335i rear end rebuild - diff and subframe bushings question

martymil

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i remember people recommeding Birds back then when i was in the renault clio community
if they are still around they must be doing things right i suppose ;)

the clunking noise from one wheel dragging... car people will know and understand why, normal people will think your car is broken and give you weird looks

you cant go wrong either way, anything is better than an open diff (except welded diff at high speeds)
I had a wavetrak and there was never and clunking or dragging noise, if one had noise there must be something wrong with their setup .
 

wheela

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Just to clarify, with my wavetrack I never had any clunking noise, or any feel of on/offish behavior - it always felt smooth, just an occasional tire squeal on slow 90 degree turns. Obviously there had to be some drag going on for a squeal to happen, but it never felt like anything was awry.
 

martymil

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The only way dragging will happen is when on acceleration due to the center locking or trying to lock up, my drexler does that especially on 180 u turns. Any hint of power will lock the center and rotate the car around and send it straight where ever your pointing the front wheels.

That's why I like the 1m/m3 diff as that's the perfect street diff. No noise, no dragging and Max traction.
 
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carabuser

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After a productive day, the exhaust is off, both knuckles are free with the axles, the diff is out and the subframe is ready to drop. After all the hard work getting to this point, I think I'll go ahead with the Quaife.

The good news is that the exhaust and the body of the car are in great condition. For some reason it's just the subframe that is a complete rusty eyesore. I'll need to inspect it for any serious rust when I remove it in the morning, it may require replacement.

Does anyone know if it's normal for a diff to leak fluid if it's tipped upsidedown? I rolled it around a bit while cleaning it up, and it shat some diff fluid out. Is there a breather somewhere?
 

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Asbjorn

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Mar 10, 2018
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After a productive day, the exhaust is off, both knuckles are free with the axles, the diff is out and the subframe is ready to drop. After all the hard work getting to this point, I think I'll go ahead with the Quaife.

Please don't waste your money on a Quaife. Yes, the rear end becomes more stable when driving over the limit with DSC=off, but be honest with yourself: How often and for how many seconds are you driving like this every year? And is that rare joy really worth the cost? Most likely not.

If you just want more grip, I suggest investing in better tires instead.
 

carabuser

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Please don't waste your money on a Quaife. Yes, the rear end becomes more stable when driving over the limit with DSC=off, but be honest with yourself: How often and for how many seconds are you driving like this every year? And is that rare joy really worth the cost? Most likely not.

If you just want more grip, I suggest investing in better tires instead.
Too late for that, I have it on the floor of my garage already :D
I know I'm not going to get much use out of it, but I'm curious what improvement it will make. I've already got the best road legal tyres I can fit.

I've finished the front end now.

In the rear, the subframe has been stripped of rust completely, painted with a high zinc primer called Electrox and then further coated with Rustoleum. Next time I get over to the garage I've got the job of refitting the subframe and some new brake lines, refitting the diff, getting the knuckles and half-shafts back on and then fitting the new control arms and brakes.
That'll probably be a couple of trips as I don't want to rush anything. I'll also need to get it aligned so it'll probably be November before I get to enjoy it on the road.
 
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carabuser

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After another day in the garage I've got the subframe in and sorted out all the brake lines. I also spent way too much time treating rust patches in the boot floor.

I started looking at the replacement knuckle and axle that I purchased and realised that something is probably amiss.
The refurbished GKN axle for the right side of the vehicle has a 32mm nut, when everything online points to it being 36mm. Not sure if that is significant as the length and diameter are the same as the original driveshaft I'm replacing.

I only noticed this after trying and failing to mate the splines in the wheel hub with the axle. It goes in halfway but gets stuck. I noticed that the splines in the hub are sharp and the ones on the axle are flat on the top.

Really annoying as I made sure to get the correct part numbers from RealOEM. It seems there are a few different designs on the E9x and it's not clear which I need, the DCT with an N54 being a rare spec doesn't help.

So , do these splines inside the hub look right? And should a replacement axle have sharp toothed splines rather than these flat ones in the photo?
 

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Cruizinmax

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Jul 18, 2018
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After another day in the garage I've got the subframe in and sorted out all the brake lines. I also spent way too much time treating rust patches in the boot floor.

I started looking at the replacement knuckle and axle that I purchased and realised that something is probably amiss.
The refurbished GKN axle for the right side of the vehicle has a 32mm nut, when everything online points to it being 36mm. Not sure if that is significant as the length and diameter are the same as the original driveshaft I'm replacing.

I only noticed this after trying and failing to mate the splines in the wheel hub with the axle. It goes in halfway but gets stuck. I noticed that the splines in the hub are sharp and the ones on the axle are flat on the top.

