What have I done? (Brake fluid change)

[glum]

Finally got around to changing the brake fluid in my 2008 Sonata. I asked about the bleeding order some time ago and that's the sequence I followed. I used my Mityvac 7201 with the 7205 brake bleeding kit.

The problem: My brake pedal, which was perfectly fine before I, uh... worked on the car, now travels about a mile and a half before resistance is felt. The brakes "work" but obviously this is not proper.

The procedure I followed:

I wanted to evacuate the master cylinder, but Hyundai has a screen under the MC cap, and I didn't want to deal with prying it off, so I left the old fluid in there, and started by topping off with Valvoline Dot 3 & 4 fluid.

Per Hyundai's specs, I started at the right rear. Made sure the area around the bleeding screw was clean, put the 7205 nozzle on there, started suction, loosened bleeder screw. I made sure that suction on the 7201/7205 was never lost. And I tightened the bleeder before removing the 7205 nozzle.

The right rear is the one that took a relatively long time, because of course all the old fluid had to be removed from the MC and pulled through the lines. I evacuated brake fluid a few minutes past the point where the fluid looked new.

Every 30 seconds or so I topped off the MC with new fluid.

Then did that procedure with the left front, left rear, and finally the right front.

I expected a full stream of brake fluid, but what happened at each wheel was that it dribbled into the 7205's hose. I didn't think that was a problem as long as suction was maintained.

I don't think the MC got too low at any point. There was no point at which I refilled it and it wasn't already close to being full to the brim.

I'm curious on what went wrong and even more curious on how to make it right. Obviously doing the same (wrong) thing a second time won't help.

Please, BITOG gurus, advice.

 

[slipangle]

You have air in the lines.
I had the same problem the only time I used a Mityvac instead of a pressure bleeder. Now I only use the Mityvac to suction the master.
The air is probably at the calipers, so you could get a helper to do the push and hold on the brake pedal.

 

[bigmike]

I can only imagine you got air into the line somehow. Do the 2 man method or gravity bleed it for awhile to see if it improves. I know alot of people use assisted bleeders, but this is why I don't - I'm just too stupid. I'd rather have a helper and do it the old fashioned way of yelling UP/DOWN.

 

[Stu_Rock]

Yes, there is air. I have no idea how it entered--maybe past a seal in a cylinder somewhere.

I had a similar problem on my Peugeot just last week, except I was starting from a completely empty brake system. The Mityvac worked fine for the front brake lines and calipers, getting the slug of air passed through very quickly and allowing no new air to enter. On the rear, however, no amount of flow ever got the air out. I had to resort to the two-person method.

 

[bepperb]

Well, did you use a grease on the threads of the bleeder screws? I'm still not sure how else air could have gotten in. I would try again with a one man bleeder or a second person helping and see what you get.

 

[cmf]

It definitely sounds like air in the lines. I have always done my brakes the old fashioned way though, so I can't really troubleshoot power bleeding. I can tell you that it came out in streams doing it the old fashioned method. If you have an assistant you might want to do the manual method once or twice to put fluid into the tube, and then pull the rest with the vacuum.

That filter screen actually saved me from having a leaf in my master cylinder. It just flew in as I was putting the funnel aside.

 

[Trav]

Go back to the first one you started with and put a piece of plastic or rubber hose on the bleeder and let it hang in a container, open the bleeder and let it drip for a few minutes.

If it doesn't start dripping with the bleeder still open push the brake pedal down slowly halfway and let up, this will get it flowing.

Tap on the caliper with a rubber mallet lightly to remove any stuck air bubbles and close the bleeder screw.
Have an assistant push down the brake pedal keeping pressure on it while you loosen the bleeder, close the bleeder before letting the pedal up.
Do this 2 or 3 times then move on the next one, make sure to top off the MC as needed during this process.

 

[HTSS_TR]

I didn't use the brake bleeder adapter 7205 (because I don't have it and I think it is not needed). I connected the suction hose directly to bleeder screw then pump the 7201 4-5 times before opened bleeder screw 1/2 to 3/4 turns. I used a hammer tapped on the caliber lightly on both sides. What I saw was a steady stream of brake fluid from bleeder screw into the suction hose of all 4 corners.

After the flush I started the engine then applied the brake 4-5 times, the first 1 or 2 the pedal went almost down to the floor, the brake pedal firmed up the last 2 pumps.

I was so satisfy with 7201 in bleeding the brake system in my 3 cars, I sold the Motive power bleeder.

 

[NateDN10]

A similar thing happened to me in the Cobalt, except that I used the two-person, no Mityvac method. I re-bled the brakes a couple months later, but it didn't help.

I was also having brake pulsation, so I replaced pads and rotors a couple months after that (January of this year). Just about a month ago, the brakes magically went back to normal.

