Brake Fluid change

[Ken2]

The master cylinder is not usually damaged when the system is open and the pedal pushed to the floor, but conventional wisdom says that it could happen.

My '96 Volvo with ATE brakes required bleeding in a sequence starting at the closest wheel to the m/c and working away. I don't know why, but it worked well.

Use a six point socket or a five-sided tubing wrench on the bleed nipple to break it loose. Soak the threads in penetrating oil first. DO NOT BREAK THE NIPPLE, or you'll have a much bigger job on your hands. A 12-point wrench is likely to round off the bleed nipple flats if it is tight. After the bleed nipple is loosened and lightly re-tightened, put a good smear of grease or pipe thread compound around the threads before you do the vacuum bleed to keep air from being sucked in around the threads.

Brake fluid is corrosive--keep it off painted surfaces. Do not let your master cylinder run dry while you're bleeding, or you'll have a much bigger job.

 

[tig1]

Originally Posted By: RiceCake
Originally Posted By: heyu
I always had good luck just changing out the fluid in just the master cylinder alone ,all the fluid in the lines does purge back and forth back to the cylinder so draining the master cylinder and refilling 3 - 4 times is usually all clean after that AND as mentioned above,,a turkey baster works great


Not really. Your brake lines are very long, narrow, and have no cyclical flow. Changing the brake fluid in the master cylinder regularly does cause a tiny bit of fluid to cycle into the top of the lines, but even in a million stops I doubt it will never cycle more then %5 new fluid to even the halfway mark down the lines.


With some 40 years of turkey basting I have seen fluid move out of the MCyl in a short time. In older cars where the fluid was very dark I have seen the new fluid change in days back to a darker colar.

 

[hypervish]

Is it a good idea to get a water bottle fill it up with a bit of brake fluid (ensuring hose is submerged in it) with the other end attached to the bleeder valve. And, then pumping the brake pedal (pushing it only as far as I would normally when stopped at a traffic light). Would that be safe?

I've seen it done before, and I think that would be easier than communicating with a a second person and telling them when to push the pedal.

Thanks to all who replied! It helps!

 

[mechtech2]

With new or rebuilt units, forget about damage to the MC from putting the pedal all the way down.
Even with used systems, it is only a chance that the 'dirt' seal will be disrupted - it has to be old and filthy. You really have problems, anyways.
Of course we can't go wrong with a short pedal stroke, but danger is over rated.

 

[JOD]

Originally Posted By: tig1


With some 40 years of turkey basting I have seen fluid move out of the MCyl in a short time. In older cars where the fluid was very dark I have seen the new fluid change in days back to a darker colar.


You've seen it move--but to where is it moving? My guess is "not very far". When I bought my current car, which was 2 years old, the dealer had appeared to do a drain/fill from the reservoir, along with a rear pad/rotor change which was done under a recall. I flushed the fluid a year later and it was pretty obvious that the new fluid never made it to the back of the car.

Of course, you can answer this for yourself. This summer (or this winter if you have a garage), just crack the bleeder on your rear right wheel. I'm willing to guess the fluid looks pretty contaminated if it's been a few years since it's been actually flushed.

 

[HTSS_TR]

Originally Posted By: Char Baby
I like the hand held vacuum pump(~$35).

Using the vacuum pump, bleed each brake one at a time in the proper order by the MFG, pumping up the vacuum to the proper Hg & cracking open the bleeder and doing this several times for each brake until you're satisfied, keeping the MC resivior full until you're complete.

There is a lot of work using small hand held vacuum pump, because it does not have a lot of vacuum. I also don't like the idea of having several tools to do different things. I use my big vacuum pump, the Mityvac 7201, to do oil change, ATF, brake ... It is so easy and so fast to bleed the brake with it. If I need to siphon any liquid, I use it.

 

[Turk]

Gosh, this reminds me my 2000 Saturn SL2 probably has the original Brake Fluid in it.

No receipt of it being done and they gave me everything.

 

[charbaby]

Originally Posted By: HTSS_TR
Originally Posted By: Char Baby
I like the hand held vacuum pump(~$35).

Using the vacuum pump, bleed each brake one at a time in the proper order by the MFG, pumping up the vacuum to the proper Hg & cracking open the bleeder and doing this several times for each brake until you're satisfied, keeping the MC resivior full until you're complete.

There is a lot of work using small hand held vacuum pump, because it does not have a lot of vacuum. I also don't like the idea of having several tools to do different things. I use my big vacuum pump, the Mityvac 7201, to do oil change, ATF, brake ... It is so easy and so fast to bleed the brake with it. If I need to siphon any liquid, I use it.

