Table of Contents
I (anonymous) did my LDU rebuild following Johan's youtube video directions. Therefore, will avoid duplication Johan's info. However, will add the following
Tesla Model S LDU specifics
Areas Johan didn't do in his rebuild
Important Details
Tricky and difficult spots
High Resolution Pictures
Some duplication of Johan covered areas. Hopefully additional info to aid someone's research effort.
Tesla service manual misses quite a few important details on dropping the rear subframe on the Model S. Below are some key tips that maybe useful.
This is no easy feat as Tesla's only jackstand points are same as lift points. This makes it more challenging for DIYer without a lift or expensive special jack stands
(Jackpoint, Rennstand, Quickjack all costing $1-$2k to get all 4 wheels off the ground). Generally, its a 2-3 phase process of jacking up each side slightly and
eventually get bigger jacking tools under the car to spread the load. Here is a method to do this. Read this post and the next post on using subframe as jackpoint.
https://teslamotorsclub.com/tmc/posts/7042911/
Here is a hard to see lightning quick video that shows removing a Model S on 4 Jackstands. Freeze frame (pausing video) reveals the usage of a cross beam
adapter (2 lift point to spread the load) on a floor jack over "some" strong area in front and rear of the battery chassis and side. But it can not be lowered completely
this way due to the limited ground clearance. Thus taking an additional step to lower tires onto a stand (wood, wheel dolly) is necessary. Same goes for raising the
car. It takes multiple steps.
Pause @ 4s mark shows floor jack+cross beam being used on the rear (not sure if wood to spread load was used, probably not as it wasn't used anywhere
else)
Pause @ 6s mark shows cross beam used without wood to spread load in the front lowering onto ramps. This is so the cross beam can be removed. Not
enough clearance to use cross beam to lower car completely to ground.
Pause @ 8s mark shows cross bream being used to lower the rear onto wheel dolly.
Pause @ 9s mark shows cross beam along the side frame rail to remove the wheel dolly and ramp to put front wheel onto the ground and rear onto wood stand
(still need some height to put belly pan on afterwards).
Tesla doesn't show any of these lift points where the cross beam is being used. But a few people have demonstrated its strong enough with spreading the load with
cross beam (2 lift points) and ideally a piece of wood on top to further spread the load
(1) Taking the Tesla Model S off jackstands - YouTube
Unfortunately, haven't found any other videos or descriptions online on how to put Model S on jack stands beyond the above speed video
Video using QuickJack @ youtube (applied to Model Y)
Here are some detailed summaries on how to put the car safely onto jack stands
https://sites.google.com/view/howards-model-s/other-diy-jobs#h.f1hay2e5pil6
HV is deadly so properly disconnecting is really important.
Tesla service manual is a bit confusing with seemingly circular links without getting this important safety step on HV disconnect. Look in the following in the service
manual
Electrical > 12V Battery and Fuses > Disconnect 12V Power (shows all Model S variations and the first responder's loop which I believe disengage the contacters in the traction battery cutting HV to the rest of the car. I heard the contactors click when I opened responder loop connector. Presumably from closed (had just powered down the car) to open.
Electrical > 12V Battery and Fuses > Vehicle Electrical Isolation Procedure (tells you how to test and confirm HV has been disconnected) NOTE you MUST be familiar with safety precautions with deadly voltage on electric cars. Understand what class 0 1000V HV glove protections are and insulated tools. Here is a long video. Watch it for your own comfort level
Hybrid and Electric Vehicle Personal Protective Equipment (PPE) and Tools - YouTube
See also EV High Voltage Safety containing more useful videos and other links.
12v battery location also changed early on. Here is a video on disconnecting both on early Model S. No need to remove the air duct piece @ 2:17 since we are not
pulling the 12v battery. 12V Negative terminal can be reached without removal
Electrified Garage: 2012 to 2014 MS RWD 12v Replacement - YouTube
Disconnect Parking Brake
Draining Coolant
Draining Gear Oil
All these steps are posted here (Read post #12-#14)
https://teslamotorsclub.com/tmc/posts/7049116/
Center of gravity is not centerline of the car
Avoid Damaging Wiring Harness During Lowering (9/2014 and earlier Model S)
Very tight clearance during initial 4-5 inches of drop
Disconnecting HV cable from inverter housing
All these steps are posted here (Read post #12-#14)
https://teslamotorsclub.com/tmc/posts/7049116/
Note these steps describes using a motor cycle jack which works fine. However, when installing the subframe/LDU back onto the car, the non perfectly vertical lift
of a motor cycle jack will be problematic as the subframe gets closer to the car chassis. Read the later install sections on the issues.
