ABS Modulator - (Master cylinder, Pump/Motor, Accumulator, Resivoir, Solenoid module)

[Jody Highroller]

Well just to Update....

As I mentioned before the motor rebuild by the company in Cali worked.

I was able to get master cylinder compression fitting leak to a slight drip. Used new flared tubing and nut.

I also mentioned my new found issue of "pedal sticking to floor"

Well, it appears I found the problem.

Note, I fully believe my LC would be back on road had I not tried to be a preventive maintenance champ and change out the MC pistion, ya know "While I'm in there"

Upon pulling assembly from firewall and removing MC piston I found this.

View attachment 1328020

View attachment 1328021

In the figures above what you're looking at is the brand new OEM master cylinder piston/plunger (whatever you want to call it) This part is easily assessable and runs about $70.00 - Part# 04493-60330 PISTON KIT, BRAKE MA - from ToyotaPartsDeal.com

Sooooo.....

I do still have the old piston kit I pulled as part of my attempted PM. It looks ok. The bore does not look scored either.

However, the 'bore chamber' spring of the master cylinder appears to be bent now, or at least misaligned as shown below. I guess when I went to install the new pistion it got misaligned. BUT I really don't see how! It's not difficult to align. But this sort of tearing of the metal could not have been from me compressing the piston to get the snap ring out, now way.

I think it had to have been misaligning and from my pumping brake pedal made the impact and subsequent tear.

I really do not want to spend 1k or 1500 on a new or refrained MC.

 

[oakback]

Is it possible to rebuild the old MC with the seals of the new?

Sorry if it's a dumb question, I haven't had any experience with these MCs (mainly motorcycles and an old Mazda).

 

[Jody Highroller]

Is it possible to rebuild the old MC with the seals of the new?

Sorry if it's a dumb question, I haven't had any experience with these MCs (mainly motorcycles and an old Mazda).

In my case I wouldn't even have to transfer the seals. However, I believe the piston can be Cannibalized, if you will.

If you ever rebuild one of these, extend the telescoping pistion before insertion and mating to the MC spring button. Then push the piston rod in. If you don't get a good seat and it is misaligned you may have the damage mine received upon startup pressurization and the pistion slams against the MC button spring. Which was not covered in the unanimous "go to thread" by Skidoo.

 

[Jody Highroller]

There is an additional valve/piston (shown in pic - far left, silver part attached to spring) lower into the master cylinder housing that I cannot removed. I found one person with the part and neither he or I could remove it with pliers.

It appears I will have to take another route to remove it

 

[Jody Highroller]

Follow up:

From my experiences I found it was best to acquire a new or rebuilt motor (euroton) and purchase a master cylinder w/ solenoid box from cruiserparts and reassemble and install.

I would not attempt to open up the master cylinder and replace the piston again. That's just me. I am not a qualified brake repair mechanic and I did more damage than good.

The best solution for me was to procure the subassemblies without getting into the internal components.

 

[nissanh]

I wonder an 02 4runner brake master pump is the same as the one we have in the 100?

 

[Jody Highroller]

I wonder an 02 4runner brake master pump is the same as the one we have in the 100?

Some say it is. I've studied the photos online of them and I believe they are different. I've also consulted with people who run refurb/reman operations in Mexico for these units and they said they were different

 

[Beazer76]

Okay, so I rebuilt my accumulator motor (sent it to Charlie at Eurton in California) and reinstalled it, bled the brakes, went on a dirt road and activated the ABS several times, then bled the brakes again. All seemed to be fine until a few days later it started to buzz again. BUT there were no dash lights or alarms this time...just the buzzing. . It started while sitting in my inclined driveway, in Drive, waiting for my daughter to get in the car. It stopped about 500 ft down the road, after I stomped on the brakes about 5 times (I might have been a bit angry). I then drove 5 miles down the road and back with no issue. I'm so puzzled at this point I don't know what to do. Anybody have any ideas?

This is the noise:

 

[2001LC]

If lucky it just need adjusting. Otherwise I'd guess pump is going out. Just motor was rebuilt right?

 

[Beazer76]

If lucky it just need adjusting. Otherwise I'd guess pump is going out. Just motor was rebuilt right?
View attachment 1740949 View attachment 1740950

According to the diagram it was the booster pump motor. I’ll see if I missed something on the adjustment. Thank you for your advice.

 

[2001LC]

Your welcome.

A quick look down from above accumulator. See if any of the rubber stop are touching the accumulator. If so loosed the two screws I circled in red to adjust so they don't touch.

Once done if squeal persist. Try a stethoscope on pump.

 

[2001LC]

BTW: pump is between motor and accumulator. IIRC Toyota only sells as a unit (pump & motor) just as seen above.

Also I know a lot of guys (shop & DIY) R&R motor while master still in rig. You can do this but it's very difficult to align the part that connect the drive shaft of motor to that of the pump. The gasket is also difficult to algin.

 

[Beazer76]

BTW: pump is between motor and accumulator. IIRC Toyota only sells as a unit (pump & motor) just as seen above.

Also I know a lot of guys (shop & DIY) R&R motor while master still in rig. You can do this but it's very difficult to align the part that connect the drive shaft of motor to that of the pump. The gasket is also difficult to algin.

