Better with the tool and I needed it to get the poly in
RTAB replacement...
- Thread starter Ducklakeview
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Unless you want to do all the bushings on the trailing arm then easier to do in situ. Would take longer to get the arm off
Yes.
First mark out with a marker how the bushing cage is aligned in the chassis (trace the cage or unbolt bolts 1 by 1 and mark the oval holes).
Disconnect connectors (brake wear sensor, abs sensor), unbolt brake hose brackets.
Then unbolt and pull the front of the arm down.
Remove cage (remove center bolt) and press out the bushing. It is easily accesible with both the bespoke tool and with generic press tools
Universal set (for virtually all bushing sizes):
http://www.ebay.co.uk/itm/UNIVERSAL-CAR-HGV-LGV-PRESS-AND-PULL-SLEEVE-KIT-BUSH-AND-BEARING-REMOVAL-SET-UK-/252502102012
Bespoke rear trailing arm bushing press set:
http://www.ebay.co.uk/itm/BMW-3-E36-E46-X3-E83-Rear-Axle-Trailing-Arm-Bush-Removal-Installation-Tool-/252494451735
BMW TIS entry for unbolting the arm:
page1
http://workshop-manuals.com/bmw/z_series_e85/z4_3.0i_m54_roadst/2_repair_instructions/33__rear_axle/32__control_arms_and_struts/2_ra__replacing_bearing_block_for_front_trailing_arm/
page2
http://workshop-manuals.com/bmw/z_series_e85/z4_3.0i_m54_roadst/2_repair_instructions/33__rear_axle/32__control_arms_and_struts/2_ra__replacing_bearing_block_for_front_trailing_arm/page_1161/
First mark out with a marker how the bushing cage is aligned in the chassis (trace the cage or unbolt bolts 1 by 1 and mark the oval holes).
Disconnect connectors (brake wear sensor, abs sensor), unbolt brake hose brackets.
Then unbolt and pull the front of the arm down.
Remove cage (remove center bolt) and press out the bushing. It is easily accesible with both the bespoke tool and with generic press tools
Universal set (for virtually all bushing sizes):
http://www.ebay.co.uk/itm/UNIVERSAL-CAR-HGV-LGV-PRESS-AND-PULL-SLEEVE-KIT-BUSH-AND-BEARING-REMOVAL-SET-UK-/252502102012
Bespoke rear trailing arm bushing press set:
http://www.ebay.co.uk/itm/BMW-3-E36-E46-X3-E83-Rear-Axle-Trailing-Arm-Bush-Removal-Installation-Tool-/252494451735
BMW TIS entry for unbolting the arm:
page1
http://workshop-manuals.com/bmw/z_series_e85/z4_3.0i_m54_roadst/2_repair_instructions/33__rear_axle/32__control_arms_and_struts/2_ra__replacing_bearing_block_for_front_trailing_arm/
page2
http://workshop-manuals.com/bmw/z_series_e85/z4_3.0i_m54_roadst/2_repair_instructions/33__rear_axle/32__control_arms_and_struts/2_ra__replacing_bearing_block_for_front_trailing_arm/page_1161/
Ok, all done now with Meyle HD bushes and limiters. Was surprised how much corrosion was present on the bolt heads and bush carriers! This added 30 mins per side as I had them on the bench grinder wire wheel, followed up with a couple of coats of black metal protecting paint dried with the heat gun. Used my trusty kitchen fitting level clamped to the bush housing and lined up with the wheel centre to set the correct position as per TIS. Think mine was on original bushes as they marked BMW, and car only on 55k.
I clamped the new bushes in the vice and slipped a couple of jubilee clips on them to make them easier to fit, but then noticed that the OUTSIDE edges of the trailing arms have a decent chamfer on them so probably wouldn't have needed the clips. Biggest PITA was fitting the carriers back in with the limiters in them as they are a snug fit. I just made sure the edges of the limiters were past the edges of the steel centre of the bush, meaning that they were actually angled inwards in the carrier, and tapped it home with a dead hammer, which slid the limiters into place. There is virtually no twisting of the carrier possible now with the limiters in, I tried the old bushes before disassembly and could easily twist the carrier by hand.
