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-

 

[Highwayrun]

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

OK, before I get a negative rep point for suggesting to bleed the front brakes to save time, I should clarify what I meant.

Immediately after bleeding the master cylinder, I like to bleed the shortest lines first, and as soon as possible, to prevent any bubbles from re-entering the master cylinder.

Afterwards, I bleed all the brakes in the normal sequence.

I also agree with Tsunari that bleeding brakes with the engine on simply allows for more hydraulic line pressure, which compresses the bubbles and air pockets, and makes their removal more thorough.

 

[Boost95]

I dont know WTF the problem is. I took both fitting off teh master cylinder and bled that. After that I tried the calipers and it would be clear and then all of a sudden a big air pocket!

 

[tsunari]

I dont know WTF the problem is. I took both fitting off teh master cylinder and bled that. After that I tried the calipers and it would be clear and then all of a sudden a big air pocket!

Yeah, if the MC went dry at any point. . . it's going to take a lot of patience and maybe a small fortune in brake fluid to get all of the air worked out . . . or you could get sick of it like I did and just take it to Satan and have them power bleed it

 

[Highwayrun]

GENERAL NOTES:
1. If this is your first time doing this procedure, expect to get it wrong quite a few times, so be patient.

The first time I bled a master cylinder, it took me an entire weekend. It really is a tricky skill to master.

 

[Boost95]

What can I be doing wrong? how am I suppose to take it anywhere with no brakes?

 

[Highwayrun]

What can I be doing wrong? how am I suppose to take it anywhere with no brakes?

I feel your pain! It brings back memories for me.

OK, which of the methods given above are you using? How about you tell us your steps and we try to find what you're doing wrong?

Here are a few more tips for bleeding the master cylinder:
*Buy and use a Mighty Vac vacuum pump--it works extremely well;
*Use the conical fittings to suck fluid from the master cylinder;
*Allow fluid to overflow from the master cylinder before re-attaching the brake lines;
*Bleed both front brakes immediately after re-attaching the lines to the master cylinder. This will ensure the air that entered the brake lines (when they were removed from the master cylinder) would not re-enter the master cylinder;
*Bleed all brakes as per manufacturer's recommended sequence.

Here are even more tips for bleeding the calipers with a vacuum pump:
*Remove each nipple and add Teflon tape to the threads, re-installing afterwards;
*Connect the vacuum pump to the nipple and draw maximum vacuum;
*Open the nipple just enough to get a trickle of fluid to escape;
*Start the car and press the brake to force fluid out of the nipple at a decent rate;
*Wait two seconds before releasing the brake pedal each time you depress it;
*Use about one reservoir worth of brake fluid per wheel, or about twelve pumps of the brake pedal.

That should take care of everything.

 

[Boost95]

Where can I get a mighty vac? I will give that a shot. I tried everything in the manuals and everything you guys have posted so far.

Thanks!

 

[tsunari]

I believe places like Harbor Freight carry them. If all else fails, I'm 4 hrs south of you- could meet u half way- let u borrow mine

 

[Boost95]

Thanks alot for that offer I got a mighty vac from the store, and I didnt have much luck with it. So I got all the wheels on and took it to my friends fathers garage. I was nervous with the brakes but I just kept them pumped up good.. All he did was loosend the bleeder screws and let alot of fluid out while the cap was off and totally filled to the brim That was a simple solution and it works perfect now. After wasting money on a 1 man bleeder and the mighty vac thats all I needed to do I appreciate all of you help guys. Take it easy

-Mike

 

[jott5555]

honestly what i use is

http://www.bmw-m.net/TechProc/bleeder.htm that guy there... it has never not worked for me.. pretty awesome..

 

[tsunari]

Thanks alot for that offer I got a mighty vac from the store, and I didnt have much luck with it. So I got all the wheels on and took it to my friends fathers garage. I was nervous with the brakes but I just kept them pumped up good.. All he did was loosend the bleeder screws and let alot of fluid out while the cap was off and totally filled to the brim That was a simple solution and it works perfect now. After wasting money on a 1 man bleeder and the mighty vac thats all I needed to do I appreciate all of you help guys. Take it easy

-Mike

AAAhhhhhhh. . . the ole gravity bleeding trick- crap, I had forgotten about that one . . . oh well . . . glad you have brakes once again

 

[Highwayrun]

I got a mighty vac from the store... After wasting money on a 1 man bleeder and the mighty vac...
-Mike

The Mighty Vac is also very useful for checking solenoids, MBCs, brake booster check valves, engine vacuum, etc. It's even excellent for setting the BOV.

 

[5150]

when bleeding the clutch do you have to have the cap on on the master cylender or does it matter?

