Margate330

Hi members,
I struggled for 2 years with an random and intermittent brake pedal fade while idling at traffic lights that has now been resolved for the time being.
Bought 2 brake actuators cheap on ebay for the purpose of having one to tear down and another as a spare in case I needed to replace mine.

-> The full update and saga of the pedal fade fix can be seen here: https://www.clublexus.com/forums/rx-...-actuator.html at post #4.

I had a crazy idea that the brake actuator could be rebuilt or at least parts swapped from one unit to another for things may be common such as the motor.
After tearing it down it seems this item was never designed to be opened or repaired as I ended up destroying it to figure out how to get it apart.

BUT- it will come apart in only one way as documented below without destroying it. Not sure why anyone would want to but it is possible.
Also, it would be nice if members can add more info on how this thing works.

>> Invited for all Lexus owners for anyone who wants to add more info how this thing actually works, theory of operation, repair cost, or whatever in the spirit of fun and research- write a thesis if you like.

Junkyard wrote all over every inch of it in yellow paint crayon but no problem, came off easy with brake cleaner.




Lets get started...
The way in is to crack open the plastic case. It is glued so I scored it with a dremmel and cracked it open like a clam but if I did it again I would try a heat gun.




Once inside we can see a good view of the Skid Control ECU. High quality board with perfect automated(not by hand) soldering. Caps still good at 17 years old(2004 RX330).




After desoldering 66 joints the Skid Control ECU is removed. The solder holes had generous room for the pins so was very easy to desolder.




Once the circuit board is out of the way a secret hidden screw can be seen.




Next to remove the actuator's motor- the solid copper core wire must be uncrimped. This wire runs thru the actuator's body in a protective sheath to the motor on the other side.




Now we have it apart in it's main components. Notice how I cut the motor wire- don't do this- I only did it because I couldn't figure out how it all came apart. Motor only has one solid core wire so it uses its body as a ground.






-> NOW FOR THE MONEY SHOT!!! 10 Solenoids(4 @ 9 ohm & 6 @ 5 ohm) and one 3 pin sensor(I think).





Here is where the quacking happens I've heard people complain about. When I turn the shaft with pliers it sounds squishy and "quacky". Very faint so just guessing and not 100% sure.




-> FEEL FREE TO ADD, ESPECIALLY IF YOU KNOW HOW THIS THING WORKS!

Felix

Great tear down Phil. I've yet to have it to actuvate since I've upgraded the front brakes for the gen 3 setup.....Basically I swapped out the front oem size centric pads/rotors after a yr or so as I found the gen2 oem brakes are a little small for the weight of the vehicle. I knew that going in w/ a gen 2.

Margate330

Thank you felix!

Wasn't sure anyone wants to see inside.
It seems there are 2 selenoid valves for fluid control for Each Wheel and 2 selenoids for controlling the Brake Master Cylinder pressure and return Lines.
Looks like the fluid is always running thru this actuator, no other way for the fluid to get to the wheels.

Hoping someone can post some more info on how this works.

Felix

After a quick bit of reading, looks like Lexus added this btake actuator which is controlled by the ecu vs abs by itself....I've felt it working a few times w/ the oem sized brakes, IIRC it felted like it needed half the pedal travel & felt easier to push the brake pedal. Totally different then I'm use to. With the gen 3 front brake setup, haven't felt it or the abs kick in thou. No tear down & repairing it, replace & toss the old one.....Similar to what a lot of ppl have been doing the last 30+ yrs or so vs repairing it......

Nodo1999

I know that the brake actuator is a common problem for the RX400h, mine is a 2007. It has finally reached the point where it chirps with the lightest press of the brake pedal and a bunch of warning lights have turned on; brake, ABS, and VSC. Initially I would disconnect the battery and then go drive on the freeway and the lights would shut off that the brakes would work ok with minimal chirping. Now the lights stay on.
Has anyone attempted to rebuild the unit to see if it is salvageable or is it junk once it fails?
I have not found any info on rebuilding it but have found some websites that offer refurbished units - actually makes me questioned what was actually refurbished.
]Any info will be appreciated.

iMSQ

Have you read error codes?
https://www.clublexus.com/forums/hyb...l#post10388337
https://www.clublexus.com/forums/rx-...s-invited.html
https://www.clublexus.com/forums/hyb...l#post11159337