Diff bushings replace or not?

[SAMM3Y]

How do you plan on pressing out the old bush out of the subframe? I have a silent block bushing removal tool which I don't believe has the right sized cup and a 20 ton H frame shop press but don't think the whole subframe will fit under it. I am planning on making some cups for my tool to do mine unless you have a better suggestion? Maybe I'll be able to get the angles on the shop press?

[chalbe]

I have the same jack if its the DK13HLQ. When I had stock suspension it would hit the felt, so I have always used ramps at the front. Great jack for a garage or shop, but it's heavy. The hydraulics can be rebuilt.

I appreciate the work that VictorH is doing. I will be doing the same later this year. I am happy to hear it hasn't been too difficult....I didn't think it was. Just one heavy part.

[VictorH]

Originally Posted by roastbeef

you're the first person i've seen with the ac hydraulic long reach jack. how do you like it? will it reach the front center jacking point by chance?

Yes, it's a nice piece of equipment. I've had it for at least 10 years, maybe more (before the prices started getting a bit crazy). If will reach the front center mount to lift the front of the car, but if you are lowered and I am just a little bit, it's tight but it will work. Parts for the jack are available from Pelican parts, since things like the O-rings on the wheels will wear out and break every once in a long while.

[VictorH]

Originally Posted by SAMM3Y

How do you plan on pressing out the old bush out of the subframe? I have a silent block bushing removal tool which I don't believe has the right sized cup and a 20 ton H frame shop press but don't think the whole subframe will fit under it. I am planning on making some cups for my tool to do mine unless you have a better suggestion? Maybe I'll be able to get the angles on the shop press?

I ordered this tool, but haven't received it yet.

https://www.ebay.com/itm/BMW-E82-E90...kAAOSwoixc0Xvx

The actual bushing removal and installation will be interesting. I'll post that process here. Talking to a couple of folks it sounds like, the best bet will be to get the bushings started with the bushing removal tool used in reverse but evidently when you get about half-way through the bushings get so tight it's next to impossible to advance them more. The suggestions has been, "use a hydraulic press if at all possible." Once I have them started and straight, I'm thinking I'll take the subframe to my track inspection shop and have the bushings pushed in the rest of the way.
My local grocery store has dry ice so I'm going to see if that makes a meaningful difference in getting the bushings started as well. I'm not really wild about heating the subframe with a torch, maybe a heat gun but I don't really want to burn the paint off the subframe.

[roastbeef]

Originally Posted by VictorH

Yes, it's a nice piece of equipment. I've had it for at least 10 years, maybe more (before the prices started getting a bit crazy). If will reach the front center mount to lift the front of the car, but if you are lowered and I am just a little bit, it's tight but it will work. Parts for the jack are available from Pelican parts, since things like the O-rings on the wheels will wear out and break every once in a long while.

Interesting. So if I brought a couple of tapered 1" blocks to drive the front wheels on, I could likely reach the front jacking point? Nice.

[pbonsalb]

Drive onto planks and there might be a lot of floor jacks that work. I can fit a $59 HF aluminum jack under the car if it is raised a few inches.

I wonder whether using a flat undertray like the Deansbimmer one helps increase clearance to get the jack under.

[EricSMG]

Originally Posted by wyatth

Curious, how built up is your car?

I am really happy with my ZCP in near-stock guise. Compared to my E46M (TCKs, Dinan monoballs, AKG bushings & mounts) it's a lovely balance for a weekend/canyon car (no track, but also not a daily). What I like is that the suspension "breathes" with real world road imperfections.
I have little desire to tweak the rear suspension in this car, but these aluminum subframe bushings continue to tempt me.
Am I stupid to consider throwing these on an otherwise stock, low mile rear end that doesn't see the track?

Wyatt!

F80Z is gone (one year of depreciation was all I could stomach - amazing machine nonetheless) and getting serious about another E9XM.

It would be hard for me to tear into a low mileage/fresh E9XM rear suspension to 'improve' something that really doesn't need improving. The rear setup in these cars is quite good and much, much more planted than the 46M.

HOWEVER - aside from the massive power, the other most defining factor of the F8X is its immense 'on rails' feeling. It is immediately noticeable... the lateral control of the rear suspension is incredible, no doubt a result of its solid mounted subframe. From this, I can see the appeal of solid subframe bushings on the E9XM as they would, presumably, provide a similar feeling and if so.... a big step up.

[M43S7RO]

FYI: Adressing question 2: BW subframe bushing ALL go in bottom up.

Dont make the same mistake I did pressing in the new BW subframe bushings. I thought they went in same way as oem but I was wrong. I received pdf with orientation from BW after I suspected I had it wrong. pdf really should be included with the product.

I bought the harbor freight 12 ton press which made installation a piece of cake.

[pbonsalb]

Originally Posted by EricSMG

Wyatt!

F80Z is gone (one year of depreciation was all I could stomach - amazing machine nonetheless) and getting serious about another E9XM.