 

[GTM]

...
Before you bleed each corner turn the car on and leave it on while you bleed
...
This will caust the brake booster to push out your remaining air pockets.

It is unfortunate that no Wiseman jumped in here but perhaps they expected that people would be familiar with basics before undertaking such a serious job.

I just came across this thread and am appalled at all the dozens of unqualified replies. There is no relationship to the engine running and bleeding a non ABS system. In the "Before you Reply" read and understand #3 before someone gets killed with this nonsense. Do NOT post anything you do not know as factual and can back it up with credible sources that can be found on the Internet including here and maybe Vfaq.

Frankly I'd like to see the whole thread removed for there is just too much to try and correct and too many possibilities of others finding it when searching.

The bottom line is if you can't bleed a bone dry brake system in 30 minutes you have a problem either in the system or your procedure.
....................

5150.... RE clutch: it doesn't really matter but probably best if the cap is off. If you are having a problem start a new thread for this is concerning brakes.

Cheers,
GTM

 

[tsunari]

. . .I just came across this thread and am appalled at all the dozens of unqualified replies. There is no relationship to the engine running and bleeding a non ABS system. . .

Cheers,
GTM

I completely agree that there is a bunch of crap to wade through on this thread, but if you can sift through it, there is still good advice. If you end up completely removing this thread, why not get rid of the dozens of threads that are never completed . . . or how about the ones that lead to no where?

I do not intend to mung up what's left of this thread, but some people on here actually do provide qualified answers:

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)

-ciao

 

[BUCK]

http://www.dsmtuners.com/forums/showthread.php?t=142083&highlight=bleed

 

[DiamondStarM]

http://www.dsmtuners.com/forums/showthread.php?t=142083&highlight=blee

The picture of the service manual posted in that thread about halfway down by Tsunari is credible as far as I'm concerned. My reasoning may not have been dead on, but after changing my calipers I bled the system many times with no results. It may be coincidence but when I did it the final time with the car turned on as recommended in the manual it pushed out all the air and the pedal was rock hard.

 

[GTM]

I completely agree that there is a bunch of crap to wade through on this thread, but if you can sift through it, there is still good advice. If you end up completely removing this thread, why not get rid of the dozens of threads that are never completed . . . or how about the ones that lead to no where?

I do not intend to mung up what's left of this thread, but some people on here actually do provide qualified answers:
-ciao

I can sift through it, however, the original poster could NOT and did NOT. Further after all the 30+ posts over the course of a week he admittedly drove the car with faulty brakes to what we were told was a professional who in short order had them bled.

I take issue with your quote advocating the booster makes it easier. You are not looking for easier nor will you "feel" bubbles escaping or the sense of a spongy pedal. You have not established if the booster, or the master cylinder freeplay is correct. If you can support this with a qualified source it will be news to me for I've never seen it in print.

While writing I see Buck has chimed in with a thread you had started asking how to bleed brakes that took you a month to solve on your own car and you didn't solve this one. He told you how to do it and it's obvious you didn't follow directions.

You can look at my profile and decide what to believe.

I will add a few things that as a professional I have learned and would have made a difference. First you _never_ pump the pedal fast, 1 to 1-1/2 seconds per stroke. Failing to observe this will cause any large bubbles to be broken into hundreds of tiny bubbles that get trapped in fittings and crevices and do not get washed as a single large bubble down stream. Don't believe me, take some cooking oil and place in a blender, mark the level, turn the blender on for a few seconds so it mixes with air. Stop the blender, mark the level, wait 10 seconds mark the level, continue to do this until it's clear again.

Bleeding brakes does not have to be a 2 person job and I rarely ask for help because I control how it's done. They actually make a spring loaded tool for this but I use a long screwdriver about 24". Slide the seat forward, tap the pedal maybe 1/2" a few times, this will relieve any trapped air just under the intake hole and allow a full charge of fluid to the M'cylr. Pump the brakes 3 times slowly as above, hold it down, slip the screwdriver onto brake pedal and the handle against the front face of the cushion. Open the bleeder rapidly, close it when the flow has stopped. Return to the pedal and release the screwdriver or stick slowly again with the conscious effort to not cause bubbles. Pump the pedal again 3 times slowly, bleed the wheel again, repeat until there is no more air, pump the pedal again, this time release the bleed slowly and look for any tiny bubbles at the nipple when it first opens. If none advance to the next wheel. When all are bled go back to the first and again check for bubbles.

I rarely use a bleed catch bottle, instead I put my index finger over the nipple and direct the spray where it will do little harm. This way you can feel and hear the bubbles as they pass under your finger tip. When you are done squirt water on any parts that may have gotten wet with fluid for the fluid will soften and peel paint.

