Powerflex Bushes

C

ChillZ4

Member
Just about to order the front and rear bush kit for my 2006 3.0si roadster. Just have a few questions about the sizes, what sizes for I need for an 2006 3.0si roadster?

Front wishbone rear bushes - 60mm or 66mm?
Front anti roll bar mounting bushes - 24mm or 25mm?
Rear anti rollar bar mounting bushes - 18mm or 19mm?

Thanks
 
Front Wishbone rear bushes - definately 66mm.

Not sure about the others. Might be woorth PMing "Curtis" as he'll keep you right - he did with me :thumbsup:

I'm not bothering with the anti-roll bar ones at the moment, I'm just doing the largest ones, i.e. those with most potential to flex.

Ally
 
Curtis has given me some great advice off line on the different bushes and their relative performance/benefits and I too will be ordering a full set of the bushes in the near future.

As a word of caution even if the oem sizes are one, then it's quite possible that if you car is not one owner from new and no bushes have been changed the wrong one's can be in. ie the fronts can easily have been fitted with 60mm and lollipops if the correct were not in stock, or in the case of mine 'upgraded to 66mm. Just a caution and suggestion to measure, especially the large front.
 
Well powerflex bushes went onto the rear of the front wishbones today.

All I can say is I echo plowy's comment. What a PITA. :headbang:
Getting the old bushes off the wishbones is a mare and then getting the old sleeves out of the mushrooms left me no option but recoprocating saw and then a lot of chiselling. Made all the worse as they are oil filled, so everything gets covered and slippy :thumbsdown:

Pressing the new and refitting was but 10 minutes.

I hope this goes some way to sort my suspension and steering 'wander'

Road test Saturday as I'm totally knackered, this evening.

No photos due to time, but plowy did a good write up before.
 
cj10jeeper said:
Well powerflex bushes went onto the rear of the front wishbones today.

All I can say is I echo plowy's comment. What a PITA. :headbang:
Getting the old bushes off the wishbones is a mare and then getting the old sleeves out of the mushrooms left me no option but recoprocating saw and then a lot of chiselling. Made all the worse as they are oil filled, so everything gets covered and slippy :thumbsdown:

Pressing the new and refitting was but 10 minutes.

I hope this goes some way to sort my suspension and steering 'wander'

Road test Saturday as I'm totally knackered, this evening.

No photos due to time, but plowy did a good write up before.
Click to expand...


So if this ends up being good, can we do my car some time after I get over there & settled in :P
 
You can use my garage, drink my coffee and I will point you to exacty what need's bashing with a big hammer... :rofl:
 
Haha, that works. Actually that's all I wanted as far as help. Big tasks like that I hate undertaking alone for the first time. It's just not how we are raised in the USAF.
 
I've had powerflex bushes since the end of January - shame they're still in the packaging and not fitted to my Z4 yet :oops:

Not too keen attempting them myself as I've got limited tools/experience, so probably a garage job for me. Will be the first time any car I've owned has been in a garage for years...
 
a11y said:
I've had powerflex bushes since the end of January - shame they're still in the packaging and not fitted to my Z4 yet :oops:

Not too keen attempting them myself as I've got limited tools/experience, so probably a garage job for me. Will be the first time any car I've owned has been in a garage for years...
Click to expand...


I know were not exactly local, but I'll give you a hand if you want to try it next time I'm home. :D
 
a11y - you're wise to get a garage to do this one without experience and tools. Not that it's that technically dificult, just you need to have the car well jacked up and enough tools to chisel, cut and beat the bushes off the suspension and then a press/big vice to get the new ones fitted into the mushrooms. They too need a lot of cutting and chiselling to get the old sleeves out.

Interestingly if I had to make a quick review they do seem to increase the harshness of the front suspension and have tightened it up. I was not aware before starting how complex my OEM's were. Sleeves of rubber, metal and plastic and oil filled too. Not simple cheap rubber bushes as the aftermarket sellers would have you believe....

Not cured my high speed 'shimy' but the alignment needs doing again now
 
cj10jeeper said:
a11y - you're wise to get a garage to do this one without experience and tools. Not that it's that technically dificult, just you need to have the car well jacked up and enough tools to chisel, cut and beat the bushes off the suspension and then a press/big vice to get the new ones fitted into the mushrooms. They too need a lot of cutting and chiselling to get the old sleeves out.
Click to expand...


Errrrrrr A11y scrap that last offer, go to a garage, still if you want to meet up sometime with some of the other 'Scottish' members maybe something could be arranged.
 
cj10jeeper said:
a11y - you're wise to get a garage to do this one without experience and tools. Not that it's that technically dificult, just you need to have the car well jacked up and enough tools to chisel, cut and beat the bushes off the suspension and then a press/big vice to get the new ones fitted into the mushrooms. They too need a lot of cutting and chiselling to get the old sleeves out.

Interestingly if I had to make a quick review they do seem to increase the harshness of the front suspension and have tightened it up. I was not aware before starting how complex my OEM's were. Sleeves of rubber, metal and plastic and oil filled too. Not simple cheap rubber bushes as the aftermarket sellers would have you believe....

Not cured my high speed 'shimy' but the alignment needs doing again now
Click to expand...

Can you not use a grinder to get the old ones off?

