Model S

Rear lower control arm failed

edited November -1 in Model S
I finally got my car back after my 85D suspension had a catastrophic failure last Thursday afternoon.

I was driving in congested traffic on a city street when I heard a loud thud, similar to hitting a pothole, yet there was no pothole. My first suspicion was that I either had a flat or a problem with my air suspension. I quickly pulled over, checked tire pressure and raised my suspension to HIGH and slowly continued on. It was pouring rain at the time so I remained in the car.

The car had a strange wobble to it so I slowly pulled into the nearest parking lot to examine the situation. I was freaked out when I saw my right rear wheel with it's huge negative camber. Called Tesla roadside and spoke to someone who told me they couldn't tow me since they couldn't see anything wrong with the car! I called CAA (Canadian version of AAA) and asked for a flatbed, which showed up within 30 minutes. It was a struggle to get the car up the ramp but the driver was quite skilled and I helped by sitting in the car and wrestling with the steering wheel.

I arrived at Mississauga SC in my wife's X prior to the tow truck and did a contact-less checkin. The tow truck arrived and again I helped by steering the car down the ramp.

The next morning, got a call from Tesla, saying they would replace the failed lower control arm under my extended warranty. I told them my wife didn't really want to be in the car again until all 4 control arms were replaced. They finally agreed to replace both rear lower arms but if I wanted to pay for the fronts they would do it. They also said my rear right air shock was damaged in the incident and needed replacing (CAD$1800). I insisted that if a part under warranty caused the problem then they should be liable for any parts that were damaged by it. A chat with the service manager and they agreed to replace it at no cost to me.

This morning they texted that the car was ready for pickup. I wasn't able to pay via the app for some reason so called into service once again, paid by phone and asked them whether the new control arms were the exact same as I had previously or where they improved? I was told they were "2nd generation".

Upon arriving back home, I checked underneath the car, saw two new rear lower control arms, but the front lower arms looked original. Then I saw that they replaced the upper control arms on both front wheels. That would lead me to think that they were more susceptible to failure than the lower arms?

On my invoice, I see they mistakenly gave both right and left control arms the part number
1027459-99-A, which from what I see is a 2014 part. The front upper control arms are listed as "2nd generation" and show part numbers 1043965-00-B and 1043966-00-B for the left and right arms respectively.

Would anyone know if my rear control arms are improved from my original ones? I suspect that from the "A" designation they are not. Are the front upper arms more likely to fail than the front lower ones?

I'm very lucky that this didn't happen to me at highway speeds. And Mississauga SC got me back on the road during the pandemic within a week, despite me having to insist on some of the repairs and paying for some of the service.


  • edited June 2
    What part of the control arm snapped? The lower control arm on the rear of a model s is pancake style and hard to break. The upper holding the car up after the lower snapped is amazing.
  • edited June 2
    What I saw was the circular part surrounding the ball joint looked like the letter "C" instead of the letter "O". That's all I could see my my vantage point. The broken arm was hanging almost near the road.
  • edited June 2
    Glad it's all repaired. The only question I have is how you know it is a 2014 part? The part number does not encode the date. Sometimes the date is printed on the part. Also when a significant part change is made, they often give it an entirely new part number, and it starts with "A" suffix.

    For example, the Model S FM radio 1143703-00-C is newer than the 1004787-01-D.
  • edited November -1
    Good point TeslaTap, no I don't know, that's why I'm posting. When I search for that part # it shows that it's for a 2014 vintage vehicle. Mine was built in May of 2015, so it's pretty close.
  • edited June 3
    @Bitjockey - You can look at the Tesla parts catalog to find the current part number:

    It requires an email to login, but doesn't seem to do anything with it. I've not gotten any emails from Tesla when using a different email than my vehicle login.
  • edited June 3
    Thanks TT, that's a great site, thanks for sharing it. But there's nothing in there that remotely resembles the part number they listed on my invoice. The complete line item was listed as "MS RR LOWER CONTROL ARM ASSY-RWK(1027459-99-A)".

    Pacific Motors lists that part as coming from a 2013 VIN:
  • Yesterday (June 2, 2020) I began reversing from street to my driveway when I heard loud grinding noise. My 2013 Tesla Model S stopped moving like it would if I raised my behind off driver's seat. I observed that the right rear wheel was ~30 degrees off vertical (massive negative camber). I looked under and saw the lower rear control arm was broken ("C" or crescent shape remained). I realize now that the related bushing was gone. If this had happened while I was driving, I would likely have experienced a major loss of control over my Tesla given its rear passenger side wheel would have seized while I was driving. Very lucky for me it happened while reversing at 1 kph to my driveway.

    There is a Tesla Service Bulletin SB-19-31-001 "Replace Lower Rear Control Arm Assemblies" for Model S vehicles built Jun 1 2013 - Jan 31 2014. I think mine was built in March 2013. What this SB describes is exactly what happened to my lower rear control arm. It no longer held the wheel in place (vertical to ground). Today (June 3 2020) Tesla repaired my car doing exactly what is called for in that Service Bulletin. That SB states it addresses a known non-safety-related which on certain Model S vehicles, either lower rear control arm might crack, causing excessive negative camber of the rear suspension. The correction was to replace both LH and RH lower control arm assemblies with updated parts.

    In my case, the Tesla Invoice which cost me $1,743.03, stated my passenger rear lower control arm broken due to outside influence. This reminds me of the Transport Canada Recall File number 2018-149 (Tesla Important Safety Recall Notice) in which it states "... Exposure of your vehicle to corrosive environments may corrode the bolts that attach the power steering motor to the power steering gear. The exposure may cause the bolts to break and result in loss of power steering assist. ..." I wonder whether this is what is meant by "outside influence" on my invoice.

