Seeking yet more knowledge on brake bleeding i

[Bob22222]

Seeking yet more knowledge on brake bleeding

First a question:
I have no idea if my 04 has dot3 or dot4 in the brake system currently. I plan to change the front calipers and flush the system. As I understand dot3 is not backwards compatible with dot4. So my logic would dictate using a recognizable brand of dot4 would be the best and safest choice. If there is something I'm missing here please let me know.

On another brake bleeding note:
it seems from numerous post here and on similar boards more than a few of us who seem experienced and quite up to the task of bleeding have had, to say the least, "issues" with bleeding 4th and 5th gen systems.
While the FSM gives a proceedure for manually bleeding the brakes system as many have noted the FSM sites a rather unorthodox order of bleeding the closer calipers first. I'm wondering if using the traditional approach of furthest first can somehow lead to drawing air in places in the MC and it's antilock gizmos that can trigger these issues.? No idea here just wondering. It don't think it's a lark that Toyota says to bleed the fronts first. Any of you techs schooled in modern systems know if other manufacturers are using similar systems also specify to bleed in this manor?

 

[m85476585]

The Owner's manual for mine specifies:
Fluid type:
SAE J1703 or FMVSS No.116 DOT 3

Personally I'd stick with that. I used Prestone DOT 3 brake fluid, and it seems fine. DOT 3, 4, and 5.1 are supposedly compatible, but I read a small number of people saying there could be issues with a higher DOT number in a system designed for DOT 3. Not sure if it's true, but better not to risk it in my opinion.

Dot 5 is definitely incompatible, but it's also uncommon.

You could always get Toyota brake fluid to be 100% safe, but it's expensive, and it shouldn't be necessary. https://www.amazon.com/Genuine-Toyota-Fluid-00475-1BF03-Brake/dp/B00AKYP15A

 

[CruzadoBlanco]

dot 3 and 4 are interchangeable, i just did the brakes on my 1st gen with valvoline dot 3/4 fluid. the only difference is boiling point. if youre gonna do a full fluid exchange then go to a full dot 4 fluid. otherwise just use either 3 or 4 or the mixed ones. just dont use dot 5 and i personally dont trust 5.1 unless its a brand new entire system.

 

[m85476585]

Here are some opinions on brake fluid by armchair "experts". So take it with a grain of salt.
https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1240289

I don't know if you can put in DOT 3 if there is already DOT 4 in a system, but I suspect that it's OK. You should ideally get most of the old fluid out when you change it, anyway. I ran a lot of fluid through one of the rear calipers until it turned lighter color just to be sure, but the worst looking (darkest) fluid was in the caliper itself, and the rest of the fluid in the system seemed OK.

 

[Bob22222]

Here are some opinions on brake fluid by armchair "experts". So take it with a grain of salt.
https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1240289

I don't know if you can put in DOT 3 if there is already DOT 4 in a system, but I suspect that it's OK. You should ideally get most of the old fluid out when you change it, anyway. I ran a lot of fluid through one of the rear calipers until it turned lighter color just to be sure, but the worst looking (darkest) fluid was in the caliper itself, and the rest of the fluid in the system seemed OK.

That (bobtheoilguy) was one of the sources I ran across as well. There does seem to be a general consensus as a researched the issues that mixing dot3 to dot4 is a no no. However, mixing dot4 to dot3 is Ok? This really seems quite contrary to reason as in each case you are still mixing one word to another, correct? I could be missing something here but it sure does a good job of escaping my sense of logic.
However, I do think you've got a good handle on it. I'll use dot3 and and do a bit of extra flushing. Brake fluid is way cheaper than brake systems.

 

[alia176]

Everyone talked about the type of fluid but not the bleeding procedure. I'd like some info on this as well.

Sent from my SM-G920V using Tapatalk

 

[CruzadoBlanco]

Everyone talked about the type of fluid but not the bleeding procedure. I'd like some info on this as well.

