Contradictory and folklore with DOT-5

[tvrgeek]

After the presentation a few years back at the MGB nationals, I decided when I rebuild my brakes the next time, I woudl go DOT-5. So, rebuilding the stag completelly. Everything new. I have had both the AP and TRW master cylinder weep into the booster. Calipers and pistons fine. Everything dry.

DOT-5 is used widely in fleets and Military and never seen any issues, Now I find rumors with no direct reference that both TRW and AP say do not use DOT-5 because it wil weep. I also see a message on White Post he does not warantee DOT-5 use. I have sent inqueries.

Flushing DOT-5 to return to 4 is almost impossible. Most solvents are bad for seals or not effective. FWIW, my B has had DOT-5 in the TRW master and slave clutch system for years with no issues.

Looking for facts with references other than " well I"

[barkerwilliams]

Perhaps there are only well's.

Whilst there may be different makes with differing chemical compounds I did a little experiment a few years back and mixed dot 4 & 5 in a jar, and left it for about a year whilst the rebuilding the car. After a year it looked very much as it did when I started, no deposits, no change in colours, nothing to the naked eye had changed.- OK its bad science, (or no science at all).

When I rebuilt the Stag everything on the clutch and brakes was new including the plumbing so I used dot 5. My TR6 has Dot 4. In use I can't tell the difference and don't see the dot 5 spongy pedal reported by others and there is no weeping.

I looked into it at the time and there were no facts just reports and feelings and entrenched positions and it doesn't seem to have changed much since them, so as always you pays your money and makes your choice. The only thing I would suggest is that Dot 5 is uncommon, so a breakdown garage, particularly on the continent might not have it onboard, so always carry a few ml.

And if you spent lots of money on that wonderful under-bonnet respray then 5 is has to be.

Alan

[trunt]

Same dilemma here, I chose to go with the devil I know.. Dot4

Always keep a spray bottle of alcohol on hand when I'm messing with it, I find its flushes it off the paintwork well.

[bullstarz]

DOT-5 is used widely in fleets and Military and never seen any issues,

The UK Military doesn't use DOT-5, ours is OX8, which is DOT 4 ( which is definitely a fact).

DEF STAN 01-5 Issue 17
Section 1E: Lubricating Oils, Fluids - OX
87
NATO H–542
OX–8
BRAKE FLUID, AUTOMOTIVE
Specification: SAE J1704, Rev Sept 2008 *
Composition: Borate ester based brake fluid.
Characteristics: Viscosity at 100°C, min … ... … 1.5 mm2/s(cSt)
Viscosity at –40°C, max … … … 1800 mm2/s(cSt)
Flash point, closed cup, min … … … 80°C
Equilibrium reflux boiling point, min … 230°C
Equilibrium reflux boiling point, with
3 percent added water, min … … … 155°C
The specification includes tests for high and low temperature stability, pH
value, effects on rubbers, corrosive properties in contact with various
metals and alloys and simulated service performance tests.
Uses: Certain hydraulic clutches, most automotive braking systems fitted with
cups and seals made from natural rubber and styrene-butadiene rubber,
operated over the ambient temperature range of minus 40°C to plus 55°C.
Also meets the requirements of DOT 4.
WARNING: This product is not compatible with mineral or silicone based
products.
Standardized Alternatives: See Table 1.
Stores Numbers:
NATO Stock No Nominal Size Navy Army RAF
9150-99-224-8089 500 ml – – + + 34D
9150-99-220-2348 1 litre 0475 + + 34D
9150-99-224-8088 5 litre - - + + - -
9150-99-220-1132 25 litre - - + + - -
* NOTE: This product implements STANAG 7093

Wouldn't use DOT 5 myself even if its got a higher boiling point and is hydrophobic (will not absorb water) as it not compatible with the more common DOT4. DOT 5.1 on the other hand is compatible with DOT4 so may be the better choice.

https://epicbleedsolutions.com/blogs...1-brake-fluid#

[Seaking]

I have purchased one of these from fleabay 331996674611 I use silicon brake fluid.

cheers Glenn

[mjheathcote]

Dot-5 is certainly pretty much maintenance free.
Had it in mine for 25 years and never touched it, apart from adjustment of level when changing front pads, never had to even bleed the system in that time.
Everything was completely new 100% before filling.
Only issue is that after 25 years the colour dye has dropped out.

[tvrgeek]

Well , Rimmer said they wil send me another Lockheed if I pay the difference as it is in stock. Well, they list the TRW in stock too and still have not made good on the $76 I had to pay to ship the first Lockheed back. I am NOT impressed with their business accumen. Waiting to see what White Post says.