Typically it's now raining so can't go hooning, I mean testing..
Mike
I clamped the new bushes in the vice and slipped a couple of jubilee clips on them to make them easier to fit, but then noticed that the OUTSIDE edges of the trailing arms have a decent chamfer on them so probably wouldn't have needed the clips. Biggest PITA was fitting the carriers back in with the limiters in them as they are a snug fit. I just made sure the edges of the limiters were past the edges of the steel centre of the bush, meaning that they were actually angled inwards in the carrier, and tapped it home with a dead hammer, which slid the limiters into place. There is virtually no twisting of the carrier possible now with the limiters in, I tried the old bushes before disassembly and could easily twist the carrier by hand.
Typically it's now raining so can't go hooning, I mean testing..
Mike
Ok, manage a good drive today, and WOW... The rear end always seemed pretty planted to me, BUT undulating roads into corners could cause a slight "self steer" from the rear, which was controllable, but definitely there.
Now, it sticks like the proverbial to the blanket, and on the same roads/bend there is NO self steering evident from the back. I think the original bushes themselves must have been very tired, as it's now also a lot easier to light up the rears in the dry, I presume due to less "slack" in the drivetrain..
Mike
Now, it sticks like the proverbial to the blanket, and on the same roads/bend there is NO self steering evident from the back. I think the original bushes themselves must have been very tired, as it's now also a lot easier to light up the rears in the dry, I presume due to less "slack" in the drivetrain..
Mike
The difference is night and day, probably the best handling mod you can do - and it's cheap! I would love to see some lap times before and after for comparison.
Ducklakeview said:
I have a set of 4 of the Upper rear balljoints here ready for fitting, they also fit the lower bush location so I have 4 to eliminate the lower bush from the upright (hub carrier), that's 33% of the flexible bushing removed from the rear in one simple swap.
I have a set of Meyle HD RTAB's on order and will compare the rubber hardness with the standard BMW one I have, I note on the bush there are two tabs on either side, these seem to be designed to either do a similar job to the limiters or to eliminate any clonks as the bush hits the housing in roll, did you check the lateral rotation of the bush before fitting the limiters?
I have a concern that there has to be sufficient movement when the suspension arm moves up and down in it's arc, as it does the joint has to twist so it needs space to rotate as it does so, the design of the housing has the two "domes" centralising the bush but leaving space for it to twist, so would the limiters be "pinched" by the bush or arm during that movement, if it does this will cause torsional loads to be applied to the arm and housing?
I can't find any info on this or if anyone has checked the required movement, so short of dropping my cars rear suspension out (not planned until October) I'm at a loss to be able to confirm the mechanical action of this?
Artful-Bodger said:
I sliced those lugs off, as there didn't seem a point to having them with the limiters, and they were making it a PITA to get the limiters in.
Mike
It looks a tight fit, problem is with the carrier bolted up into is location it's really difficult to check the movement of this part, only way I can see of doing it is to use longer bolts and spacers to lower the housing down so it's visible whilst measuring the gaps, I'm taking the car off the road in October and I will test this movement with the old soft bushes in place so it's easier to move them.
Really need to know what's going on in this location as you can see it's been designed with the lateral rotation in mind.
Really need to know what's going on in this location as you can see it's been designed with the lateral rotation in mind.
Artful-Bodger said:
My practical experience of changing suspension to non-stock components is limited to prepping club rally cars some years ago so I claim no great knowledge, other than to say a blind search for rigidity completely misses the point of suspension compliance and it's role in keeping you on the road, as well as tolerably comfortable. So it's great to see you are really thinking through what's happening at that point of the suspension.