Interesting you mention the complexity. All I think with such things is, what is the next weakest link, as it'll wear faster, then get ready for worse NVH too :D


PS, has it sorted the weird motorway wibbling/steering feel at speed? I have a thought on what that might be, but doing more reading first (EPS related maybe)

Dave
 
Dave,

Without labouring the process you unbolt the mushroom from the undersire of the body and then have a choice to either drill and cut the old bush off to leave its sleeve alone on the wishbone to then grind a slot in and fetch off, or to in effect chisel and drive the whole item off the end of the wishbone. Once on the bench it and then be cut and drilled to bits and the remaining sleeve pressed (you'd be lucky) or cut and chiselled out of the mushroom. I'm sure it's not without good reason that BMW supply them prebuilt and no doubt have a suitable puller for use on the wishbone.

My next port of call one the geo is reset with the bushes has to be the EPS. If you find anything where it is triggered into giving random tiny left and right inputs then do let me know.
 
Richard, no problem LOL. My father-in-law's got a good amount of experience (as a home mechanic) with a selection of tools, but his response after looking at some fitting guides for the bushes was "F*** that!" :D . I might approach the guy in Bonnybride who does the alignment and see if he'd change the bushes too, but insurance is due in a month or 2 so not a priority...
 
cj10jeeper said:
If you find anything where it is triggered into giving random tiny left and right inputs then do let me know
Click to expand...

Not sure how it works yet, but the EPS has a self-centring mechanism, so it sounds like an artificial force is applied to help right the steering to dead ahead. From early reading it looks like this is measured/applied relative to the steering lock rotation sensor.

My concern was that if the sensor is sending signal 'centred' at 0 lock, yet due to alignment being done non-symmetrically (imagine turning the nearside track rod end adjustment 5 turns one way, and then the offside one 5 turns the other way, the tracking would be 'the same' but the rack would be off-centre, and the steering wheel would look 'off'), the actual natural position where the wheels want to track is maybe not where the rack and so sensor is 'centred'

So, are the wheels settling at equal toe, as they naturally do, and positioning the rack/steering wheel at say 1 deg lock, and the EPS is saying "1 deg off centre" apply some self-centering force, and doing it, and then it gets to 0 deg on the sensor, so it relaxes the force, and the steering then pulls again to equalise the toe, and so on, a circular feedback loop.


The logical fix would be to check that the alignment people set the steering rack centred properly (must be a way to check that the rack is actually dead centre, not the steering wheel, or the sensor, but the actual rack itself)...
Also, the sensor centre position can be calibrated/reset... but I'd check that what it thinks is centre is actually rack centre. Resetting it to cure the problem when the rack is offset from dead centre isn't ideal due to ackerman and camber/toe with steer geometry kinematics.


That is all just a theory for now, I'm not sure how it works in detail until I read more of these documents. But it would make sense and would generate the issue being noted.

Hmmm

Dave
 
OK - so an interesting idea and I can certainly follow the logic of what you suggest. I'd need to read up in the TIS about various set up procedures and would like to see the documents you have.

First check I went through with the alignment shop was a check that the wheel is the correct number of turns lock to lock. Also the wheel was checked for centre, granted it could be a whole spline out and these tests are not accurate to a degree or so.

Thinking deeper if your proposal was the case the steering would continually to put a force in one direction. Say it thinks it's off by a degree anticlockwise, so applies a force clockwise. I correct to what I want ie 'real straight ahead' and it reapplies. This would be felt as either a repeating or continuous pull to one side. Trouble is the issue I have is making the wheels turn one way then the other, so the 'force' is being applied in a random pattern either way.

It also only happens between about 65 and well let's say 80. If it were EPS then why not do it at other speeds? Selecting sport which reduces EPS input, does not make it any more or less.

Put 120 miles on the clock today and it's the most bizarre feeling I have ever had in a car steering when on mirror smooth surfaces and this 'hand of god' rocking the steering wheel gently.

I have to take the X5 into the dealers tomorrow so will see if they know of any cause on the Zeds.
 
Yeah, the one side only thing may rule my thought out as the cause... who knows what the tolerances are, or damping factors in the setup.

It may well be that between 65mph and 80mph there is a latency issue between input and EPS response, on the mappings. I have no idea really :D

I guess one interesting check is to turn the engine off on a steep down hill (so EPS off), and see if at full weight the steering is playing around still.


I have simply downloaded these PDFs... (google them)

01_E85_Complete_Vehicle.pdf
04a_MS45_DME_Part_2.pdf
09_E85_Adv_Safety_Electronics.pdf

And so on, the file names linked to when it can't find them (from the menu on the left) are the ones you'll want to search for... there are 14 in total.

If you PM me your email address I can zip and send.

Not LOADS of info in them, but they give an overview of all the main components and fault diagnostic of them. Handy reference material for any owner... should be in the owners manual imho :D

Dave


edit:

06_E85_Chassis_Dynamics.pdf
http://www.bmwclub.lv/files/06_E85_Chassis_Dynamics.001.pdf

Pg 7 > 16 of that document... well worth a read!
 
Cheers Dave,

I have thos pdf's sawved so can read them :thumbsup:

I wonder about disconnecting the EPS to test. There must be a safe way.

Ah well I'll continue to investigate, but won't give it to BMW to simply fit a new column and rack for min £1,000 plus labour and then tell me it's because I don't have RFT's...
 
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