What Break fluid...?

I look for Dot 4 and when I do I get Castor oil LMA synthic

Castrol Gt Lma Dot4

it is synthetic also... I thought I was not to use SYNTHETIC in this system

I can not find the LMA dot 4 non synthetic...

any one have a link to non synthetic or please set me straight that this is the correct fluid...

oh,
dash lights lit and all windows working... Yeah!

 

GT LMA has always been synthetic, they just recently changed the label.
You do not need girling crimson or anything like that for an XJS, it isn't made anymore anyway. If you have a much older car and somehow miraculously still have working seals in it, you can put DOT5 silicone fluid in it.

DOT4 (glycol based synthetic like you buy in any store) was the specification on mid-range MGBs. You have nothing to worry about in an XJS that is a decade or more older.

I've been running dot 4 GT LMA in my car for five years. The seals were bad when I got it. Replacing the leaking reservoir to master cylinder hoses brought up pressure and blew out my master cylinder. Rebuilding my master cylinder blew out my crappy rear caliper seals. Haven't had any leaks since then, these were because the car was old and sat for 13 years, not because it had the wrong fluid in it.

If you can find it, the lockheed super dot 4 is even better than the GT lma. The only difference between these and cheap prestone at the store is that they have better moisture absorption and the boiling point doesn't drop as far as seeing use.The castol thing is just sort of a weird myth people have held onto, not wanting to mess something up in their car, they have tried to stick with girling, even though its the same glycol base synthetic brake fluid as any other dot 4

Synthetic was recently added as a marketing thing, because the best stuff out there now must be synthetic...

If you are lucky or unlucky enough to have a non ABS car and your wallet can handle it, the purple **** is awesome. It won't ruin paint and it is not hygroscopic. Do not put it in an ABS car because it will aerate in an ABS system.

 

all brake fluid is synthetic, ie dot3 and dot 4, they just recently started labeling it as such which has caused some confusion. It's silicone fluid you want to avoid not synthetic.

 

Silicone fluid will not damage the cars seals, which is what he is worried about. What he is thinking of is the old natural rubber based seals, which were used longer in europe and can be damaged by synthetic type oils and brake fluids.

For example, iif you had an MGB in the 60s and put dot3 commonly available in america in it, it would eat away the seals and the braking system would leak and fail. You had to put girling crimson in it
Mid-way through production, Dot4 became the standard on MGBs and the rubber was changed to synthetic.

Many people got all this confused and just continued trying to put the old stuff in the car to prevent it from being damaged. Not knowing better, they kept grabbing girling brake fluid, which was what they knew. This is why everyone thinks Castol GT LMA is the "right" fluid for the XJS, when it is just regular synthetic brake fluid.

 

http://www.mossmotors.com/SiteGraphi...luid_long.html Silicone fluid should not be used in a car with any glycol based fluids in it. That's why I said to avoid silicone...Again ALL fluid today is synthetic but you don't want to go putting silicone in a car with dot3 or dot 4 in it.

 

Yes. You are getting confused.

It is simply saying you cannot mix silicone fluid and glycol fluid, not that you cannot use silicone fluid in a car originally specified to use DOT 3 or DOT4.

If you read the moss article it even talks about the advantages and disadvantages of switching over and recommends doing so during a big brake job or overhaul, so that you can thoroughly flush the system of glycol base fluid.

 

Um no, I'm not confused one bit. All brake fluids ARE synthetic....you want to avoid putting silicone fluid in your car IF it already has dot 3 or dot 4 in it. ( we're not talking wholesale change/flush, I'm talking about adding or topping up.). Grabbing synthetic fluid is nothing more the 5 year ago style dot 3 or dot 4 with the catch phrase synthetic on it.

 

Okay, he didn't specify whether he was "topping up" or not. Since you should never need to "top up" brake fluid, I am assuming if he wants brake fluid he is changing it out. So he was asking on advice on the correct fluid to put in the car.

You never mentioned topping up or mixing fluids, you just told him flat out to avoid silicone brake fluid. If you just phrased it that way and meant to tell him to avoid mixing them rather than avoiding it altogether then I guess you aren't confused, I was just addressing what it seemed like you were saying and I wanted to be clear with the OP because his confusion is the reason for this thread.

 

Basically jonathan, all brake fluid you can buy today is synthetic, we haven't used natural rubber in braking systems in a long time and those systems used brake fluid you would recognize more as a "hydraulic fluid".

If you want to replace brake fluid, put DOT 4 in it. Any dot 4 will do, they all meet the DOT4 specification. Fluids like lockheed super dot 4 and gt LMA simply are better at avoiding moisture absorption and lowering their boiling points.
There is no reason to use DOT3, because it simply meets lower specs than dot 4. You can use dot3, but it *basically* won't last as long.

