Yet another ALB thread

bruckner

bruckner

Contributing Member
Joined
13 June 2009
Messages
202
Location
Montreal, Canada
After a hard braking that triggered my ALB on crappy tires last year, my ALB pump started cycling every 10 seconds or so. I quickly removed the relay to stop the pig squeal going down the road. I then ordered a clever kit to exercise the solenoids, did multiple runs of tests and all 4 solenoids seemed to behave normally, fluid is clean. Now the pump will engage briefly when I first get going with the car (once a week on average), and usually won't be heard again on a normal drive, and no ALB light on dashboard. However now the slightest, faintest, most benign intervention of the ALB (like hitting a pebble or two just before coming to a full stop) will trigger the pump, leading me to believe the pressure in the system is not that high. Which begs the question... pressure switch? Accumulator? Solenoids? Thoughts?
 
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Yes, likely accumulator.
 
warrenw said:
Is there foam in the reservoir after it runs? If so you have a solenoid not sealing properly.
Click to expand...

I never looked in the reservoir right after a drive where the ALB (and pump) was triggered, but there surely is foam when exercising the solenoids using the harness.

Am I right thinking the pump would cycle every few seconds if a solenoid seal was the culprit? Pressure wouldn't hold for long with a valve not sealing correctly. Seems like pressure builds normally in the beginning of each drive and pump doesn't run if ALB isn't activated for the rest of the drive, but pump immediately runs if ALB is triggered.

I just found out that replacement accumulator and pressure switch cost a small fortune, if at all available new. Now I see why some disable ALB altogether when it fails. I just like the car's systems to work as designed...
 
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At this stage, I'm ready to conclude it's the accumulator. I did yet another run of solenoid exercice with the harness, this time with more knowledge acquired reading through the forums. I can say that the pump appears to reach maximum pressure within 3-4 seconds, meaning the pump runs freely for a few seconds before it suddenly slows down and sounds like it is struggling, and during that time fluid level hardly moved from the max line; if I insist a few more seconds running the pump, I can see fluid flowing back into the reservoir through (I assume) a return valve. I then energize any one of the solenoids and fluid will flow in the first 2-3 clicks, then the solenoid opens and closes with no pressure at all in the system; running the pump again will result in the same behavior described above.

I assume swapping accumulator (if I find one) requires removing the whole ALB out of the car? Also, I read about the necessity to purge pressure in the system before opening it up, is it safe to assume that running one of the solenoids will relieve all pressure, or do I need to slowly purge from the lower valve?
 
The accumulator is ~USD$300.
http://jp-carparts.com/honda/part_d...type=NSX&cartype=19668&fig=B&fig1=2420&fig2=3

Just bleed the system of pressure and R&R the accumulator.

You midas swell just rebuild the whole system; it will likely be full of debris.

Also, clean the magnetic pickups.

A better way to disable the system during servicing is to jump/short the pressure switch on the body side. The system will just think all is well and not throw an error.
 
bruckner said:
At this stage, I'm ready to conclude it's the accumulator. I did yet another run of solenoid exercice with the harness, this time with more knowledge acquired reading through the forums. I can say that the pump appears to reach maximum pressure within 3-4 seconds, meaning the pump runs freely for a few seconds before it suddenly slows down and sounds like it is struggling, and during that time fluid level hardly moved from the max line; if I insist a few more seconds running the pump, I can see fluid flowing back into the reservoir through (I assume) a return valve. I then energize any one of the solenoids and fluid will flow in the first 2-3 clicks, then the solenoid opens and closes with no pressure at all in the system; running the pump again will result in the same behavior described above.

I assume swapping accumulator (if I find one) requires removing the whole ALB out of the car? Also, I read about the necessity to purge pressure in the system before opening it up, is it safe to assume that running one of the solenoids will relieve all pressure, or do I need to slowly purge from the lower valve?
Click to expand...

Only from your description, it sounds like pressure is building, the fluid is coming back into the reservoir, it may be a leaking solenoid valve.
 
Thanks for all the invaluable expert advice. I will make a video of the pressurization process. Surely there must be a way to diagnose before spending the 300$ to get a new accumulator. I'm thinking the pump wouldn't start struggling after just a few seconds running if it was just a leaky solenoid?
 
