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[blue_dream]

Hi
Bloody hell, i'm not sure to these polybushes myself, if the bushes need replacing on the arms the complete arm gets replaced and much easy to do, i'm lead to believe that the front bush that goes into the sub frame is the one that takes most ware due to front motion under braking etc.
   I can remember along time back that their was a recall on the wishbones from someone but were fitted to vectras, same thing as yourself, arm snapping at weilds, but some were saying this was too the car being jacked up on them. 

[D]

Glad you are ok Al.

[terry paget]

I do not understand the thinking behind the vertical rear bush. Common sense tells me it should be horizontal and in line with the front bush - that would achieve a maintenance free lower wishbone, controlled by the MacPherson strut. Are rear vertical bushes common on other cars? Is there any paper explaining the wisdom, or even the point, of the vertical rear bush?

That's exactly what I was thinking, the Senator had this arrangement but the horizontal bush was at the rear but I always wondered why it didn`t have two horizontal bushes.

To stop the wishbone moving backwards under braking. How else are you going to achieve that? 

How indeed, X30XE. I should have thought of that. Other cars have other links, tie rods, etc. for this purpose. Opel have found a way of doing it all with two bushes.both quite flexible. The design makes for good handling, comfort, silence and long life. I suspect it leads to uneven front tyre wear, but who knows? .

[Nick W]

I do not understand the thinking behind the vertical rear bush. Common sense tells me it should be horizontal and in line with the front bush - that would achieve a maintenance free lower wishbone, controlled by the MacPherson strut. Are rear vertical bushes common on other cars? Is there any paper explaining the wisdom, or even the point, of the vertical rear bush?

That's exactly what I was thinking, the Senator had this arrangement but the horizontal bush was at the rear but I always wondered why it didn`t have two horizontal bushes.

To stop the wishbone moving backwards under braking. How else are you going to achieve that? 

How indeed, X30XE. I should have thought of that. Other cars have other links, tie rods, etc. for this purpose. Opel have found a way of doing it all with two bushes.both quite flexible. The design makes for good handling, comfort, silence and long life. I suspect it leads to uneven front tyre wear, but who knows? .

ALL of the strut suspended cars I've owned or had anything to do with have suffered from wear in the suspension bushes. It didn't matter whether they used the anti-rollbar as a stabiliser(Capri, Sierra etc), or had separate arms to do the same job(Avenger, BMW etc).


I think the Omega setup(and it's used on Escorts and Fiestas to name others) is probably the least durable; and it's worse the heavier the car gets and compounded by large wheels and tyres. Does that sound familiar?

[aaronjb]

Speaking of front suspension.. wandering around Goodwood Revival yesterday I took a look at the front lower arms on an Aston Martin DBR2 replica (beautiful, beautiful car) and noticed that they are a mirror image of the Omega lower wishbone; the front locating point uses a rose joint with the bolt passing down vertically while the rear uses a rose joint with the bolt passing through horizontally.

Picture says a thousand words: http://2.bp.blogspot.com/-aqxkdwgeIBE/UVX__PSwIwI/AAAAAAAAAjk/Bi4G0S84Rks/s1600/IMG_0115.jpg


But, a similar vintage Jaguar would use a single long pivot bolt going through both sides of the lower arm meaning the whole arm rotates around the pivot bolt.

Again, a picture says a thousand words: http://valvechatter.us/wp-content/uploads/2011/12/SCAN0366.jpg


If only I understood the why's & wherefores of one design over the other.

[Nick W]

Speaking of front suspension.. wandering around Goodwood Revival yesterday I took a look at the front lower arms on an Aston Martin DBR2 replica (beautiful, beautiful car) and noticed that they are a mirror image of the Omega lower wishbone; the front locating point uses a rose joint with the bolt passing down vertically while the rear uses a rose joint with the bolt passing through horizontally.

Picture says a thousand words: http://2.bp.blogspot.com/-aqxkdwgeIBE/UVX__PSwIwI/AAAAAAAAAjk/Bi4G0S84Rks/s1600/IMG_0115.jpg


But, a similar vintage Jaguar would use a single long pivot bolt going through both sides of the lower arm meaning the whole arm rotates around the pivot bolt.

Again, a picture says a thousand words: http://valvechatter.us/wp-content/uploads/2011/12/SCAN0366.jpg


If only I understood the why's & wherefores of one design over the other.

It seems to depend on what parts were in the bin, how the designer had seen it done before and how much cheese he'd eaten the night before.

[Diamond Black Geezer]

Remember this was the 50s, and design was in a very much different state to what it is now. Motor Cars not even existing was still in living memory.

There was still much more experimentation with the 'basics' of vehicle design whereas now the experimentation lies in magnetic shock absorbers, computer systems like next-gen Traction Control EBD etc... more extensive use of alloys, how cheap can we make this before it fails and costs us lawsuits etc..

Nowadays many aspects are just taken as read, as a given. But in the 50s there was still plenty of rich modification of suspension design, and there simply was no 'norm'.

[Marks DTM Calib]

If you look at the sub frame design of the Omega, it would be quite a challenging to support a horizontal bush in the rear part of the wishbone and allow the bolt to be accessed.

[Gaffers]

If you look at the sub frame design of the Omega, it would be quite a challenging to support a horizontal bush in the rear part of the wishbone and allow the bolt to be accessed.

Indeed.  Even on the XJR where you have quite a bit of room, getting access to remove the bolts is...interesting....

[terry paget]

What you need to think about is the construction of the genuine bushes, they are a rubber with an internal pocket and shape which means they remain stiff but, can absorb shock loading, polyurethane simply can not do this 

The optimum would be some kind of ball joint that allowed zero lateral & longitudinal movement but permitted the arm to hinge up & down.

The genuine rear bush that I cut open had a ball formed half way along the steel centre bush and the rubber formed around it. Given the small space available it is going to be very difficult to come up with something that works better than the genuine VX part.

I believe the front bush is not a simple short fat rubber cylinder, but a complicated item with a solid centre and a porous outer. Now you say the rear bush is similarly a complicated rubber structure. I have never cut one up and have none lying around at the moment. I presume the poly replacement is a simple cylinder of polyurethane, much less yielding than the rubber original. Clearly a lot of development has gone into the design of the wishbone and its bushes. I am surprised  some folk think they can improve upon it.

[05omegav6]

Front bush should have oil filled bladders within... Some cheapy ones don't, Atp cheapies do.

Nothing porous about them though

[Kevin Wood]

Nothing porous about them though

.. until you start cutting them out with a hacksaw.

[05omegav6]

Nothing porous about them though

.. until you start cutting them out with a hacksaw.

They do get rather messy

[05omegav6]

Right, wishbone removed... had failed at the end of all four welds, and in pretty short order too by the looks









Also some interesting wear on the stainless bush, suggesting that the arm might have been able to move as intended...



Anyways, clearly summat wasn't right, and it will be interesting to see what state the passenger side is in when I remove that tomorrow...

[Lazydocker]

It doesn't help that the bush carrier isn't welded all the way around either.

Glad yo escaped with nothing more than brown trousers though