If you were doing a brake job, replacing hoses you would use the jam screwdriver to hold the pedal under pressure and will block off the intake in the M'cylr so it doesn't drain dry. If you have to replace the M'cylr then pre-bleed on the bench rapping on the cylr with a hammer handle. Leave the plastic plugs in place tap on the clevis rod until you have no more bubbles escaping from the intake port. Install, put the jam stick in place, attach each line with care, hopefully you didn't rough handle the lines and there will be fluid right at the end. Tighten the lines, remove the jam stick, open 1 line 1/2 turn, rap on the M'clyr with hammer or screwdriver handle until you see the fitting is wet, tighten. Repeat for the other line, if you have done you job well you will not have to bleed the wheel cylrs.

If you have to get into a proportional valve for repairs or if the system was dry they should be bench bled if they are off the car, if on the car then each fitting should be bled as above but not trying to build any significant pressure. Note these can be a real PIA, if excess pumping has happened the piston has a nasty habit of traveling to one end and getting stuck. If this happens you will never bleed the brakes on 2 wheels. The solution is an easy fix, give it a few good smacks with the hammer handle and bleed again at the fittings.

The whole idea here is to have the least amount of fluid loss and introduce the least amount of air. Some systems will gravity feed when a nipple is opened do not get careless and let the resivoir run dry. I don't remove the seal on a brake fluid bottle, instead I poke a couple 1/8" holes and invert in the resivoir so it will provide plenty of fluid for the average job.

For a basic bleed this is a 10 minute job using this method. If you had replaced all the lines it still wouldn't have taken more than 20 minutes since you may have to repeat the normal process twice.

...................

You would never get me to use any suction device on an old system for it's too easy to suck air past soft seals that do not leak under pressure.

That's my 2¢ from hundreds and hundreds of brake jobs.

Note from the last poster (DiamondStarM) if you have ABS then the procedure may require the pump to be activated with the key. This may also be true with a mechanical belt driven booster pump. Look at the pictures/diagrams and you will see the relationship between a vacuum boost is just a push rod with no fluid exchange.

Cheers,
GTM

 

[tsunari]

. . .
I take issue with your quote advocating the booster makes it easier. You are not looking for easier nor will you "feel" bubbles escaping or the sense of a spongy pedal. You have not established if the booster, or the master cylinder freeplay is correct. If you can support this with a qualified source it will be news to me for I've never seen it in print. . .

While writing I see Buck has chimed in with a thread you had started asking how to bleed brakes that took you a month to solve on your own car and you didn't solve this one. He told you how to do it and it's obvious you didn't follow directions. . .

"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)"

I was not "ADVOCATING" anything, simply stating what happens if you do bleed the brakes with the motor running. I made no statement that having the motor running would make bleeding the brakes easier/quicker/failsafe/better or any other spin someone may have put on that statement . . . simply that the pedal is easier to depress.

(Isn't that why we HAVE brake boosters in our cars??) Try this. . . accelerate well into boost and depress the brakes fully, now while still accelerating, release the brake and depress again. . . aH!!! It's more difficult to depress this time-- that's all I meant.

And yes, Buck did chime into my thread a while back providing a sound proceedure for bleeding brakes as you have done here and I assure you I followed it exactly. So does this mean that since I had a problem I could not solve on my own, one that I needed the assistance of someone else, that my information is less credible? Hmmm . . . interesting . . . so much for 1st-hand experience being the best teacher.

But I digress- BUCK, GTM, both of you have provided sound solutions/proceedures to bleeding brakes- that is fact. Aside from minor details, that is exactly how I have always been taught to bleed brakes and how I have been doing them for 10+ years. I do not see the point in continuing in this manner, if you have anything further to discuss I would gladly take this off-line in PMs so as not to muck this thread up any further.

-Ciao

 

[GTM]

...
So does this mean that since I had a problem I could not solve on my own, one that I needed the assistance of someone else, that my information is less credible? Hmmm . . . interesting . . .
...
I do not see the point in continuing in this manner, if you have anything further to discuss I would gladly take this off-line in PMs so as not to muck this thread up any further.
-Ciao

Contentious posturing "ain't going no where" with me as is attempting to bully me or any one else around here with "anything further~".

The previous statements and your own problem taking a month to solve do not establish a sense of credibility or is your sarcasm. As a college student who can read and write may provide some with the impression you know the subject. The fact you gave advice with authority and didn't solve these 2 instances in a timely or satisfactory manner would indicate to me you need more training or experience before you hurt someone.

Cheers,
GTM