Brake fluid questions

[hate2work]

I have seen a couple members on here mention that they just turkey baster out the old BF, then top off with new, just like they do with their PS fluid.

Does the new BF actually mix with the fluid in the lines, thereby refreshing all the BF?

Or do you have to flush the lines to get new fluid in them?

If so, what's the point of doing the turkey baster method with the BF?

 

[HTSS_TR]

You need to flush the brake system, turkey baster is okay with power steering system but not with brake.

 

[Mustang_Cougar]

Good choice for a topic...I just had the wife bring home some syringes & surgical tubing for the same "procedure."

BTW: I'm probably wrong in this reasoning, but if the BF isn't recirculated (and ultimately, "mixed") then why would there be such a relatively large BF reservoir in vehicles?

 

[bepperb]

A shampoo/conditioner/hand lotion pump dominates the turkey baster, for what it's worth.

 

[DeeAgeaux]

When I flush the bf I have clean clear BF in the resovoir.

6 months later it is yellowish.

1 year later it is dark black/brown.

So it must circulate.

 

[Chris Meutsch]

I have my mechanic do the whole system. Costs me more but I feel more comfortable knowing it's all 100% new, all at the same time.
Brake fluid is a highly-neglected object in the world of maintenance and arguably the most important fluid for your safety. Get it done every 2-3 years, especially if you've opened the reservoir during a brake job and REALLY especially if you have ABS.

 

[RRich]

Originally Posted By: Mustang_Cougar
I'm probably wrong in this reasoning, but if the BF isn't recirculated (and ultimately, "mixed") then why would there be such a relatively large BF reservoir in vehicles?

As the pads wear down the pistons move out in the caliper bores. The area behind the piston fills in with brake fluid and the level in the master cylinder goes down. You can almost plot your disc brake pad wear by the level of fluid in the master cylinder.

 

[qship1996]

I completely have the fluid changed at every brake job, in between{1x/year} I turkey baste out the resivour and refill with fresh fluid- even if the fluid never fully "circulates", brake fluid being hygroscopic absorbs moisture,and the installation of a resiviour full of fresh dry brake fluid lowers system moisture levels as the new dry fluid pulls some moisture out of old fluid until equalized,lowering total moisture levels throughout the system.

 

[Mustang_Cougar]

Originally Posted By: RRich
As the pads wear down the pistons move out in the caliper bores. The area behind the piston fills in with brake fluid and the level in the master cylinder goes down. You can almost plot your disc brake pad wear by the level of fluid in the master cylinder.

Makes all the sense in the world...thanks for explaining.

 

[tig1]

Over a short period of time BF does move through out the system. I have used the TB method for 40 years and it works well. I do it every oil change and my fluid at the wheels always looks great.

 

[wantin150]

To really see if it does, use ATE Blue and check at the calipers every month.

 

[Stan]

Yes Qship that is what is going on…the equalization of the moisture levels. I do full bleeds as that is the best and sometimes just do a bowl suckout and refill from time to time since it is so easy to do.

 

[3Toyotas]

So is there any upside to just doing drain and fills routinely?

Or would it just be a waste of time and fluid?

 

[Kestas]

This topic has been hashed over and over repeatedly on this board. Years ago I challenged somebody - anybody - to put this question to rest. Like wantin150 suggested, do a complete and proper brake flush with one color fluid, then swap out the fluid in the master cylinder with another color fluid, such as ATE blue. Some time later, maybe a year, see what color fluid comes out of the rear corners, and how long it takes for the fluid to change color. Nobody has yet reported back.

I personally believe that people change the master cylinder fluid because the dark fluid is readily visible and it's easy to swap out. Most importantly, it makes them feel good doing it. Proper flushing by bleeding all four corners is hard. I don't think there is enough brownian motion for the master cylinder fluid to migrate all the way to the calipers and mix properly, even with the slight back-and-forth movement of the fluid.

 

[bigmike]

Originally Posted By: DeeAgeaux
When I flush the bf I have clean clear BF in the resovoir.

6 months later it is yellowish.

1 year later it is dark black/brown.

So it must circulate.


I'm not so sure. This is the same coloring intervals I notice when I flush my brakes.

 

[bigmike]

I always flush the brakes every 1 to 1.5 years, no matter what. It is not hard to do, but more so irritating. On my truck, it's actually easy and takes about $12 worth of fluid and a 1/4" hose. On a car, a little more work due to removal of wheels.

I don't see any reason in changing the fluid in the reservoir unless I'm in the process of flushing it. I'm sure it couldn't *hurt* however.

That being said, neglecting the braking functions on a vehicle is the absolute biggest no-no in my book.

 

[cos]

Quote:
To really see if it does, use ATE Blue and check at the calipers every month.
+1

 

[Paul2007]

Two things: Mark the TB so nobody makes a "mistaeak". Second, I agree with Chris. Pull the old fluid from the master cylinder and bleed the system every 2 years.

 

[tig1]

Originally Posted By: Kestas
This topic has been hashed over and over repeatedly on this board. Years ago I challenged somebody - anybody - to put this question to rest. Like wantin150 suggested, do a complete and proper brake flush with one color fluid, then swap out the fluid in the master cylinder with another color fluid, such as ATE blue. Some time later, maybe a year, see what color fluid comes out of the rear corners, and how long it takes for the fluid to change color. Nobody has yet reported back.

I personally believe that people change the master cylinder fluid because the dark fluid is readily visible and it's easy to swap out. Most importantly, it makes them feel good doing it. Proper flushing by bleeding all four corners is hard. I don't think there is enough brownian motion for the master cylinder fluid to migrate all the way to the calipers and mix properly, even with the slight back-and-forth movement of the fluid.


Your wrong about that. My 40 years experience with the TB meathod has worked well for me. I have kept cars or trucks for many years and the fluid is always clean at the wheel when brake work is done.

 

[MonumentOiler]

I'm not sure if the new fluid and the old fluid will mix that much because they are pretty much the same but I am sure that the new dry fluid will absorb water from the old.

Flush is pretty easy though.