New Brake Fluid

[Carmudgeon]

While I can applaud the recognition of the need for brake fluid maintenance, if you're going to do it, do it right, and flush the system with a pressure bleeder. Sucking out and refilling the reservoir isn't going to do anything to the fluid in the caliper cylinders, or the lines.

Valvoline Synpower was a good, cheap fluid, but alas, has been discontinued. Its replacement is a run of the mill DOT 3/4 fluid.

While it doesn't quite match up in the wet boiling point, the new formula Castrol LMA is a good substitute.

 

[kr_bitog]

If your car has ABS, it is better to use DOT 5.1 to replace it rather than DOT 4. Typical DOT 5.1 fluid may not has higher boiling point than the best of DOT 4, but it is definitely higher than DOT 3 and works better with your ABS in winter month.

 

[Hootbro]

Originally Posted By: kr_bitog
If your car has ABS, it is better to use DOT 5.1 to replace it rather than DOT 4. Typical DOT 5.1 fluid may not has higher boiling point than the best of DOT 4, but it is definitely higher than DOT 3 and works better with your ABS in winter month.


Someone can correct me if I am wrong, but "DOT" specs are not superseding specs but different specs for an intended application.

So a car that calls for DOT 3 may not handle DOT 4 or DOT 5.1 due to seals that may not be compatible with the other DOT specs.

Brake fluid is not like oil that can go up a spec rating and be backward compatible.

 

[moribundman]

Originally Posted By: Carmudgeon
While I can applaud the recognition of the need for brake fluid maintenance, if you're going to do it, do it right, and flush the system with a pressure bleeder. Sucking out and refilling the reservoir isn't going to do anything to the fluid in the caliper cylinders, or the lines.


I believe you are misunderstanding me, but I wasn't clear about it. I am not suggesting the turkey baster method is ever an acceptable substitute for a proper flush and bleed. I have never advocated this method, nor do I endorse it in any way. On the contrary, I flush and bleed my brakes religiously at the prescribed interval.

My plan would involve first flushing and bleeding the brake as I normally do. Then remove fluid from the reservoir and top off with ATE Blue. Then, a year later, when flushing, I would be able to see if the theory that brake fluid homogenizes throughout the whole brake system is true. Now, even if it turns out to be true, I would still not advocate the turkey baster method simply for the reason I already mentioned in my previous post: the dirtiest fluid is the one that is expelled immediately when a caliper is bled. The turkey baste method will in no way get that filth out.

 

[moribundman]

Originally Posted By: kr_bitog
If your car has ABS, it is better to use DOT 5.1 to replace it rather than DOT 4. Typical DOT 5.1 fluid may not has higher boiling point than the best of DOT 4, but it is definitely higher than DOT 3 and works better with your ABS in winter month.


DOT 5.1 brake fluid is more hygroscopic than DOT 4 brake fluid is. You trade better fluid performance for a shorter service life.

 

[moribundman]

Originally Posted By: Hootbro
Someone can correct me if I am wrong, but "DOT" specs are not superseding specs but different specs for an intended application.

So a car that calls for DOT 3 may not handle DOT 4 or DOT 5.1 due to seals that may not be compatible with the other DOT specs.

Brake fluid is not like oil that can go up a spec rating and be backward compatible.


Most DOT 4 brake fluids meet also DOT 3. Whenever choosing a fluid, one should obviously ensure compatibility, which commonly is stated clearly on the container.

 

[Carmudgeon]

Originally Posted By: moribundman
I believe you are misunderstanding me, but I wasn't clear about it.


My comment wasn't directed at you, just a general comment for the OP and the thread.

As anal, or "meticulous" (to put it kindly) as much of the BITOG demographic is, it's surprising that there are strong advocates for such ineffective shortcuts when dealing with a critical safety system on a vehicle.

Flushing the brake system isn't particularly difficult nor expensive for a competent home mechanic, so there's little to be sacrificed from doing it properly, and much to be gained.

That spotless, no-wear drivetrain that one preserves with the best oil, used oil analysis, and magic Rx elixirs won't do a bit of good if the car runs off the road if the brakes fail.

 

[moribundman]

Originally Posted By: Carmudgeon
Originally Posted By: moribundman
I believe you are misunderstanding me, but I wasn't clear about it.


My comment wasn't directed at you, just a general comment for the OP and the thread.


You mean I wrote my diatribe for naught?

 

[Carmudgeon]

Originally Posted By: moribundman
You mean I wrote my diatribe for naught?

Well, if there were any other frustrations you needed to work out, just consider those worked out.

 

[moribundman]

Uh, no, I'm good, but thanks anyway.

 

[kr_bitog]

Originally Posted By: moribundman
Originally Posted By: Hootbro
Someone can correct me if I am wrong, but "DOT" specs are not superseding specs but different specs for an intended application.

So a car that calls for DOT 3 may not handle DOT 4 or DOT 5.1 due to seals that may not be compatible with the other DOT specs.

Brake fluid is not like oil that can go up a spec rating and be backward compatible.



Most DOT 4 brake fluids meet also DOT 3. Whenever choosing a fluid, one should obviously ensure compatibility, which commonly is stated clearly on the container.


Most of DOT 5.1 is compatible with Dot 3 and 4, some DOT 4 with higher boiling point will have thicker viscosity than DOT 3, and may cause problem with ABS on cold temperature.

 

[DrD]

As far as I know, the only real incompatability within brake fluids is DOT5 (silicone based) vs. everything else (DOT3, 4, and 5.1 - Glycol Ether / Borate Ester based).

 

[ddombrowski]

I think one of the biggest reasons that people on this site, as maintenance oriented as they are, still drain/refill the resivoir only is because many times no matter how much better a real flush is, if its not your car, its not going to happen, and draining/refilling the resivoir is better than nothing.

I always flush the brakes on my car from the calipers. But I've showed my father in law and my uncle how to suck the fluid from the resivoir and refill it, because otherwise, it wouldn't ever get changed at all. They don't have the initiative to change the fluid themselves, and they're certainly not going to have to pay to get it done. When you compare it to doing nothing, I think it has its benefits.

Some more anecdotal evidence: My mother's jeep has about 120k miles on it. Since about 60K, after every other oil change, I usually drain the resivoir and refill. Fluid is pretty dark before I change it, and when I refill it, it usually takes about a week to get dark again.