As soon as lateral cornering loads are introduced in to the equation with road surface and camber changes you will get (and need), movement the trick for the designer is harnessing movements to affect geometries in a useful way, so every bush, spring and damper is designed to work literally in 'harmony'. In the case of many multi-link set-ups a slight 'rear steer' is engineered in to affect understeer/oversteer traits. This is why I'm suspicious of 'upgrading' single components (e.g. with solids or poly), you may improve one characteristic but adversely affect another, sometimes you won't realise until the machine is on the edge.
This is a nice little read on elastokinematics where the author admits that suspension design is largely a case of design convention and trial and error (sorry, 'development') so it's interesting to read about members experiences
https://books.google.co.uk/books?id=NSlSJtEy-NIC&pg=PA31&lpg=PA31&dq=Elastokinematics&source=bl&ots=Mp131mcq3c&sig=M0W3WrI1Pd4hMitbCfNDGa6_T8U&hl=en&sa=X&ved=0ahUKEwip-NK4mtPOAhUpLsAKHerZCSsQ6AEIWjAL#v=onepage&q=Elastokinematics&f=falseCouldn't have put it better myself Ewazix.
Chassis engineering is a very complex topic, the need for all components to work in their correct geometry is critical and few realise what the combined effects of loads have on your chassis and components!
I have that book on my shelf
I highly recommend Alan Staniforths work on the subject in the "Race and Rally Car source book", that was the first text book I read on the subject years ago, opened my eyes to what I was getting into!
Chassis engineering is a very complex topic, the need for all components to work in their correct geometry is critical and few realise what the combined effects of loads have on your chassis and components!
I have that book on my shelf
I highly recommend Alan Staniforths work on the subject in the "Race and Rally Car source book", that was the first text book I read on the subject years ago, opened my eyes to what I was getting into!
Ewazix said:
If that really is your greatest fear, one should definately stay away from limiter rings as there lies the biggest limitation/restriction in compliency movement within the suspension of the rear axle, not within the fact to use polyurethane or not.
In fact, most limiter rings are even harder than most polyurethane bushings, so the latter one would be a great compromise within your reasoning :wink: :roll:
But all of this is specualtive content. It contains no recorded or proven facts. We know how bmw built the rear axle but what it was ment or prognosed to do is all pure speculation. In that light all aftermarket hop up parts arguments can be swept off the table, and the stock car will probably be the fastest car. But we all know that isnt the case.
Someone's put a great deal of thought into this problem and come up with these -
http://www.markertmotorworks.com/bmw-suspension-coilover.
They do however look suspiciously like the ball joints from the upper arm in a billet housing, they claim to have good nvh isolation so I assume they have mounted the balljoint in a damping medium inside the billet casings, possibly a polyurethane sleeve?
If that is the case you get the benefits of purity of motion of a balljoint, sealed for protection so service life should be good.
I am trying to find some reviews to get an idea how well they work as you have to take any sales brochure with a degree of scepticism!
http://www.markertmotorworks.com/bmw-suspension-coilover.
They do however look suspiciously like the ball joints from the upper arm in a billet housing, they claim to have good nvh isolation so I assume they have mounted the balljoint in a damping medium inside the billet casings, possibly a polyurethane sleeve?
If that is the case you get the benefits of purity of motion of a balljoint, sealed for protection so service life should be good.
I am trying to find some reviews to get an idea how well they work as you have to take any sales brochure with a degree of scepticism!