I'm at a loss to explain it, but I'll take it!

 

[glum]

If there was simply air in the line(s), I'd expect it to be mushy, but have some resistance early in the travel. But there's essentially no resistance until I'm into the "HOLY %@*#!" range of pedal travel. It's not like I'm used to driving a car with air in the brake lines though, so maybe I'm wrong.

Originally Posted By: HTSS_TR
I didn't use the brake bleeder adapter 7205 (because I don't have it and I think it is not needed). I connected the suction hose directly to bleeder screw

OK stupid question time... What size tubing is required, and how do you mate it to the 7201? I assume you use the (bigger) main tube of the 7201 (the one that goes directly into the top of the 7201), and the smaller tube that mates with that (so far it's as if you were going to evac oil through a dipstick tube), then just put the brake fluid tube over the smaller one. Correct?

I have no one to help me until the weekend, and driving the car like this isn't fun, so any 1-person method would be good.

 

[eljefino]

Do you think you got air in the ABS system? What happens if you go find some sand then hit the pedal hard to activate it?

When I one-man it, I jam a 2x4 between the pedal and the seat cushion, and adjust the seat track so it's nice and tight.

 

[HTSS_TR]

Originally Posted By: glum

OK stupid question time... What size tubing is required, and how do you mate it to the 7201? I assume you use the (bigger) main tube of the 7201 (the one that goes directly into the top of the 7201), and the smaller tube that mates with that (so far it's as if you were going to evac oil through a dipstick tube), then just put the brake fluid tube over the smaller one. Correct?

I connected the main tube to the 7201 reservoir, then connect the flexible brake bleeder tube to the main tube via the black connector, then connect the flexible brake bleeder tube to bleeder screw. You don't use either 2 smaller tubes to extract oil in bleeding the brake system.

Mityvac 7201 -> Main Tube -> Black adapter -> flexible brake bleeder tube -> Bleeder Screw.

 

[huffmuds9320]

I use a very simple brake one person brake bleeder method shown in this video below. It works very well considering how simple it is. You can find one person brake bleeder kits at the store as well.

http://www.youtube.com/watch?v=UvyztDFHhaY

 

[cmf]

Originally Posted By: glum
If there was simply air in the line(s), I'd expect it to be mushy, but have some resistance early in the travel. But there's essentially no resistance until I'm into the "HOLY %@*#!" range of pedal travel.


If there's a little air then it feels mushy, if there's a lot of air then it feels like you're pushing air until all the air has compressed. It would technically also feel mushy as you are pressing it through the range of motion that the brake pad is engaging but since it's already almost fully depressed, and consequentially very abbreviated at that point, it's not noticeable.

If it's not air then it's something much more expensive and much less likely.

 

[glum]

Thanks for the advice HTSS_TR, but I decided that I don't want to try the 7201 again. Maybe it's the 7205, maybe it's my car... Don't know. I'm really sorry I took your time with that question.

So since I don't have an assistant, don't trust vacuum bleeding, won't bring the car to someone else, and really don't like driving my car like this, I just ordered a Motive pressure bleeder. I don't even want to say how much I paid for shipping but I cringe when I think about it.

To all who have taken the time to reply,

 

[mechtech2]

You let the MC ge.t low.

 

[glum]

Originally Posted By: mechtech2
You let the MC get low.

I don't know... Maybe. But I topped it every ~30 seconds at most, probably 5 times per wheel.

 

[Big_Kat]

Originally Posted By: bigmike
I can only imagine you got air into the line somehow. Do the 2 man method or gravity bleed it for awhile to see if it improves. I know alot of people use assisted bleeders, but this is why I don't - I'm just too stupid. I'd rather have a helper and do it the old fashioned way of yelling UP/DOWN.


+1... the only time i get to yell at people for good reason!!

 

[HTSS_TR]

Originally Posted By: glum
Thanks for the advice HTSS_TR, but I decided that I don't want to try the 7201 again. Maybe it's the 7205, maybe it's my car... Don't know. I'm really sorry I took your time with that question.

No Problem.

Originally Posted By: glum
So since I don't have an assistant, don't trust vacuum bleeding, won't bring the car to someone else, and really don't like driving my car like this, I just ordered a Motive pressure bleeder. I don't even want to say how much I paid for shipping but I cringe when I think about it.

Motive pressure bleeder may work for you, but it didn't work very well for me. I tried both and 7201 works flawlessly for all my cars. I was glad that I had been able to sell the Motive pressure bleeder on Craigslist for not much less than I paid for it 2 years ago.

 

[1kickbuttranger]

Originally Posted By: bepperb
Well, did you use a grease on the threads of the bleeder screws? I'm still not sure how else air could have gotten in. I would try again with a one man bleeder or a second person helping and see what you get.


If the MC never got low, then this would be the only other thing.