Booster Pump / Accumulator Noise diagnosis

[bdruff]

Used? Not remanned? How many miles were on the donor?

It didn’t say. It said that it was tested and they offered returns. I’m going to work on it tomorrow. Maybe open up the black box and see if I can see anything obvious. I don’t even really know what I’m looking for. I’m leaning towards buying the whole damn thing at this point.

On a positive note. I can take the assembly out in 7 minutes now. Give or take

 

[Landcruiser949]

It didn’t say. It said that it was tested and they offered returns. I’m going to work on it tomorrow. Maybe open up the black box and see if I can see anything obvious. I don’t even really know what I’m looking for. I’m leaning towards buying the whole damn thing at this point.

On a positive note. I can take the assembly out in 7 minutes now. Give or take

Please take pics of what you see inside. Might just be a faulty connection or something shorted out. Are you in CA by chance?
I would message the seller and ask how many miles were on the previous unit.
Did you check the hose that's on your old unit for cracks and all that?

 

[bdruff]

Please take pics of what you see inside. Might just be a faulty connection or something shorted out. Are you in CA by chance?
I would message the seller and ask how many miles were on the previous unit.
Did you check the hose that's on your old unit for cracks and all that?

Will do. I'm on Fresno CA. I have some electrical cleaner. I'm going to try cleaning the connections and maybe some light air with the compressor inside the box. I did inspect the hose bitbot looked good

 

[Landcruiser949]

Will do. I'm on Fresno CA. I have some electrical cleaner. I'm going to try cleaning the connections and maybe some light air with the compressor inside the box.

Awesome. Let me know what you find in the box. I go to Clovis quite a bit. If you are able to figure it out id be glad to pay you to fix my unit. Especially if it involves soldering.

 

[bdruff]

Awesome. Let me know what you find in the box. I go to Clovis quite a bit. If you are able to figure it out id be glad to pay you to fix my unit. Especially if it involves soldering.

I think it's going to come down to replacing the Master cylinder assembly. I can soldier, but I don't even know what I'm looking for. Unless it's very obvious, I'm probably just grasping at straws.

 

[Landcruiser949]

I think it's going to come down to replacing the Master cylinder assembly. I can soldier, but I don't even know what I'm looking for. Unless it's very obvious, I'm probably just grasping at straws.

So you just bought the motor (black motor under the assembly) and the accumulator?

 

[bdruff]

So you just bought the motor (black motor under the assembly) and the accumulator?

The booster assembly which is the accumulator, the pump, and the motor.

 

[Landcruiser949]

The booster assembly which is the accumulator, the pump, and the motor.

Gotcha. So everything but the black box?

 

[bdruff]

Gotcha. So everything but the black box?

Not exactly. The master cylinder is a separate piece. I actually rebuilt my master cylinder. I'll research, but from what I understand, the black box is part of the master cylinder assembly and not sold separately.

 

[2001LC]

I see no way to do anything to ABS control unit (black box). I've open one up, here some pictures.
From a 98 Land Cruiser

 

[bdruff]

I agree. I follow a thread from skiddo on the master cylinder rebuild. He opened up the box and posted pictures also. Doesn't look like there is any fixing it.

Included for your viewing pleasure is photo with cover plate off to show top of solenoid valves. Do not do this, not required for rebuild, I was just curious.
View attachment 442122

 

[bdruff]

I see no way to do anything to ABS control unit (black box). I've open one up, here some pictures.
From a 98 Land Cruiser

View attachment 2191917
View attachment 2191922
View attachment 2191923

Do you think the abs control unit can be swapped out?;I just rebuilt my master cylinder.

 

[2001LC]

Yes it can. It's how I got that one to bust apart. It worked out fine.
But this was not a noise issues. Codes, which I don't have them, as diagnosed by Dealership. Indicated it was the ABS unit. We picked up an ABS unit and swap it out. The wire was heavily corroded. I suspect the bad brake control wire played a roll in damaging the ABS control unit. It just a suspicion I have.

I'm 99% sure a corroded brake control wire damages the commutator of motor. As I've seen many of those bad commutator and wire combos. But only one of these, where corroded wire was attached to a bad ABS Unit.

But for the noise issue, for the first time. I'm now seeing another part we may need. It looks like an O-ring, and is not sold separately. If the LP & HP switch in ABS control unit is bad, we should get a code and be able to test them. But if this O-ring is part of the problem, we're out of luck. Unless someone can find a replacement. The replacement O-ring would need to be made for brake fluid and be the exact size. Any variation size, type or guilty of rubber and we could cause a problem!

Here in post #353 you'll see what looks like O-ring. It's on a part inside master cylinder in the back. It's around the assembly the master plunge we can buy fit into.

Master Cylinder Rebuild - DIY

I would replace the wire and inspect the motor while you do and use the best one. But your issue is not likely the motor based on your test, fact brakes work and what you mechanic said. Although it is possible the motor is intermittently working, which opening up motor you'll know. If no other...

forum.ih8mud.com

 

[bdruff]

Honestly don't know where to go from here except to buy the entire master cylinder assembly including the brake booster assembly

 

[2001LC]

The test on previous page from FSM that are posted. Should indicate if booster HP or LP switches bad. If they check out okay, we very little else we can replace..

 

[grundsethp]

2001LC

Do you still have those parts? since you have opened up the black box, can you see if there is continuity from PH and PHG pins to any of the electrical components pictured. It you find the component that is connected to PH, that may be the high pressure switch. I would assume PHG is a common ground so a lot of circuits would be connected to that pin. If the pressure switch can be identified, it may have a part number on the part.

 

[bdruff]

5p is the connector on the left? I want to test the pressure switch. FSM says test the resistance from ph to phg.

This is kinda new to me.

 

[bdruff]

2001LC

Do you still have those parts? since you have opened up the black box, can you see if there is continuity from PH and PHG pins to any of the electrical components pictured. It you find the component that is connected to PH, that may be the high pressure switch. I would assume PHG is a common ground so a lot of circuits would be connected to that pin. If the pressure switch can be identified, it may have a part number on the part.

View attachment 2192060

View attachment 2192061

I haven't taken the black box apart. I don't know that it would help me looking at the pictures. I might test the resistance like you suggested but I don't know how to do that.

 

[bdruff]

Following the FSM.

Disconnected the connection that I think is 5b.

Pumped brakes 40 times with ignition off.

Resistance measured 1

Reconnected 5b and turned on the ignition.

Pump ran for around 40 seconds then stopped. (Good)

Unplugged 5b connector and ohm read 1.6-2.

Brakes have crazy pressure. Pedal is hard to press down.

 

[Eyedaho]

Following the FSM.

Disconnected the connection that I think is 5b.

Pumped brakes 40 times with ignition off.

Resistance measured 1

Reconnected 5b and turned on the ignition.

Pump ran for around 40 seconds then stopped. (Good)

Unplugged 5b connector and ohm read 1.6-2.

Brakes have crazy pressure. Pedal is hard to press down.View attachment 2192145

With the ignition off and the after pumping the brakes your resistance measured 1kohm, right? AKA 1000 ohms. The 1.6-2 isn't crazy high for a closed switch, but could indicate that the switch contacts are starting to fail. Does your meter read 0 ohms with the leads touching?