If you don't want to worry about moisture absorption and changing brake fluid every 2-3 years, you can switch to DOT5 IF you don't have ABS.Do NOT put DOT5 in an ABS system. You would need to dump the old glycol fluid out of the system and flush the braking system with alcohol before putting DOT5 in the system.

It costs more, but is nice when you rebuild an entire braking system, because it will be long before it needs service and it is nice for the fluid to be the same. As mentioned before, it is also nice because it won't damage paint. When restoring an older car, its a great option.

 

Two things ....

- silicone brake fluid should not be used in a street driven vehicle due to the
characteristic soft pedal associated with this type of brake fluid

- there have been discussions in the X308 section as to the "super" in "super dot4".
it turns out by looking at the specification of the original fluid that the "super" does
indeed have a meaning. they just didn't have a North American specification for it. there
is a European specification. the "super" refers to a low viscosity variant of DOT4 brake
fluid that is meant to help ABS systems modulate faster. ATE, Pentosin and Motul all
have such brake fluids in their product lines. I use the ATE out of habit, and a
preference for brake fluids packaged in metal cans as opposed to plastic.

++

 

The softer feel of DOT5 is an exaggeration that has grown larger from mouth to mouth as a result of the relatively low number of people that have actually used it. For all intents and purposes, it is a myth.

Compressibility changes with temperature, and the temp range at which movement becomes significant is the range that glycol fluid will vapor lock and fail entirely.

The difference is less than the difference between switching to braided steel flexible hoses. I can stop an MGB, that has no brake booster and rear drums, perfectly fine with DOT5.

 

This is the key point. Go by the DOT specification required (in this case DOT 4) and pay no real attention to brand name or claims of 'synthetic' etc.

Converting a car from DOT 3 or 4 to DOT 5 is a different can of worms. DOT5 is not interchangeable or intermixable with any other spec.

 

There's a "low number" of people using dot 5???? Really?

 

found a good buy on this


WOW, !!!

Thanks Guys!

I have a 1992 XJS V12.. yes with ABS and it is the Kind of ABS I had not seen before...

I think it is a cool design...

I have been wanting to do a fluid refresh (exchange as much as possible) in the reservoir with out doing a full drain flush and fill

so I could top up w that not that it is down it is not....

 

That's an excellent choice of fluid.

 

Given the myth that it turns your brake pedal into oatmeal and the fact the number of people who own and operate non-ABS cars is much lower than newer ABS cars, yeah......

Ironically tons of motorcyclists use DOT5 everyday and in many places I've been that's the only way to buy it.

I'm surprised you don't run it in your TR6. I'll run it in my Jag as well whenever I rebuild my front calipers.

 

That'll work fine man. That is actually a decent way to exchange some fluid, its better than nothing at all. Many people don't change their fluid for years and years because it is a much bigger project than changing out the reservoir.

Don't forget to fill it to the same spot it was at. If you top it up completely, next time you change your brake pads, you will find fluid has overflowed in the reservoir and damaged your fenders paint.

 

From what Ive read about Dot5 is that it cant be mixed with Dot3 or 4. It doesnt absorb water so it can leave water bubbles in the system causing damage. It has a lower compression rate which results in softer pedal.
I also read that Dot5 is the brand name, not the rating.
The Dot stands for department of transportation 3 or 4.

 

Dot 5 is standard just like DOT 3 and DOT4, but they couldn't get any glycol based fluids to meet that standard. It is not a brand, it is a standard for brake fluid set by the US department of transportation. By the time it came about, we were switching over to to ABS systems, which it cannot be used in.

It does not run a risk of forming water bubbles, because it is hydrophobic. It will not absorb moisture. Glycol based dot 3 and 4 do absorb moisture, and this can cause several problems, it can damage internals, freeze and create blockages, as well as lower the boiling point of the fluid, which is why brake fluids have wet and dry ratings.
Additionally glycol fluid will eat paint, another disadvantage.
The difference in compression is exaggerated by many people who have never actually experienced the difference, and just say it because someone else said it, just like criticizing the electrical system of an E-type they have never been in, much less owned or repaired.

 

While DOT3 and DOT4 absorb water, DOT5 absorbs air. This is why it is recommended to only use DOT3 & 4 that came from a sealed container, because an open one(admittedly like those I generally use) has the "potential" to be contaminated. The Issue with DOT5,(having extensive experience with this, due to my history as a dealer mechanic for Harley-Davidson, which used it exclusively since @1976, but moved away from it in 2005 with the introduction of ABS on The big "Dressers", and the like) is that the pressures of bleeding tend to force some of the air in the system to dissolve into the fluid, only to "boil" back out in a day or two of sitting at relatively low pressures while the brakes aren't being applied. Its the same thing that happens to divers when they get "the bends" It's a PITA but if you can get the bubbles that collect out, DOT5 does work really well, just not in conjunction with Anti-Lock brakes.