I pulled the motor/pump and accumulator from the MC, leaving the MC in. It was a bit of a pain to put back together and align the lines correctly to keep them from cross threading. I will check the alignment of rubber stops you mentioned above for sure and report back.

 

[2001LC]

I don't think this has to do with your sounds. But did you check the wires on ABS side.
I find this a lot:

 

[Beazer76]

I don't think this has to do with your sounds. But did you check the wires on ABS side.
I find this a lot:
View attachment 1741049

I did. Those actually have to be disconnected to remove the motor. I cleaned them as well. They weren’t that bad.

Also, I checked my spacing from the rubber stops and they didn’t look out or whack at all. I just wish I knew if that noise was the pump or the motor itself. I can’t believe it would be the motor though since I just had it rebuilt.

 

[gil12]

Consider replacement of the accumulator also, some have suggested it is a part that needs periodic replacement.

 

[PADDO]

Okay, so I rebuilt my accumulator motor (sent it to Charlie at Eurton in California) and reinstalled it, bled the brakes, went on a dirt road and activated the ABS several times, then bled the brakes again. All seemed to be fine until a few days later it started to buzz again. BUT there were no dash lights or alarms this time...just the buzzing. . It started while sitting in my inclined driveway, in Drive, waiting for my daughter to get in the car. It stopped about 500 ft down the road, after I stomped on the brakes about 5 times (I might have been a bit angry). I then drove 5 miles down the road and back with no issue. I'm so puzzled at this point I don't know what to do. Anybody have any ideas?

This is the noise:

Others have fixed that noise by replacing the silencer tube o ring and spring. I also don’t know if just activating the ABS is as good or effective as a proper Techstream controlled ABS bleed, but if you didn’t open up the hydraulics it shouldn’t be a factor. There are tests you can do to check the health of the brake assist accumulator - basic would be to time the no pressure to charged pump run time (expect ~30-40 seconds) then see how many pumps it takes to bleed off pressure with IG off (about 20 pumps) and the FSM details tests to check brake pressure at the calipers with a gauge.

 

[2001LC]

Good chance it is the silencer tube, o-ring and spring as @PADDO suggest.

I too have wonder if dirt road ABS activating is as good as through tech stream. Is there's some way to test this?

If you decide to go all new and sell your pump:

I found the cheapest new OEM motor, pump and wire is out of mid east. 4796060010 Toyota PUMP ASSY, BRAKE BOOSTER Price: 694$, Weight: 2.584kg - PartSouq - Auto Parts Around the World $733 includes shipping.

For $870 4707060010 Toyota PUMP ASSY, BRAKE BOOSTER W/ACCUMULATOR Price: 793.23$, Weight: 5.523kg - PartSouq - Auto Parts Around the World it comes with accumulator. Good idea to order bushing and two more nuts and screws for wire ABS side also.

Last part I order from this site was here in 3 days.

Note: Use your VIN when ordering to assure correct part number.

 

[savirc]

Good chance it is the silencer tube, o-ring and spring as @PADDO suggest.

I too have wonder if dirt road ABS activating is as good as through tech stream. Is there's some way to test this?

If you decide to go all new and sell your pump:

I found the cheapest new OEM motor, pump and wire is out of mid east. 4796060010 Toyota PUMP ASSY, BRAKE BOOSTER Price: 694$, Weight: 2.584kg - PartSouq - Auto Parts Around the World $733 includes shipping.

For $870 4707060010 Toyota PUMP ASSY, BRAKE BOOSTER W/ACCUMULATOR Price: 793.23$, Weight: 5.523kg - PartSouq - Auto Parts Around the World it comes with accumulator. Good idea to order bushing and two more nuts and screws for wire ABS side also.

Last part I order from this site was here in 3 days.

Note: Use your VIN when ordering to assure correct part number.

2001LC,

I have the squeal coming our of motor or accumulator I'm not sure which and I felt it at the pedal, periodically lacking full brake power happen twice in two days after a trip to Big Bend over the weekend that required multiple times of ATRAC. No lights but I've had the lights and squeal at HIH8 and then it all passed.

I don't want to mess around with trial an error with something so critical for safety which leads to my question. If buying the above part with the accumulator buying everything except the reservoir?

What's the difference between the part above and the full unit?

Is it just the brake controller and cylinder?
Thanks for your help.

-CR

 

[2001LC]

The master or ABS (black box on side) is what we can't buy separate. BRAKE MASTER CYLINDER | LEXUS LX470 UZJ100L-GNPGKA UZJ100 | Lexus | Genuine Parts Catalogs | PartSouq Auto Parts Around the World Input your VIN on main page, then you'll see what can and can't be bought for you specific year and month of production.

Your issues could be a number of things combined or one issue; Adjustment of accumulate bracket, old fluid needing flushing, bearing in booster motor failing, pump failing, accumulator failing, leaky caliper piston seal, master plunger seal, etc... Heavy braking heats up brake fluid and it's effectiveness is diminished. If fluid is old it has moisture in it, this will cause it's boiling point to drop.

I suggest you take to a Toyota Dealer and have them check it out. Unfortunately they to often just say replaces the whole master brake assembly. So ask them to be specific.