Taking apart a 5th gen 4WS actuator - guide

[Anzezaf]

Has anyone here done it and can offer any advice? I'm leaning towards making one fully functional unit out of two that aren't in a perfect state.

I know the shop manual specifically states that the actuator shouldnt be taken apart and therefore should be replaced as a whole.
But since these are getting hard to come by, I'm left with little alternatives.

[K30DPC]

I'll be watching this thread.
I'm in quite similar situation. Mine is working, but makes squeaky noise. I have replacement but it does very similar. I'm sure it's the actuator, all suspension parts have been tested. Little wiki would be nice.

[Anzezaf]

@K30DPC I also had a squeaking sound in the actuator when the wheels turned. I sprayed some lubricating oil through the lock pin hole and it solved the problem
I know the manual says not to spray anything there but I did it, nothing bad happened and it solved the problem

[Anzezaf]

No one has any clues to give I'm kinda waiting for any feedback before I start wrenching on it

[Drax]

i dont remember anyone here taking one apart, my only suggestion is to search the Wiki area or do a search on google

[Vtecmec]

I've never seen one split open, though I suspect there's not actually too much to it when you're in there.

Just take detailed photos at every step and clearly mark / bag all the bits as best you can.

I believe in you.

[Anzezaf]

So I got around to taking the thing apart. It's really not that hard, anyone with some common mechanical sense is able to do it.
The system is really a basic one - an electric motor that drives a long threaded rod, which in turn drives the direction of the wheels.
So - steps of disassembly:

1. Open the boots of the inner joints and remove the inner joints. I sadly dont have a picture of this step, but it involves un-bending a washer that is bent around a nut - for safety reasons I presume (so the joint cannot unscrew itself). The washers are quite hard to unbend without any special tools, and I didn't want to start whacking away. So the course of action for me was: Wrap some tin foil around the ball joint to protect it from debris and carefully cut the bent tabs away with an angle grinder. Really nice and quick results - just be careful not to cut too deep, to not damage the wrench splines on the inner joints - you will know what I'm talking about.

2. Remove the motor / cover / casing. Should be 6 screws and once you remove them just pull it apart. The brushes on the motor include the plastic connector that seals against the metal body of the actuator. Dont lose the oring gasket that is on the connector and the oring gasket that seals the motor to the unit! Other than that, once you remove the motor you can pull apart the brushes - they just slide off the commutator.



3. Optionally - remove the circlip inside. I don't quite know what the function of it is, I presume it's somehow securing the bearing.



4. Remove the steering sensors - again nothing but bolts and don't lose the gaskets. Be careful, the bigger sensor is held on with an extra wire harness metal bracket so it needs 5 screws to remove. 2 screws for the smaller sensor.




5. Remove the end cover, it involves 4 bolts, nothing much there just don't lose the oring gasket. My unit is dirty and in bad condition - there is/was a big green plastic washer in the unit that somehow got smashed to bits and turned to mush. The green washer can be seen once you open this cover and you see the residue on the cover (This is the second 4WS actuator that I noticed had this problem, it may turn out that every 4WS actuator has developed this problem with age - degraded plastic that gets crushed under the pressure of the spring)



6. Remove the 4-notched nut securing the spring holder. I fabricated a tool from a metal pipe (ID must be 27.5mm or less, and OD must be 33mm or more). I used an angle grinder to cut out the 4 studs to engage with the nut and turned it with a pipe wrench.



7. Slide the spring holder out. It has a small rod that is caught in the arm of the smaller (sub) sensor so wiggle it out. You can also unscrew the hex screw of the sub-sensor to free up the little arm so you can remove the spring holder. You can see the shaft on the bottom of the pic in step 9, and the spring holder just has a small metal stick that goes in there.
Ignore all the dirt and mush - this part is obviously busted and I need to source a replacement. (This is the second 4WS actuator that I noticed had this problem, it may turn out that every 4WS actuator has developed this problem with age - degraded plastic that gets crushed under the pressure of the spring)



8. At this point the main axle is able to slide out, although I would not recommend it (you risk spilling the bearing balls). If you do want to remove it just turn it until it's free. It only comes out one way - pull it out from the end cover side. It wont come out the side where the motor is.



9. What you should be left with is the main bearing. I cant imagine being able to remove this nicely, since it turns in the housing along with the nut securing it. I presume the factory used a special tool to hold one nut while turning the other (there's the metal nut nicely seen on the pic, and another one smaller inside it, darker color so its harder to see). I decided to leave the bearing inside since it looked nice and had no free play or any apparent damage. I'd just be risking more damage to get it out.



10. When reassembling just follow the procedure backwards. The main challenges are re-attaching the sub sensor arm to the spring holder, and repositioning the gaskets when tightening parts together. Also, don't get grease on the motor brushes / commutator surface.

Info about refurbishing the spring holder:
This is how the renewed spring holder piece looks - to disassemble it and remove the old plastic, the thing needs to be put in a vice grip and the riveted sections drilled out carefully. Then unscrew the vice to uncompress the spring in a controlled manner so it doesn't fly in your face and causes you severe injury. Fabricate new washers (explained further below) and reassemble the unit by putting it in a vice grip again and welding the sections back again. I paid some shop to TIG weld mine. Also be careful, the welds must not protrude up from the flat surface, like the previous riveted heads didn't poke out.





To refurbish the unit I fabricated some new washers for the spring holder piece. I am attaching the technical drawing for the washers - the material of choice for me was POM Acetal copolymer (a rigid plastic suitable for CNC machining). The washers need to be CNC machined due to varying thicknesses of the washers. The overall tolerance is +/- 0.2mm

[Anzezaf]

I cleaned everything up nicely and since the unit was already mounted on my car and threw no electronic errors, I plan on rebuilding it with new gaskets. Will source them in the coming days and maybe try to do this project thru the upcoming holidays

[Vtecmec]

Excellent. Thank you for the detail. This needs to go in the Wiki.

[indigolemon]

Excellent. Thank you for the detail. This needs to go in the Wiki.

Agreed, @Anzezaf do you mind if I make a PDF of your post and add it to the knowledge base?