Really annoying as I made sure to get the correct part numbers from RealOEM. It seems there are a few different designs on the E9x and it's not clear which I need, the DCT with an N54 being a rare spec doesn't help.

So , do these splines inside the hub look right? And should a replacement axle have sharp toothed splines rather than these flat ones in the photo?
This is likely normal. The BMW axles have a tiny bit of "knurling" for lack of better word that makes them a slight press fit. There is a axle installation tool made for this job. https://www.turnermotorsport.com/p-...bearing-hub-installer-kit-bavarian-autosport/
 

carabuser

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I found a 7 piece puller tool on eBay for £40 so I've just ordered it. Looks identical to the Bavtech and Laser tools but at a half the cost. It was branded as Nielsen.

Given how similar the tooling is I suspect that they are all made in the same factory.

I also realised I forgot to order new diff bolts so I've used the old ones for now just to get the driveshaft fitted and I'll come back to the project in another couple of weeks and finish it off.

Also notices a weeping AC line up front and some nasty rust on the power steering hoses so i'll get that sorted over winter. It really is endless 😆

Meanwhile the Z4 is completely problem free with 0 corrosion.
 

carabuser

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Well the job is finally done. Was hard to find time and willpower to finish it. It stopped being fun right after the first seized brake union, but I still have no regrets. It started out as a control arm change due to an advisory on my annual inspection and ended up in £4k of parts.

It took me another 4 days of solid work since my last update, getting free weekends to spend in the garage is tricky.

I wish I had the determination to properly document things, but when you are laying on your back getting rust in your eyes and your hands are covered in blood and grease, you don't really feel like taking photos! It also turned from perfect summer weather, into the non-stop relentless UK winter rain during the course of this project.

The big kick in the balls came just as I started to re-assemble the parking brake shoes on the rear right where I had installed a new knuckle that I purchased on eBay from a very low mileage car. I noticed that the hub on the new knuckle sat way farther out so knew something wasn't right. It turns out that the 135i has a slightly longer wheel hub than every other E8x and E9x cars which meant that I needed to buy another hub and also replace the bearing since removing the hub destroys the outter race. That also gave me the headache of having to press in new bearings and hub which I managed to fuck up on the first try and destroy my nice new FAG bearing.

Around this time I did start to fantasize about buying a nice garage-queen CPO Porsche Cayman. Thinking about it's nice smooth rust free underbody and non-seized bolts. But the Porsche forums are boring and I'd get bored without having something to fix.

It was also incredibly difficult to reassemble and correctly torque down all the new control arms as the upper control arms in the rear are buried so deep in the subframe that it's impossible to get anything other than a spanner on them. So those ones had to be torqued using the double spanner trick and the use of my own poorly calibrated guestimation of torque.

Everything else was fairly trouble-free. The driveshaft puller I purchased was an absolute life-saver and because everything I was putting back on the car was brand new, it just bolted together easily.

After getting everything reinstalled and on the ground, I jumped in the car and headed for an alignment, but as soon as I got the car onto the road, everything just felt completely fucked, there were horrible clunking noises and the car felt like it wanted to flip over when going any faster than about 5mph. I thought I had really messed something up so I cancelled the appointment and went back to the garage to inspect my work. After an hour of checking torques and clearances I decided to do some googling and it turns out that it's all normal because my alignment is way out. After I got the courage to drive it again, I (very slowly) drove to an alignment shop where they got it all back into spec (minus the extra front camber from the M3 arms). They remarked that it was indeed as far off correct alignment as it could possibly be, which is to be expected when you remove and re-attach every single bolt.

So the car is back, from the short drive back from the alignment I can say that it's absolutely perfect now. It feels completely different to drive but I've replaced and upgraded so many parts that I have no idea which things made the big improvement. The diff is certainly doing work though, I disabled the "ediff" and took it for a spin on my local greasy cold wet country roads and it really does feel more stable, it would be hard to compare traction but the rear twitches much less. In fact the entire car feels smaller and tighter which is what every car enthusiast wants ;). I suspect the big improvement comes from the front M3 arms and the stiffer subframe bushings but I'll play around with the new diff a little more once I get more miles on it.

I'll trawl through my phone and upload a few photos. I also took the opportunity part way though to fit some new interior trim into the car to replace the basic silver plastic trim with some nice "anthracite maple" BMW individual trim I got for a steal on eBay.
 
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carabuser

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Just putting all the bits I changed into my maintenance tracker, this is the £4k breakdown:

Quaife LSD and new seals all-round on diff housing.
£1,600.00​
Fitted by Birds BMW. New Fluid (Vaico 75W90)
New control arms:
M3 parts used on front for increased camber, upper and lower used on rear, rest standard E92 parts.