After 20 something years with my Mity-Vac and loaning to others, the handle is now broken. Although I can still attach a small vice-grip to stem and activate the the pump, I am ready for a new pump. I will look into the #7201 for bleeding brakes.

 

[charbaby]

I can usually get my Mity-Vac Pump to ~25-27in.Hg, which is pretty good and it draws the brake fluid in the it's resivior quickly.

I am just so used to using the hand held Mity-Vac and like it so much, I haven't even thought about using something else that may infact work better.

 

[charbaby]

Originally Posted By: HTSS_TR
Originally Posted By: Char Baby
I like the hand held vacuum pump(~$35).

Using the vacuum pump, bleed each brake one at a time in the proper order by the MFG, pumping up the vacuum to the proper Hg & cracking open the bleeder and doing this several times for each brake until you're satisfied, keeping the MC resivior full until you're complete.

There is a lot of work using small hand held vacuum pump, because it does not have a lot of vacuum. I also don't like the idea of having several tools to do different things. I use my big vacuum pump, the Mityvac 7201, to do oil change, ATF, brake ... It is so easy and so fast to bleed the brake with it. If I need to siphon any liquid, I use it.

I think that the hand held MV vac pump has enough vaccume but, it needs a larger resivior as I have to dump it often and start again. Which is what causes the extra work, I guess!

But, when I close the bleeder valve and dump the old fluid, I also replenish the master cylinder with more brake fluid.

I guess it's extra work, I just never though of it this way as I am always alone and don't have a helper to do the extras such as keeping the MC full of fluid

 

[rslifkin]

With the big mityvac, I'd assume you hook it up, top off the MC, get a vacuum going, and then move over to keep the MC full until you're ready to dump the vacuum and move on to the next caliper.

 

[HTSS_TR]

Yes, with the big reservoir I need to top off the MC 3 times for rear wheels and 2 times for front wheels.

I think the main advantage of 7201 is it can be used for many siphoning jobs. I used to think that specific tool for specific job, for bleeding brake I bought Motive pressure bleeder but it didn't work very well for rear wheels, because it didn't have enough pressure to force the brake fluid out. I sold it and use 7201 and it works great.

 

[The Critic]

Originally Posted By: mechtech2
Suck out the old fluid first, and put in fresh.
THEN start your bleed.


With one caveat....on some cars, if you lower the fluid level below minimum, the float will get stuck and you will need to remove the reservoir and master to unstick it....not fun. I was at the Honda dealer recently and a tech told me that a few people in the shop had run into this, so be careful.

Originally Posted By: Bgallagher
Pretty standard my friend. You got it!

Remember to start at the farthest caliper from the master and work your way up. usually when I am doing this I would adjust my rear brakes (if drums) and clean the brakes. Might as well when you are in there


Few modern cars use the furthest to nearest sequence. A lot of them now call for a diagonal sequence. Hondas for instance, use LF, RF, RR, LR. So, it is best to consult the factory service manual before proceeding.

Also, I would clean/lubricate the slide pins, as well as clean-up the rust under the caliper bracket clips so that the pads can slide smoothly. Use silicone grease (3M or Motorcraft) for the pins and molykote for the bracket and clips.

Originally Posted By: tpitcher
Gosh, this reminds me my 2000 Saturn SL2 probably has the original Brake Fluid in it.

No receipt of it being done and they gave me everything.



When I had my Saturn, pressure bleeding it with the Motive was the way to go.

 

[aualtima3.5]

Originally Posted By: mechtech2
I am quite familiar with starting at the farthest wheel when bleeding. Everyone has heard this.
The more I think about it, the less I am convinced that this is necessary at all. In a closed hydraulic system, a good bleed ends up the same.

BTW, with ABS systems, do your homework first on your specific car! Many require specific bleed techniques.


I have bled just the front two on my LHS after replacing the front calipers. Brakes are firm as a ... freshly bled system...

I don't recommend it, though. Just goes against 'the rules.'

 

[charbaby]

I have blead Honda systems both ways. The end result seems to be the same...

...Honda's way, meaning Criss/Cross(LF, RR & RF, LR) &

The standard way, meaning RR, LR, RF, LF and including the proportional block if equipped with a bleeder.

 

[HTSS_TR]

Originally Posted By: Char Baby
I have blead Honda systems both ways. The end result seems to be the same...

...Honda's way, meaning Criss/Cross(LF, RR & RF, LR) &

The standard way, meaning RR, LR, RF, LF and including the proportional block if equipped with a bleeder.

Try the opposite of standard order: LF, RF, LR, RR next time, you will see no difference in brake feel or performance.

