How do YOU do a brake fluid flush ?

Never done it ... this topic came up before as a spinoff some time ago ... and I called two Chrysler dealers and three bigger service centers asking how they did it .. I was surprised

-Lay down some towels in case of spilling
-Turkey baster out the reservoir
-Fill Reservoir with fresh fluid
-Push through using the pedal starting with the farthest wheel, checking the reservoir level often until it's clean/clear fluid.

I try not to push the pedal all the way to the floor on old cars or ones with dirty fluid.

I run DOT4 in everything, usually ATE SL.6 for ABS/ESC vehicles or ATE TYP. 200 for non-ABS vehicles.

I'm willing to bet the dealers typically don't flush fluid whatsoever, there's nothing about it in most owners manuals.

So dusty .. are you suggesting that some dealers charge for it .. and don’t actually do it OR even try to do it ?

IIRC ... the typical dealer charge was 180$

as golduster said.
or use one of those vacuum pumps with the reservoir at each wheel, pumping until clear, new fluid is present.
still need to keep close eyeball on master so to not run it dry.

I'm saying its not usually a suggested service item.

Clearly you got a "we don't want to do it" price, because on a non-rusty car it's a cake job.

I'm an engineer at a company that makes a lot of OEM brakes, though I work on stability control and not calipers, even our garage techs bleed by either pushing through or by using a pressure bleeder that hooks up to the cap. If a dealer had one of those, they should be done in under 45 minutes including taking the wheels off.

Even the fluid I suggested should only cost you like $15 for a liter which is enough to do anything smaller than a full size truck.

X 2

Only difference is I gravity bled the system. I usually didn't upsell a brake flush but my writer loved to try, especially on a major service.



Tim

With a pressure bleeder, open each bleeder until the fluid runs clear. Newer systems with ABS are more complex, they require a scanner to run the ABS pump.

Unless there is a ton of air in the ABS system you don't need to run the pump. You won't get 100% of the old fluid out since some will be in the pump and accumulator areas but that's okay. If you are doing it every 2-3 years it will come out at the next change.

Also forgot to mention that I use a pickle jar and clear tubing from home depot to catch the fluid on the other end.

We have a machine, pressure fills the master with hoses that suck the fluid out of each corner. Moisture is what kills brake fluid. The higher humidity areas of the country should do it every 2-3 years. Drier climates can go longer.

I read a recent Mopar Action article by Rick E, and he'd recommended going over to DOT 5, after doing a full flush (DOT 5 can't be with the earlier grades apparently). Is he right; if you're already doing a system flush, is it better to swap to 5?

As far as I can tell, maintenance schedules to flush brake systems first appeared in the owner's manuals of Japanese cars and then spread to domestic.

I put disposable aluminum pans sized about 1 ft x 2 ft behind the wheels to catch drips. Depending on the locations of bleeder valves, it may not be necessary to remove the wheels.

Remove old fluid from master with a turkey baster or similar and fill with new fluid. Note that if you flushed this same system a few years ago, the old fluid may not be very dark. For that reason, have several clear jars and retain a sample of old fluid to show the color.

Starting with the most distant wheel cylinder from the master, usually right rear, attach a clear plastic tube to the bleed valve, open the bleed screw, and allow the cylinder to gravity drain into a clear jar. If it won't drain, gently push the brake pedal half travel to get it started. It helps a lot to have a weight on the outlet end of the plastic tubing to keep it submerged in the jar. I use a 3"-4" section of stainless tube as a weight. Closely observe the color of the draining fluid using the retained color sample of old fluid. Once new, clear fluid is detected, close up, refill the master, and move to the next wheel closest to the master, usually the left rear, then right front, and left front.

Each time I've done this, it took about a quart of brake fluid. Never let the master go dry.

Some parts store bleeder kits want you to pull a vacuum on the clear outlet tubing. My experience is that this is not needed. Gravity does the job. Besides, a vacuum pulls air bubbles down the bleeder valve threads, giving a false impression of air bubbles coming out of the system.

First post nailed it. Clean the master reservoir. Fill with clean fluid. Push fluid through at all the wheels until it all runs clean. I do it. Often with a pad change since you're already there. Moisture and dirt pushed out. If you're paying attention, it makes the brakes feel better.

I work at a Toyota dealer, we do lots of brake flushes. We have a Wynns X-tend machine which pressurizes the M/C, and has a recovery hose that goes on the bleeder screw. Several minute flush on the right rear to replace the fluid in the master and RR caliper/cylinder, two minutes on the rest of the wheels. It is definitely a part of the maintenance program.

Most of the posts are spot on.
Every time I buy a (used) car This is one of the first things I do on a full service. I try to install 'Speed Bleeders' when I do a car. This way it takes just one to pump the brake pedel.

On my 84 Dodge Rampage I used my Myovac and sucked out the Espresso coffee from the master cylinder. Then working the weight adjustable proportional valve I bled RR, LR, RF LF.

Every 3 years. We are wet up here.

Every time I've done it I've bled like normal or let it gravity bleed. Doesn't take too long to do either way.

