Glycol based brake fluid is poisonous & toxic - Rolls-Royce and Bentley Forums
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post #1 of 9 (permalink) Old 09-09-2019, 04:07 AM Thread Starter
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Glycol based brake fluid is poisonous & toxic

May I just point out glycol based brake fluid IS poisonous and toxic and is such classified accordingly. Indeed like anti-freeze can cause severe kidney damage and death.

It cannot even be transported in the UK by Royal Mail and only certain carriers here licensed to transit 'hazardous goods' in UK or EU or to ship internationally.

This is what Royal Mail state on their website


Poisons, toxic liquids, solids and gases
Including substances that are liable to cause death or injury if swallowed........
  • International destinations - Not allowed in the mail
  • UK destinations - Not allowed in the mail

by N Sharma - ‎2002
Three cases of poisoning with toxic glycol based brake fluid are reported who ... Chemical Company, a leading producer of automobile liquids, brake fluid is a ...

and finally NAPA quote.......
5 Mar 2014 - Product Name: NAPA...... DUTY DOT 3 BRAKE FLUID ..... TSCA (TOXIC SUBSTANCE CONTROL ACT): all components are listed on the TSCA

Information source GOOGLE

I hope this clears up any mis-appropriate information being stated on the forum in some posts.

Where glycol based brake fluid is required, with the need for the additional lubrication for engine brake pumps, originally it was specified only Castrol RR363 which is no longer produced by Casrol but old stock is available in some places......alternatives have been made up from DOT3/4+10% Pharmacutical grade castor oil.

Check your car handbook or manual to see what is recommeded and NEVER use any other mineral alternative where glycol based brake fluid is specified as it can react with ALL the seals


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post #2 of 9 (permalink) Old 09-09-2019, 07:50 PM
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Flying Spares have recently advertised that they have commissioned a new manufacturer of RR363 to the same specification as the Castrol product. Apparently Castrol have given the specifications to this new supplier. I haven't purchased any yet but am considering it.
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post #3 of 9 (permalink) Old 09-09-2019, 10:10 PM
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Some time ago a RROC member started initial deliveries of RR363. They currently have an ad in the latest issue Flying Lady the RROC magazine.

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post #4 of 9 (permalink) Old 09-10-2019, 01:20 AM Thread Starter
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Glad to read there is an alternative to 'Castrol RR363 in the USA from GRM and they do boldly put on the front a warning. 'Harmful or fatal if swallowed'

When I worked at Jaguar/AM under Ford ownership it was compulsory under health and safety ISO/BS standards that everywhere liquids were used or stored we had to have a 'spill kit' and complete content specification sheets supplied by the manufacturer of the contents of the liquid so in case of any accident this could immediately be supplied to a surgeon, doctor or hospital.

So we somewhat got to know what these liquids contained and especially useful as Castrol was a preferred supply changed under Ford ownership from what was previosly Mobil would have been seen on cars like the Jaguar XJS Le Mans winner.

I did watch also from these spec sheets the supply of Castrol GTX slowly diminish its ZDDP content another concern for many classic car owners.

My understanding Castrol have sold/given their original formula to Bentley. I am not sure what Bentley have decided to do in marketing any of this.

Several 'home brew' suppliers have adopted the use of the term RR363 obviously claiming it was specified by RR/B when in deed it was actually 'Castrol RR363' that was specified.

A bit like the old Coke Cola wrangle many years back and perhaps a little loophole with these homebrew suppliers just using the term RR363.

At the conclusion I know many RR/B owners and friends who have been using DOT3/4+10%PG castor oil for well over 10 years and some having clocked up over 50000 miles in that period.

Is there also some other secret ingredient Castrol put into their RR363 that these homebrew suppliers know that I don't know

I still have two litres of original Castrol RR363 in the litre tin containers and two litres in the plastic bottles. When these have gone I will be speaking with my chemist or beautiful ladies at the town massage parlour and get some castor oil and make up my own.

BTW castor oil is NOT poisonous.... we used to be given a large spoonful as children many years ago if we had a poorly tummy trying to wag a day off school. Trust me you would never complain again.

All the best


Last edited by Steve E; 09-10-2019 at 01:23 AM.
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post #5 of 9 (permalink) Old 09-10-2019, 12:54 PM
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While castor oil is not poisonous, per se, it is a powerful purgative.

And having had to use it years back prior to some lower GI diagnostic studies, I can say that "powerful" is a bit of an understatement. One does, of course, have to take it by mouth for it to have that effect.


The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr

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post #6 of 9 (permalink) Old 09-10-2019, 08:24 PM
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According to what Flying Spares say there's more to Castrol RR363 than DOT3 with castor oil. I think there's some emulsifying agent to help the DOT3 and castor oil to stay mixed and some other additive to prevent freezing at extremely low temperatures. I'm no industrial chemist nor expert but have been using DOT4 + 10% castor oil for the past 20,000 miles without any detected adverse effects.
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post #7 of 9 (permalink) Old 09-11-2019, 02:24 AM Thread Starter
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Hi Shadow11,

Interesting points but I do think a bit of a sales pitch from the home brew manufacturers and they don't really know.

An emulsifier sounds logical though but the one advantage of the RR system is the fluid does sort of move around the system to some extent with the feedbacks to the reservoir.

As for the 'freezing' the whole problem with DOT fluids is they are hydroscopic and absorb moisture. The longer the fluid is left without being changed the liquid abilities to avoid freezing are seriously diminished. Also the moisture, as some evaporates causes the oxidisation and I have seen the bottom of master cylinders rotted and pitted through.

However the fact fresh DOT brake fluid can freeze/solidify at temperatures below -40 degrees C, castor oil is around -18 degrees C it starts to solidify. Obviously totally unacceptable to support cold climates so again logical what you say if Castrol put in something to compensate to avoid solidifying.

For sure though if you live in a cold climate with DOT brake fluid do make sure regular fluid changes are done as usually it is always the one thing no one bothers doing.

All the best from warm sunny UK

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post #8 of 9 (permalink) Old 09-11-2019, 10:52 AM
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Hi Steve, As you say the system is recirculatory but I think that the fluid at the extremity of the brake lines tends to stay there which attracts corrosion due to a build up of moisture at the calliper pistons. I flush and change the fluid every couple of years but also occasionally bleed off a little fluid at the callipers between fluid changes and think that this helps to keep the callipers lubricated, possibly overkill but I do it as a precautionary measure. Greetings from sunny southeast Ireland where it usually only rains between the showers.
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post #9 of 9 (permalink) Old 09-11-2019, 12:34 PM Thread Starter
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Hi Shadow11,

I don't think what you do is 'overkill'..........I do exactly the same.

I also feel it makes sure the bleed nipples get regular turns so prevents them getting siezed up and difficult to remove if ever needed to for a rebuild.

All the best

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