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bruckner said:
Thanks for all the invaluable expert advice. I will make a video of the pressurization process. Surely there must be a way to diagnose before spending the 300$ to get a new accumulator. I'm thinking the pump wouldn't start struggling after just a few seconds running if it was just a leaky solenoid?
Click to expand...

Watch the video and read the re build procedure. Three bolts and a brake line. It is easier to take the entire unit out of the car.
The pump slowing and labouring tells me the accumulator may be build pressure then the sol valve will leak.


Sent from my iPhone using Tapatalk
 
warrenw said:
Watch the video and read the re build procedure. Three bolts and a brake line. It is easier to take the entire unit out of the car.
The pump slowing and labouring tells me the accumulator may be build pressure then the sol valve will leak.
Click to expand...

Is there a pressure valve in the system that returns excess pressurized fluid back into the reservoir?
 
warrenw said:
No, the pressure switch shuts down the pump.
Click to expand...

Invaluable bit of info. I'm still at odds trying to understand why the pump cycles on its own every few seconds for a short while (definitely not the max 120 seconds period I read somewhere), seems to me that pressure would never reach the point where the switch turns off the pump if fluid is leaking back into the reservoir, yet the pump never runs for more than a few seconds at a time.
 
Your information is a bit conflicting.

> the pump will engage briefly when I first get going with the car (once a week on average),

Typical dirty or internally leaking modulator.

>However now the slightest, faintest, most benign intervention of the ALB (like hitting a pebble or two just before coming to a full stop) will trigger the pump,

Signs of fouled magnetic sensors.

OR

possibly a bad pressure switch or open connection.


>the pump cycles on its own every few seconds for a short while

?? is the ALB engaging? Is this during stops, go's, or just derping along down the road?

A bad accumulator doesn't hold pressure, it just fills with uncompressible fluid and the pump immediately stops.

**

It is really hard to give a discrete answer without some detailed tests: actions, reactions, and pressures. I actually have a the ALB SST but found it to be marginally useful because the ALB system is simple. It is also a lot easier to diagnose a failed component from an intermittant failing component.


Recommend that you go to a slick road and perform a couple of long panic stops: does the ALB engage (how many modulations? and time the pump runs?)

Is the ALB engaging on a whim?
 
drew said:
Your information is a bit conflicting.

> the pump will engage briefly when I first get going with the car (once a week on average),

Typical dirty or internally leaking modulator.

>However now the slightest, faintest, most benign intervention of the ALB (like hitting a pebble or two just before coming to a full stop) will trigger the pump,

Signs of fouled magnetic sensors.

OR

possibly a bad pressure switch or open connection.


>the pump cycles on its own every few seconds for a short while

?? is the ALB engaging? Is this during stops, go's, or just derping along down the road?

A bad accumulator doesn't hold pressure, it just fills with uncompressible fluid and the pump immediately stops.

**

It is really hard to give a discrete answer without some detailed tests: actions, reactions, and pressures. I actually have a the ALB SST but found it to be marginally useful because the ALB system is simple. It is also a lot easier to diagnose a failed component from an intermittant failing component.


Recommend that you go to a slick road and perform a couple of long panic stops: does the ALB engage (how many modulations? and time the pump runs?)

Is the ALB engaging on a whim?
Click to expand...

The behavior I described in my first post is the current situation, although it's happened a few times that, strangely, the pump would cycle every few seconds for a short while during the drive, without ALB ever being activated. I see how this is conflicting, the system performs in one of these two ways, thankfully the majority of the time I hear the pump running on initial start up as it should, but then the pump will trigger with the ALB kicking in. For certain a healthy system must build enough pressure to allow a few interventions of the ALB without needing the pump to increase pressure again. Seems like my system produces and holds (most of the time) barely enough pressure to be over the minimum level monitored by the pressure switch, but pressure immediately falls below that threshold if the ALB kicks in.

Perhaps I should describe what I mean by "bening" intervention of the ALB. I don't think a wheel sensor is at fault, ALB seems to intervene when it should, I'm running sticky tires on asphalt in regular driving conditions, no high speed max brake force applied that would require a sustained intervention of the ALB for a few seconds (surely isn't enough pressure in my particular system to withstand that!). By bening intervention I mean a slight, very brief, kick in the pedal, when coming to a stop over slippy surface. I'll grant you it doesn't happen often but I find it highly abnormal that such a minor incident would require re-pressurizing the system. Also the fact that, as mentioned above, it's happened a few times that the pump would cycle on its own every few seconds, I'm paying particular attention to how the system behaves.

