2018 Failed ABS HCU Teardown

[Choupique]

Finally got around to ripping into my failed HCU today. Found the root cause for my failure. The spring behind one of the brushes is either broken or the channel is gunked up or something. When I push the rotor slightly away, it loses contact. Push it the other way and the other side brush will hold contact most of the way, but not entirely.

Someone who was inclined to do so could repair this themselves. The motor is easy to remove. The intermittent contact makes perfect sense with the dashboard disco and it's seemingly random dependency on bumps.

So, if you are tight on money and a little handy with DC electric motors or have a good starter/alternator shop nearby, this is certainly worth exploring. I totaled mine taking it apart, but it could be done more carefully and reassembled.


Free brush spring


Bound up brush spring


Brush with contact


"Brush" with no contact


Motor housing


Motor rotor


Pump plungers

 

[Phylodog]

Thanks for the info, mine is doing the same and that makes sense. I thought it was likely a busted solder joint but perhaps not.

 

[Choupique]

You could potentially pull the motor off without removing the HCU. It's held on with only two bolts but i dont remeber if there are brake lines in the way or not. If yours has the same problem you could likely have it fixed at a starter/alternator shop.

I'd love for somebody to try it. I might bring mine by to see if it's repairable just for my own knowledge for when my next one craps out.

 

[Daw14]

Thanks for the pics and write up, this may be of help for those who like to do it themselves. Thanks again.

 

[Dutra]

Exact same thing happened to me. Pics look very similar lol. Same year too. Shame there is no recall on this.

 

[Choupique]

It's the same part for all the gen 4 trucks but very disproportionately affects the 2018s. There's some kind of wiring or programming difference with the 18's. We have a large fleet of these trucks and the 18's are perpetually having this failure.

 

[Choupique]

Exact same thing happened to me. Pics look very similar lol. Same year too. Shame there is no recall on this.

Your motor had the same issue with the brush being stuck in?

 

[Dutra]

Yes.

ABS/Traction control FIXED!!!

My 2018 Power wagon has had the ABS/Traction control problems for awhile now. Finally got around to fixing my truck myself and with a buddy. No help from the stealership and some help with Ram Cares. But I never got the part from them! Found the part pretty fast just a google search, but the...

www.ramforum.com

 

[Choupique]

Excellent, thanks. It makes perfect sense. I'd wager that is the primary failure mode for these. Absolutely amazing that in 2023 we have ancient technology like motor brushes causing serious reliability problems

I bet a stiff spring and some Emory cloth and some dielectric grease would fix it right up.

Also, why'd they locate the thing right on top of the strut tower? That's probably the most vibrating spot on the whole damn truck.

 

[DaveSharp]

Finally got around to ripping into my failed HCU today. Found the root cause for my failure. The spring behind one of the brushes is either broken or the channel is gunked up or something. When I push the rotor slightly away, it loses contact. Push it the other way and the other side brush will hold contact most of the way, but not entirely.

Someone who was inclined to do so could repair this themselves. The motor is easy to remove. The intermittent contact makes perfect sense with the dashboard disco and it's seemingly random dependency on bumps.

So, if you are tight on money and a little handy with DC electric motors or have a good starter/alternator shop nearby, this is certainly worth exploring. I totaled mine taking it apart, but it could be done more carefully and reassembled.


Free brush spring


Bound up brush spring


Brush with contact


"Brush" with no contact


Motor housing

View attachment 520270
Motor rotor


Pump plungers

You can see it has a really bad contact pattern.