chicopriest

So I get in the Z to go to work today and noticed that the ABS warning light was on. I don't think that it has ever come on so I was a little worried. The car drove fine but I noticed this continuous humming sound all the way to work. At first I thought it was the fuel pump. I get to the parking lot and turn her off and there’s a reasonably loud humming noise coming from behind the passenger seat. I take the top trim off the ABS system and its very warm. The humming continues even when the car is off. Any ideas? I know there's probably a thread on this arleady but i'm at work and don't have that much time to search. Any help would be appreciated.

chicopriest

So I go back to check on the Z and shes still humming away. When I get in it smells of cooked brake fluid. I had to disconnect the ABS control unit. Is this safe to drive without it? I figure I just wont have ABS.

sailorjason

Sounds like that pump is probably burned up.

chicopriest

Ok, Im trying to put 2 and 2 together here. I got off the phone with Courtesy Nissan and they suggested checking the relay. No problem. But as im looking at the ASC diagram at courtesyparts.com I noticed the anti skid actuator has bleeder valves. Now a few months back I replaced as much of the brake fluid as I could and when I went to bleed the actuator, I noticed it didn't have any bleeder valves on it. SOoooo, could their be an air pocket in the actuator that is causing this?

sailorjason

If you had air in the lines it would intermittently be phyisically more difficult to brake. I don't think it would be the relay because of the humming that you said you heard, but it is not uncommon for that to be the problem of the ABS system on these cars. Not to mention it is cheaper to replace so most people start either with the relay or the fuses.

chicopriest

Well I drove the car home with the actuator disconnected. I didn't notice any difference in braking, but then again I wasn't racing home either. I let the car sit for a few hours and reconnected the harnesses. Apparently that fixed it because the humming stopped and the ABS warning light is off. I turned the key to ON and listened to the relays. It sounds like there is quite a bit of relay bounce but it clicks 2-3 times then engages. I'll try driving it like that and see if it happens again tomorrow.

sailorjason

to see if it is the relay, when it sticks tap on it with the back of a screw driver a few times. If the light goes off, it is the relay. Where did you disconnect the actuator at? Did you check for corrosion?

chicopriest

I opened the trim right behind the passenger seat and disconnected the harness from the actuator. Everything looked good, no rust.




Also, can anyone post a pic of theirs? I'm really curios as to where my bleeder valves are supposed to go.

91zxtt

As far as I know, if you disconnect the actuator, the only thing that won't work is the ABS. our braking system should work just fine.

When I replaced the brake fluid in my Z with synthetic fluid, I installed speedbleeders. I also bought one for the Actuator unit. I was able to bleed the actuator. You should try bleeding the actuator.

CanyonCarver

I had this same problem a couple of times in the past. It never reappeared after thoroughly bleeding the brakes at all six points. When I heard the pump running continously, I was like "oh ****, it's gonna burn up". I ended up disconnecting the battery to get it to stop. Reconnected the battery and the pump stayed off.

Another individual had the same problem. He took it to a shop where they replaced the relay as above. He never had a reocurrence either.

In the middle pic of your 3 pics, the bleeders are under the black cover shown.

chicopriest

I tried taking another look and I think im still missing them. Are they in these pics?

CanyonCarver

okee dokee, I guess different years had different ABS set-ups.hat one is a little different than all of the others I've seen.

chicopriest

Could it be a remanufactured unit?

CanyonCarver

It looks like a completely different unt. All of the Z32 ABS pumps that I've seen have five lines going to it. ie: 2 lines in from the MBC and 3 lines out, one to each front wheel and one for both back wheels.

I would still focus on the relay and a complete system bleeding. If there are no visible bleeders on the pump, you'll need to bleed more at the wheels. One approach is to use some of that blue colored brake fluid. Then you bleed until you bleed blue. (pun intended)

MikeZ

My car does this from time to time(like a few months intermitten). Usually stops around three hours after It starts. I''ve bled my brakes, and but it still happens. I think I read somewhere that Z's(mine a 95 so...) have a self check mode on the ABS but i am not exactly sure. Wat I do know is that when you hear the noise, prepare for your breaks to lock. Because your ABS does not work when it's running like that.

chicopriest

Hmm, Anyone have any pics so I can compare actuators?