BuggyofMildDiscomfort

Nitrogen. Sometimes Argon.

BuggyofMildDiscomfort

Also:



Damn

BuggyofMildDiscomfort

Okay, a little progress after collecting more parts and a bit of machining fun all day today, trying to correct most of the problems with the hubs/bearings - a few of these I should really have spotted, I was wary about the seals these use from the very start but assumed a big racing firm that made them for a lot of £100k+ rally cars must have had things running well enough that I should just use them how they came (well, apart from our own uprights in the centres of them, anyway).
Bit of a mistake, obviously, and I've since learnt that other teams that used to or are still running these have all had similar problems with dirt and water ingress and damaged bearings.

Now as I said before, I found about 5-6 areas that had issues, either the seals themselves, machining stackup tolerances or just outright poor practice on picking fitup clearances generally. I'd normally go into more detail as you guys know on exactly what and why - but I'm going to keep it relatively sparse I'm afraid at the moment, as the firm that bought up the old business that originally made these doesn't seem to know how to fix them, doesn't really want to sell us spares as they want them for their ongoing customers who are having issues (so we can't even get one spare barrel and bearing housings to be able to make ourself a spare corner up with the extra upright we have already) and I know a few of the guys from the racing read here too
So there might be a bit of work on there fixing old sets and I don't really intend to give away my findings, apologies, but I will still show what's being done anyway, just without specifics of why

First up the bearing casings got re-machined due to some design clearance issues:



Some new bearing lock rings/seal retainers were made up, slightly thicker material, different sizing, and thoroughly chamfered, deburred, etc, which was quite a long job for 6 plates with all those holes to countersink from both sides on the drill press...



And some pre-load rings for the bearings were made up to correct an issue there, originally they don't run any:



I also knocked off the bearing face and outer sealing face from the hub barrels, so I could clean up and machine those due to some silly choices on tolerances there too - you can see just how much water made its way into the barrels here between the bearings just from the surface staining:



While I was at it I filed and chamfered the threads on the barrels where the cutouts are for the lockring, as the partial threads where they were machined through had distorted and made getting the threaded preload rings off a nightmare. I've cleaned the barrels up with some abrasive nylon brushes since this but I'm half tempted to bead blast them back clean completely.
Speaking of those threaded rings:



Even after a quick cleanup with emery on the old bottom one there you can see the damage from the debris caught in the seal. So newly machined ones instead are replacing them, which also have some modifications to sizing because the old ones also had some machining or tolerance errors - or perhaps deliberate choices to try to fix the water ingress issues - and appear to have melted the bigger inner seals in spots...



The inner rings I knocked off the barrels above got remachined too as you can see.

And finally some different sealing methods - the original seals they used in these were some machined down things that they'd clamped in a fixture and narrowed down to fit. That mean the seals twisted in the housings as they were no longer stable or round enough after machining. These new seals fit full width with no messing around machining them, meaning they're much stiffer axially and shouldn't suffer from that again. They should also be far more effective at keeping dirt out than the originals do to some changes in fitting, something I wish I'd changed when I saw the problem with the originals to start with.
I will explain this one though as I expect people will ask - the black ring is a modification made to prevent the spring that energises the lip seal (you can just see it on a standard seal in the background there) getting knocked out by debris. It's a form of sealant that actually foams into a sponge so it's very soft and doesn't affect things too much.
Not something you'd ever usually bother with as it changes the sealing effectiveness slightly - but it's necessary for all the dirt/mud/rocks things get exposed to in this type of racing.



Anyway, need to let that foam up and cure for a day and then start putting things back together with some redesigned gaskets, seals, grease, etc.

Nottm_S2

Don't understand how you diagnose all this stuff but the attention to detail is very impressive
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BuggyofMildDiscomfort

I've always kinda enjoyed problem solving and trying to delve into core issues with faults rather than the surface level fixes (some people with these barrels just poured some wicking loctite down the front side of the seal area and thought that would do it because they didn't investigate well enough..obviously didn't work). I'd say it's almost a speciality at this point. Maybe that's not a good thing as it just shows we broke too much stuff....

Nottm_S2

The thing is every car is quite complex so they will all have 'faults'

My old M3 had weak throttle actuators, BMW never fixed it even though it was there on the prev gen M5

Same as the fragile bottom end

How much of the forensic engineering you are doing goes on in the industry I dunno but I suspect not enough

It's cool to read about dude

BuggyofMildDiscomfort

That's one together, after a little more machining work, also, a bearing with Pot Noodle for scale. Highly scientific units those:



And yes I was hand packing bearings with grease. No it's not advisable. Yes I still did it.

Here you can see where the barrel goes and the bearings and seals sit a bit easier:





And then torqued up, new modified lockplates fitted:



And all assembled and ready to go:

BuggyofMildDiscomfort

And all back together, gotta put the floor and under armour back on the car before we can test it though. They feel much smoother and far less tight than initially, which is good, you needed a fair bit of strength just to spin them before given the size of the seals dragging, etc.

martin j

I remember hand packing bearings with grease, tub of grease- hacksaw blade- and patting the grease from the top until it was all the the way through, must be a better way.

BuggyofMildDiscomfort

I could have 3d printed some tooling to push it through and get it perfect but I was in a hurry, it's still not the best thing to do as your tend to contaminate the bearings/grease slightly by hand even with gloves compared to the clean areas they're normally packed in. However the grease fill was a bit low on these and I wanted to try a lower consistency grease with a heavier base oil instead of the stock polyurea #2.

The good news is that after a test run up and down the lane here, everything bedded in nicely, bearings are running much cooler than previously, noticeably less drag on the rear wheels and the car rides much smoother from the damper work.
The turn in is a noticable chunk better, whether it's a little too flighty remains to be seen but better that than another season of fighting understeer.

Bad news, it blew a front brake line out leading to squeaky bum time and a dent to the workshop wall...luckily the car is okay, and even better is at least it happened now. Not quite sure how it looks like it's split clean across, the theory at the moment is either a rogue stone strike or a faulty crimp that damaged the hose, every other line looks fine.
So it's still going to be a rush to sort it for the event at Tong this weekend!