Brake Bleeding Problems *sigh*

[Boost95]

Well, I spent the day doing a NON ABS conversion on my 92 AWD. I ran all the lines etc which wasn't all that bad. After everything was back 2gether it was time to bleed the brakes. I am using a one man bleeder system. Starting at the passenger's rear. No matter how many time I try it still has air bubbles in it. After time I moved on to the drivers rear then the pass front. Both of them took me about 2 times to get all the air out. I then tried the drivers front which acted the same as the passanger's rear. time after time I had bubblesWTF

When I was running the lines that go to the master cylinder from the front of the proportioning valve I removed the Master Cylinder to make it easier to manuver the lines in there. Will this have an effect on what im doing? Thats the only thing I can think of.

I also checked for leaks and they are all fine. Please give me some pointers

Thanks,
-Mike-

 

[ForceFedRed]

By a one man bleeder system I'm imagineing a mity-vac (hand held vac pump) and a plastic container that the mity-vac pulls the fluid into.

First, you should have done what is called bench bleeding the master cylinder since you may have gotten air into it while it was removed. Sometimes little air pockets in master cylinders are extremely difficult to bleed because of the angle that the master cylinder sits when installed. I would look more into this if what I tell you next is not the case.

When bleeding a brake system the way you are, with vacuum, its common for air to be sucked past the threads of the bleeder screw. This may be the bubbles you see in your clear tubing. To test this, starting with the corner that is the furthest away from the master cylinder use your bleeder. While it is still pulling fluid from the bleeder screw, tighten it, as another common happening when vacuum bleeding is you will actually pull the caliper piston inward a bit, and when the vacuum is relieved, the seal will move the piston outward ever so slightly, this can pull air into the caliper. Keep your reservoir from going empty and move to the corner next closest to the master cylinder. After you're done with all 4 corners, get in and pump the brakes a few times, of course the pedal will be hard because you will not have vacuum assist for more than a few pedal pushes. Start the car if necissary and see how the pedal feels.

If you're not successful, get a buddy and do it the standard way with someone holding the brake pedal. If you need more clarification on this type of bleeding, ask here and we'll see you get the info you need.

Hope this helps.
JRM

 

[Pure92TSi]

You could also go to advance auto and get some speed bleeders. They work very nicely.

 

[Boost95]

By, a one man bleeder. All im using is a bottle and the clear tubing you put over the bleeder screw. How do I do the master cylinder? I didnt think there was a way to do the master cylinder.

Thanks

 

[DiamondStarM]

This happened to me after doing my dual piston conversion, the porblem is that the master cylinder went dry. Before you bleed each corner turn the car on and leave it on while you bleed (starting with the right rear, then left rear, then right front, then left front) This will caust the brake booster to push out your remaining air pockets.

 

[Boost95]

Really? I will try that and see how it goes. You were getting bubbles in some of the lines not matter what?

Thanks,
Mike

 

[DiamondStarM]

Yea, I bled the car like three times and I still had no response from the pedal, after doing it with the car turned on it started pushing out huge bubbles. Let us know how it goes.

 

[Boost95]

Ok, so do all 4 wheels with the car running?

 

[DiamondStarM]

Yea, thats how I ended up doing it, I did turn it off in between each wheel (ie. jacking the car, removing the wheel, setting up the bleeder ect.) Just as long as its on while you are pumping the pedal.

 

[NAT01]

Mike, lemme know how it went. If you need another guy to try it the two-man way, lemme know. I e-mailed you and gave you the days I might be available. Later

-Chris

 

[Boost95]

Thanks, but I burnt my hand pretty bad so its going to need to wait a day or so.

Thanks,
MIke

 

[Boost95]

Well the burn wasnt as bad as it felt when it happend. So I went down and tried it agian. I did it with the car started. The bubbles seemed smaller but I still cant get rid of them. I tried it about 6 times with no changes

 

[DiamondStarM]

you are placing the catch bottle higher then the bleader screw correct?

 

[Boost95]

Yes Sir

 

[NAT01]

Just lemme know Mike. Friday or Saturday look like the best bet for now.

-Chris

 

[Boost95]

Alright, thanks. I will let you know I I dont get it figured out 2day or 2morrow.

