E70 Subframe was rusting quite badly

[Greydog]

Quite a long time back (2006/7) the rear diff on my 4.6is was making horrible noises my local BMW Specialist quoted Diff from BMW £970 plus Labour so all in almost £2k
I got a rebuild kit from a company who specialise in Classic car transmissions "Bearing Kits UK". The rebuild was fairly straight forward the only fiddly bit from memory was the Input shaft has a compression sleeve which you have to take care not to over tighten. I also had to make some shims to get backlash right, rebuild was at just over 60k now at 160+
From memory they like to only deal with the Trade so I ordered the Kit through my Business maybe worth checking them out

[Leslie]

Thanks Greydog I think the ones on ebay are the very same company, they say they have a video of the noise but can't see it on my fone so will try later . I have secured a used diff in fact complete with subframe etc after a stressful few days trying to get it picked up, a man drove down to London during night 150 miles each way to avoid m25 gridlock on off-chance it was still there, which is on its way to me no quarantee its any good but part numbers seem to match so we shall see. I have seen a video on pinion sleeve tightening and it seems a faff to get right plus with no front flange holding the input shaft needs a plan as there is nothing to hold it from turning. I didn't think you could even adjust preload on these.

[Greydog]

From memory (always dangerous) your quite right torque on the pinion shaft is very low about 30ft/lbs I adjusted backlash with shims behind the drive shaft flanges got a local engineering company to make them up backlash was IIRC 45thou
Good luck with the replacement, while mine was out I dropped the subframe had it blasted and powder coated replaced the whole rear end all bushes and arms plus new eccentric bolts.

[Leslie]

A look on you tube and it seems torque on the pinion for these ball bearing ones is 0.4 to 0.6nm basically zero but you have to wind it up first to slowing squeeze the crush tube until the slack is taken up. That is the tricky part , The endfloat clearance is shims but these are basically the circlips and are stamped with a number and must go back on the same side as they are different thicknesses My subframe is quite rusty and if the one coming is better id ideally change it and powder coat the replacement but I an flat out trying to get a 205 gti ready for paint soon and really don't need the hassle at the minute plus cost of new hoses etc etc and downtime. Tax is out end of this month and it will be sorn the way things are going not paying 360 for it to sit in the drive

[Leslie]

Got the x5 back yesterday with the secondhand diff now fitted , did 150 mile towing today and all seems ok so far . I stripped the old one down today , needs a big pair of circlip pliers to squeeze those spacers to get them out ,I only had a medium sized pair and they struggled , side bearings come out easily after you sand round the ring of built up rust then crown wheel lifts out . Side bearings look perfect to me and would go again, each side has different sized shim so need to be back where they came off.
Withe the crown wheel out you can't turn the pinion by hand bearings must be in a bad way and bottom of case is full of metal swarf , the bearing I can see on pinion looks ok must be inner one is toast. Thought you might like to see some pics Will take the pinion out at a later date when I managed to get it held to undo nut.

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IMG_20220915_151834.jpg (241.12 KiB) Viewed 956 times

[sapphireblack]

Proper mechanicing

[X5Sport]

Proper mechanicing

Nah……where’s the ‘Ammer’ an screwdriver? Good set of cutters though



At least the crown and pinion are intact. As you suggest, bearing failure likely issue.

[Leslie]

It would rebuild I think best kept in case the other has short life , can never find those damn cutters when I need them lol must have had them out for something else as no use here , put a face shield on as those circlips could spring out and leave a mark and I've already been mashed by a tin of grease that fell abiut 10 foot out of the loft in the garage when I moved the wooden ladder the day before now that smarted a bit, hit me on the temple with the lip of the bottom of the tin ...ouch !
I don't think anybody will sell me just the pinion bearings so id have to buy a full set at near 300 quid but as I found out the 3.64 diff is in short supply and command high prices