 

[heyu]

Originally Posted By: RiceCake
Originally Posted By: heyu
I always had good luck just changing out the fluid in just the master cylinder alone ,all the fluid in the lines does purge back and forth back to the cylinder so draining the master cylinder and refilling 3 - 4 times is usually all clean after that AND as mentioned above,,a turkey baster works great


Not really. Your brake lines are very long, narrow, and have no cyclical flow. Changing the brake fluid in the master cylinder regularly does cause a tiny bit of fluid to cycle into the top of the lines, but even in a million stops I doubt it will never cycle more then %5 new fluid to even the halfway mark down the lines.


Well you stand corrected ,,Any car i have emptied the master cylinder AND wiped clean with a paper towel had dirty fluid from the lines purged back to the master cylinder in less than a hundred miles (not a million stops that you claim) Have you never tried what i suggested for proof?? ,,Then what do you know to quote ? ,,I have even gravity bled rear brake lines through the master cylinder

 

[charbaby]

Originally Posted By: HTSS_TR
Originally Posted By: Char Baby
I have blead Honda systems both ways. The end result seems to be the same...

...Honda's way, meaning Criss/Cross(LF, RR & RF, LR) &

The standard way, meaning RR, LR, RF, LF and including the proportional block if equipped with a bleeder.

Try the opposite of standard order: LF, RF, LR, RR next time, you will see no difference in brake feel or performance.

Well, I don't currently own a Honda. I was just mentioning this from past Honda's that I have owned.

I did in fact, do this(Bleed the Fronts 1st/Rears 2nd) on my daughters '06 mazda3 due to the fact that I was doing some front brake work(inspect, clean&lube sliders and bleed). I felt no differences.

At a later time, I did the rears(inspect, clean&lube sliders & bleed) and still felt no differences.

When I finaly did the whole brake job(4 rotors/all pads, clean/lube/bleed) and blead the system again the old fashon way(rear to front), I still feel no differences

I'm not convinced that the procedure that is followed in bleeding brakes, is as important as just "DOING IT" as a good PM! Although I do have my preferences!

 

[kam327]

I just flushed the brake system on my Explorer this weekend.

I bought a "one-man bleeder" device from Advance Auto. It was junk and I wouldn't recommend it, but it seemed to work well on the first two calipers I did (the two rear). It has a tapered plastic fitting that you push into the bleeder plug oriface until snug, tubing from the tapered fitting to a check valve (to prevent air ingress into the caliper), and then tubing from the check valve into the collection bottle.

The provided collection bottle was way too small so I just dangled the check valve and short tubing into a larger 1 qt empty container. Once secured, I turkey bastered the reservoir, refilled, and pumped the brake pedal a few times. I found I could pump the pedal well over 20 times before the level in the reservoir reached the "low" level, at which point I promptly refilled the reservoir. I must’ve pumped over a quart of fresh fluid through the line to the right rear caliper. Then continued on to the left rear caliper.

By the time I got to the right front caliper, the third in my sequence, I started noticing small air bubbles in the tubing leading to the collection container, which immediately told me the tapered plastic fitting was no longer air tight. At that point I turned it into a 2-“man” operation and called my wife out to the garage to pump the pedal until I saw no air in the tubing and closed the bleeder plug. To be safe I repeated this on the rear calipers.
On the test drive, I noticed the pedal was easier to depress than it was before but stopping power was as good as ever. Not sure how old fluid would’ve caused more resistance in the brake pedal.

I don’t know why you’d need to close the bleeder plug at the end of each pedal pump to prevent air ingress – as a previous poster recommended. As long as you maintain fluid in the tubing leading to the collection container, and better yet (as another previous poster suggested) submerge the end of the tubing in fluid in the collection container. Then there’d be no way for air to be sucked all the way back up the drain tubing and into the caliper.

 

[HTSS_TR]

Originally Posted By: Char Baby

Well, I don't currently own a Honda. I was just mentioning this from past Honda's that I have owned.

I did in fact, do this(Bleed the Fronts 1st/Rears 2nd) on my daughters '06 mazda3 due to the fact that I was doing some front brake work(inspect, clean&lube sliders and bleed). I felt no differences.

At a later time, I did the rears(inspect, clean&lube sliders & bleed) and still felt no differences.

When I finaly did the whole brake job(4 rotors/all pads, clean/lube/bleed) and blead the system again the old fashon way(rear to front), I still feel no differences

I'm not convinced that the procedure that is followed in bleeding brakes, is as important as just "DOING IT" as a good PM! Although I do have my preferences!

Exactly, the sequence of bleeding furthest first or nearest first makes no difference that I can tell after bleed my cars brake systems.