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Castrol LMA Lo Moisture Absorbsion and Natural

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I pulled the brakes again and found that the rubber had turned into a squishy version of their original shape - not liquified but certainly not firm either.

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For the more cautious folks, you might soak one of the seals in the intended brake fluid for a couple of days before installing. If it ruins the seal, don't put the whole car together with that combination. Lot easier than tearing everything down afterward.
D
 
His brakes still work, perhaps?
/ubbthreads/images/graemlins/grin.gif
 
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For the more cautious folks, you might soak one of the seals in the intended brake fluid for a couple of days before installing. If it ruins the seal, don't put the whole car together with that combination. Lot easier than tearing everything down afterward.
D

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Good advice.... but. If you are going to go through all that trouble then why not just use LMA and be done with it ???
 
I don't know if this applies, but... the second car I ever drove was a 1977 Spitfire that my dad got me while I was in school in about 1982 from a friend of his who owned a used car lot. Shortly after I took ownership, the clutch pedal was dripping, the carpet was wet, and the paint around the master cylinder was softening up. My only car before this was a '72 Chevelle, so I didn't know what this stuff was all about. We took it back, the guy "fixed" it, and within a week, it was back. Returned it again, he "fixed" it again, and another leak. At this point, I asked him if the message on the filler cap "Use Girling fluid only" (or something like that) was significant. He had never noticed it but didn't say anything.

He fixed it again, I brought it home and it never leaked again. I wonder if he used something different that last time?
 
I just got done reading through a bunch of SAE specs on brake fluid (oh joy). these are the tests that are used to determine rubber compatability for the diferent types of brake fluid. The tests for rubber compatability refer to two materials: SBR (spec: Philprene) and EPDM (spec: Nordel). Both of these are synthetic rubbers. This test is used for all of the different types of brake fluid. From this it appears that any kind of natural rubber compatability is just serendipitous chance and not part of a requirement for a particular fluid.
FWIW

Dick
 
In the late 60's a friend with a TR-4 had his brake master seals turn to mush, he'd dumped "something" in it. I've been 'superstitous' ever since. Castrol, and later, LMA only. Never had the dreaded "meltdown." I suspect it's all moot at this point as synthetic rubber seals have been the norm for decades now.

<opens a new bottle of LMA> /ubbthreads/images/graemlins/grin.gif
 
thanks for the MSDS. i wondered how to get that. I now wonder how to get an understanding of what is supplied in brake kit elastomers. Is there a law or regulation or SAE standard? i think Camping found SBN and EDPM... are these Buna S and ?
Philprene and Nordel sound vaguely familiar, but not daily conversation.
Can we ask Moss what they spec in their kits?
whoa nelly
carello
 
I will do some more research on the rubber specs. I saw all of them listed when I searched for the fluids. Not having looked yet, my guess is that we will find that all the NEW elastomers will be compatible.
The tricky part is knowing what is currently in your car, or in the ratty looking rebuild kit box that just came in the mail. By now, it is pretty likely that the supply chain has been purged of natural rubber, but there are likely to still be a few kits out on the shelf in places like Pumpkin Flats that may be NOS. Rubber parts are one area where the newer materals (not necessaryily the parts, but the materials) are better than the original.
 
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Rubber parts are one area where the newer materals (not necessaryily the parts, but the materials) are better than the original.

[/ QUOTE ] Anyone who has used current replacement suspension bushings or bits such as the rubber boots on tie rod ends might question that statement! /ubbthreads/images/graemlins/confused.gif

Hopefully it IS true with brake seals....
 
Okay folks, i have some new information that might be incredable! My original statement was from tech FAQ at KIP motor company. So thinking i actually knew something and of course looking to more tech help as well i wrote the following email to KIP.
Hi Kip motor, i have been looking over your tech help on brakes and i find that the info is not correct -

2. Why can&#146;t I use generic brake fluid in my British car? Answer - British brake & clutch systems use natural rubber components which are only compatible with vegetable based brake fluid. American brake & clutch systems use synthetic rubber components which are only compatible with mineral based brake fluid. The only vegetable based brake fluid commonly available in the US is CASTROL GT LMA. Use of improper fluids or mixing of fluids can lead to complete failure of brake and clutch hydraulics. Use of any fluid other than CASTROL GT LMA violates all warranty on brake/hydraulic parts.

*British brake systems or replacement overhaul kits have not use natural rubber in the past 40 years.
*Castrol LMA is not a vegetable based fluid. see pdf MSDS -
https://safetydatasheets.bp.com/ussds/ame...06000220003.pdf

Certainly other reasons can be used to ensure the customer uses Castrol LMA, but your tech credibility should be an important marketing tool as well.

Soooooooooooooo.................... they wrote me back right away with the following.

carello,
Your information is incorrect. Look closely at the MSDS sheets, there is no chemical formula listed, just a family. Rubber compounds in British brake systems are in fact different from their American counterparts. The British actually have five different commonly used classifications for brake fluid; conventional British fluid, conventional American fluid, Rolls/Bently type fluid, NATO standard fluid, silicone based fluid.

In addition, rubber compounds currently in use for most applications are virtually identical to those used forty years ago.

