Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

[johu]

No he must have replaced it with the DELETED text himself.
When I delete spammers I can delete their posts along with the user. Sometimes I delete users that have no posts and haven't been active for more than a year. But never ones that posted something

[howardc64]

Does anyone know what happened to howardc64?

hello, I deleted the contents myself, Johan is developing the website and info. Hope that helps. Thanks

[asavage]

Bit of crossposting: coolant manifold plug of 6061:
https://www.myrav4ev.com/threads/anothe ... post-30941

Teaser:

Rotor temperature sensor/display:
https://teslamotorsclub.com/tmc/posts/8230849/

Teaser:

[Boxster EV]

I’ve bitten the coolant delete bullet too. Just fitted this from Revolt Systems in California. My car is used as a Daily, so didn’t have the time to have off the road whilst the existing manifold was modified. Took about 2 hours to fit.

[asavage]

Some notes & pics on my journey:

LDU rotor cooling bypass ("Coolant Delete") modification

LDU rotor coolant bypass plug

LDU special disassembly tools

LDU Rotor End Cap removal tool

LDU rotor removal puller tool

LDU rotor temperature monitor (display)

LDU rotor temperature sensor: installed

LDU rotor temperature display: early prototyping with bad alignment.

[sirpewe]

What do you use for seal material (brownish on the maifold)?
And do you have any drawing or cad file for the plug you like to share?
Or possibly if you can sell a plug?

[asavage]

What do you use for seal material (brownish on the maifold)?

That picture is misleading; if you follow the link, it makes more sense. The red gasket you see above is for the pressure test jig I set up to provide proof positive that the plug would not leak.

The red gasket is not used for mounting to the LDU.

And do you have any drawing or cad file for the plug you like to share?

Follow the link, please.

Or possibly if you can sell a plug?

Howard & Mr. Hyde have a batch of SS formed sheet metal plugs coming, that will be cheaper than machined aluminum ones like mine. If you follow that link, you'll read that my two plugs were machined locally by a fellow who doesn't want to get into production; he does only one-off prototype stuff like this.

If there was sufficient demand, I could have a run made by eMachineShop.com . If I bought around (50), I could sell them for about $30 + shipping, but I doubt there will be sufficient demand, and the SS sheet metal plugs will be cheaper; most people will probably want to go that way instead.

I prefer the machined aluminum plug, myself.

[jrbe]

JLCPCB does cnc work now. You can setup a commission based on your design there if you want.

myrav4ev wants you to login to look at pictures. Not everyone wants an account.

The design could be modified to have an o-ring on the OD of the plug. If threading that bore in the housing is an option / easy to do, an o-ring plug / bolt can be used to hold the plug in place.

[asavage]

JLCPCB does cnc work now. You can setup a commission based on your design there if you want.

Lots of places do machining. I got one easy quote from one place, got a ballpark figure, and I'm not interested in chasing lower prices or lower minimum quantities. I'm retired and don't need the hassle of retail sales again. I already "sell" pre-assembled ethernet cables for the Tesla Powertrain Diagnostics program used in the RAV4 EV, and that's been hassle enough. Plus the inevitable people who receive something and then don't like it/claim it doesn't fit/claim it ruined their LDU/etc. Not gonna be me.

myrav4ev wants you to login to look at pictures. Not everyone wants an account.

You know what? I don't care. I am active in three communities around the LDU, and I'm only going to post this info once; it took HOURS -- almost two man-days -- to put the pics and descriptions together, and if someone can't be bothered to run down the pics, I just don't care anymore. Don't want to create an account? I get that. Go do your own measurements on your own LDU and make your own mistakes.

I can't make information barrierless for everyone.

It doesn't matter if I posted on Instagram, X, TikTok, or FB, somebody would complain that "it's too hard" to find the info. I wrote an entire G'damn Wiki on the Tesla GEN1 OBC and still had complaints about this, that, and that other thing. If I put it on YT, I'd get compaints. If I offered to mail detailed specs via snail mail, I'd get complaints. Github? Complaints -- got one just last week from there.

And then there's the people on phones who complain that the pictures are too large and their phone won't render them properly. I've run a hobby website forum for DECADES and have heard it all before, and I'm done trying to accommodate every last person's issue with FREE content.

I spent $50 on Toytota online subscritions and an entire Labor Day weekend a couple of years ago, pulling service content for the RAV4 EV, collected as much as I could and put it in a ZIP file . . . and got complaints that it was "too hard to find things".

In the past, I tried to maintain info in multiple locations, and it just multiplies the work. If you miss an update on one site, you field questions/corrections well into the future, and you just can't maintain multiple data stores. It has to be one place, I chose my one place (the RAV EV is the community I'm not active in), and it'll have to do.

The design could be modified to have an o-ring on the OD of the plug. If threading that bore in the housing is an option / easy to do, an o-ring plug / bolt can be used to hold the plug in place.

Yup, could be done with an o-ring seal instead of Loctite 640 . . . but I discarded that idea fairly early on a year ago. A mechanical retainer would be required, as you noted. And there's no need to ever remove the plug for any reason, so why bother with installing a failure point (o-ring)? Gluing and pressing it in is adequate and has no downsides over an o-ring seal.

[sirpewe]

Thank you for the fast feedback, much appreciated.

That picture is misleading; if you follow the link, it makes more sense. The red gasket you see above is for the pressure test jig I set up to provide proof positive that the plug would not leak.

[asavage]

The second plug, .005" oversize + Loctite 640, passed 30 PSI for two hours with no leakage. 30 PSI pressure differential is at least ten times what that plug should ever see, so I was satisfied with the result.

