IMS center bolt
 

I am about to rr my clutch,RMS and ims. I am making my tooling and my question is does anyone know the thread and size of the center bolt on the original? I need to get the correct coupling nut for my puller.
Thanks, Dave

Mine had an M8 1.0 mm center bolt, it`s a 1999 Boxster. I wouldn`t waste an original dual row bearing at such a low mileage though by pulling it out. Just a thought.

Thanks appreciate the quick response. I’m changing it with low miles mostly due to the clutch..... which leads to the RMS. Which leads to the IMS. I would prefer to remove the inner seal on the IMS bearing but there’s no way to remove without pulling on the inner race which is fine to get it out but not to reuse. Too much stress/damage unseen to comfortably trust it after that. I see videos of guys “tapping” on the inner race driving it in that last 16th inch possibly damaging the bearing. This is done on the way out. I went back and forth on leaving it completely can’t go that either.......

Why remove the inner seal? I removed the outer seal to allow engine oil lubrication and other than that left the original bearing as it was. The car has been running for 2 years since with no problems.

I agree. Removing the inner seal wouldn`t make any further difference.

Wouldn't the oil flow from the inside outward? Keeping the inner seal in blocks the oil flow. Maybe not completely, but it surely restricts it.

The inner seal side of the bearing is in the IM shaft, so the only oil on that side is oil that has passed through the bearing and is trapped in the shaft. The good stuff is on the outside.
The PCA videos with Jake Raby explain in detail what is happening with the IMSB.

So a couple questions, the really crappy oil that comes out when the bearing is pulled is there because of the inner seal causing stagnation or in other words because the inner seal doesn’t allow the oil to flow thru the bearing? Does the Retrofit LN bearing have an inner seal or does it let the oil flow thru or rely on immersion and splash?
I appreciate you guys and your knowledge.........

The original bearing is sealed with grease filled inside. IMS is a tube with about a liter of air trapped inside, since both ends are closed. When the engine warms up, pressure rises within IMS, and after a while air will leak through the bearing`s seals, creating vacuum when the engine cools down and the pressure drops. Eventually this will cause the oil to seep into the IMS, and will fill it, since the entire shaft is submerged in oil. Since it does not circulate so well, and you can`t drain it when replacing engine oil, it will become darker and crappy than the rest of the oil in your engine. So, if you just remove the outer seal, the bearing will get sufficient lubrication from outside. Somewhat depending on the oil level in your crankcase, it will get direct oil from being submerged, from splash, plus oil mist.

As far as I know the retrofit has no seals.

Thank you Homeoboxster, to my surprise the retro kit showed up today and it has one seal, the inner. As of now I think I’m going to inspect in place removing the outer seal, if I have any doubts I’ll replace. I’m having no luck finding the m8 x 1.0 coupling nut for the puller. I contacted LN for a source and was told that they are going to start loaning tooling (2021) for free with purchase from them. I bought from Amazon so as far as tooling I’m SOL but the kit was $200 less expensive and according to Amazon returnable thru 1/31.
Thanks for the help and loan of your knowledge.

A wise course to take IMHO. If eventually you do want to change the bearing see the videos on Youtube by Ben Burner. He made or improvised all the tools necessary, for almost nothing.
https://www.youtube.com/watch?v=UJ5WwbgQejs
From there you can link to his complete series of IMS bearing replacement videos.

Tool kits are often offer in for sale forums.

Thanks Mike, I got the puller/tools figured out, bought the correct tap and drill bit from Amazon delivered next day. Bought a 1/4” coupling nut, drilled and rethreaded to m8x1.0, same for the puller rod..... and red loctited matching bolt in the rod.I’ll let you know

Just now that you spent so much time and effort on making a tool don`t feel obligated to use it ;)

I went in to my 23,250 mile 1998 Box and as the pictures show the dual row bearing was on its way. I pulled the seal on the bearing and found the bearing cage was broken but still in place and the balls just starting to go but races looked good.......there was surprisingly very little metal. When I pulled the bearing there was some in the tube but again very little, used paper towels on a set of magic fingers first with diesel fuel on the towel, I have a borescope and there is now nothing in the tube. I pulled the filter and it was spotless, dropped the oil and pan also spotless. The oil and filter had 500 miles. bought the car with 9100 miles in 2017. the oils been changed 4 times since I've had it with one being at the PDI. every filter has been cut and inspected with each. Did a 5000 mile cross country trip last July and changed the oil before I left and when I got home and inspected that filter as well, all have been spotless.
I know I'll be flamed, but I think I'm going to put it back together. I ordered a LN spin on filter and mag drain plug. I have a filter cutter so I'll change the oil at 50 miles first and inspect the filter, then 500 and then 1000mi. Your thoughts........




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Anybody know why you’re not supposed to use compressed air to blow the dust out
On your dual mass flywheel and no solvents “brakeclean”?

Very interesting. Seems to be the perfect example of IMSB failure in a car that has not been driven enough. I inspected the IMSB on a 2000 Boxster with 115,000 miles on it, I pulled the outer seal and verified the bearing, it was fine. I put a new o-ring on the flange and put it back on, it has been running ever since without problems.
Was there any grease left in the bearing... or oil?
I find your course of action reasonable. With the bearing seals in place it seems to me that very little metal would be circulating.

No there was no grease whatsoever. Hey my tooling worked great..........

Are you saying you found the cage like this after removing the seal? Looks like a perfect cut.

Today I pulled the IMSB flange off the engine that I bought on ebay last Juin (and that just arrived after being stuck at the border) and the bearing is perfect. I removed the outer seal to check it out... turns smoothly and there is no play. Unless closer inspection reveals something I will put a new o-ring on the flange and button it up. The engine is supposed to have just under 99,000 miles on it.