Found these for the front to match any rear improvements, not bad pricing for the work involved!
http://www.uucmotorwerks.com/FCAB/
So if your looking for well thought out suspension control there are products out there, albeit at a price, again though reviews from owners would be good, I have a couple of designs for something similar for the front I was working on, but the backs a real headache, the complex movements of the bush as the three arms work in differing arcs mean a balljoint is without doubt the correct solution but isolating the nvh will take a fair bit of thought, although the Marketmotorworks RTAB's look the way to go I would like to know what's inside.
http://www.uucmotorwerks.com/FCAB/
So if your looking for well thought out suspension control there are products out there, albeit at a price, again though reviews from owners would be good, I have a couple of designs for something similar for the front I was working on, but the backs a real headache, the complex movements of the bush as the three arms work in differing arcs mean a balljoint is without doubt the correct solution but isolating the nvh will take a fair bit of thought, although the Marketmotorworks RTAB's look the way to go I would like to know what's inside.
GuidoK said:
I think you might have 'misunderstood' what I was saying about the need to consider the whole suspension system when changing components. I'm happy to follow respected technical authors and the likes of Chapman, Parry-Jones, or Renaultsports Terry Baillon who all espouse the need for control, harmonisation and road-usability in chassis systems (rather than random fitment of individual 'race inspired' parts). I'll put it down to my bad and move on :roll:
Luckily nobody does things here 'random'.
If we still followed chapman, we'd have rubber donuts instead of cv joints
In BMW terms that is we'd still drive on horrible runflats...
Everything you buy at a price is a compromise. And the z4 is certainly no exception imho. I certainly dont follow the 'stock is best' or 'the manufacturer knows best' opinions. Loads of things are suitable for improvement on the z4, especially driveline and suspension, and you can experience that for yourself once you start modding the z4 like I did, especially if you want more performance and want to end up with a much much faster car (the difference with a stock z4 is pretty incredible).
More comfort might be difficult, you'd best buy an slk or some other non drivers car. comfort and build quality are not the z4's strongpoints to begin with.
If we still followed chapman, we'd have rubber donuts instead of cv joints
In BMW terms that is we'd still drive on horrible runflats...
Everything you buy at a price is a compromise. And the z4 is certainly no exception imho. I certainly dont follow the 'stock is best' or 'the manufacturer knows best' opinions. Loads of things are suitable for improvement on the z4, especially driveline and suspension, and you can experience that for yourself once you start modding the z4 like I did, especially if you want more performance and want to end up with a much much faster car (the difference with a stock z4 is pretty incredible).
More comfort might be difficult, you'd best buy an slk or some other non drivers car. comfort and build quality are not the z4's strongpoints to begin with.
Chapman was a pioneer in technology advancement, and if we followed him now we would be admiring his developments of recent years!
He was a true genius.
Anyone who has worked on suspension development knows the difference between just buying bits out of a catalogue and sticking them on, and people who understand what is happening and work to resolve the issues, manufacturers have several problems they have to resolve and take the most cost effective route to resolve them, the RTAB is a prime example, it only takes a few minutes study to see just how many planes the bush has to move in, a balljoint is the real remedy but nvh reduction them becomes expensive to achieve, so for a road car the use of rubber, which is very extensively tested and designed to move in the particular way required, is the acceptable compromise, do you really think just stuffing a plastic bush in there is even remotely as well developed?
Most people who modify cars have little clue as to what they are really doing as they have no engineering background, take NVH for instance, people just assume it's about comfort, but far from it, high frequency vibration is one of the biggest killers of electronic components, can cause cracks to develop and rattles and squeaks to start from interior trims etc, that's totally unacceptable on a road car.
The we have the guys who don't put any thought into what their mods are doing to the structure of the car, take coilovers on the back of a Z4, the standard spring perch feeds the loads into the chassis rails and distributes them over a wide area, this is a critical design which the maufacturers spend huge amounts of time and effort on, coilovers apply all the loads into the inner wing and turret, a component not designed to accept these kinds of loads, on a race car you would tie in the roll cage to the mounts and use these to spread the load across the vehicle, on a road car your relying on sheet steel with no support, not a good idea!
How about lowering your car, did you ever consider the suspension geometry is now working in a different range, resulting in the roll centers being displaced, the roll axis being changed, camber gradient being put out of control parameters?