Due to the air leakage mentioned above, I've been carefully wrapping teflon tape on the bleeder threads being careful to keep it away from the hydraulic circuit. I have also tried the Russel one man bleeders with success, but I usually just use clear tube into a glass jar so I can watch the color change of the fresh fluid & bubbles.

That relatively inexpensive Mity Vac brake bleeder that holds a gallon of fluid works well for me. I also use the very high temp DOT 4 fluid as I've seen how hot my front rotors get on a road coarse. I've seen new corvettes with the rotors glowing cherry red coming off Willow Springs after a few laps.

Vehicles vary, the newer LX cars even require that the car be at a certain angle (rear elevated) when bleeding brakes.

Air leakage at the bleeder threads when using a clear tubing will fool you in to thinking you have air in the system only open the bleeder 1/2 turn, when I encounter that I put a few drops of oil on the threads it seals them up for the time.

FIRST THING ... I’ll bet most of you posting here have done more brake work IN A COUPLE OF MONTHS than I’ve done in my lifetime!

But let me ...

What happens to all that old junk fluid AND TRASH in the bottom part of the caliper during the flush process ?

Shouldn’t the caliper be removed from the brackets and turned 180 degrees to get everything out ?

On dual master cylinder equipped vehicles - does any brake fluid from one reservoir merge with the other reservoir at any time in a normally functioning system?

No

Didn’t think so.

So why do guys still advocate bleeding the right rear first, then left rear, then right front then left front.

Just wonderin’.

I’m guessing just a habit from the old single master days?

Mostly habit. ABS? if not, typically the rear line will run to the rear, then split. Same with the fronts, single line out will split at some point. Just trying to get the air out of the longest runs first. Hit all 4 corners, run the pedal a few times, and hit all 4 corners again two or three times to verify. Use clear tubing on the bleeder to see what's coming out.

Depends. Does your OCD let you sleep at night if you don't? Unless the system was really nasty, I just run it until I get clean fluid. I suppose one could pull the caliper and shake it up or turn it upside down and pump some fluid through. If it's that bad, maybe need to fix or replace the components.

OCD and properly emptying and cleaning out the junk brake fluid ?

Whaaat ? ... might I suggest you FOCUS on the topic at hand !!

I was trying to answer th.....oh look, a squirrel!

Ahhhh YES .... cMc .., the squirrel !

take a look inside the plastic reservoir of a new vehicle that has a single fill spout peeking out from under the cowl. it will fill BOTH sides of the master, with a divider wall only about 3/4 of the height of the reservoir. yes, they DO mix until the fluid level reaches a certain point, due to "xxxx" happening.
the old iron, four bolt masters were indeed separate chambers that could not merge with each other.
and then again, look at the "cross brake" operation of certain K cars and early minivans. those were bled left rear, right front, right rear, left front. [or maybe the opposite, i forget]

Good point Moparx - but thankfully no one here has brought up the K car system in this discussion and if they did the rear right then rear left would not hold true either. (I forgot about those split systems back in the day).

Anything merging in the common reservoir would still not dictate rr/rl then fr/fl I don’t think.

The common plastic reservoir Mopar master cylinder is open in the top of the tank to equalize the level under normal conditions. Once fluid exits the master cylinder front and rear systems are separate, or should be. ABS and some weird experiments from the past will be different. I try to not work on any of that anymore and just deal with the race/muscle car stuff.

That's what motivated me to get a pressure bleeder.

No, don't do it, its a different chemistry fluid. It's an absolute no-no on an ABS/ESC vehicle especially, Keep in the gylcol fluids (3/4/5.1). New systems only if paint is more important to you than brake pedal feel.



I know that specific car well, but for a brake fluid flush there should never be any air in the system, and it has no way of getting in (cap is still the highest point in the system). When you do have air, the ESC module being on the passenger side of the car behind the headlight makes it have more runs of almost horizontal tubing so they want some bubbles in that to come back to the master cylinder.



The diagonal split system is the most common system on the road now, basically in everything short of pickups, wrangler, charger/challenger/300 has it now. So FR/RL is one circuit and FL/RR is another. If Doc is talking anything FWD, it's got that system.

As far as why you'd bleed the furthest away first, its just to get the longest run done first. If you were taking air out you'd want to do this anyway so it's a force of habit.

So how much new fluid is used to do a flush like this? several minutes at each bleeder with a pressurized system sounds like it could be several gallons of fluid.

I called a local Toyota dealer here ... service manager was speechless...when asked about the COMPLETE FLUSHING of the caliper !

I'll bet.

Well cMac ... how would YOU shuck and jive if you jsta quoted on a complete brake fluid flush for 180$ when the way they do it does NOT flush out ALL the contaminated fluid ?

That sounds downright cheap, that's an hour of labor around here at a dealer.

Dealership labor rates are 180$ per hour ?

....and they’re not doing the job right ??

This is what I do.
No idea what some might charge as I can't see paying 4 something I can do myself.
I would suggest looking for some one offering the job at a price a person would find exceptable.