    I have photos and video of the affected wheel & related broken lower rear control arm. Tesla returned both left and right side lower rear control arms to me. There is obvious corrosion visible to me about the broken crescent portion.

    I think this is a safety defect but that is just my opinion.
  • edited June 4
    @richardgayne, I can't believe that a part like that would break on a 6 or 7 year old car. Had you hit a curb real hard I can understand it being your problem. I think that Tesla has a problem with these parts and probably more will show up soon. I would try and see if they couldn't give you a better price do to the fact you didn't cause the problem.
  • edited June 4
    @richardgayne, I agree with you it is not a rare incident; today on TMC forum I heard from someone with a CPO signature where it happened to him (fellow Canadian). They repaired it under his CPO warranty.

    It's very likely that the thin aluminum ring is very susceptible to stresses from weight and corrosion, in our case, from salt on the roads in winter.
  • edited June 4
    For that amount a money I would send it to a metals lab to determine if the fracture was caused by stress, or fatigue or stress corrosion cracking. In the case of the latter two I think you have a case for a design defect. They pretty much admit that because of the existence of the SB...
  • I have informed Transport Canada (2020-0975) and have earlier today provided what was requested.
  • edited June 4
    Glad you got it fixed. From my reading of the forums over the past several years it does not seem like a common failure. You were just lucky I guess. ;)
  • Hi tes-s, Lucky? I guess but then so was bijockey whose posts above began June 2, 2020 describing same failure in my opinion. Seems like it's not as uncommon a failure as you seem to suggest.
  • edited June 10
    @richardgayne - Scary. Had you ever taken the car in for maintenance? I know it's not required, but having Tesla check the car out every couple of years seems worthwhile. They would handle any open service bulletins at that time as well. I know on my 2013 S, I took it into service every year when I owned it. That was back when they recommended annual maintenance and they totally checked over the car.
  • Reply to May 2019 Tesla Service Centre - Toronto Lawrence had my car in for service on their hoist to replace the steering rack assembly. No mention was made to me by Tesla of any open service bulletin. That is not surprising in that Tesla Service Bulletin 19-31-001 dated January 3 2019 - see my June 3rd post above - did not apply to my VIN.

    At Transport Canada's request made on June 12, I shipped to them my broken right hand lower rear control arm assembly together with the left hand lower rear control arm assembly. I don't know how much time Transport Canada requires to conduct their expert examination of these parts. Their findings will inform next steps, if any.
  • edited June 16
    In the meantime, I must say it is not a good idea to place a jackstand under the lower control arm lug.

    Some folks have done this.

    Not saying it caused the failure. I will guess integranular stress corrosion cracking.
  • edited June 16
    "Seems like it's not as uncommon a failure as you seem to suggest."
    Uncommon failure.
  • edited June 16
    Highly uncommon without a traumatic instigation.
  • edited June 16
    The front left control arm failed while reversing in parking lot. Luckily was still in warranty 2015 model S.
    Damage to tire &internal mud guard.
  • edited June 17
    Spoke to long time Tesla tech today about this issue of control arms. He’s unaware of any issue with rear control arms failing. He’s seen a few front failures, but always occurring in low speed, parking lot situations when stress is greatest—dry steer, full lock. Never has seen anything at speed when the part is not stressed.
  • edited June 17
    201585D here with 175000km . The rattle noise developed in the wheel cavities when driving on bumpy surfaces. I took my car to my friends garage and lifted up in the hoist and investigated. The upper links had excessive play so I took it to Mississauga Tesla service and replaced the rear ones of course paid. NowSame noise in my front wheel wells , book an appointment to replace the front links as well.
  • edited June 19
    BH....very informative. Had a clicking noise when steering in the conditions you mentioned. It makes sense when I think about it.
  • edited June 19
    I had a front control arm replaced when the bushing wore and developed a front end clunk/rattle. Saved the part. No structural failure, just rubber wear.
  • edited July 2
    In had something fly up into the R front wheel causing a metallic rattle when moving and a blowing noise after stopping. Tesla repair in Dedham, Ma said inside of wheel scored and needed replacement. Lower front control arms also replaced. When they went to align vehicle couldn't get it aligned fully. On further inspection Tesla said right front subframe was damaged. Said it was a safety issue and needed replacement ($2100). Car had been pulling slightly to the R before accident. Car had been sideswiped while parked in September with damage to entire L side of car and R front wheel well (car parked next to tree close to curb and well had large indentation). Body shop that did repair wanted to check out damage to subframe and insurance adjuster had a look. No bending or fracturing of subframe seen, just wearing of an aluminum washer that was riding on the steel frame. The wearing had impacted the oval shape of the washer so that the alignment bolt couldn't fit tightly enough to keep the car in alignment. The washer on the other side was noted to have early wear also. Has anyone else had similar problems with their front subframes?
  • edited July 15
    I had an nearly identical issue! Rear passenger suspension failure. After normal drive home from work with nothing out of the ordinary happening. I put the car in reverse and began to back up towards my driveway and the wheel tire nearly fell off. Very unnerving since I was on the freeway over the weekend traveling 85 mph, thank God this didn't happen then.

    I was even able to pull up my dash cam footage and see the exact moment the part cam flying out from under my car.

    2013 Tesla S85 rear lower control arm catastrophic failure.
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