Synthetic brake fluid making breaks airy?

[jrebolloso]

Hi. Does anyone know if using synthetic brake fluid 3/4 will cause any issues with our 3rd gen brake system?

I upgraded to the Tundra 13WL brakes and accidentally used synthetic brake fluid 3/4. Afterwards, the brakes were very airy and soft. Multiple bleedings later, I decided to take it to Firestone.

Firestone asked about the fluid used and I told them synthetic, they said synthetic brake fluid does not work on our 3 gen runners. Firestone told me I would need to take it to the dealer and have the whole brake system replaced; calipers, master cylinder, lines, ABS, the whole enchilada!

So does anyone here know if synthetic break fluid 3/4 causes any issues? Do you think just flushing the brake system will resolve this problem?

Thanks!

Jaime

 

[rjaudi]

Well don't go back there. Valvoline Synthetic Dot 3/4 is fine and that's what I use. You do not want to put DOT 5 silicone brake fluid in a ABS system though. You may need to bench bleed your master cylinder.

 

[02SE]

I think the Firestone dealer assumed when you said "synthetic" that you were referring to DOT 5 Silicone based brake fluid.

Mixing DOT 5 brake fluid in DOT3 or DOT 4 brake fluid filled systems will cause real problems. And would require replacing seals, etc.

If you did in fact use a DOT 3 or DOT4 fluid, your system will be fine. But it does sound like you have air bubbles in the system that need to be bled out.



(edit) as already mentioned in the above post.

 

[binhsterbinh]

You'll probably need to activate the ABS to clear the air out of lines. Then proceed to reflush/bleed the front lines with new fluid. Any Dot3/4 Fluid should be fine. Try activating ABS in a gravel road or parking lot.

After installing my Front 4-piston RL calipers on my TL, I had a spongey pedal feel that would go down to the floor almost at instances. Activating the ABS and rebleeding the lines did the trick for me. I did all four lines to be sure, but usually just the front near the ABS controllers should suffice.

 

[kakarot]

jrebolloso,
Don't go back to Firestone, I just flush my brake fluid using Valvoline Synthetic Dot 3/4 and it's working fine. You properly has air bubble like everyone is saying, make sure you bleed it out. I did my last night and I have to bleed it twice just to make sure there is no bubble.

Hi. Does anyone know if using synthetic brake fluid 3/4 will cause any issues with our 3rd gen brake system?

I upgraded to the Tundra 13WL brakes and accidentally used synthetic brake fluid 3/4. Afterwards, the brakes were very airy and soft. Multiple bleedings later, I decided to take it to Firestone.

Firestone asked about the fluid used and I told them synthetic, they said synthetic brake fluid does not work on our 3 gen runners. Firestone told me I would need to take it to the dealer and have the whole brake system replaced; calipers, master cylinder, lines, ABS, the whole enchilada!

So does anyone here know if synthetic break fluid 3/4 causes any issues? Do you think just flushing the brake system will resolve this problem?

Thanks!

Jaime

 

[ChildrenOfBodom]

Here's another view point:

I have the Tundra 231mm brake upgrade and I originally had brakes meant to fit in the 15" wheel.

Now the thing is, the 2 bolt Master Cylinder on the 4Runner is a 1" bore. The increased surface area with the pistons in the caliper make the pedal effort ratio much higher. It also makes the pedal mushier, because now you have to push more fluid to stop the vehicle.

My solution: 1 1/16" bore master cylinder. While that 1/16" does not sound like much, the extra size equates to more fluid being pushed when you use your pedal, which should cure the mushy pedal syndrome.

I have yet to do the swap, but I will in the next few days. I will update you.

I have an intense case of nosedive, too, so I am installing a manual prop valve for the rear brakes which will eliminate the Load Sensing Proportioning Valve, which comes on 3rd gens without ABS.

Good luck!

 

[J.A.]

I have also recently switched both my 3rd Gen and 4th Gen over to synthetic brake fluid and have not experienced any adverse issues.

Toyota 4Runner Brake Fluid Flush

 

[jrebolloso]

Hey rjaudi. Yeah, i've never had a bad experience at a firestone and have used them often in the past. but this guy was just full of BS. I also got the Valvoline Synthetic Dot 3/4 and the guy kept saying it's not really synthetic 3/4 but DOT 5 synthetic/silicone instead. I went back and showed him the bottle and he still stood by his word. a few folks have told me about the bench bleed. i'm thinking maybe a full brake flush first? any comments on that? seems like a bench bleed is more work and more money. any thoughts?

thanks rjaudi.

Well don't go back there. Valvoline Synthetic Dot 3/4 is fine and that's what I use. You do not want to put DOT 5 silicone brake fluid in a ABS system though. You may need to bench bleed your master cylinder.

 

[jrebolloso]

yeah 02SE, that's right. and after showing the guy the bottle he still claimed it was really DOT 5. i'm thinking that mixing the synthetic with the regurlar might have done something? maybe i should have fully flushed the norm before going synthetic? do they mix?