https://teslamotorsclub.com/tmc/posts/7052883/
https://teslamotorsclub.com/tmc/posts/7059182/
https://teslamotorsclub.com/tmc/posts/7052883/
Used a 1/8" thick 2 feet x 4 feet tempered hardboard ($8 Home Depot) to cover the table top. Heavy LDU components can sit on 2x4s and slide around fairly easily
on the tempered hardboard.
https://teslamotorsclub.com/tmc/posts/7052908/
Read post #16/#17/#22
This is brute force. There are other methods
https://teslamotorsclub.com/tmc/posts/7054101/
Seal remover might be easier if can clear the coolant tube in the middle.
Drill and tap threads and use a bolt to push it out. Some seals have thicker cages (triple lip PTFE seals) and cage is ~2mm from bottom of coolant manifold sleeve
so need to be careful and not drill into the manifold
Tesla Large Drive Unit (LDU) Motor Teardown and maintenance - Page 6 - openinverter forum
Tesla Large Drive Unit (LDU) Motor Teardown and maintenance - Page 6 - openinverter forum
My rotor was rusted onto its sleeve preventing it from coming out. Had to hammer it out and risk damaging the bearing (it actually seems to have survived) Read
the bearing testing sections
Tesla Large Drive Unit (LDU) Motor Teardown and maintenance - Page 6 - openinverter forum
Tesla Large Drive Unit (LDU) Motor Teardown and maintenance - Page 6 - openinverter forum
Earlier LDU revisions included an AEGIS to ground the current from the rotor from traveling to the metalic bearings and micro arc welding the raceways. Since
switching to ceramic bearings, AEGIS ring seems no longer present. For more background info on the Aegiring, see the Q&A page .
Tesla Large Drive Unit (LDU) Motor Teardown and maintenance - Page 6 - openinverter forum
https://teslamotorsclub.com/tmc/posts/7059182/
This wire travels between the 2 gearbox halves. Need to disassembly the connector to pull the wires out of inverter side to truly separate the 2 halves.
https://teslamotorsclub.com/tmc/posts/7059313/
I believe pulling the wires out of the connector actually broke small plastic stops inside the connector. When putting the wires back into the connector later, they will
slide out easily without snapping in. However, the blue tab will keep them locked in place.
Alternative solution is the remove the inverter. There are drawbacks and benefits.
Drawbacks include opening up 3 o-ringed coolant passages (not easy to put inverter back without risking o-ring damage, read later sections on inverter
removal) All the screws holding inverter to the gearbox casing have yellow loctite on them. Probably loctite 577 (glycol resistant) if want to reinstall to original.
Benefit include a very light weight gearbox half which probably makes sealing the 2 gearbox halves togehter easier later.
https://teslamotorsclub.com/tmc/posts/7068569/
https://teslamotorsclub.com/tmc/posts/7069409/
I believe I erronously thought the bearings were bad due to hammering out the stuck rotor. But after installing new bearings, it made the same rail road track gap
noise when spinning the rotor on V wood blocks. I discovered these bearing expect very leveled rotor. My table was small and unfortunately sat one of the V blocks
on the tempered hardboard while the other V block did not. Just this slight height difference caused the rotational noise. The new bearings were eventually installed
and running on the car without any noises.
Read Bearing Testing section here
I did this 2x since playing with bearings first time. I think best method is shop press of course but not necessary. Bearing splitter and puller can be arranged to
press it in
https://teslamotorsclub.com/tmc/posts/7123529/
https://teslamotorsclub.com/tmc/posts/7159427/
https://teslamotorsclub.com/tmc/posts/7124722/
Note the SKF lock nut is not the same as OEM
https://teslamotorsclub.com/tmc/posts/7195693/
Read Bearing Testing section here
https://teslamotorsclub.com/tmc/posts/7160320/
Read caution on using a press
https://teslamotorsclub.com/tmc/posts/7161207/
Read Testing New Bearings section here
https://teslamotorsclub.com/tmc/posts/7195693/
Read Bearing Testing section here
Since my newly installed ceramics bearings sounded similar to regreased old bearings that took a light sledge hammer strike to remove stuck rotor, we can guess
high quality SKF ceramic bearing is actually quite durable. Both ceramic balls and race ways. However, don't have proof since didn't reintall hammered one back
into the car. Ceramic balls are made with a sintering process. Research papers have outlined this can have micro cavities internally. So at $100+/ceramic bearing.
