Hard Brakes

[rian]

This could be due to the new fluid being Dot 4, all Toyota's (should) have dot 3 fluid, and although it should only be a difference in boiling point between the grades, the rubbers inside the cylinders can swell and cause a crap pedal. You might be able to pick up a bottle of genuine Toyota Dot 3 fluid at a Toyota dealership if you're keen

 

As far as I know DOT 3, DOT 4, DOT 5.1 are all compatible/interchangeable (some sort of glycol?) whereas DOT 5 is silicon based and that's the one that will mess with your seals.

[Trev]

As far as I know DOT 3, DOT 4, DOT 5.1 are all compatible/interchangeable (some sort of glycol?) whereas DOT 5 is silicon based and that's the one that will mess with your seals.

 

Nope if it doesn't have 'dot 3 or 4' on the cap then you can't interchange, look at new mazda's, 200* model cars and you can only run Dot 3 due to a compatibility issue.

[rian]

Nope if it doesn't have 'dot 3 or 4' on the cap then you can't interchange, look at new mazda's, 200* model cars and you can only run Dot 3 due to a compatibility issue.

 

Interesting. All the people I've spoken to who have used DOT 4 or DOT 5.1 in place of DOT 3 have not had any problems. I've even used DOT 5.1 in some of my cars (Toyotas) and have not noticed any changes or issues. Maybe only some cars have issues with it, yet it's easier to just buy the correct fluid than it is to replace your brake components. I'm going to look into this as I've just recently put DOT 5.1 in my brown KE70's clutch and brake systems because I was too lazy to order in a high boiling point DOT 3, it would suck to have to change it all. :(

Edited September 28, 2012 by rian

[Trev]

If you want to look at brake fluids from a chemical standpoint DOT 3 fluids are based on glycol and glycol esters. DOT 4 fluids are much like DOT 3 fluids, but also contain borate esters. There is another rating called DOT 5.1 that consists of borate esters.

 

Also have a read of this:

http://www.nbsbrakesupplies.com.au/technical-information/dot-3-and-dot-4-brake-fluids.html

[bAKER]

I work at toyota dealership. put toyota dot4 in everything. as far as toyota is concerned it is interchangeable. dot5 to 3 is not.

sounds like a master leak, one of the old o rings has been unsettled with the new fluid. so its leaking past into one of the other lines.

 

Edit:

Test brakes.

Hold your foot on the pedal hard, if it starts sinking, its a hydo leak.

If it does move, turn the car on while your foot is on the pedal, it should sink a bit then stay solid, if not its a booster leak.

Edited September 29, 2012 by bAKER

[Clapped out]

^^^^^^^^^^Spot on, had the exact problem not to long ago, O rings in the master went, caused the pedal to go rock solid, wouldn't release, at it was only 18 months old.

[19914afc]

If it uses dot 4 you can only use that but if it uses dot 3 you can use dot 4 as well.

Brake problems are pretty easy really not much to them at all, if you have an old master cylinder only do half pumps of the pedal takes a bit longer but because the piston wouldn't have traveled all the way being old it's not good to pump the pedal all the way to the floor, if you're still getting problems just get a new master cylinder not expensive for the piece of mind you get knowing you now have a new one, just bench bleed it before putting it in and be done with it.

 

And if you don't know what to do or don't understand something fully go take it somewhere to get it done, don't just try and then find out that you got it wrong when you run up someones ass or try to emergency stop from hitting someone and hurt or kill them, not saying you don't understand but some people don't and then find out at the worst time. It's people like that who should make you need a license to buy car parts, haha.

[troyota]

Decaying of rubber lines is also a common cause of a hard pedal

[Trev]

These Toyota mechanics above should go and speak to Nissan and tell them they are doing it wrong and then go and tell castrol and penrite to update their lube guides to state that you can use dot 4 in place of dot 3.

[Evan G]

there you go guys. you tried argueing/expressing your opinion with trev. ^^^

 

the lesson is to never try

[GJM85]

The car brakes fine but is very rear bias. There are no leaks inside or out.

 

Its running ke70 rotors, girlock calipers and ke55 229mm rear drums. Ive always used dot 4 in all my cars. In fact I havent even seen dot 3 on the shelf in years.

Edited September 29, 2012 by GJM85

[Trev]

You can use what you want but I will use what is on the cap and always will but I was taught that by proper workshops.

 

Oh and look, another brake fluid spec that states the same.

 

One last note on the DOT ratings: Systems designed for a particular type of fluid (especially prior to the wide distribution and use of DOT 4 fluids) should continue to be filled with that fluid. For example, in a car that was delivered with DOT 3 fluid, the internal components of the system (seals, brake hoses, and fittings for example) were specifically designed and tested for compatibility with the chemical composition of DOT 3 fluid. Because the DOT 4 grade fluid typically contains a different chemical composition, compatibility of system components may be an issue.

 

This has recently been proven which is why they didn't go through with the phase out of DOT 3 fluids and which is why it is more common to see it on shelves now than what it ever has.

[bAKER]

ToyotA designed their brake fluid and engine oil to be used in all their old systems. Eg. Toyota 10w30 is recommended by Toyota to be used in hilux 5L ediesel engines. We do what Toyota tells us.

[ke70dave]

If all the brake bits are new or re conditioned then its most likely that they suit dot 4 anyway.