NB Upright/Knuckle variations
 

Were there any changes over the years to the rear uprights/knuckles between the NB and the NB MSM cars?

I don't think so. The MSM did get a different steering rack though. IIRC the rest of the suspension/subframes are the same across all NBs.

Weird, that's what I've been told over and over. Here's the issue that I'm currently having. I'm trying to put a MSM torsen with MSM halfshafts in my 01. A friend ran this exact diff/halfshafts in his NA and had no issues whatsoever. I've also heard from others that it will work without any issues. The only person I have heard otherwise from was Hustler who had a friend that had some sort of issue.

When it's installed in my 01 and the halfshafts are being tightened it has some light contact on the back of the upright/knuckle. Not enough to cause the tire to be completely locked, but enough to make it very difficult to spin and that tells me something's wrong. Thought I would try to find out a definite answer before moving on or throwing more money at this.

Where is it contacting? The only thing I think could make a difference in uprights would be the sport brakes (which were the standard size brakes on MSMs). Does your car had the OE sport brakes?

I tried to get a camera back in there to get a picture, but it just wasn't happening. Basically the back side of the upright is contacting the halfshaft just prior to the abs ring. it may also be on the inside, but I can't see in there. It only happens as it's tightened and that makes sense because it pulls it closer. I have the base model brakes on the rear and I'm not sure if the uprights are different because of that or not. I'm going to pull it off later on today and compare it to other axles. Just really makes me wonder if the contact was happening when it was on the other car or not.

Fuckinghell..I'm trying to find a picture of the MSM axles vs the normal 1.8L axles. I hate Google and I hate m.net search right now.....nothing but garbage.

I got the PM...
There are different sized splines at the hub floating around from the Mazda catalog. I'm not sure which, but the first set of half-shafts I bought in a swap as the spline was too large for the hub. Sorry I can't be more precise or give more info. Luckily I had two torsen swaps laying around.

Lifted the car up a bit and was able to get some pictures. The splines on the hub side are identical to my non msm axles. If it wasn't binding I would even think it looks as it should. Here's a couple of pictures that show it as I start to tighten the nut on the half-shaft. As it gets pulled further in either on the outside or the inside it starts to contact enough where the axle will only move with a lot of force, both sides are the same.

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I know the size of the splines/diameter of the axle on the hub end is the same across the board. Hmmmm. I wonder it's an abs/non-abs thing. When I get home I'll crawl under my GF's MSM and under my car and havbe a look...her car is ABS..mine is not.

Played with it a little more and verified that it is not the abs ring causing the problem. Pulled it out and compared it to an older axle I had laying around. Here's a few photos of both the MSM (w/abs rings) and regular axles from the hub side.

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get a micrometer out and go to town.

Well, what I'm wondering is if the upright has a slightly different shape for the taper on ABS or non-ABS axles? As in a non-ABS car will accept only non-ABS axles and an ABS-equipped car will accept both ABS and non-ABS axles. Clearly the diameter of the axle with the ABS ring is larger than the non-ABS axle as seen by the exposure of the axle boot end on the non-ABS axle. This would change the area where the axle meets the upright.

Like I said, I'll look at both cars in my garage and see if my non-ABS axles (2002 w/sport) is also the "smaller diameter" on the end by the upright.

I heard recently that a non-abs can accept them and that the ABS ring was discarded and all was well. This is just hearsay, but trust the source it came from. He rebuilds stuff I would easily want to throw away. I will get him and confirm for sure, for sure...

Jason, get in touch with Eliminator on M.net. I believe he's done the MSM diff/axle swap.

Here's what the back of the upright looks like. I've sent out a few part requests to find a set of these from a 01+ abs car as well as a MSM car. For whatever reason, the MSM half-shafts will work with NA uprights, but for the NB cars they had to change things up, at least in my 01 without abs.

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Placed an order last night for a pair of MSM rear uprights/hubs. Probably a week or so before they arrive, but I'm determined to sort this out.

Do yourself a favor and pack those bearings with AMSoil "Race Grease" to make them last substantially longer.

Another interesting update. Sent a pm to a fellow over on m.net who recently did the MSM diff swap and he ran into the same issue. He just attributed it to the seals being new and didn't think much of it. He drove the car for a few miles and says that when he jacks it up now it spins freely just like the other axles/diff did when they were on the car. Any thoughts on this?

Dunno about that....it'll be up to you to try. I did confirm that my non-ABS axles have the smaller ends like the non-ABS ones in your pictures.

Got the MSM uprights and they are identical to the ones from my 01. The difference between them is that my 01 still has seals that are complete and look new. The MSMs were torn off where it would pinch when installed. Guess this is how Mazda wanted it to be.