£850.00​
TRW-JTC1426
TRW-JTC1427
TRW-JTC1424
TRW-JTC1423
TRW-JTC1430
TRW-JTC1431
TRW-JTC1428
TRW-JTC1429
BMW-34522283017
BMW-37142283867
BMW-33322406291 x2
BMW-33322406290 x2
New rear subframe bushings
£240.00​
Condor Speed Shop Rear Subframe Bushing Kit
New bolts from BMW
£200.00​
New exhaust gaskets and bolts
£30.00​
BMW exhaust gaskets, grade 12.9 nuts/bolts from eBay
Removed rust and repainted subframe with Bilt Hamber Deox-Gel and Electrox. Coated over with Rustoleum black
£50.00​
Removed rust above rear subframe area and coated with Electrox
New rear drop links
£35.00​
Lemforder 29934 01
New rear headlight level sensor
£70.00​
Febi OEM part
New jack pads
£35.00​
Febi part
Used rear right knuckle
£100.00​
Used from a low mileage 135i - Requires new hub as offset is incorrect
New GKN rear right half-shaft
£100.00​
GKN OEM part
New hub and wheel bearing
£120.00​
Febi hub (32806) - FAG Wheel Bearing
New brake hoses x6 (front caliper, rear subframe and rear caliper)
£70.00​
OEM ATE hoses
New brake hardware all-round (bushings, rattle clips, slide pins)
£60.00​
OEM ATE parts
New rear calipers
£150.00​
OEM ATE parts
Rear discs and pads
£140​
Jurid OEM
New hard brake lines x2 (long one over subframe and short on passenger side)
£60.00​
Long pipe from BMW, short pipe aftermarket)
New heatshields in rear, above the diff and below the driveshaft-diff coupling
£75.00​
BMW parts
New rear ARB bushings
£6.00​
Febi OEM part
Rear brake pad wear sensor
£10.00​
ATE OEM part
Used interior trim - Anthracite maple
£120.00​
eBay
 
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carabuser

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Underside photos during re-assembly, much less rusty now and new shiny heatshields: (the yellowish stains are Fluid Film and rust treatment)
P_20231021_131231.jpgP_20231022_140040.jpg

The driveshaft puller, really recommended:
P_20231021_135955.jpg

The difference between a 135i hub and a 335i hub:
P_20231103_233546.jpg

Pressing the new hub and bearing in the second time around:
P_20231104_113843.jpgP_20231104_115439.jpg

The old poverty silver trim and the new BMW individual trim:
P_20231023_120300.jpgP_20231023_160530.jpgP_20231023_140008.jpg

The new less rusty brakes and subframe: (I did torque the axle nut and stake it once the car was on the ground)
P_20231104_211449.jpg

The finished product that looks absolutely identical to how it did before I went through this whole process :)
P_20231106_165259.jpg
 
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pbondar

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May 30, 2020
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Well done….i too has some pretty hairy handling when I did the M3 front steering / suspension parts till it was aligned..ditto on the rear when the garage that fitted the rear camber arms couldn’t get their shit together..

one question on e-diff…

I wonder whether it needs to be toggled off for two reasons..

If the major ‘weakness’ of the Quaife is apparently a catastrophic loss of total traction if a rear wheel unloads then the e-diff should intervene adding braking torque to the unloaded wheel allowing more net torque to be applied to the other wheel?

Surely the e-diff only intervenes when it determines one wheel is rotating much faster than the other which normally, even with a mere Quaife should be a rare event..?

Of course if you want to drift..then that’s not a good idea…
 
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wheela

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Jun 4, 2021
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Well done….i too has some pretty hairy handling when I did the M3 front steering / suspension parts till it was aligned..ditto on the rear when the garage that fitted the rear camber arms couldn’t get their shit together..

one question on e-diff…

I wonder whether it needs to be toggled off for two reasons..

If the major ‘weakness’ of the Quaife is apparently a catastrophic loss of total traction if a rear wheel unloads then the e-diff should intervene adding braking torque to the unloaded wheel allowing more net torque to be applied to the other wheel?

Surely the e-diff only intervenes when it determines one wheel is rotating much faster than the other which normally, even with a mere Quaife should be a rare event..?

Of course if you want to drift..then that’s not a good idea…
I like your thought, and I don't know the answer. The only thing I have to add is that I'm under the impression e-diff actually makes a lot of intervention, even before big traction loss. I certainly could be wrong, I'm only under that impression because when I got my car CPO the sales guy was telling me about how the break pads wear faster from that, despite them supposed to not be wearing faster, because it's always applying break to adjust. Not sure if e-diff would be fighting the quaife or working together? It seems plausible the e-diff could be calibrated to play nice with the LSD though, if one knew how🤷‍♂️