Sent from my SM-G920V using Tapatalk

ive always bled mine farthest to closest. and i always do the fronts even if i only disconnected the rear to either pull the axle housing or the 3rd or what ever. just always be aware of the fluid level in the master cylinder so that you dont run it dry and have to have it bled with the scan tool and abs pump.

 

[AuSeeker]

That (bobtheoilguy) was one of the sources I ran across as well. There does seem to be a general consensus as a researched the issues that mixing dot3 to dot4 is a no no. However, mixing dot4 to dot3 is Ok? This really seems quite contrary to reason as in each case you are still mixing one word to another, correct? I could be missing something here but it sure does a good job of escaping my sense of logic.
However, I do think you've got a good handle on it. I'll use dot3 and and do a bit of extra flushing. Brake fluid is way cheaper than brake systems.

I think the issue is if a brake system is designed to use Dot 4 you don't want to mix Dot 3 as it may do harm to the system designed for Dot 4, but a system designed for Dot 3 can use Dot 4 with no harm to the brake system.

 

[Bob22222]

I think the issue is if a brake system is designed to use Dot 4 you don't want to mix Dot 3 as it may do harm to the system designed for Dot 4, but a system designed for Dot 3 can use Dot 4 with no harm to the brake system.

I've been thinking about this most afternoon while out working on my roof and have come to a simalar conclusion. I can imagine the rumor that dot3 being not compatible with dot4 began with the prior knowledge that it is Ok to use dot4 in dot3 systems coupled the additional information from manuals covering systems requiring dot4 cautioning against using dot3. In reality while dot3 is chemically compatible with dot4 it would not meet the flashpoint specs a dot4 system requires.
Actually, if true, this would be another case to the internet distorting true information into mis-information.

That's why I ponder and ask these silly questions. Searching the net for answer is great but if I've any doubt I try to find an experienced source I believe I can trust. In the case of anything related to a 4Runner this is that place.

Probably the best advice I've ever received was "take nothing for granted"

 

[alia176]

ive always bled mine farthest to closest. and i always do the fronts even if i only disconnected the rear to either pull the axle housing or the 3rd or what ever. just always be aware of the fluid level in the master cylinder so that you dont run it dry and have to have it bled with the scan tool and abs pump.

How did you bleed your system? Pump the brakes and open up the nipples, use the Techstream software or some other method? This is what i'd like to get a handle on. Since our system is not vac assisted, I figured a diff method is being used to bleed this system.

 

[CruzadoBlanco]

How did you bleed your system? Pump the brakes and open up the nipples, use the Techstream software or some other method? This is what i'd like to get a handle on. Since our system is not vac assisted, I figured a diff method is being used to bleed this system.

just the normal way. have the key in the on position and have some one press the pedal down and open the bleed screw then close it and repeat. just check the fluid level after every couple cycle of bleeding to make sure the master cylinder doesnt go dry. if it does then your in a world of suck. thats when you have to have a techstream to run the ABS based auto bleed.

 

[alia176]

just the normal way. have the key in the on position and have some one press the pedal down and open the bleed screw then close it and repeat. just check the fluid level after every couple cycle of bleeding to make sure the master cylinder doesnt go dry. if it does then your in a world of suck. thats when you have to have a techstream to run the ABS based auto bleed.

Ahhh, gotcha. Thanks for the info.

 

[Bob22222]

Ahhh, gotcha. Thanks for the info.

http://www.toyota-4runner.org/4th-gen-t4rs/145716-brake-bleeding-w-abs-w-o-sst-tool.html
You might like to look here. Particularly, post#3 siting the factory recommendations concerning manual bleeding. Though e seem to have many members much brighter than Toyota when it comes to Toyota on this site these days.
Yes, there's a lot of confusion and debate on how to correctly bleed these things.

I, myself, have never done the job on this type of system. But I will be " " "experienced" in the matter soon I've taken all precautions to research this from every angle I can find. And feel confident my "experience" will be positive.

I do think you'll broaden your understanding of the system if you read the sited link completely and carefully.

Almost forgot a big thanks to Cabowally is in order.