General Franklin Tools & Stilo Rear Bushes.

[Shadeyman]

Thats exactly what I was told by a Fiat dealer.

He also told me to carefully insert a spike into the bush to make sure there was no oil left in there. They can be under pressure, oil will squirt out and can be warm even hot if the car was driven for a long period just before the seal is broken so be carefull and wear goggles.

Once the oil is out the rubber can be easily removed.

Edit
Once we have a diffinative tested solution perhaps a MOD could create a "Sticky"?

 

[yellowstilo]

found a picture of the bush in my archive with the arrow visible...

 

[Davren]

Yes, it's because the internal passageways of the oil filled cavities of the bush are very cleverly designed, very much like a fluid shock absorber the oil is forced from one cavity to another. They give different resistance or stiffness to forces in one direction and more fluid damping in another. In one direction it has bump stops of almost solid rubber but in another direction it allows dampened movement

So it does a lot, it dampens low frequency noise, then, the next step, it dampens movement with the oil and then it provides a rubber bump stop if the deflection goes too far. That's why it's called a silentbloc. But that means it has to be inserted with the correct orientation

I understand about the oil moving from one chamber to another and about the internal bump stops, but unless I've missed something, this still doesn't explain why the bushes have to be orientated a particular way.

The center metal tube of the bush is fixed solid to the car body and also bonded to the inside of the rubber part of the bush. The outer metal cylinder of the bush is fixed solid to the axle and also bonded to the outside of the rubber part of the bush.

Any suspension movement between the inner and outer parts of the bush is rotational, so why should it matter where the oil chambers and bump stops are in relation to the car body or axle? Whichever direction the arrow is, the forces between the two parts of the bush would still be the same.




The only other forces I can think of that could come into play with the design of the bush are:

1. As the axle mounting plates, and therefore, the bushes are mounted at an angle to each other and not in line, the inner and outer parts of the bush are not concentric while the suspension is moving verticaly. The oil chambers and bump stops may need to be in a certain position to avoid them being crushed as the suspension moves.
2. Gravity. :nono:

This end on picture of a new bush with the metal plate removed shows two hollows in the rubber. The small cut-out in the center tube is the direction the arrow would point to, so the two hollows would be top and bottom when the bush was fitted to the car.

 

[Davren]

Once we have a diffinative tested solution perhaps a MOD could create a "Sticky"?

Once we have a definative solution to everyone's satisfaction, I'll definately be making it a "Sticky". This unresolved problem has been dragging on for too long.

 

[Deckchair5]

I would think it's the angular lateral movement of the beam when cornering that needs to be firmly controlled and not allowed to go wild so that's why the bump stops are aligned in that axis. Then even when the bush fails and loses all its oil there would still be yaw control of the beam in corners and the flapping and knocking free movement of the beam would be just in the vertical plane

That's why, when the bushes fail, people talk of a banging at the back on bumps rather than a loss of control of the rear end

 

[Shadeyman]

The unusual design of the rear subframe is designed to tighten up the rear of the car during cornering. I was given the Truck of a Skateboard as a simplified example of what the rear subframe does on a Stilo. The bushes are the most important part of this clever design. The stops/buffers and chambers need to be in particular positions to allow this to happen correctly. So the orientation of the bushes when being fitted is critical to the performance of the rear end of the car, whether that be its ability to silence uneven roads, cornering or just how long the bushes last.

 

[Deckchair5]

Yep I'd go with that

That will be why, if you have a close look at the complete assembled beam i posted earlier, one bush has one of its 3 cutouts facing vertically down and on the other bush it's upwards

 

[Davren]

Yep I'd go with that

That will be why, if you have a close look at the complete assembled beam i posted earlier, one bush has one of its 3 cutouts facing vertically down and on the other bush it's upwards

This is similar to the instructions in the Grande Punto eLEARN except that it says the small cut-out in the center of the bush should point down for the left bush and up for the right bush. This means the GP bush would be fitted 90° different to the Stilo bush.

I'm beginning to think that although the GP and Stilo bushes are the same now, they may not have been the same when the GP eLEARN was published. This could also explain why the GP tool I bought appears to be of no use to the current Stilo bush.

 

[keviwal]

Hi,
Now i,m totally confused , not difficult i know.
So can anyone tell me the orentation is it arrows facing forward or facing backwards, sorry i have totally lost the plot on this now:bang:

Cheers

Kev W

 

[Shadeyman]

Hi,
Now i,m totally confused , not difficult i know.
So can anyone tell me the orentation is it arrows facing forward or facing backwards, sorry i have totally lost the plot on this now:bang:
Cheers
Kev W

The arrow points in the direction of travel(towards the front of the car). I'm still trying to get 100% clarification of this.

