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My supercharger clutch bearing is noisy, no surprise, so I'll be replacing it. Bearings seem easy to find, but I'm having a hard time finding the snap ring that retains the bearing. The snap ring in mine is in horrible shape. It seems someone attempted to remove it with a sledge hammer and a dull beaver. It's already broken clean through, as well as having chunks missing so there is no chance of reuse.
Does anyone here have a source for them? I found this, but its for such a different application I'd be shocked if it fit the C32: http://weistec.com/all/mercedes-benz/c/c-63/2012-2014-w204-m156/supercharger-upgrades-parts/spare-parts/idler-snap-ring.html
I can find a source after disassembling it and measuring the bore diameter and ring thickness... If that's what I have to do then I will follow up here with specs and sources to hopefully help someone else in the future.
Here's a pic of the trashed snap ring, because every post is better with pics ☺️
Mars - the easiest way for me to hold the SC pulley is to use a large hose clamp around the clutch portion aft of the belt.
The clamp will hit an engine boss, and hold the pulley while you loosen the bolt.
I did not look at mine, but that snap ring looks about right with the radius notches. It does appear to be missing the pin holes to remove the ring.
Dont force anything when pulling or putting back on. It’s a tight fit but not interference.
Mars - the easiest way for me to hold the SC pulley is to use a large hose clamp around the clutch portion aft of the belt.
The clamp will hit an engine boss, and hold the pulley while you loosen the bolt.
I did not look at mine, but that snap ring looks about right with the radius notches. It does appear to be missing the pin holes to remove the ring.
Dont force anything when pulling or putting back on. It’s a tight fit but not interference.
Great idea about the hose clamp trick, thanks!
Those notches looked sketchy to me, but if others can confirm they're supposed to be there that would make me feel a lot better. If you look at the bottom right of my photo you can see the hole on one end of the ring, and the other end is also there, I did a terrible job framing the photo that's all. If you look real close at the lower left side of the photo you can see what looks to me like a crack in the ring, just below one of those notched parts.
The bore for the bearing is supposed to be 55mm (according to the bearing dimensions), so if this is a standard-sized metric internal snap ring rather than something oddball, this one here should fit properly: https://www.mcmaster.com/#98455A144
If those missing sections of the original ring are intentional, to act as spring relief, then the standard taper section snap ring (like the one I linked to there) should be a suitable substitute (as long is it fits correctly, of course). If those notches are not supposed to be there then the correct substitute would be a constant section snap ring, in which case it seems the only ones available have different ends (notched instead of holed)... making them only slightly less inconvenient than an eaton style ring to install and remove (hint: eaton rings are a purple nightmare). If that ended up being the case, I'd still be tempted to go with the tapered section ring... I can't imagine there being enough thrust to not only overcome the friction fit of the bearing but also jeopardize the slightly reduced contact surface between the outer bearing race and the face of the ring. I would think that much force would also ruin the bearing.
If someone else could check their retaining ring for those notches, I would greatly appreciate it!
That makes me feel a heck of a lot better about the proposition of substituting a tapered section ring... additionally, I noticed that the bearings used on the E55s are retained with tapered section rings from the factory.
If, despite appearing to be cracked, my old ring turns out to be ok I am still going to replace it if the ones I order are the correct thickness to fit properly. If they do fit, since I'll be left with 4 from the pack of 5, I'll have extras that I'd happily mail for free to anyone who needs or wants one (they're easy to booger up during removal, especially if you're trying to get by without properly fitting snap ring pliers).
The job is done! Took a while to figure out how the clutch assembly came apart, what looked like broken off ends of a pin wrench were actually alignment dowel pins. They were a little boogered up so removing the washer underneath the bolt head was a pain.
The old bearing came out with light pressing, I used a little benchtop arbor press. If you look close in the photo, there's a light color ring around the inside bore of the bearing housing, that's where most of the interference fit seems to be. It feels like Teflon or HDPE. Be careful if you heat up this part, not to damage that ring.
Turns out the snap ring was fine, what looked like a crack was just a funky artifact in the black oxide coating. Good thing too, because the new ones I ordered are too thick! The original ring is 0.060" thick, and the ones I ordered are 0.080". For anyone looking for advice on snap ring pliers, Knipex are the way to go. Worth every penny.
For pressing in the new bearing, I warmed the housing with a torch, until it was barely hot enough that holding it was uncomfortable. I used the same arbor press, of course care is required to ensure only the outer race is pushed against. Turns out the pulley from an A3 Volkswagen alternator is the perfect outer diameter. I chucked one up in my antique lathe and turned a recess into the face to ensure the inner race of the bearing received none of the force. Here's a gratuitous pic of my makeshift pusher, and the clutch with new bearing installed, sitting on the old Boston-made Rivett lathe. :-)
I forgot to mention! The gap between the clutch plates measured about twice what it should have been! I was able to make up a stack of shims from the originally installed ones that got it right down to 0.008", the low end of the spec. I am really surprised at the amount of wear.
02-19-2018, 06:23 PM