No, don't do it, its a different chemistry fluid. It's an absolute no-no on an ABS/ESC vehicle especially, Keep in the gylcol fluids (3/4/5.1). New systems only if paint is more important to you than brake pedal feel.

DOT 5 is silicone based, but from my understanding they can be mixed with DOT3 &4. The DOT won't leave it up to the end user to make that call whether they can be mixed or not, they are compatible correct? Please elaborate on pedal feel. Does the DOT 5 compress more than the glycol based 3 and 4? On a fresh system why would it be a disadvantage to run 5?

Jeff

My understanding with DOT5 is that the system has to be entirely flushed COMPLETELY ..,, the plus with 5 is that you never have to worry about any moisture contamination

https://ebcbrakes.com/product/brake-fluids/

Here is a pretty good explanation. I guess I was confusing 5.1 with 5.

Jeff, I couldn't say, either way. I saw it in the MA article and it popped my interest, as E'berg said it was good swap. I was interested if anyone here had ever converted over to 5, and if it WAS better.

Never done not one in 50 years. I got a 65 Plym with original fluid, looks great, original trans fluid and original rear end oil, maybe in 2065 i might change it out.

I just clean the MC, add clean fluid and push it out all 4 corners until it runs clean. Call it a day.

The only way to totaly get the calipar 100% clean is to pull it apart. No amount of bleeding will get all the crud out.
But, is it needed most times? NO.

If I buy a used car and know the brake fluid is Expresso colored its time to pull the piston (s) out and clean. This is when I spend the $100 bucks or so and get all new flex hoses too.

Case in point. My 78 LRT has been sitting dead for 15 years. I am building its 410 stroker now and when I get the truck in the shop I will be replacing the master cylinder to a 2 bolt, the vac booster, the rubber flex hoses and any of the steel lines as needed. I will be pulling the Calipers and wheel cylinders apart to clean and inspect them. Its easy work.

One of the first things I drilled into my sons head,
"If you add to the GO you have to add to the WHOA" .

it's better to stop BEFORE you go. [in my opinion ]

But there can/could be issues with seal compatibility, DOT5 can deteriorate or swell some seals depending on their rubber composition...

True. But fluid can become dirty, contaminated and/or absorb moisture. Clean fluid and bleeding usually helps a pedal if you're paying attention.

Maybe I’m missing something but how can fluid become dirty, contaminated and have moisture if the system is closed? Now if you have a line brake then I say maybe.

DOT5 could cause some gelation or possibly be incompatible with the seals in the master cylinder as well. Chemicals that aren't intended to be mixed.

DOT5 can't absorb water or air from the fluid, it will not be absorbed and is more difficult to bleed, will not keep the water in suspension so any pools of water (there is moisture in the air) won't benefit from any protection the gylcol fluid could provide. You absolutely want the fluid to absorb it vs it pooling separately (like oil and water separate) This along with the slightly higher compressibility would make your pedal longer. It also will not flow through your ABS valves like the glycol fluid, so it will mess with the calibration at the very least.



The system is absolutely not closed. The master cylinder has venting in it in all cases so fluid can flow when there is a leak or a need for more volume (such as pumping). They are usually venting slits or small holes in the membrane that are hard to see. The dirt is usually either from pushing the pistons back in during a pad change OR some level of leeching from the rubber parts, or wear of the seals or bores.

Cudaman its foolish not flush & bleed your brakes,It takes so little & the gaines are huge.



Brake fluid is highly hygroscopic moisture gets in regardless through the M/C lid seal & caliper/wheel cyl.seals the fluid becomes discolored & rust forms,the pedel feel can be night & day after flushing,try it I dare U.

I find it tends to happen more frequently with power bleeders they create more velocity & pull air through the threads easier.

Huh?????

When you loosen the bleeder screw and put a Myovac suction type device on and pull a vacuum it can suck air around the screw threads.

The power bleed system that pushes fluid from the master cylinder will not do this.

Heard from a guy who I had talked with before about STICKING CALIPERS


He said that moisture laden brake fluid can make the phenolic resin pistons in many of the calipers swell and then stick in the bore

Very true. Use a clear hose on the bleeder, watch and listen. You will see it. Pulls air around the threads and out the bleeder.

It can trick you into thinking it still has air in it. That's why I like to push, rather than pull, fluid through the last few times I crack the bleeder to see what's coming out.

So when you say “pedal feel” you’re saying water can be compressed but brake fluid can’t? Or that the water and fluid will combine to make it feel bad? Or water is heavier and will go to the lowest line and rust it through (if it sets for a long period of time)? Or maybe if the fluid still moves around it won’t rust but the discoloring gives you the impression its no good? Kinda like rotating my cans of soup in the pantry to keep them fresh. Like I said, never in the 55 years of messing with cars have I ever changed fluid and my brakes have always worked very fine. Like washing lug nuts, useless
40+ cars through the years

Water can not be compressed. But it will cause rust and corrosion. Moisture (humidity) will be absorbed by brake fluid and it will also substantially lower the boiling point of the fluid causing the pedal to go away if you manage to reach that boiling point.

If not flushing works for you, carry on carrying on. But I will not follow your example nor do I recommend it to others. YMMV.