We have spent alot of time researching, confirming and testing this data. If you don't care to take our information as presented, use whatever fluid at your own peril.

Kip Motor Company
972-243-0440
www.kipmotor.com
www.antiquedistributorcaps.com
'The Authority on post-war British vehicles'

This latest KIP answer sounds very credible, but not technical. Please sombody find another data point!
vegetable/ mineral i still dont know.
natural rubber/ Buna S i still dont know.
 
Sounds like you touched a nerve at Kip. /ubbthreads/images/graemlins/hammer.gif

And hey, they may be completely right about using LMA, and completey wrong (more likely out of date) about WHY.

Here's my last cite. (Castor Oil MSDS)

https://www.jtbaker.com/msds/englishhtml/c1500.htm

OK - cheers mates. /ubbthreads/images/graemlins/thirsty.gif
 
For whatever it's worth, the following is a quote from a Triumph TR4A Owners Manual (text in [brackets] added by me for clarity): "Where the proprietary brand [of brake fluid] is not available, other fluids which meet the S.A.E. 70 R. 3 specification may be used." That must mean SOMETHING, eh?

But then gosh, how do we know that Castrol GT/LMA is truly the "correct" fluid? I mean, it doesn't even mention "Girling" on the product label any more. So, is it correct for my 1960 Herald, or should I be seeking "Wakefield Castrol Brake Fluid" or perhaps some NOS Castrol Girling Crimson" or the later special "Green" or "Amber" (which, I think, is what became GT/LMA), depending on what year my car is?

Truth is, I'm a big fan of GT/LMA and use it on my Triumphs with very good luck. One car had it in the (rebuilt and then not disturbed again) brake system for the better part of 20 years without a problem. Yeah, I know it should have been changed more often, but it wasn't...and didn't cause a problem.

But then there was this MkIV Spitfire that belonged to a friend of mine until last year. I'd maintained and repaired it for him for over 20 years. About 14 years ago, I rebuilt the original tandem master cylinder and bled and topped off the system with...the Prestone fluid he'd supplied. About three years ago, the car finally needed new rear wheel cylinders and hoses (replacing originals!), and the master cylinder was again weeping just a bit. Since the reservoir was pretty tired and since I wasn't sure it was worth trying to rebuild it again...and because I got a great deal on a brand-new genuine Lucas Girling master cylinder, I put in the new master cylinder and other parts. Again, my friend provided me with lots of fresh Prestone brake fluid, as he did this past year when I redid the brakes on his MGA. No problems with either car.

Sorry, that's not very scientific, and it doesn't answer the question about whether British brake seals are made out of natural rubber, synthetic rubber, Play-Doh [tm] or what.
 
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2. Why can&#146;t I use generic brake fluid in my British car? Answer - British brake & clutch systems use natural rubber components which are only compatible with vegetable based brake fluid. American brake & clutch systems use synthetic rubber components which are only compatible with mineral based brake fluid.

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Sigh. Funny how folks get it in their heads that "American" brake fluid is somehow mineral based. Usually the definition of mineral based oil means petroleum based, no? There is NO mineral oil in ANY brake fluid meeting DOT 3, 4, or 5 specification. And why not? Because it would destroy the brake seals, which have (gasp!) natural rubber in them. That's why service manuals for modern cars have warnings throughout the brake service manuals saying not to get grease, oil, or anything petroleum-based on them.
 
I did a little bit more searching through the standards and found some additional information. All of the standards refer to brake fluid as petroeum and non-petroleum based. I think that may be the source of the mineral based wording. There is nothing about vegetable based anywhere that I could find.
I checked out the specs for DOT 3 fluid (SAE J1703 rev 4/04) and it referes to a non-petroleum based, glycol ether based fluid. The interesting part comes next:
"These fluids are designed for use in braking systems fitted with rubber cups and seals made from natural rubber (NR), styrene butadiene rubber (SBR) and a terpolymer of ethylene, propylene and a diene (EPDM)."

The DOT 4 material is based on SAE J1704 and is a borate ester chemisty.

Going to the Castrol website for LMA it indicates that it meets DOT 3 & DOT 4 specs.

According to the SAE spec., if you look on the bottle and it says that the brake fluid meets SAE J1703, it is compatible with natural rubber seals. This may or may not be completly within the DOT 3 spec (I have to pay $ to veiw the FMVSS specs), but if it says that it meets J1703 it will be natural rubber compatible. I just did a quick look and both Prestone and Penszoil meet the SAE spec. In most cases I think it will have the appropriate SAE spec on the bottle.

I think the folks at Kip are simply passing along the old hearsay. The standards are what companies actually make their products to meet.

Dick
 
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The interesting part comes next:
"These fluids are designed for use in braking systems fitted with rubber cups and seals made from natural rubber (NR), styrene butadiene rubber (SBR) and a terpolymer of ethylene, propylene and a diene (EPDM)."



Dick

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This all makes sense now. What I get from all of this is that if you use the DOT3 stuff, even if you have natural rubber mixed in with synthetic rubber on the car, there should be no problem.

I would have to think that in earlier times, there WASN'T any brake fluid that was compatible with BOTH...hence all the confusion over what to use. /ubbthreads/images/graemlins/hammer.gif
 
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