 

[Davren]

As yellowstilo posted earlier, for the Stilo the arrows point forward in the driving direction of the car.

I think that's the only part of the process we are certiain of so far and is the way I will be fitting my bushes. (eventually)

 

[keviwal]

Hi again,
Right thats that cleared that up then

:worship::worship::worship::worship:

Cheers guys

Kev W

 

[Shadeyman]

As yellowstilo posted earlier, for the Stilo the arrows point forward in the driving direction of the car.

I think that's the only part of the process we are certiain of so far and is the way I will be fitting my bushes. (eventually)

Idealy the position of the original bushes should be marked on the subframe and the new bushes aligned the same when fitted. This of course only works if the bushes have never been changed after leaving the factory. Your service history should help determine this.

 

[Deckchair5]

I don't think the cutouts or their position are really of any importance. After all they don't attach to anything and are there just so you can push past the top hat washer and directly onto the bush when installing it. The important bit is to have the arrow facing along the line of the swinging arm as that lines up the internal rubber in the bush with the direction of travel of the car

But if you're replacing both bushes then you'd end up with one cut out at the base and one at the top depending on which side you're looking at but that's just coincidental for lh or rh


This is mine (I think) with a cutout at the bottom.

 

[yellowstilo]

As yellowstilo posted earlier, for the Stilo the arrows point forward in the driving direction of the car.

I think that's the only part of the process we are certiain of so far and is the way I will be fitting my bushes. (eventually)

Yes, the arrows point forward and in line with the welding seam of the axle - as soon as i have scanned the Service News procedure i will post it as a PDF (if it's size is allowed).
It is obvious the three cutouts will be rotated 180 degrees on the opposite side, if you would take them as a reference one arrow would point rearward instead of forward.

 

[davidthelodge]

My understanding is u need a press to fit the replacement bushes, but I dont think needing a press to fit bushes is totally unique to a stilo wagon rear bushes. Making the new bush smaller to make it fit in the axle easier does'nt sound right to me. Some garages will have a press, its just a sod of a job 2 do, which is why so many wagons are sold when the bushes go.

 

[Shadeyman]

My understanding is u need a press to fit the replacement bushes, but I dont think needing a press to fit bushes is totally unique to a stilo wagon rear bushes. Making the new bush smaller to make it fit in the axle easier does'nt sound right to me. Some garages will have a press, its just a sod of a job 2 do, which is why so many wagons are sold when the bushes go.

Like I said in my previous post(53) its now common practise for the interference fit to be reduced because the bushes are sold at the larger end of the scale due to them having to fit different aged cars and models. Most dealers send the subframe to a local machine shop and most machine shops do it the easy way by reducing the interference fit. Some may reduce the bush size, some may increase the subframe bore size, some may even use heat but one way or another they reduce the interference fit when installing.

Personelly heat is ok for the removal of the bushes but I don't like the idea of using it to install them. The amount of heat needed would surely have a bad effect on a rubber bush.

 

[Argonought]

Like I said in my previous post(53) its now common practise for the interference fit to be reduced because the bushes are sold at the larger end of the scale due to them having to fit different aged cars and models. Most dealers send the subframe to a local machine shop and most machine shops do it the easy way by reducing the interference fit. Some may reduce the bush size, some may increase the subframe bore size, some may even use heat but one way or another they reduce the interference fit when installing.

Hang on a bit here This is from just one discussion with a Fiat dealer (which as we all know are not above making mistakes).

That some fitters, and indeed some Forum members, may reduce the inference fit in order to save having to use a heavy duty press is not in question.

However, it's a big jump to state this is common practice.

What we really need to see is a technical bulletin on the subject - as I believe yellowstilo is looking into.

 

[Shadeyman]

Hang on a bit here This is from just one discussion with a Fiat dealer (which as we all know are not above making mistakes).

That some fitters, and indeed some Forum members, may reduce the inference fit in order to save having to use a heavy duty press is not in question.

However, it's a big jump to state this is common practice.

What we really need to see is a technical bulletin on the subject - as I believe yellowstilo is looking into.

I spoke to a dealer and their machine shop, they both said it was common practise. Of course the bulletin may inform us that Fiat recommend it to be done using a press but that does not mean it is always done that way. They both said it was common practise because the price of a press and tool is so high. I see no reason to doubt them?

 

[yellowstilo]

here is the Fiat Service News Bulletin about the Stilo bushes replacement....