Brake Fluid Difference

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This is for a couple of panthers and Landcruisers, nothing fancy.
Please, educate me on brake fluids. Bosch claims 3, 4, 5.1 compatibility and longer service life. Isn't 5.1 lower viscosity?
Castrol claims their 3 and 4 formulation absorbs less water. Valvoline claims some other miracle.
And then there are 'lowly' brands and store fluids.

Or in this case, regularity trumps everything else?

TIA
 
I noticed a bit spongier pedal once when I went from factory fill to Prestone. People seem to really like Valvoline but I wonder too.
 
In this case, regularity trumps everything else
smile.gif


Regular fluid changes are MUCH more important than what brand you use. Even cheap Walmart brake fluid is just fine if you change it every few years. Even a fluid change when replacing your pads and rotors is sufficient.

Most cars never get new brake fluid and go to the junkyard on their factory fill
crazy2.gif
 
Originally Posted by slacktide_bitog


Most cars never get new brake fluid and go to the junkyard on their factory fill
crazy2.gif




Which begs the question, how necessary is it? I'd be willing to bet 95% of vehicles never see new brake fluid and never encounter any problems.
 
Originally Posted by Silver
I noticed a bit spongier pedal once when I went from factory fill to Prestone. People seem to really like Valvoline but I wonder too.


I can't imagine this was due to the fluid. Hydraulic fluid is not compressible.
 
Apparently you only have to worry about boiling "wet" brake fluid on the racetrack, street driving shouldnt get hot enough either way. I heard toyota has no maintenance schedule for brake fluid. I generally flush brake fluid when I change pads. 5.1 is more resistant to boiling so I would use that one.
 
Originally Posted by Kage860
I heard toyota has no maintenance schedule for brake fluid. I generally flush brake fluid when I change pads. 5.1 is more resistant to boiling so I would use that one.

But they do call for regular brake fluid flushes on Lexus models and dealers will almost always push a BG/MOC/Wynn's brake fluid service on you.

I've had friends tell me they almost lost their brakes in the mountains when their factory fill fluid starts to boil. For that case, I recommend flushing regularly but it's dependent on the fluid used. For that reason, I prefer ATE or Castrol fluids. They come close to OEM Japanese fill(DOT 3 based on borate esters, ATE and Castrol GT LMA are DOT 4 borate esters too) and offer higher wet/dry boiling points.
 
Originally Posted by Throt
Originally Posted by slacktide_bitog


Most cars never get new brake fluid and go to the junkyard on their factory fill
crazy2.gif




Which begs the question, how necessary is it? I'd be willing to bet 95% of vehicles never see new brake fluid and never encounter any problems.
That claim is really difficult to prove either way. Old brake fluid is gross and full of particulates, in addition to absorbed moisture. I wouldn't want it in any hydraulic system let alone my brakes.

If it was OK to never change the manufacturers would market it as "lifetime" brake fluid. No one changes their transmission fluid either and that's labeled as lifetime to the point of not having a dipstick. Why the discrepancy?
 
Originally Posted by gathermewool
Originally Posted by Silver
I noticed a bit spongier pedal once when I went from factory fill to Prestone. People seem to really like Valvoline but I wonder too.


I can't imagine this was due to the fluid. Hydraulic fluid is not compressible.


+1. You may have gotten a bit of air into the system when you bled out the old fluid.
 
Last edited:
Originally Posted by Throt
Originally Posted by slacktide_bitog


Most cars never get new brake fluid and go to the junkyard on their factory fill
crazy2.gif




Which begs the question, how necessary is it? I'd be willing to bet 95% of vehicles never see new brake fluid and never encounter any problems.

Come here to Colorado with brake fluid that is 4-5 years old and you will find very fast how important it is.
Considering that law enforcement knows that, if you ever decide to go to visit Pikes Peak, on the way down there will be forest service officer who will check temperature of your rotors. If it is above 300f, you are out for half an hour.
 
I drain and refill brake fluid on my vehicles every 75,000 miles. I have 3 Toyotas and none of them are required per the Owner's manual, I just do it since brake fluid absorbs moisture over time. I use what ever is available at Wal-Mart - usually the bigger bottles of Prestone.
 
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brakes are like oxygen, you never miss it-them until you don't have any!! those that tow or haul with their rides need better reliable brakes + surely living or traveling in a mountainous area makes upkeep most important + of course good brakes do little with bad tyres especially in the wet or snow, but thats another subject for sure!!
 
I have had great success using Bosch 5.1 fluid in several vehicles. To me it's a one size fits almost all. It's an upgrade to most OE fluids regarding wet boiling point. Most are unaware that some OEM's went to a different material for brake hose lining, thus drastically reducing moisture migration into the hose and eventually fluid.

Never hurts changing fluid, but the reality is modern hydraulic brake systems suffer very little moisture intrusion issues vs old systems. I'd venture to say changing most modern vehicles fluid at 100,000 miles is adequate. But this is BITOG, so we are all OCD, and will never allow that lol
 
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Originally Posted by anndel
I drain and refill brake fluid on my vehicles every 75,000 miles. I have 3 Toyotas and none of them are required per the Owner's manual, I just do it since brake fluid absorbs moisture over time. I use what ever is available at Wal-Mart - usually the bigger bottles of Prestone.

Brake fluid change is not mileage based, it is time based. Moving or not, they absorb moisture. 75k? if you do 20k a year your fluid is not worthy.
 
Originally Posted by AzFireGuy79
I have had great success using Bosch 5.1 fluid in several vehicles. To me it's a one size fits almost all. It's an upgrade to most OE fluids regarding wet boiling point. Most are unaware that some OEM's went to a different material for brake hose lining, thus drastically reducing moisture migration into the hose and eventually fluid.

I've been using ATE's SL6 in two of my more recent brake flushes, it does help with brake feel/response and while I haven't tried activating the ABS on one car a friend says he feels the ESP(Subaru VDC) operates more transparently.
 
I change brake fluid when it looks dirty. It's usually around the 3 year mark. My owner's manual calls for DOT 3 or 4, and Super Tech DOT 3 works fine for me. Takes about an hour and $5 for a Qt of Super Tech DOT3.

I see these quotes for $120, $90, and $80 for a brake flush and shake my head (plus tax and shop supplies). Jiffy Lube and Sears Auto were the most reasonable quotes I found at $60.
 
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