fun car guy Posted October 31, 2021 Share Posted October 31, 2021 My son and I are trying to finish the brake work on my '89 coupe and have discovered an air leak where the feed goes to the left front. The right bleeds great but we can't get anything from the left but could hear it leaking air each time we depress the brake pedal, traced it to where the line connects to the master, I just hope there isn't any air trapped in the master making this an even bigger project. Link to comment Share on other sites More sharing options...
2seater Posted October 31, 2021 Share Posted October 31, 2021 I have never heard of that being an issue? The three brake lines all connect to the bottom of the ABS block bolted to the side of the master. Do you have access to a vacuum pump, such as a Mity Vac to pull fluid through or perhaps a pressure bleeder to push it? Link to comment Share on other sites More sharing options...
Ronnie Posted October 31, 2021 Share Posted October 31, 2021 Sometimes it's hard to tell where sounds like that are coming from. I would rule out the Cruise Control vacuum relief valve on the brake pedal making the noise before moving on. If there is a vacuum in the reservoir tank it could make a noise like that each time you press the brake pedal. Just a shot in the dark but it's worth checking out. Link to comment Share on other sites More sharing options...
fun car guy Posted October 31, 2021 Topic Author Share Posted October 31, 2021 1 hour ago, 2seater said: I have never heard of that being an issue? The three brake lines all connect to the bottom of the ABS block bolted to the side of the master. Do you have access to a vacuum pump, such as a Mity Vac to pull fluid through or perhaps a pressure bleeder to push it? No, afraid not. Are you saying you suspect an air lock in the master? That doesn't seem possible since the right front works fine! We've pulled the connection we know is leaking air but no fluid comes out of the master. Link to comment Share on other sites More sharing options...
fun car guy Posted October 31, 2021 Topic Author Share Posted October 31, 2021 32 minutes ago, Ronnie said: Sometimes it's hard to tell where sounds like that are coming from. I would rule out the Cruise Control vacuum relief valve on the brake pedal making the noise before moving on. If there is a vacuum in the reservoir tank it could make a noise like that each time you press the brake pedal. Just a shot in the dark but it's worth checking out. We can easily see and hear where the air is coming from, it's where the left brake line connects to the master. We pulled the line but the flaring looks fine even though it's still leaking air! Link to comment Share on other sites More sharing options...
fun car guy Posted October 31, 2021 Topic Author Share Posted October 31, 2021 So my son and I discussed this and decided to disconnect the line from the master and discovered, someone, sometime tightened the fitting leaving several inches of brake tubing up inside so there was no seal! He then slid the fitting up to the flange as it should have been and threaded it back on tight, no more air leakage! However, no matter how many times we pump the brakes, nothing comes out and the pedal has no resistance, just goes down to the floor. Considering that the right one is fine but nothing comes out on the left, is it the equlizing valve or maybe something within the master? Link to comment Share on other sites More sharing options...
2seater Posted October 31, 2021 Share Posted October 31, 2021 I guess your definition of easily seen must be different than mine as the connections are on the bottom of the valve block for the anti lock. 🙂 Is this an "air" sound when depressing the pedal or upon release. No, I am not suggesting the master has an air lock, just that I have never heard of that being an issue. If it "squirts" air when depressing the pedal, it must be being forced out by some sort of pressure being applied, which would suggest fluid is behind it. Is this the line that was disconnected for weeks and did the reservoir drain out during that time? Link to comment Share on other sites More sharing options...
2seater Posted October 31, 2021 Share Posted October 31, 2021 5 minutes ago, fun car guy said: So my son and I discussed this and decided to disconnect the line from the master and discovered, someone, sometime tightened the fitting leaving several inches of brake tubing up inside so there was no seal! He then slid the fitting up to the flange as it should have been and threaded it back on tight, no more air leakage! However, no matter how many times we pump the brakes, nothing comes out and the pedal has no resistance, just goes down to the floor. Considering that the right one is fine but nothing comes out on the left, is it the equlizing valve or maybe something within the master? Thoroughly confused by this description now? Link to comment Share on other sites More sharing options...
Ronnie Posted October 31, 2021 Share Posted October 31, 2021 1 hour ago, 2seater said: Thoroughly confused by this description now? ^^^ x2 Link to comment Share on other sites More sharing options...
fun car guy Posted October 31, 2021 Topic Author Share Posted October 31, 2021 Confused by my description or by the reason this is happening? I'm telling you the right brake works fine but there's no fluid coming out of the left and asking what you think might be the problem, any ideas? Link to comment Share on other sites More sharing options...