It would be hard for me to tear into a low mileage/fresh E9XM rear suspension to 'improve' something that really doesn't need improving. The rear setup in these cars is quite good and much, much more planted than the 46M.

HOWEVER - aside from the massive power, the other most defining factor of the F8X is its immense 'on rails' feeling. It is immediately noticeable... the lateral control of the rear suspension is incredible, no doubt a result of its solid mounted subframe. From this, I can see the appeal of solid subframe bushings on the E9XM as they would, presumably, provide a similar feeling and if so.... a big step up.

If you drive hard, you will notice stiffer subframe bushings compared to good condition stock ones. The rear end wiggle on turning at speed goes away. Instead, the rear end pretty much takes a set and stays. Stock, it wiggles. Drive a car with stiff or solid subframe bushings and you should notice it. You obviously don’t need them to have fun with the car, but they do make a difference with pretty much no downside. Stiffer diff bushings have a downside — whine.

[EricSMG]

Originally Posted by pbonsalb

If you drive hard, you will notice stiffer subframe bushings compared to good condition stock ones. The rear end wiggle on turning at speed goes away. Instead, the rear end pretty much takes a set and stays. Stock, it wiggles. Drive a car with stiff or solid subframe bushings and you should notice it. You obviously don’t need them to have fun with the car, but they do make a difference with pretty much no downside. Stiffer diff bushings have a downside — whine.

Yes, we are saying the same thing.

My F80 experience has taught me that this is a huge upgrade, even just in normal driving. Nothing ever jostles the rear end - the car always tracks precisely where you put it regardless of what the tires may encounter. It's remarkable and gives immense confidence. The F80 also rides significantly 'harder' than the E9XM so no free lunch. Rear impacts are sharp and pointy and ultra direct - good for performance bad for comfort. Surely the solid mounted subframe contributes to this.

It's just that the stock E9XM is very good in this regard and doesn't 'need' an upgrade in this area even though improvements are possible.

[pbonsalb]

F80 is probably even better than an E90 with stiffer subframe bushings due to additional suspension improvements. I’d take one (with some mods to substantially increase power) over my E90 but am inclined to just wait until I can afford an AWD big power car like a 911 Turbo. The problem with RWD and big power is putting it down. Might be fine in warm weather on a good road, but those two don’t exist in much of my driving. Even my E90 with bolt on mods can’t put its power down off the line very well.

[VictorH]

Just a little work today.
The passenger side brake wear sensor and wheel speed sensor are no issue to disconnect from the holder inside the fender well.

On the driver's side I found it easier to just remove the whole suspension height sensor with it's wiring as one unit and tuck it into the back bumper cavity. My picture shows the sensor connection disconnected but you don't need to do that. The white plastic clip on the sub-frame that is holding both the suspension height sensor and wheel speed sensor can be pushed out from the cut-out in the sub-frame from the back-side with your finger.

Also, since the brake lines need to be opened I figured to just remove the rear calipers with the mounting bracket in one unit and remove the brake line at the hard-line connector. No need to wire up the calipers and can be easily put back on prior to re-install of the subframe.

[VictorH]

Close to removal now, parking brake cables removed, tried to remove backing plates from the rear hub but the bearing carrier would need to be removed and this is not worth the effort, so I just left them loose so it's less likely to get bent or damaged when I maneuver the sub-frame around.

Last three items to remove
1) Lower shock mount
2) V-brace to front sub-frame mounts
3) Brake line transition from body to sub-frame (the brake lines people generally don't replace because they're such a pain to get to).

Front diff bushings seem to look okay.

[wyatth]

Great work, Victor. Are you replacing anything else "while you're in there?"


Eric, glad you chimed in, I've always valued your suspension input. But you're making this tougher.

[Redd]

Originally Posted by EricSMG

My F80 experience has taught me that this is a huge upgrade, even just in normal driving. Nothing ever jostles the rear end - the car always tracks precisely where you put it regardless of what the tires may encounter. It's remarkable and gives immense confidence. The F80 also rides significantly 'harder' than the E9XM so no free lunch. Rear impacts are sharp and pointy and ultra direct - good for performance bad for comfort. Surely the solid mounted subframe contributes to this.

I can confirm that E9xM with solid rear subframe bushings does not ride 'harder/harsher'. Agree with the wiggle/jostle of stock subframe bushings. I noticed it immediately going over bridge joints even when daily driving. Rear end would wiggle going over a joint/rut in the road even when tires were still in contact, and that bugged the hell out of me. Put in solid subframe bushings and the wiggle was gone, and it didn't feel any harder than before. Inspires a lot more confidence especially when you're in a high speed sweeper and encounter some roughness in the road surface.

[Redd]

VictorH can you show a pic of your diff bushings - front and rear - when they are out? I did mine 40k kms ago and wondering if I should change them again since I'm getting some work done on the diff soon.

[EricSMG]

Originally Posted by wyatth

Great work, Victor. Are you replacing anything else "while you're in there?"


