View Full Version : Brakes....again

04-13-2008, 02:35 AM
It is now the LX's turn for a brake job...I know, here we go again right :lmao:

Front pads are at 2/32 and rears are at 7/32 (no plan to replace them yet). Front rotors can't be turned (would end up below spec) so they are getting replaced along with a flush of the fluid.

Question on the fluid...When I did the brakes on the 80 I used the Valvoline Synpower synthetic brake fluid and still have one of the big bottles left. Valvoline no longer makes the Synpower stuff :( so I bought a couple big bottles of Napa DOT 3 fluid.

First, can I mix the synthetic and non-synthetic fluid? If yes then will doing so gain me much? I know the synthetic has a higher boiling point than the Napa stuff.

Second, I got the Napa stuff based on the suggestion of the Burt parts guy (not Joe, some other dude) vs buying the little bottles or Toyota OEM. Before I open it and start using it anyone have suggestions on something better to use?

04-13-2008, 03:33 PM
I use regular DOT3 on everything, not just my rigs but daughter's, stepdaughter's, wife's, etc. I also buy the big (quart) bottles. I have no experience with, nor do I ever remember reading anything about, potential down sides to mixing DOT4 synthetic (silicone based) fluid with regular DOT3, other than if it's supposed to get DOT4 such as Audi for example, stick with the silicone stuff.

I suppose if you have doubts you can always just bleed the heck out of it to flush out all the DOT4.

BTW I just noticed your sig line. When Kipper posted that I just about literally did a ROTFLOL. Definitely a LOL episode.

04-13-2008, 03:36 PM
Second thought - re-reading your original post, I am wondering why flushing fluid? Just replacing rotors and pads doesn't require flushing fluid, only if "while I'm already working on the brakes" PLUS the fluid is old, dirty and shot. Otherwise I'd leave well enough alone.

04-13-2008, 09:24 PM
Thanks Jeff...

I'm flushing the fluid as part of my (late) baselining :) - No history on when it was done last so now that I've done it before and now how to do it, I figure it'll only take me a week this time :hill:

I did some searching and reading online and decided to go pickup some Castrol GT LMA something or other stuff. Higher boiling points (dry and wet) than the Napa stuff. I don't tend to ride my brakes or anything and I use gearing when towing to help slow down but still I like the higher boiling point and it was the same price.

I also found out (it is right on the bottle :doh:) that you can mix the Valvoline synthetic with non-synthetic without worry. Alas, the bottle is open (though it wasn't) so it is a moot point. In my reading the common theme I saw was that people state to get rid of any open bottles of brake fluid after they have been open for more than a month...

04-14-2008, 01:30 PM
In my reading the common theme I saw was that people state to get rid of any open bottles of brake fluid after they have been open for more than a month...

LOL! It is SO funny what misinformation is distributed on the internet, even stuff that doesn't pass the sanity test.

If you aren't supposed to use brake fluid that had been opened more than a month, the same logic would dictate that you MUST completely flush ALL the brake fluid in your automobile at least once a month! Totally silly of course, especially when you consider that the two things that happen to brake fluid is dust/dirt/rust contamination and water adsorption, neither of which can happen in a capped plastic bottle!

04-14-2008, 01:55 PM
I would not mix DOT 4 and DOT 3, personally. BTW, the silicone based fluid is DOT 5, stay AWAY from it unless you want to replace everything in your brake system. DAMHIK, did this on a motorcycle. DOT 5.1 is not silicone based.

I would use DOT 4 over DOT 3 due to the higher boiling point. You may want to check your specs on your modern vehicle, as DOT 4 may be the minimum specified. Get a logon to the Toyota technical site and download all you can of the FSM!!

I would also use opened brake fluid, but not if it were open more than a year - the reason is that it is hygroscopic. In other words, opened fluid would be as degraded by atmospheric moisture as fluid already in use in your vehicle. Thus, you would be wasting your time to use it! Atmospheric moisture is introduced into a partially used bottle, and yes, it gets absorbed, and yes, the boiling point goes down. Maybe not as big a factor on old drum brakes, but it is with disks. A sealed bottle has very little atmosphere and it is not refreshed with moist air every time you open it. Probably not as dramatic a change as in Seattle though. :lmao:

I flush my entire brake system annually or biannually. Your brake components will last MUCH longer doing so. Easy to do with a pressure bleeder. I flush the motorcycles' systems too. Sure, the brakes will work, but having seen the innards after not doing so vs. doing so, I can vouch for the level of internal corrosion etc. I don't care to have corrosion in my brake system, towing a camper down Vail Pass, rolling 35s, and getting cut off by Susie Soccermom etc.

The Chili has the best brakes of any vehicle we own, or have owned, even on 35s. I aim to keep it that way. It will light up all four 35s if I am determined to do so, or simply plant my nose on the windshield if Susie shows up.

Sorry to hear that Synpower brake fluid is NLA. I rather liked the stuff. Less harsh on paint than conventional. I think I still have an unopened quart. Synpower PS fluid on the other hand is junk and will destroy a PS pump. Or so I found out. I have a lot of that too. :lmao:

04-14-2008, 02:48 PM
Interesting info guys :thumb:

Per the FSM etc. etc. the "approved" brake fluid for a '97 LX450 is DOT3. FAQs etc. state DOT3 or DOT4 are fine...

The old fluid has been opened for 6+ months IIRC. I'm going to donate that to Nakman and his Scout.

I have been real happy with the brakes on the 80 after doing those so I'm hoping for the same on the LX. Nice and day difference between the two :thumb: (although the rigs are very different).