ALB issue

[JKLedbetter]

I finally got around to making a switch box for flushing the solenoids in the ALB system. However, very little fluid is moving. I get one little whoosh, a tiny amount of movement of fluid in the reservoir, and then the solenoids just click. After I run the pump again I get the same thing.

So then I tried bleeding the system with the T-wrench. Again, very little fluid moving. The reservoir on the T-wrench should be filling at least half way up per cycle and I'm barely getting anything.

Can someone explain how the accumulator works?

I'm guessing it probably works like the pressure tank on a water well, where incoming water compresses air in the tank, but if the amount of air gets too low, then it takes very little water going out of the tank to trip the pressure switch. If this is how the accumulator works, then how do you check to see if it has enough air, and how do you add air if it is low?

Kennon

[stephen]

There is a pump that pumps fluid into the accumulator. Perhaps the pump is bad.

[paulo57509]

Originally Posted by JKLedbetter

I finally got around to making a switch box for flushing the solenoids in the ALB system. However, very little fluid is moving. I get one little whoosh, a tiny amount of movement of fluid in the reservoir, and then the solenoids just click. After I run the pump again I get the same thing.

So then I tried bleeding the system with the T-wrench. Again, very little fluid moving. The reservoir on the T-wrench should be filling at least half way up per cycle and I'm barely getting anything.

Can someone explain how the accumulator works?

I'm guessing it probably works like the pressure tank on a water well, where incoming water compresses air in the tank, but if the amount of air gets too low, then it takes very little water going out of the tank to trip the pressure switch. If this is how the accumulator works, then how do you check to see if it has enough air, and how do you add air if it is low?

Kennon

With the system pressurized, you shouldn't see much fluid movement in the reservoir when you open the solenoid. If there is air in the system you'll see bubbles when the solenoid is opened. Once all the air is expelled, you'll see essentially nothing happening in the reservoir. The initial "whoosh" you're seeing is normal. It diminishes because there's no more fluid pressure once the solenoid is opened.

If you're not getting fluid flow into the bleeder wrench, there's little or no pressure in the system. Either the pump is bad, you have a leak or (if you're manually pressurizing the system) you're not running the pump long enough.

The accumulator is a two chambered vessel with the two halves separated by a rubber diaphragm. In one chamber is nitrogen gas (it's factory sealed); the other side is the brake fluid. If the diaphragm is punctured, you're essentially screwed.

Please read the attached. It explains in detail how the ALB system works.

Also attached is a DIY procedure for flushing and bleeding an NSX ALB system. Both the early NSX and Legend systems are similar. The only difference is the NSX is a 4-channel system, the Legend is a 3-channel system. The procedure is the same for both.

[JKLedbetter]

Update:

The symptom which had originally prompted me to flush the solenoids was that the pump was running frequently.

Since then, the frequency has gradually reduced, and the run time for the pump has also declined. I suspect this indicates that any remaining air (nitrogen) on the air side of the diaphram has leaked out.

I tried to order a new accumulator, but like so many G1 parts, it has been discontinued.

Does anyone know which accumulators, if any, from other models can be substituted? It seems like it shouldn't be too big a deal if they are different, as long as the line in and the line out are the same. It's just a high pressure reservoir with a diaphram separating fluid from air.

-Kennon

[Tippey]

Anything that will fit will be equally as old as your car

i believe 1990-1993 integra GS and 1991 accord SE ABS parts are very similar if not identical so you could look into that.

[cakes]

I haven't heard of an accumulator going bad, but on both by G1s the pump has gone bad. That stupid pump is the Achilles heel of these cars.

Have you used the ABS recently on loose ground? sometimes when the system hasn't been used in a while and you suddenly use it, a solenoid will stick open and will force the pump to run until it hits the 120 second limit. Just go to a parking lot and slam the brakes several times to get the solenoids moving.

This is how I've bled the system after replacing the pumps. Connect a hose to the bleeder valve and directly connect the battery to the pump. The green wire is ground and the other wire is positive. I've ran it on for 30 second increments, while continually topping off the fluid in the reservoir. Then once everything is connected I took it to a parking lot and "exercised the system."

You could try a JY for an accumulator, it's most likely that it still works and its the pump that's bad in the JY car.

EDIT: It looks like the NSX uses practically the same system as the G1, except for the additional channel. I figured they would have redesigned and put updated components into it since it's 4 years newer.

[JKLedbetter]

After discovering the website for a man who recharges Anti-Lock Brake Accumulators for Audi's, I finally got around to removing my accumulator, intending to send it to him to see if he could recharge it.

However, after draining the fluid, it still seemed rather heavy, so I removed the screw from the Nitrogen side, and out came brake fluid. I assume this means the diaphragm has a hole in it and therefore attempting to recharge it would prove fruitless.

-Kennon

[JKLedbetter]

I further confirmed the diaphragm is bad by blowing air through it.

I found a business with the website UsedABSPumps.com which has used accumulators. They claim the part is cleaned and tested, and has a full money back 30 day warranty. Have any of ya'll ever done buisness with them, or know whether or not they can be trusted?

Since a bunch of ya'll have disabled your ALB due to bad pumps or bad modulators, wouldn't one of you be willing to sell me your accumulator?

-Kennon

PS Does anyone know for sure if the nitrogen side is pressurized, and if so, to what pressure? And if so, how did they pressurize it? There is only a screw, not a valve. How could they have gotten the pressure to stay in while inserting the screw?

[paulo57509]

Originally Posted by JKLedbetter

.....Does anyone know for sure if the nitrogen side is pressurized, and if so, to what pressure? And if so, how did they pressurize it? There is only a screw, not a valve. How could they have gotten the pressure to stay in while inserting the screw?

That's a good question. Thinking out loud.....

The ABS pump presurizes the brake fluid in the accumulator; when the ABS is activated that fluid needs to push on and activate the pistons in the modulator on order to increase the volume in the service brake lines releasing the brakes.

If the nitrogen side of the diaphram is at atomsperic pressure when it's buttoned up, will it still provide enough pressure against the brake fluid to activate the pistons in the modulator? I don't think so (just a gut feeling).

IIRC, the manual does state to open the accumulator screw to relieve the nitrogen pressure before discarding the accumultor. This implies that the nitrogen is under some amount of pressure. How much, I'm not sure.

Now why would anyone throw away a perfectly good accumulator? It's like, "Why would anyone throw away a perfectly good head (skull)?"

[JKLedbetter]

Went to the junkyard yesterday and found a 91 Accord with ABS (but it had no insignia indicating SE trim level). Removed the accumulator, and even though I couldn't blow through it, I suspect it is bad as there was brake fluid in the nitrogen side. Is it possible that as the nitrogen seeped out over the years, brake fluid seeped in, and the diaphragm is really still good?

I also noticed 2 or 3 '93 Accords (EX & LX) with the G2 style pump & accumulator, as well as a couple of Vigor's with the same setup. Has anyone ever tried to retrofit the G2 setup onto a G1? They are more readily available.

The main differences seem to be: A) the Accumulator/pressure switch assembly is combined into the same assembly with the pump, B) the accumulator is smaller and is attached with a threaded neck rather than 3 bolts, and C) the pump motor is larger.

Seems like the main issue would be whether or not the G2 pump draws more current.

-Kennon