I did a few stops on a gravel road yesterday. As far as the engagement point, it seemed normal to me, fairly hard braking was required to get ALB to kick in. When so, the brake pedal would return a single kick back, and of course the pump would run through the experiment. I did that 10-12 times.

Thanks so much for your patience and help!
 
Removing the accumulator is easy from under the front of the car. Jack it up and put a jack stand at the left front, access is easy.

Once the accumulator is off, you can gently insert a round-tipped probe in the hole. If the diaphragm is good it will stop the probe. If it has failed the probe will go all the way in. Easy to check.

If it's good, you have another problem.
 
I imagine you would get the abs light if the accumulator/diaphragm is bad due to the long running of the pump, I think it is 2 min. or so.

if the pump runs intermittently, that usually indicate something is leaking slowly and it is worse during the cold climate. the pump would stop in some cases after the abs unit warmed up/improved sealing from the radiator's heat.

Wavey1 said:
Removing the accumulator is easy from under the front of the car. Jack it up and put a jack stand at the left front, access is easy.

Once the accumulator is off, you can gently insert a round-tipped probe in the hole. If the diaphragm is good it will stop the probe. If it has failed the probe will go all the way in. Easy to check.

If it's good, you have another problem.
Click to expand...
 
>I imagine you would get the abs light if the accumulator/diaphragm is bad due to the long running of the pump, I think it is 2 min. or so.

The 120 second timeout period is if the system cannot develop enough pressure to engage the pressure switch. Generally, the modulator is the issue, but a bad pump is also a cause.

A bad accumulator would be an immediate building of pressure and the pump stop almost immediately.

This is presuming no external leaks.
 
The pump is two components: an electric motor that drives an eccentric that drives the pump. Any of those parts can fail, and it sounds like your eccentric needs to be greased, it should "rattle" and not squeal.

I have seen two units with burned out motors and another with a bad pump (no pressure). It is reasonable that the pump could fail by not building adequate pressure, but you would need pressure gauges and the necessary hardware. The ALB unit is highly componentized and those components can easily be R&R'd.

If you want to get down and dirty with the diagnostics: You are out of luck, The workshop manual recommends replacement of the entire unit.

The KA7 Legend *might* have parts to scavenge inexpensively. New parts are also available from the usual JDM suppliers (amayama.com and jp-carparts.com).

You would probably be spending more time and money on test equipment/procedures than attempting a rebuild of the system.
 
nis350 said:
I imagine you would get the abs light if the accumulator/diaphragm is bad due to the long running of the pump, I think it is 2 min. or so.

if the pump runs intermittently, that usually indicate something is leaking slowly and it is worse during the cold climate. the pump would stop in some cases after the abs unit warmed up/improved sealing from the radiator's heat.
Click to expand...

My accumulator was bad and the only symptom was frequent running of the pump, no ABS light. And the ABS light works.
 
Finally got around to rebuilding my modulator using warren's kit. Bad news though, upon inspection my accumulator is shot: I can stick a wire in there and touch the metal case at the bottom. No hint of even a residue of a membrane.

On the hunt for a replacement accumulator. If unsuccessful, I may consider deleting altogether.
 
Hello everyone.

I know it's not good forum about my problem, but I think I can get help only here. I bought 6 month ago Civic Shuttle from 90. It got ALB system. My problem with is when I drive car it cannot get pressure. While in driving it work for like 5 to 8 second to get pressure and then for 10 to maybe even 30 seconds I don't hear pump and then again it's same thing. I have to remove fuse called "ALB 2". Normally ALB system work when I test it, but it all times making pump to getting it's pressure. I found video on youtube what is part to repair it, but I don't know if I can buy it anywhere to Shuttle. I don't know it's the pump is same exactly like on NSX or other and it's why I asking with help. Sorry for my bad english and sorry that I wrote this here, because I don't know where to find help. Please be forgiving for me.

Regards All :)
 
I am from Poland, and I will try to contact with Honda supporter in my country but I got question. Which parts number are required (I mean o'rings) to buy/change when searching in catalog ? I ask because it will be easier to describe in ASO what I need just using part numbers.
 

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