Brake Fluid

[petroboy]

I've noticed in the past that the fluid level sensor is very sensitive, so I get a brake warning light under spirited turns when the fluid is only a touch lower than absolutely full. I replaced my brake fluid with Motul a few months ago and am now getting the warning light again. I need to add a bit of brake fluid to top it off but prefer not to open a new bottle for only a few teaspoons of fluid.

Question: Can I use lower-priced (and more readily available) brake fluid to top off my reservoir, or is it a bad idea to mix Motul with a cheaper fluid? The answer may be painfully obvious to most of you, but not to me, and I'd rather ask the question than never know the answer.

[tmr]

I've also used Castrol LMA for years with no problems on other cars, including my old Elan. I'm now getting ready to flush the systems on the Elise and have read a few things on other forums about Motul having higher than normal water absorption and thus requiring more frequent flushing. Being lazy AND cheap, this isn't something I want to do. Has anyone else heard similar tales about Motul? Castrol LMA is sounding pretty good at this point...

[kestrel74]

another Super Blue vote

[JoeTodd]

Two questions. In the Lotus Elise owner's manual it says to use a non-mineral fluid from a container marked with a yellow and black symbol.

Q1. Has anyone seen such a mark on brake fluid sold in the USA?

Q2. Should we assume that "Synthetic" (i.e. Valvoline) is non-mineral?

Thank you for your help.

[Rennstore]

After a few thou pad sets and hearing a TON of experiences - go with Motul RBF 600.

Doesn't stain everything blue like the ATE Blue - FWTW.

[tesprit]

Originally Posted by tmr

I've also used Castrol LMA for years with no problems on other cars, including my old Elan. I'm now getting ready to flush the systems on the Elise and have read a few things on other forums about Motul having higher than normal water absorption and thus requiring more frequent flushing. Being lazy AND cheap, this isn't something I want to do. Has anyone else heard similar tales about Motul? Castrol LMA is sounding pretty good at this point...

I have heard the same thing about the Motul and while it is a good high boiling point fluid for track day cars where you are changing it all the time, it absorbs to much water for regular street use.

I too have been very happy with Castrol LMA over the years for my street cars and it really does absorb less water than the others. My Elise is running it right now with no problems and the fluid is showing much less contamination than the original stuff Lotus used, so +1 for Castrol LMA if you aren't tracking the car.

[elise/europa]

DOT 3 or 4, with adequate boiling for your requirement. High boiling temp is good if you use the car on track, if not, you just need the respect the recommended DOT. Typically, some named for "ford" vehicle have pretty high boiling temp at very low cost, not very good for track. Me, I am using Motul 600 or 660.

Don't use DOT5, many people think that's better since the number is higher, but it is not, it is more spongy, and less agressive to the paint if some leak.

[TimMullen]

Originally Posted by tesprit

I too have been very happy with Castrol LMA over the years for my street cars and it really does absorb less water than the others. My Elise is running it right now with no problems and the fluid is showing much less contamination than the original stuff Lotus used, so +1 for Castrol LMA if you aren't tracking the car.

Another +1.

I've been using Castrol LMA (Low Moisture Absorption) fluid for many years in my cars and have had no problems.

Keep in mind that if you are having fluid boiling problems on the track, you may need to change to a fluid with a higher boiling point (although Castrol LMA is above average). But, those fluids with higher boiling points tend to more readily absorb moisture, and their boiling point drops dramatically at that point. The LMA will last much longer without going "bad" and even then, still has a pretty good boiling point. For street use, and even for track use unless you are boiling your fluid, I'd consider going with Castrol LMA.

Originally Posted by elise/europa

Don't use DOT5, many people think that's better since the number is higher, but it is not, it is more spongy, and less aggressive to the paint if some leak.

DOT 5 fluid is silicon based, and is not compatible with DOT 3 & 4 fluids or systems. If you change to DOT 5, you have to completely replace all rubber (seals and hoses - including those in the ABS unit) to ensure that there are no problems. Additionally, it's hard to pour DOT 5 into a system without mixing in some air (what gives the spongy pedal). Not worth it for the average car. But DOT 5 is great for show cars and collector cars not driven very much or very hard.