Perhaps safer just to replace.
Read Testing New Bearings section here
https://teslamotorsclub.com/tmc/posts/7195693/
For ceramic bearings, reading section on rotating rotors on V block here
https://teslamotorsclub.com/tmc/posts/7160320/
If not need to remove the inverter, best to avoid it. Mine was removed to avoid slide hamer impact when pulling out spun and stuck 6207 bearing from the bore. It
didn't take much force for removal so Inverter removal was unnecessary.
https://teslamotorsclub.com/tmc/posts/7159500/
If want to remove inverter to avoid disassemble temp sensor connector, read here
https://teslamotorsclub.com/tmc/posts/7195693
https://teslamotorsclub.com/tmc/posts/7159517/
https://teslamotorsclub.com/tmc/posts/7182122/
Note you may want to think about the alignment marks on the rotor and primary shaft to consider the assembly sequence
https://teslamotorsclub.com/tmc/posts/7203861/
https://teslamotorsclub.com/tmc/posts/7182122/
https://teslamotorsclub.com/tmc/posts/7182132/
Note on if decide to assemble upside down for better inverter footing
https://teslamotorsclub.com/tmc/posts/7182122/
After gearbox is assembled upside down. Its not too hard to rotate it right side up. Just place 1-2 2x4s under stator and inverter housing (make sure all housing torx
bolts are in) and rotate it against the motor mount near axle opening.
I had a faint speed related whine around 30mph that was not present prior to rebuild. One possibility could be assembling the 2 case halves with 3 shafts mounted
on one side and loaded radially. The best alignment is probably have shaft pointed up during mating the 2 case halves. This may require providing support on the
bottom as the combined assembly with inverter is quite tall and heavy. But most of the weight is towards the bottom at the motor stator/rotor. This LDU did have a
downhill regen whine aronud 25-30mph prior to rebuild so perhaps there were already problems that changed from dis/reassembly + replacing 3 bearings (6207,
6208, FAG)
Wait 24 hours for sealant to fully cure before ATF leak test
https://teslamotorsclub.com/tmc/posts/7185645/
For ATF choice, read "ATF" section here
https://teslamotorsclub.com/tmc/posts/7185566/
post's attached PDF has 3 pages including approximate measurements of triple lip PTFE and SKF seal.
Read Coolant Seal installation notes here
https://teslamotorsclub.com/tmc/posts/7195693/
It is very likely there are many installation errors with PTFE excluder lip seals. If the excluder lips were never stretched and mounted on the manifold to install for
the first time. It is guaranteed it will fold. Even if has been stretched but left to shrink on its own for several days or even hours... it will be more likely to crimp the
excluder lip on instatll.
https://teslamotorsclub.com/tmc/posts/7185645/
Review Notes on seal Fitment section above
https://teslamotorsclub.com/tmc/posts/7185665/
Read section on "Coolant Leak Scare" on torque value for lower manifold bolts
https://teslamotorsclub.com/tmc/posts/7195693/
Wait 24 hours for sealant to fully cure before ATF leak test
https://teslamotorsclub.com/tmc/posts/7188435/
IMPORTANT, the rear motor mount for the LDU is a weak welding spot. Have a very controlled way of landing the LDU onto the subframe to avoid bending/twisting
the welded on plate. And I guess avoid rocket launches! Not good for the older battery pack fuse either haha.
Frame Failure called "Normal Wear and Tear" by Tesla Service | Tesla Motors Club
https://teslamotorsclub.com/tmc/posts/7188435/
https://teslamotorsclub.com/tmc/posts/7190925/
https://teslamotorsclub.com/tmc/posts/7190963/
Routing Coolant Manifold Drain Tap