LDU rotor cooling bypass ("Coolant Delete") modification
- Thread starter asavage
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Unless I have a fresh o-ring (not really possible in this instance), I always add a bit of RTV as a backup sealer.
I usually use Permatex Mega-black for almost everything. Alex from QC Charge recommends a quick setting version, see
and then skip ahead to 41:58 for manifold installation.
I usually use Permatex Mega-black for almost everything. Alex from QC Charge recommends a quick setting version, see
and then skip ahead to 41:58 for manifold installation.
Any RTV is sufficient for this application; it doesn't see either pressure nor serious temperature swings, so any RTV you like.
I used ultra black by PermaTex.
It goes almost without saying that silicone sealants work only on oil-free surfaces, so surface preparation is more important than any particular brand or grade of RTV.
I used ultra black by PermaTex.
It goes almost without saying that silicone sealants work only on oil-free surfaces, so surface preparation is more important than any particular brand or grade of RTV.
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ToyTesla
Member
I completed the coolant delete bypass mod last week. I used the Stainless cup block-off method from Armstrong.
https://armstrong-mobile-forklift-r...&q=false&category_id=OFZJ2ZCVNNQRWQANTM2DMIU6
Very happy with results. This was done on my 2013 Rav4EV with 91K miles. It had a motor replacement under warranty by Toyota about 6 years ago. I thought I was protected from the leaking seal problem until i read that most replacement motors (rebuilt) may be more susceptible to the problem. The seal that I removed for the procedure looked in good condition, but the rubber was extremely stiff and had already begun to fail. I didn’t see any moisture or corrosion problems when I did the mod, nor did I have any symptoms. This started as a preventive maintenance mod, but I can see now that the failure had begun. I would highly recommend this or any of the other bypass solutions available. Many thanks to everyone on this board that made this problem aware. Special thanks to both AlFlash and ASavage. Some photos from the procedure.
https://armstrong-mobile-forklift-r...&q=false&category_id=OFZJ2ZCVNNQRWQANTM2DMIU6
Very happy with results. This was done on my 2013 Rav4EV with 91K miles. It had a motor replacement under warranty by Toyota about 6 years ago. I thought I was protected from the leaking seal problem until i read that most replacement motors (rebuilt) may be more susceptible to the problem. The seal that I removed for the procedure looked in good condition, but the rubber was extremely stiff and had already begun to fail. I didn’t see any moisture or corrosion problems when I did the mod, nor did I have any symptoms. This started as a preventive maintenance mod, but I can see now that the failure had begun. I would highly recommend this or any of the other bypass solutions available. Many thanks to everyone on this board that made this problem aware. Special thanks to both AlFlash and ASavage. Some photos from the procedure.
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ToyTesla
Member
In that first photo in your 2nd post, are you using a drill bit to cut the channel? Did you drill multiple holes and then smooth it out?
It's an end mill, which looks like a drill bit but with (often) more flutes, and the end is (often) flat, not pointed.
https://duckduckgo.com/?t=ffab&q=end+mill&iax=images&ia=images
Note: you should never chuck an end mill in a Jacobs-type chuck, as in a drill motor. End mills mount in a specialty holder ("collet") that itself mounts in a spindle on a mill or mill drill or similar.
(I am not a machinist but I sometimes play one at home)
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A die grinder with a rough burr mounted (1/4" shank) is a good hand-held tool to cut a channel like this. A Dremel and any of several burrs (1/8" shank) would work, as would using the edge of a cut-off wheel type accessory.
https://duckduckgo.com/?t=ffab&q=end+mill&iax=images&ia=images
Note: you should never chuck an end mill in a Jacobs-type chuck, as in a drill motor. End mills mount in a specialty holder ("collet") that itself mounts in a spindle on a mill or mill drill or similar.
(I am not a machinist but I sometimes play one at home)
---
A die grinder with a rough burr mounted (1/4" shank) is a good hand-held tool to cut a channel like this. A Dremel and any of several burrs (1/8" shank) would work, as would using the edge of a cut-off wheel type accessory.
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ToyTesla
Member
You can zoom in on this photo. It may give you a better idea of my set-up. It’s a Sherline milling machine. With an end mill, like Al pointed out in his post.
Attachments
I believe I've collected pretty much everything I need to do the coolant delete. Has anyone tried heating the stator or running a hair dryer into the opening once the manifold is off and being worked on? I don't have the time, space, tools (and most importantly experience) to remove the LDU and even partially rebuild it, so I'm hoping to just do the coolant delete and hope for the best. Sounds maybe like a half-measure sure, but I figure if there's any moisture in there, why not at least try to remove it since it will be open anyway. I'm just attempting to extend the life of the car without spending a lot.
"Moisture" isn't the same as coolant. Find yourself some coolant -- anybody's will do -- and slop some on your garage floor or any non-porous surface. And wait for it to evaporate. It doesn't. Glycol holds on to the water, and prevents evaporation. You can let glycol-based coolant sit for weeks and it looks the same as when you poured it out.
Similarly, coolant soaked into the stator cannot be dried via heat nor airflow. You have to dilute the glycol significantly before you have any chance of drying it out.
Mine had corrosion on the stator laminations, but was dry up at the gearcase end of the stator cavity. The outer rotor bearing area was quite ugly, and I stopped driving it immediately the first time I had an I/C warning.
That's why I pulled the rotor, suspended the LDU at a slight angle, and sprayed a water-based cleaner (very dilute) and used a sponge-like tool to remove as much corrosion as I could.
After running a lot of water over everything, spraying upward, downward, behind things, I then sprayed IPA in there, which dilutes water and helps drive it out to where you can mop it up, plus IPA does evaporate. I blew warm air into it via a space heater for a week, testing the isolation resistance of the stator windings (using an insulation tester, not a DMM) daily.
You're not going to make any headway at all with a hairdryer unless you dilute the glycol. And pulling the rotor required special tools I had to make, for mine (others have better luck).
Similarly, coolant soaked into the stator cannot be dried via heat nor airflow. You have to dilute the glycol significantly before you have any chance of drying it out.
Mine had corrosion on the stator laminations, but was dry up at the gearcase end of the stator cavity. The outer rotor bearing area was quite ugly, and I stopped driving it immediately the first time I had an I/C warning.
That's why I pulled the rotor, suspended the LDU at a slight angle, and sprayed a water-based cleaner (very dilute) and used a sponge-like tool to remove as much corrosion as I could.
After running a lot of water over everything, spraying upward, downward, behind things, I then sprayed IPA in there, which dilutes water and helps drive it out to where you can mop it up, plus IPA does evaporate. I blew warm air into it via a space heater for a week, testing the isolation resistance of the stator windings (using an insulation tester, not a DMM) daily.
You're not going to make any headway at all with a hairdryer unless you dilute the glycol. And pulling the rotor required special tools I had to make, for mine (others have better luck).