Ronnie Posted October 31, 2021 Share Posted October 31, 2021 1 hour ago, fun car guy said: I'm telling you the right brake works fine I'm confused by the description for several reasons. I don't see how several inches of brake line could be slid up inside the master cylinder and still be tightened down to stop an air leak. I also don't understand how the right brake could be working fine when you say the brake pedal has no resistance and is going all the way to the floor. I'll admit, I'm not all that familiar with the Teves master cylinder and valve body where the lines connect to it. There must be something I'm missing about what you are trying to tell us. Link to comment Share on other sites More sharing options...
fun car guy Posted November 1, 2021 Topic Author Share Posted November 1, 2021 3 hours ago, 2seater said: I guess your definition of easily seen must be different than mine as the connections are on the bottom of the valve block for the anti lock. 🙂 Is this an "air" sound when depressing the pedal or upon release. No, I am not suggesting the master has an air lock, just that I have never heard of that being an issue. If it "squirts" air when depressing the pedal, it must be being forced out by some sort of pressure being applied, which would suggest fluid is behind it. Is this the line that was disconnected for weeks and did the reservoir drain out during that time? No, we just disconnected the line at the master, pumped the brakes w/o anything but air coming out. Reconnected it but it's totally dry. Link to comment Share on other sites More sharing options...
fun car guy Posted November 1, 2021 Topic Author Share Posted November 1, 2021 Of course I disconnected the line at the old caliper but only long enough to cut it off just below the fitting too, slip on a new fitting and flair the end connecting it to the new caliper. Through all that time there was no fluid whereas there was plenty on the right. Link to comment Share on other sites More sharing options...
2seater Posted November 1, 2021 Share Posted November 1, 2021 Okay, I still don't understand the description of the excess line, but it sounds line the lack of fluid to the left front is an old issue that was likely there before all the repairs started. Any time the brake line is disconnected, and the reservoir has fluid in it, it should drool fluid from the lower end. Normally the front brakes would be on a port common to both of them but since this is an anti lock system, the two front brakes go through the valve block bolted to the side of the master cylinder so there is independent control. I haven't reviewed a diagram of the valve block itself but since it has the ability to block or dump pressure to the caliper when it activates, I am guessing there is valve that may be hung up? This is just an uneducated guess without proof. Is the amber anti lock light on by chance? If so, maybe looking to see if there are codes stored for the system? Link to comment Share on other sites More sharing options...
fun car guy Posted November 1, 2021 Topic Author Share Posted November 1, 2021 Interesting! Yes, both the amber anti-lock and the red brake light are both lit so you may be on to something. If so, I can only hope there's a way to free the valve as I don't want to replace the master, I'll check for any codes and get back to you. My estimation as to how much of the fluid line was inside the master is likely an exaggeration but needless to say, was a surprise. However the flared end was clearly not where it should have been, allowing air to pass but no fluid. Thanks for your help! Link to comment Share on other sites More sharing options...
2seater Posted November 1, 2021 Share Posted November 1, 2021 I don't have any answers to what is going on, just a guess since there was no fluid present before the bleeding procedure was started. As far as I can tell, the valve block on the side of the master is replaceable but cannot be serviced, as well as the master itself, per the FSM. From my experience with the boost pump and trying to get it to function if dry, it requires some external force to bleed the air out. A vacuum pump on the outlet of the boost pump gets it to prime pronto, so sometimes a little help is needed. The entire brake system is designed to move fluid, essentially non compressible. If there is air present somewhere, the items designed to move fluid may have a hard time dealing with it as the volume is so much greater and it is compressible so it must first try to compress the air to a point where it will move the fluid. It kind of boils down to: the fluid can push the air but the air may have a hard time pushing the fluid. A MityVac style brake bleeding kit isn't terribly expensive and can be used for other things even if it doesn't help in this case. If both the red and amber lights are on, does the boost pressure pump run with the key on, and more importantly, does it eventually shut off and the red light go out? Does the fluid level drop in the reservoir if the pump is running? Is it possible to post a photo of where this additional line is/was located? By definition, a flared fitting must have contact with a metal seat and the tube nut must be able to exert force on the tube side of the flare to effect a seal. If the tube can pass through the area where the seat should be, something is very wrong or it is not a flare type connection. Link to comment Share on other sites More sharing options...
Padgett Posted November 1, 2021 Share Posted November 1, 2021 (edited) BTW any time the red (Brake) is on, so will the yellow (ABS). Unless the parking brake is on (only time will get red without yellow). Edited November 1, 2021 by Padgett Link to comment Share on other sites More sharing options...
Ronnie Posted November 1, 2021 Share Posted November 1, 2021 26 minutes ago, Padgett said: Unless the parking brake is on (only time will get red without yellow) I think you can add low brake fluid in the reservoir to that. Link to comment Share on other sites More sharing options...
2seater Posted November 1, 2021 Share Posted November 1, 2021 All true regarding the red light but you can have a yellow without the red, which was part of what I was looking for. 1 Link to comment Share on other sites More sharing options...
DAVES89 Posted November 3, 2021 Share Posted November 3, 2021 Why don't you try this so we are sure the pump is actually pumping fluid and not air. Turn the key on and open one of the rear bleeders and put some pressure on the brake pedal. Tghis will cause the pump to run and fluid to come out of the bleeder [under pressure]. If that happens then we know that the pump is working and that fluid is moving. 1 Link to comment Share on other sites More sharing options...
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