159/Brera upper wishbone bush analysis - Alfa Romeo Forum
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159/Brera upper wishbone bush analysis

Ive been looking for a long term fix to the upper wishbone bush issues that are well documented on this site. I have been trying different setups with the upper wishbones and thought Id report my findings as maybe interesting to others, especially to those that keep their cars for a long time. Im not claiming to be an expert mechanic or engineer. This turned into a bit of an essay so if you dont want to read it all, the conclusion as at the bottom of this post!!

Standard bushes:

The front bush has a white plastic insert between the rubber part that rotates with the arm over a metal sleeve, the sleeve is fixed in position when clamped by the fixing bolts. Inside the plastic insert it has grooved channels all around it with a small amount of grease in (from new), overtime the sleeve dries up and the plastic hardens and gets very stiff to the point it gets stuck and can no longer rotate freely. Ive noticed they get more stuck in warmer weather, or when the car hasnt been used for a few days!! Once this bush starts to get stuck with age and from drying up, it makes a right racket. As seen here:
The rear has a metal insert around that rotates with the arm around a metal sleeve, but its also designed to slide forwards and backwards approx 5mm each way to allow the arm to flex. It is assumed this is done to absorb hard knocks to the suspension and to cushion knocks felt through the steering. The sleeve in this also gets to the point of almost seizing as it normally dries up and goes rusty over time due to being more exposed to muck in the wheel arch (the front bush is sealed). Once seized it fails to rotate and also doesn’t allow for the sliding flex movement, this can cause a clattering noise which can resonate through the cars body.
You can check how ‘stuck’ your arm is by undoing the ball joint nut, and separating from the hub, it should move freely and quietly up and down by hand, they often don’t! If you have new arms, clamp them in a vice and test how freely they move before fitting.
I believe that nearly all the noisy ones are due to the front, rear or both bushes getting to the point of nearly seizing up. Once it starts to seize it starts to rotate via stretching the rubber bush, this causes the rubber bush to tear over time and wear out prematurely. Note that otherwise the rubber part of the bushes is up to the job and is not the problem here. A seized bush is not good for handling as it will hamper suspension movement.

I have tried the following setups:

Supaflex, Powerflex and standard bush).

Standard Alfa Romeo made in italy (TRW) Arm/Bushes (approx £163 each) and you will need new ball joint nuts! Additionally some Alfa dealers and specialists offer a cheaper alternative (I think they are made by Febi) but I havnt tested these.

These move very freely and quietly for a while, they can last the longest (upto 60k miles)

They have lots of compliance in them to flex which contributes to tyre and alignment issues.
Bushes can seize.

Standard pattern Arm/bushes (q-drive, Delphi , meyle) etc (approx £50-90)

Cheap cost in short term.

They have lots of compliance in them to flex which contributes to tyre and alignment issues.
The rear bush slides side to side, this gets rusty and seizes.
Front bushes seizes very quickly. Infact I have had a q-drive one out of the box that would not rotate freely on the front bush when held in a vice from new - (this ended up being a candidate for PU bushes).
Most of the pattern arms proove to be false economy in long run.

Arm with Powerflex bushes (£180 plus cost if new arms are needed). You need to factor in the time/cost to press out old bushes from arms, Additionally : Pro alignment is a must adding extra cost.

The inside of the PU bush is textured to hold in supplied grease, the PU bush should rotate with the arm around the clamped in metal sleeve which has a offset hole for adjustment, the metal sleeve can be adjusted while the mounting bolts are loosened with the supplied hook spanners. Nylon washers are used on either side of the bush to assist rotation. The Powerflex bush is not as stiff as it seams, despite being the stiffest black type, when held in a clamp they do offer some movement compared to the supaflex bushes.

Castor/Camber adjustment
Improved handling/tyre wear.
Sharpens steering feel.

Expensive and complex alignment needed.
In my opinion the Powerflex bushes need to be improved to allow them to move a little more freely. They can often squeak due to being too tight requiring yearly regreasing/rebuilding (alignment will need to be done again if rebuilding unless you can somehow mark the positions). If they are allowed to dry up and squeak for too long then the textured inside of the PU bush wears and smoothes out.

Arm with Supaflex bushes(£50 plus cost if new arms are needed). You need to factor in the time/cost to press out old bushes from arms.
The Supaflex bushes are just 2 piece PU bush that is textured inside to hold in grease. These have a centred hole around a metal sleeve so are not adjustable. Unfortunately not only is the material used very stiff, but the bushes are a little too wide for the sleeve and these can be very stiff when fitted.

Sharpens steering feel.
Cheaper cost.

These bushes are very stiff and offer hardly any movement, the bushes are very plasticy (obviously they are plastic anyway but there is no ‘bounce’ in them). Even the black Powerflex bushes offer way more compliance than these do.
The bushes are too wide and clamped in too tightly, the 2 part bushes don’t meet in the middle of the arms, they don’t fit quite right and need approx 1mm taking off both ends to allow the metal sleeve to be clamped in instead of the bush which should move with the arm.

If you can live with the tyre wear, stick to the original Alfa supplied arms, if you don’t mind the possibility of rebuilding bushes each year due to squeaking and prefer the improved feel and handling, use the Powerflex bushes.
I was looking at a BMW X5 upper wishbone today, if you squinted your eye it looked the same as the 159s, however it had a much better freely rotating bush design. We need a new arm/bush design that gets to the source of the noise issues and premature wear issues caused by stiff movement, its priority must be to rotate freely and is maintenance free, and ideally allows camber/castor adjustment. I dont think it matters if its rubber or PU, as long as the rotation doesn’t stick and stress the bush!!
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Interesting & Informed thread, appreciated.

In terms of the squeak. I have been trialling the use of Greese nipples in the arms to allow for the reapplication of greese into the PU bush without a rebuild and can coinfirm that this approach solves the squeek and allows the regular reapplication of greese to the inside of the PU bush.

There is a thread in this forum you can review to see the approach and progress.
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After major tyre wear issues I changed the upper and lower wishbones for aftermarket standard ones in view of the setting up of the pu ones.
However the biggest factor in wear was having a 4 wheel alignment done at Kwikfit. They spotted a worn track rod ball joint so after both rods and ends were changed, they adjusted the tracking and the rear toe.
The steering was noticeably lighter when they'd done it and so far, after 3months, wear seems to be even although I am taking easy on some tighter bends as tyres have cost me over £1000 in 12months due to bursts and previous shoulder wear.
Although I agree that stiffer bushes help, I think there is just too much body roll in fast cornering which causes geometry changes and contributes to the wear.
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