Air In ABS Actuator

la_fx35

la_fx35

Staff
Moderator
Location
Chicago
Car
2017 QX70S
Name
Andy
I got air bubbles in the ABS Actuator. How did I got air in ABS Actuator? I sucked out too much fluid from the master cylinder when I was change out the brake fluid.

The brakes on my FX35 is very soft. Anyone knows of a way/method of bleeding the ABS Actuator other than going to the stealer dealer? I've bled it with the 2-man method, vacuum, and injection methods multiple times and it still soft. So I took it into Firestone last night to have them bleed it, they told me there is no air bubble in the lines and everything is working fine. They suspect there are air bubbles in the ABS Actuator. They hooked two different scanner tools (a Snap-on and one other one. They said they' were very good scanners) to it to activates the solenoid valves but its no go. The Snap-on was able to communicates with the ECU, but cannot activates the solenoids. The other one was not able to communicates with the ECU. They suggest to go the dealer or someone/shop that have scanner tools that can activates the ABS solenoids.
 
Had this issue with my wifes Rav4. The lid cracked and broke off leading to an almost empty canister. No amount of bleeding got rid of the slight softness. The brakes worked fine, just soft. Was going to take it to stealership, but sold it instead :-)



TapaTalkin'
 
Yeah, activates the abs will dislog, but since the brake is soft its hard to engage the abs. That one method others have tried, but I need to find some remote slippery road like a dirt or gravel road and hope there enough ahead of me if the brake can't stop the car.
 
i had a issue with my brakes also when i put in SS lines and bleed out the whole system. i bought a motive brake bleeder and bleed the crap out of it and i saw tiny tiny bubbles coming out. What it does is pressurizes the brake system to around 10-15 psi at the brake fluid holder. might help. Also its recommended that your pump the brakes before you open the bleeder. The brakes are much better now.

would putting the fx on jack stands and putting it into drive and braking trigger the abs? just thinking it would be like skidding on ice scenario.
 
Something that might help, to bleed the air in the brake lines / system, the manual is suggesting a certain order of wheel sides as follows: rear right, front left, rear left, and front right. The manual does not explain why, but I guess it has to do with fluid mechanics / gravity with respect to the system geometry so that all air is kicked out, something that if not followed might result in having trapped air still, why not giving this bleed order a shot and see what it does?


Sent from my iPad
 
Were you able to get this resolved ? And if so how? Thinking about doing a brake job in a month and wanted to be prepared in case I ran into thr same problem

sent
 
No have not resolved. I took it to another shop, they said to me if they needed a scanner that can communicates and activates the Nissan ABS Actuator, they can find one. It's all talks. Anyhow, they bled the system again and replace the master cylinder, the pedal still feels mushy. They clamp off all four brake hoses and the pedal was solid. The un-clamp the rear hoses and the pedal when mushy right away. So they tells me it a possibility of a collapsed hose or caliper. There is no leak anywhere. They wanted $192 to replace the two rear brakes hoses and I said no thank you. The brake hoses are cheap, so I will start with replacing them first and see how it goes.

In retrospect, this brake job that I did differently then all the other brakes job was I emptied out the old fluid from the master cylinder. I mean completely empty and I'm pretty sure that's when air got into the system. Never do that again!

I did another brake job a few day ago with swapping out calipers and brake fluid. I t went without any issue. I left the old fluid in the reservoir and keep filling it with new fluid until the I see new fluid comes out of the bleeder screw. I could have suck some old fluid out to save some new fluid and time. Just keep in mind don't dried out the reservoir and you will be fine.
 
Question to you HA what made you empty out the entire resivoir in the first place w/o doing the re-fill in conjuction with opening/closing up the bleeder. otherwise seems to me that air would get trapped in the line. I've always did it the way that you've describe on the last job that you did. If there is another way of doing it please let me know Thanks.
 
Not sure why I decided to complete empty out the reservoir in the first place. I went overboard on taking out all the old fluid out, I guess. The bleeders wasn't open wide the reservoir was empty though. The first shop I went to saw traces of a new master cylinder that i installed and taken off, so they suspect that I did not bench bleed it properly and introduce air into the ABS actuator. The second shop, replace with my new master cylinder and clamp off the hose with good hard pedal feels. So that tells me, after all there may not be air in the ABS actuator and it could be the hoses or caliper instead.
 
I say replace the lines because that is what it sounds like to me. plus it sounds like the cheapest as well. Dont worry your an excellent mech and you will get it take care of. Your "The Man"
Another quick question are you running 22 or 24 with coilovers or HR?
 
Thanks for the encouragement. If you're referring to the avatar pic, I'm running 24 x 10 with 30 profile tires and coilovers.
 
The ride on the 24 was surprisingly very nice and smooth. No harshness at all. Yeah, I adjust the ride height just an inch or so above the tires. Not into the slammed look myself.
 
La_fx35 .... Another thought, if the bubbles are very fine, then theoretically it will be impossible to separate them from the oil even by gravity, because of surface tension and obviously the high viscosity of oil, and the mix becomes more compressible (moving from pure oil which is not compressible towards air-oil mix which is more compressible), this might as well explain the softness while braking as the pedal has to travel further to compress the mix, and a spring action will be felt against the foot. This can happen when squeezing air hard into oil, which might has happened in your case with the master drum pushing air through when the reservoir was fully drained.

I guess that, one way to resolve this will be to keep bleeding the oil from all wheels while the reservoir is kept full the entire process to fully replace the contaminated oil. This might require a large amount of oil.


Sent from my iPad
 
I waiting on the brakes hose that I have ordered to arrives and then completely bleed the system again.
 
:embarrassed: :shame: I've made the biggest mistake ever since I've been messing around cars. This brakes problem have costed me $500 and 30 hours+.

The problem was created from having the rear calipers cross mounted onto the knuckle. I mounted the passenger side to the driver side and the driver side to the passenger, which in turn positioned the bleeder valve at the bottom of the caliper/piston housing. As air naturally wanted to goes up, and there is no where for it to escape. Once mounted correctly, the bleeder screw is at the top and air rises to the top and out of the bleeder valve, problem solved!

Thank you all that have helped me with this problem.
 
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