-Mike

 

[Highwayrun]

You need to bleed your master cylinder, as ForceFedRed suggested.

Since you stated that you removed the master cylinder, you definitely need to bleed the master cylinder before bleeding the calipers.

You can find methods of bleeding the master cylinder from your shop manual, and from the internet.

 

[Boost95]

I tried to find how to bleed the master cylinder but I cant come up with anything. Do any of you know how to do it?

 

[Highwayrun]

There are a few different ways to bleed the master cylinder. I'll give you two ways here.

Method 1 (I think this is the shop manual method):
*Remove one fitting from the master cylinder and place your finger over the hole.
*Have an assistant slowly depress the brake pedal while you release air and fluid from the hole.
*Repeat until no more bubbles are released.
*Replace the fitting.
*Repeat the procedure for the other fitting(s).

Method 2 (My preferred method):
*Same as method 1, except that I use a vacuum pump to pull fluid from the master cylinder outlet ports, instead of having an assistant press the pedal.

*********
GENERAL NOTES:
1. If this is your first time doing this procedure, expect to get it wrong quite a few times, so be patient.
2. Use plenty of clean water to wash up brake fluid spills after you're done.
3. Make sure to bleed the calipers thoroughly right after, or else air may re-enter the master cylinder.
4. Never let the master cylinder run low.

 

[TRBOBLU]

1)Fill the reserve tank with brake fluid.
2)Keep the brake pedal depressed.
3)Have another person cover the master cylinder outlets with a finger.
4)With the outlets still closed, release the brake pedal.
5)Repeat steps 2-4 three or four times to fill the inside of the master cylinder with brake fluid.

From Mitsubishi service manual

 

[Boost95]

Thanks alot guys, I appreciate it. I'll give it a shot 2morrow when I have an extra set of hands

 

[Boost95]

Well, I bled the master cylinder. After doing that alone the pedal had more feel to it. Went to start with the passenger rear caliper. It was bubbles at 1st and then it was almost clear. Then it was huge bubbles again. no, the resi didnt go dry. This should be a simple process but im f'ing something up.

-MIke

 

[Highwayrun]

You'll get bubbles from the caliper first. Then, the bubbles that were in the line where you reconnected to the master cylinder, will make their way to the caliper.

Keep doing what you're doing. (Bleed the front brakes first if you want to save a little time.)

 

[TRBOBLU]

(Bleed the front brakes first if you want to save a little time.)

I would still bleed the brakes according to procedure. Start car, then do Passenger rear, driver front, driver rear, passenger front.

 

[tsunari]

You seem to be in a similar situation when I took my calipers off to paint them and change out my lines to SS. . .

I let the master cylinder go dry and ended up bleeding the system so many times I got fed up with it and took it to the dealership to get power-bled. This is where they pressurize your reservoire with a machine pumping in fresh brake fluid, while vacuum is applied to the caliper.

To give you an idea of how much air was in the system, we bled the entire system for a good 30-45 min. Most of the time was spent on the rear passenger caliper . . . tiny tiny bubbles just KEPT COMING! But it was SO well worth the $ b/c when I left there- I had brakes again. . . and if I hadn't, they would've thrown it back up on the lift and done it again until it was finished.

To make your life more simple, i would HIGHLY suggest going to speedbleeder.com and picking up a set for your calipers. If I had these back in the day, I might not have had to take it to the dealership. Just hook up a line, crack the bleeder open, slowly pump the pedal 3-4 times, re-fill the reservoire, continue pumping . . . SO much better than the Mity Vac.

On a side note . . . running the motor while bleeding the brakes only provides vacuum to the brake booster so it's easier to depress . . . no other hidden magic (except for maybe ABS . . . but I dunno 'bout that)

Good luck man- dont give up!

*****EDIT*****
Another note . . . if the 1G is setup like the 2G, the proper sequence to bleed is Passenger Rear-Driver Front, Driver Rear-Passenger Front . . . reason being, those pairs are on the same 'circuit' @ the master cylinder. So bleed the longest line in the circuit first, then the shorter of the two, then switch to the other circuit. -- good luck