I think the Firestone dealer assumed when you said "synthetic" that you were referring to DOT 5 Silicone based brake fluid.

Mixing DOT 5 brake fluid in DOT3 or DOT 4 brake fluid filled systems will cause real problems. And would require replacing seals, etc.

If you did in fact use a DOT 3 or DOT4 fluid, your system will be fine. But it does sound like you have air bubbles in the system that need to be bled out.



(edit) as already mentioned in the above post.

 

[jrebolloso]

binhsterbinh, activating the ABS sounds like a pain in the butt. got any links for this? i couldn't find anything.

You'll probably need to activate the ABS to clear the air out of lines. Then proceed to reflush/bleed the front lines with new fluid. Any Dot3/4 Fluid should be fine. Try activating ABS in a gravel road or parking lot.

After installing my Front 4-piston RL calipers on my TL, I had a spongey pedal feel that would go down to the floor almost at instances. Activating the ABS and rebleeding the lines did the trick for me. I did all four lines to be sure, but usually just the front near the ABS controllers should suffice.

 

[jrebolloso]

hey kakarot, think it's just due to mixing the normal fluid with synthetic? should i just get the whole system flushed and go with synthetic?

jrebolloso,
Don't go back to Firestone, I just flush my brake fluid using Valvoline Synthetic Dot 3/4 and it's working fine. You properly has air bubble like everyone is saying, make sure you bleed it out. I did my last night and I have to bleed it twice just to make sure there is no bubble.

 

[jrebolloso]

Thanks COB and keep me up to date. gonna try a few things first.

Here's another view point:

I have the Tundra 231mm brake upgrade and I originally had brakes meant to fit in the 15" wheel.

Now the thing is, the 2 bolt Master Cylinder on the 4Runner is a 1" bore. The increased surface area with the pistons in the caliper make the pedal effort ratio much higher. It also makes the pedal mushier, because now you have to push more fluid to stop the vehicle.

My solution: 1 1/16" bore master cylinder. While that 1/16" does not sound like much, the extra size equates to more fluid being pushed when you use your pedal, which should cure the mushy pedal syndrome.

I have yet to do the swap, but I will in the next few days. I will update you.

I have an intense case of nosedive, too, so I am installing a manual prop valve for the rear brakes which will eliminate the Load Sensing Proportioning Valve, which comes on 3rd gens without ABS.

Good luck!

 

[kakarot]

You have three choices
1. bring it a shop and have them flush & re-fill (cost maybe $79.99 depend)
2. Take off the reservoir and empty all the old fluid and give it a good cleaning let it dry completely. Re-fill with whatever you want to use synthetic Valvoline dot 3/4 or just regular dot 3 then bleed the fluid untill you think you are getting the new fluids keep an eye on the reservoir in-case your are low on fluid, just re-fill and continue bleeding. (cost $10 t0 $13 for fluids)
3. Buy a brake bleeder kit $30 to $40 and do it yourself.

I'll take # 2 over 1,3 anytime save $$$. That is what I did over the weekend.
what ever you choose good luck.

hey kakarot, think it's just due to mixing the normal fluid with synthetic? should i just get the whole system flushed and go with synthetic?

 

[02SE]

yeah 02SE, that's right. and after showing the guy the bottle he still claimed it was really DOT 5. i'm thinking that mixing the synthetic with the regurlar might have done something? maybe i should have fully flushed the norm before going synthetic? do they mix?

If the bottle you used says "Silicone DOT 5" anywhere on the bottle, then the Firestone guy is right.

If the bottle says it's DOT 3, and/or DOT 4, then the Firestone guy doesn't know what he is talking about.

You said that the bottle you used clearly said DOT 3/ DOT 4, so the fluid you used is fine. Find a shop that knows what they are doing, and have them bleed the whole system.

Good luck.

 

[cfranck1]

Dot 5 fluid is a purple color.

Dot 3 and Dot 4 are clear in color.

It sound like it's just in need of a good bleed.
Try to find a shop that has a BG brake flush system(probably dealer), We have one here in the shop I work at and it did wonders for my Accord.
BG Products, Inc.

 

[binhsterbinh]

binhsterbinh, activating the ABS sounds like a pain in the butt. got any links for this? i couldn't find anything.

It's really simple in dirt or gravel or when it's wet outside. Basically just lay on the brake in a straight flat surface with noone behind you really hard until you feel the pedal pulsate due to ABS activation.

After this, make sure to have a buddy help you rebleed the system.

 

[jrebolloso]

it was the master cylinder, but now another problem!

so i changed out the master cylinder and everything worked very well for about two days and a 5 hour road trip. but tonight on my way home from work, the brakes locked up and now they will not disengage! i was able to drive the truck a couple of miles until i got home but i wasn't able to reverse due to the locked brakes. anyone have any idea? thanks again.

 

[jrebolloso]

Update:

I know it's kinda late but wanted to update anyone interested in the solution. The problem was a pinched brake line all along!

 

[19963.4lsr5]

That sounds like a bad master cylinder. Its not floating. Was it a new master cylinder or a reman?