On race cars they use different pick up points on the chassis or hub carriers to set the geometry where the tyre needs it, on a road car you have used up valuable wheel movement and ruined the fine geometric control, none of this is good, if your in a fast corner and have used up 20mm of your wheel travel in roll, if you hit a bump mid corner your suspension can hit the bump stops causing instant weight transfer to that wheel and snap oversteer!
Most cars can be balanced and the suspension tuned to give good roll and bump control in corners, just look how stable the top class rally cars are in bumpy corners at high speed to see the ultimate in suspension control, a "fast" car is one that can use the tyres to their grip limits and be balanced and controllable on the limit, most modified cars are barely in the ball park!
Modifying a car is far more complex than you think!
He was a true genius.
Anyone who has worked on suspension development knows the difference between just buying bits out of a catalogue and sticking them on, and people who understand what is happening and work to resolve the issues, manufacturers have several problems they have to resolve and take the most cost effective route to resolve them, the RTAB is a prime example, it only takes a few minutes study to see just how many planes the bush has to move in, a balljoint is the real remedy but nvh reduction them becomes expensive to achieve, so for a road car the use of rubber, which is very extensively tested and designed to move in the particular way required, is the acceptable compromise, do you really think just stuffing a plastic bush in there is even remotely as well developed?
Most people who modify cars have little clue as to what they are really doing as they have no engineering background, take NVH for instance, people just assume it's about comfort, but far from it, high frequency vibration is one of the biggest killers of electronic components, can cause cracks to develop and rattles and squeaks to start from interior trims etc, that's totally unacceptable on a road car.
The we have the guys who don't put any thought into what their mods are doing to the structure of the car, take coilovers on the back of a Z4, the standard spring perch feeds the loads into the chassis rails and distributes them over a wide area, this is a critical design which the maufacturers spend huge amounts of time and effort on, coilovers apply all the loads into the inner wing and turret, a component not designed to accept these kinds of loads, on a race car you would tie in the roll cage to the mounts and use these to spread the load across the vehicle, on a road car your relying on sheet steel with no support, not a good idea!
How about lowering your car, did you ever consider the suspension geometry is now working in a different range, resulting in the roll centers being displaced, the roll axis being changed, camber gradient being put out of control parameters?
On race cars they use different pick up points on the chassis or hub carriers to set the geometry where the tyre needs it, on a road car you have used up valuable wheel movement and ruined the fine geometric control, none of this is good, if your in a fast corner and have used up 20mm of your wheel travel in roll, if you hit a bump mid corner your suspension can hit the bump stops causing instant weight transfer to that wheel and snap oversteer!
Most cars can be balanced and the suspension tuned to give good roll and bump control in corners, just look how stable the top class rally cars are in bumpy corners at high speed to see the ultimate in suspension control, a "fast" car is one that can use the tyres to their grip limits and be balanced and controllable on the limit, most modified cars are barely in the ball park!
Modifying a car is far more complex than you think!
And see there you go wrong. polyurethane isn't a 'plastic bush' :roll:Artful-Bodger said:
I have an engineering background. do you?
the Z4's interior rattles and squeaks to begin with on stock suspension. So from factory its apparantly an unacceptable road car?
And what is and isnt acceptable is a personal point of view. I think everybody here can make that judgement for themselves. They dont need an internet forum for that.
This is about rtab's. I'm sure that if you buy a coiloverset at intrax (I think the only company that sells a rear coilover for the z4), they can advise you how to brace and reinforce the rear shock towers to take the load. They are a very knowledgable company with far more experience in engineering than you or I have. They did the suspension for michael shumachers world titles for example.
Yes I did consider.
No its not, You think that all people here are somehow very stupid, dont do their homework and just slab on some bits.
But still you didnt know as it turned out that 'M rtab bushings' are the same as normal z4 rtab bushings or that the upper outer ball joint can fit the lower outer rubber. Not that you should, because you know, modifying a car is far more complex than you think.
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