Alfa Romeo Forums banner

Bad ABS Electropump?

1.9K views 13 replies 7 participants last post by  bobsiopener  
#1 ·
Hi All,
I was working on my Milanos braking problem this weekend and found some intresting finds. When turning the key to the on position I didn't hear any activity from the electropump/accumulator and there was no pressure to the rear wheels when the brake was pushed. So the first thing we did was pulled the connector from the bottom connection on the electropump and checked the voltage. We measured 5V I thought that was weird instead of seeing around 12 was what i was expecting. The fact that i'm seeing any voltage makes me think that the fuses and relays are ok (although I didn't think to check these to be sure). The next thing We were thinking to put 12 volts to the electropump from the battery to see if it turned on but before we did this we noticed that the 2 pins on the electropump are effectivly shorted we were reading like 1 ohm across the terminals. This was a shocker to me and would be suprised that the fuses aren't blown. Is this a normal situation with a bad pump that the two terminals get shorted? I would have expected it to become an open circuit.
My guess is that the electropump is bad. Is the only solution for this to convert to the GM unit? I see that centerline has an accumulator but thats diffrent from the pump right?
thanks,
Bob
 
#2 ·
I've also just purchased a Verde with ABS pump issues and found the existing threads in the Milano forum very helpful. Check through these for guidance.
In my case, the PO had replaced the accumulator but that did not fix his problem. So, I knew I had to replace the pump and have done so with the GM unit from ac-direct.com (now ~$375). This did not fix my lack of rear brakes so I am now replacing the master cylinder with a known good used unit. One step at a time approach. You should also inspect your rear rotors, are they getting any contact at all?
Keep us posted on your progress.
 
#3 ·
I looked through many old posts and found them very helpful as well. I am getting a used electropump and accumulator from a friend on the BB and will replace it. The previous posts defiantly describe everything to diagnose and fix the ABS system bu I couldn't find an answer to properties of a failed pump. Do the Power/Ground terminals of a bad pump become shorted. Also any guess why I would only get 5 volts.
 
#4 ·
I'll look to others to answer the electrical problems as I did not have them just a worn pump. I hope your replacements work and you don't face the same dilemma I had after replacement with a worn master cylinder.
 
#5 ·
If you're feeling brave, apply 12V to the pump and see what happens. The low voltage could be an almost blown main fuse (located right next to the pump under a black plastic cover) or poor contacts on the relays (above the clutch pedal and a pain to reach). Often a motor will fail open because the winding burns or the brushes fail to make contact, but it is possible to fail closed, especially if things have been heated up for a while.

The accumulator is on top of the pump and won't have any impact on what you are seeing because it is just a pressure vessel. Once you get your pump running you might find that you need to replace the accumulator to prevent the pump from running EVERY time you hit the brakes (should take 5 or more pedal pushes before the pump runs).
 
#6 ·
Is there a fuse on the 87?

Hi,
I found in a previous thread someone said that there was no fuse for electropump on the fender for 87 models. someone else replied that there was, but no one else stated who was right. Can anyone else verify if it's there? I searched and could not find one.
I replaced the electropump and accumulator with the buick conversion. After I had the old pump out I tested it and it still worked :mad: but i guess its best to have replaced it anyway. So My problem still remains that I need to figure out why I am getting only 5V.
I figured I could do a cheap work around by having the 5V kick on a relay that gives 12 to the electropump but I worry that this could just be putting a small bandaid on a bigger problem. What are some thoughts on this?
thanks,
Bob
 
#7 ·
That bandaid sounds "scary" - to me :eek: Yeah, find the root cause and fix it properly.

Roxanne is an 87 and has the fender fuse for the ABS pump. There HAS to be a fuse - i cannot imagine Alfa having it un-fused :confused: Well, on a 2nd thought, maybe I can :eek: :rolleyes:

Do you have the manual (incl the ABS section)?

Jes
 
#8 ·
Bob, the wiring diagram states that there is a fuse in the circuit. That pump draws a lot of current so please insert a fuse if one is missing! Sounds like sometime in the car's past (along with some other '87s too) the fuse was deleted because they blew up with some regularity but no one put the effort to track down the root cause.
 
#9 ·
I put in a autoresting breaker as my first pump poping fuses over and over. (it had chunks of plastic inside and would jam time to time)
I would swear the the fuse was in the fuse box. I had a box of fuses I keept puting in untill I put in the autoreseting breaker. but that was a long time ago. and I have never had a problem with a poped fuse after that. and if I did it will auto fix as soon as the overload is removed.
 
#10 ·
Fusible Link

I think it is actually a fusible link, not technically a fuse, on the fender. On my old Milano the ABS pump stopped working completely and I thought there was power to the pump. So car was towed and diagnosed and turned out the fusible link had blown. It seems that maybe some power gets through the link after it is burned out, but not enough to run the pump? In any event, I would definitely check the link before assuming the pump is bad. Total pump failure, i.e. no pump noise as you describe, sounds more like an electrical problem than pump failure.
 
#11 ·
Still can't find a fuse

Hi,
I still can't find a fuse in the engine bay and everything looks original Alfa. As you can see in the first photo, The connection to the electropump goes into a sleeve, right above the coil. The sleeve then goes all the way into the cabin. I did find a fuse on the fuse box that looks similar, shown in the second pic, anyone know what this does?
I measured the voltage on the relay and two of the terminals were ground, one was 12V, and the other was around 8V.
 

Attachments

#14 ·
I figured the fuse was unrelated but I was hoping that there might have been a chance. When i took those pictures today I went with the purpose of finding that fuse and i'm almost positive it's not there. I followed the wire from the electropump into the sleeve that it runs into the engine bay and there was no black box or anything. I specifically looked around the coil because I had read it was there. I will take very thorough pictures when i go down next time. I appreciate all the help and detailed descriptions.