered: 5-2009
Posted on Wednesday, 27 December, 2017 - 06:21 am:   Edit PostDelete PostView Post/Check IP

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.
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Anton Kiseliov
Yet to post message
Username: akak

Post Number: 1
Registered: 5-2018
Posted on Monday, 21 May, 2018 - 11:16 pm:   Edit PostDelete PostView Post/Check IP

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!
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Omar M. Shams
Grand Master
Username: omar

Post Number: 1523
Registered: 4-2009
Posted on Tuesday, 22 May, 2018 - 12:07 am:   Edit PostDelete PostView Post/Check IP

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.
Omar
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2575
Registered: 6-2009
Posted on Tuesday, 22 May, 2018 - 12:55 am:   Edit PostDelete PostView Post/Check IP

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

or

OMAR363: 15% castor oil, 85% DOT3 or DOT4 brake fluid

Brian
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2576
Registered: 6-2009
Posted on Tuesday, 22 May, 2018 - 01:52 am:   Edit PostDelete PostView Post/Check IP

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

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