[sirpewe]

I found a drawing (yours?):

Are these the dimensions you used? (you mentioned .005 oversize which would equal 0.127mm so perhaps reduce 55.2 to ~55.1mm)
I have a contact that can help me mill and lathe so I will go and try this.
Plan to seal the cap with loctite 638 or 648.

Are there any risk of leakage on the other side (where the "tube holder" is pressed in) or does this has a tight fit from factory?

BR
// Per

[asavage]

That's not mine, though roughly the right idea. Some of us batted around several sets of dimensions. You'll notice that there's no counterbore dimension on that drawing, and it's 2mm too shallow IMO. And I wouldn't normally specify outside radii such as that; from an engineering standpoint, I prefer chamfers on outside 90° edges, and radiused corners on inside ones.

This is the drawing I handed to my lathe man. mm in blue ink, inches in pencil. Scale is correct.

Tesla LDU Coolant Manifold Plug, 20240408

I believe that the SS formed sheet metal plugs coming are 55.2mm (.008" OS) and are designed to deform & crush into place, similar to a seal cage. I am skeptical that that much interference fit is needed/desired in a more-solid 6061 plug, so I started with .003" OS, and while that would have worked fine, I liked the fit of .005" OS better. I have a "feel" for this, but while I worked in a mechanical engineering department with real engineers, I'm not one myself, and am more of a cut-and-try man when it comes to this kind of thing.

Also, the lathe man agreed that .003" would be "enough", so I let him convince me And, with the lightly pressurized system in the LDU, and an appropriate sleeve/bearing mounting compound, it would be.

[asavage]

I’ve bitten the coolant delete bullet too. Just fitted this from Revolt Systems in California.

While machining a part such as this is relatively straightforward for those with the skills to draw it and with CNC, what will impress me is when somebody will start offering the various formed o-rings for the LDU. AFAIK, these are currently unobtainable, and having bespoke formed o-rings made isn't as simple as handing a drawing and a slug of metal to your local machinist . . . or is it?

I was verrrry careful handling mine, knowing that if I damaged or lost one I'd be unable to replace it.

[Boxster EV]

While machining a part such as this is relatively straightforward for those with the skills to draw it and with CNC, what will impress me is when somebody will start offering the various formed o-rings for the LDU. AFAIK, these are currently unobtainable, and having bespoke formed o-rings made isn't as simple as handing a drawing and a slug of metal to your local machinist . . . or is it?

I was very careful handling mine, knowing that if I damaged or lost one I'd be unable to replace it.

Yes, they are seemingly unobtainium. I have a couple of spares that I managed to source from broken drive units. I also ran a very light bead of high performance RTV over contact surface to make double sure it sealed.

[asavage]

Because the cooling system is unpressurized, the seals don't have a lot of forces working against them, but still . . . elastomers don't remain pliable forever, and best practice is to replace them when they are disturbed. The fact that replacements aren't readily available is likely the only reason that we're re-using them.

RTV can reasonably replace/supplant them, but vastly complicates future R&R work. You'll see in my other thread RE special tools for the LDU that I could not reasonably remove the glued-on rotor end cap without building a puller adapter, because of the large surface area that Tesla glued (the edge of the ~12" dia cap), and that they used SO MUCH of the stuff, even though it doesn't have to seal anything but perhaps rainwater splash.

Beating on things to disassemble them isn't professional because it can change their dimensions beyond what glue and bearing tolerances can compensate for.

[Boxster EV]

What alternative do Tesla have for the end cap? Gaskets are not infallible either.

[asavage]

My point isn't that a gasket would be a more effective sealing solution for rainwater, it's that it makes disassembly -- even by professionals -- several times more difficult, for no good reason.

Some alternatives to RTV: the rotor end cap could have had:

• a formed elastomeric seal, such as is used on the inverter cover. I don't particularly like the inverter's seal, but it seems to work OK;
• an o-ring, which would have been ONE more machining operation on the existing casting. I really like this idea, as non-formed o-rings are readily sourced (or assembled on-site/in the field) and do not affect fit-up tolerances;
• a flat gasket; a mature technology for centuries. A downside is the variability of flat gaskets, which on an assembly such as the LDU affects axial play of the rotor. I would probably not spec a flat gasket here, were I asked.

Instead, they went the Subaru way and used robotic RTV squirting, putting serviceability way down their priority list. But I bet that assembly costs were pennies less.

Other advantages to RTV sealing is that it conforms to many surface irregularities, so machining tolerances can be lessened, and it seals on a relatively larger surface area than do o-ring or most engineered formed elastomer solutions. It's very susceptible to surface contamination upon assembly, though. It's big advantage is cost reduction during assembly -- more than negated by how difficult it is to remove the stuff to service it. Seriously, try out the various silicone-based RTV removing agents, and you'll find that until you get into the big $$$ solutions, none of them truly work. Not acetone, not MEK, not WD-40 or gasoline or diesel or anything you can buy off-the-shelf for less than hundreds of dollars, and until you get into really dangerous temperatures that would ruin the stator, not heat either. Even if you have a suitable RTV-dissolving compound at hand, you can only treat the edges of the rotor cap, so you can't break the bond because Tesla applied so much that it wraps around to the inside of the stator housing.

I've worked in the service industry through almost all my careers, and I see this kind of bonehead engineering everywhere: make it as cheaply as possible, assume it only has to make it out of warranty, and "we can keep burning things and burying things forever (until Mars)" mentality.