air getting in brake lines - 2000 Infiniti touring
#1
air getting in brake lines - 2000 Infiniti touring
Hi, How can I find the source of the air leak into the brake lines?
I have to bleed the right front and left rear brake lines about every week, as I keep finding air in the calipers when I open the bleeder screw. It is affecting the way the car drives and the left front brakes are running hotter and producing brake dust more than the right front.
I have replaced the caliper on the left front that is running hot, all four brake hoses, and the master cylinder.
I have to bleed the right front and left rear brake lines about every week, as I keep finding air in the calipers when I open the bleeder screw. It is affecting the way the car drives and the left front brakes are running hotter and producing brake dust more than the right front.
I have replaced the caliper on the left front that is running hot, all four brake hoses, and the master cylinder.
#4
#5
Ambient pressure air does not magically introduce itself into a closed system with a higher pressure. So, "anyways", I have no idea. Good luck.
#6
Supporting my theory of air entering the system, what if brake fluid cooled from a heated state and there was some water in the system that vaporized, then a temporary vacuum would be created as the steam condensed.
Last edited by Mharvey500; 06-27-2019 at 06:22 AM.
#7
Yes, that's why you are supposed to replace the brake fluid every few years.
#9
I'm taking seriously the MC suggestion and I should try bleeding it on the car. After that I will get a pressure bleeder to look for leaks.
#10
this is how i did mine for the bmw.
you must pump it very very slowly it took a long time to get everything out of it because
the little bubbles will stick to the inside. Even hitting the brakes and mc with a hammer works to knock them loose.
by https://www.flickr.com/photos/156811228@N08/, on Flickr
you must pump it very very slowly it took a long time to get everything out of it because
the little bubbles will stick to the inside. Even hitting the brakes and mc with a hammer works to knock them loose.
#11
So, if it's the MC then it must be storing air where it doesn't get pressurized like not in line with the piston because the brakes improve a bit after bleeding and then degrade after a day or so.
By improve, I mean the drivability improves and I think the pedal is slight firmer but I could be mistaken. By degrade I mean the driving gets choppy and there is more heat generated at the left front wheel.
By improve, I mean the drivability improves and I think the pedal is slight firmer but I could be mistaken. By degrade I mean the driving gets choppy and there is more heat generated at the left front wheel.
Last edited by Mharvey500; 06-28-2019 at 04:32 PM.
#12
could be
it's worth trying maybe the booster isn't pushing the mc all way completely in where the bubbles are.
Take it off and do it on vice with a screwdriver. its a ***** but so is your brake situation
but remember to literally push it in in slow motion you will see little micro bubbles going up the line
where just pumping it doesn't get them out.
it's worth trying maybe the booster isn't pushing the mc all way completely in where the bubbles are.
Take it off and do it on vice with a screwdriver. its a ***** but so is your brake situation
but remember to literally push it in in slow motion you will see little micro bubbles going up the line
where just pumping it doesn't get them out.
#13
could be
it's worth trying maybe the booster isn't pushing the mc all way completely in where the bubbles are.
Take it off and do it on vice with a screwdriver. its a ***** but so is your brake situation
but remember to literally push it in in slow motion you will see little micro bubbles going up the line
where just pumping it doesn't get them out.
it's worth trying maybe the booster isn't pushing the mc all way completely in where the bubbles are.
Take it off and do it on vice with a screwdriver. its a ***** but so is your brake situation
but remember to literally push it in in slow motion you will see little micro bubbles going up the line
where just pumping it doesn't get them out.
I will put speed bleeders on both front calipers being a dual system, and slowly pump away a whole litre of brake fluid.
Last edited by Mharvey500; 06-28-2019 at 05:33 PM.
#15
I will do visual inspection for fluid and if no fluid then invest in a power bleeder to pressurize the system and look for leaks. But first I'm hearing on this forum that most likely there is air in MC from the time it was installed. .
#16
Is it true that air in brake lines can cause caliper drag or am I chasing a red herring?
It is true I am having an issue with air in brake lines. I discovered an undertorqued brake line in the master cylinder corresponding to the side getting air. I can't properly bench bleed my master cylinder due to unremoveable plastic mesh in fill opening. It is messy and not completely gets air out. So I am driving and bleeding until the air works it's way down the lines.
I'm not convinced the caliper drag will be completely go away with full removal of air as generally that is not recognized as a cause, but in this case appears to be an aggravant based on my driving experience. Next step would be to question the ABS control unit or the proportioning valve or brake booster because I've replaced everything obvious.Perhaps I should disable brake booster just to test.
It is true I am having an issue with air in brake lines. I discovered an undertorqued brake line in the master cylinder corresponding to the side getting air. I can't properly bench bleed my master cylinder due to unremoveable plastic mesh in fill opening. It is messy and not completely gets air out. So I am driving and bleeding until the air works it's way down the lines.
I'm not convinced the caliper drag will be completely go away with full removal of air as generally that is not recognized as a cause, but in this case appears to be an aggravant based on my driving experience. Next step would be to question the ABS control unit or the proportioning valve or brake booster because I've replaced everything obvious.Perhaps I should disable brake booster just to test.
Last edited by Mharvey500; 07-20-2019 at 07:19 PM.
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