Eric, glad you chimed in, I've always valued your suspension input. But you're making this tougher.

Haha, indeed.

It's easy for us to get sucked into the 'upgrade' fever but you have to ask yourself if you have any issues with the stability of the stock rear end. Surely things can be better but sometimes ignorance is bliss. I remember being quite impressed with my 30k mile E90M's road handling... big step up from the 46M, which was my reference point, as so I had no urge to upgrade the rear subframe bushings.

But now.... as my reference point has changed.... hmmmmm.

Originally Posted by Redd

I can confirm that E9xM with solid rear subframe bushings does not ride 'harder/harsher'. Agree with the wiggle/jostle of stock subframe bushings. I noticed it immediately going over bridge joints even when daily driving. Rear end would wiggle going over a joint/rut in the road even when tires were still in contact, and that bugged the hell out of me. Put in solid subframe bushings and the wiggle was gone, and it didn't feel any harder than before. Inspires a lot more confidence especially when you're in a high speed sweeper and encounter some roughness in the road surface.

Bingo.... big time. It's the bumps, while set into a high(er) speed turn, where you notice it most.

[VictorH]

I'll detail all the bushings with lots of pictures when I get there.
Only plans at this time are all 3 diff bushings and the solid sub-frame bushings.

Things I wish I could do, but not at this time.
Diffs on-line 3-clutch LSD
PFC Z-45 rear BBK

I do have one upgrade coming which I'll show the install in this thread when it comes.

[wyatth]

Originally Posted by Redd

I can confirm that E9xM with solid rear subframe bushings does not ride 'harder/harsher'. Agree with the wiggle/jostle of stock subframe bushings. I noticed it immediately going over bridge joints even when daily driving. Rear end would wiggle going over a joint/rut in the road even when tires were still in contact, and that bugged the hell out of me. Put in solid subframe bushings and the wiggle was gone, and it didn't feel any harder than before. Inspires a lot more confidence especially when you're in a high speed sweeper and encounter some roughness in the road surface.

Originally Posted by EricSMG

It's easy for us to get sucked into the 'upgrade' fever but you have to ask yourself if you have any issues with the stability of the stock rear end. Surely things can be better but sometimes ignorance is bliss. I remember being quite impressed with my 30k mile E90M's road handling... big step up from the 46M, which was my reference point, as so I had no urge to upgrade the rear subframe bushings.
But now.... as my reference point has changed.... hmmmmm.
Bingo.... big time. It's the bumps, while set into a high(er) speed turn, where you notice it most.

Actually, of every subframe review written on this site, these 2 might be the strongest for me. They address an instance I do notice, and think is a bigger issue on the street versus track, and something that is true regardless of transmission. Wheel hop on launches is not something I'd venture to fix, since it's no issue to me. Getting unsettled mid-sweeper from real world tarmac conditions? No bueno. Not like it's a problem per se, but I notice it and would appreciate it being improved. It's the lack of any downside with these mounts that really seals the deal, so few parts is that actually true of.

Victor, sorry for the semi-jacking of your thread.

[SAMM3Y]

Originally Posted by VictorH

I ordered this tool, but haven't received it yet.

https://www.ebay.com/itm/BMW-E82-E90...kAAOSwoixc0Xvx

The actual bushing removal and installation will be interesting. I'll post that process here. Talking to a couple of folks it sounds like, the best bet will be to get the bushings started with the bushing removal tool used in reverse but evidently when you get about half-way through the bushings get so tight it's next to impossible to advance them more. The suggestions has been, "use a hydraulic press if at all possible." Once I have them started and straight, I'm thinking I'll take the subframe to my track inspection shop and have the bushings pushed in the rest of the way.
My local grocery store has dry ice so I'm going to see if that makes a meaningful difference in getting the bushings started as well. I'm not really wild about heating the subframe with a torch, maybe a heat gun but I don't really want to burn the paint off the subframe.

Yeah don't heat it.. I wouldn't. I would destroy the old bush with a drill bit before trying heat. I've done a few control arm bush already in the press and was surprised at how much pressure it took.. they go with a pop.

[nickauger]

Originally Posted by SAMM3Y

Yeah don't heat it.. I wouldn't. I would destroy the old bush with a drill bit before trying heat. I've done a few control arm bush already in the press and was surprised at how much pressure it took.. they go with a pop.

Just done the job last week, i've try the drill trick but subframe bushing have aluminium in the middle of the rubber. I hand up removing everything on the subframe and press out bushing on my 30 ton press. You need to be 2 , one leveling the subframe and the other on press pump. I've found some old wheel bearing race to fit under the subframe and then i press them out.

[VictorH]

Got the bushing tool I ordered this afternoon. I don't have the sub-frame off yet so I don't know how this tool works. The quality appears to be adequate, the nuts are good, just cant tell if the threaded rod is high quality (i.e. high tensile strength) or not. If the rod breaks I guess we'll know.