Technical multiwagon rear bushes

[roy lovelock]

Hi peeps,

i know this is covered ground, i had to change the bushes on the wifes multiwagon last year and in the end i ground of the outside of the bush housing to get the things in.
anyways, my multiwagon has now blown one of the bushes on her and i am about to change them both, anyways i decided to get the job done properlly and purchased an 12tonnes press for the job. rang up the dealer and asked for 4 new bushes (so i can do the job without waiting for parts again in the future).
anyways the dealer stated that this job was impossible, and using a press will just ruin the bushes.....
has anyone actually used a press to put the bushes in?, i know some have used anvils etc but im planning to put them in without any grinding or honeing will this be do able - i dont really want to distroy any bushes like i did last time.
i must admit this isnt a job im looking forward to on sat lol.
thanks
roy

 

[Deckchair5]

anyways the dealer stated that this job was impossible, and using a press will just ruin the bushes.

If the job is impossible then I'd have to ask why Fiat sell the bushes? And if you don't press them in then how else are they going to go in? By magic dust?

Have you looked through this thread?
https://www.fiatforum.com/stilo/191048-bang-rear-when-going-over-bumps-then-read.html

It's obvious that originally Fiat planned it to be a whole unit replacement just like the front wishbone and garages and techs were saying it had to be a whole unit replacement for many years but times move on and the bushes became available separately. The heavy interference fit between the bushes and the beam may be ok for when it's being assembled in the factory but isn't helpful for replacment in the field. It should be no tougher to fit the bushes than any other car's suspension but they are still the original spec bushes with a way over the top dockyard interference fit.

I'd make it a much more sensible light interference fit by reducing the bushes outside diameter, stick the bushes in the freezer overnight, grease em up and they ought to go in with fairly conventional pusher/puller

Having said that, garages seem to be quoting £200- £300 to fit including bushes and I'd go for that any day of the week

It would be lovely to have someone measure the inside diameter of the bush housing to within .001" and then it would be easy to work out the ideal bush outside diameter. Then people could have the bushes machined down ready to fit. Do you think you can do that Roy?

 

[Davren]

It would be lovely to have someone measure the inside diameter of the bush housing to within .001" and then it would be easy to work out the ideal bush outside diameter. Then people could have the bushes machined down ready to fit. Do you think you can do that Roy?

@ Decks.... The dimensions were measured by paulf1408. Posts 11 & 12 here:

https://www.fiatforum.com/stilo/233049-knocking-rear-near-side.html

 

[yellowstilo]

the original tool used by Fiat for this job is an hydrolic press so i don't understand they say it will ruin the bushes....
it's more important to use the proper tools between the press and the axle bushes- Fiat uses a press plate with 3 notches that engage in the 3 openings of the side plate of the bush and a bush with the right diameter to support the axle at the other end.

 

[Deckchair5]

Cheers Davren (and Paulf)
I'd never seen that post. Well that's it then, if the new bushes are significantly larger than the old ones coming out then it's a hernia or cylindrical grinding machine time

 

[roy lovelock]

thanks guys thats what i thought, if it was impossible how the hell could they have done it in the first place. As ive stated ive got a 12 tonnes press so im hoping this will make mincemeat of the job, but i will again as a matter of course take off a few thou on the bushes just to be on the safe side.
thinking about it, i wonder if this fit is actually causing the problems with the bushes... the way im thinking is the bushes are impossible to move under normal conditions so they are under constant strain. normally bushes will be under stress in load conditions but it will twist back to normal position but on the stilo it cant do it because of the fit. eventually something have to give... just my take mind you.
i will have to see how long the wifes car bushes last as they are ground off and under far less stress than the original were.
thanks
roy

 

[A3jeroen]

Last summer I used a mechanical press after sanding the axle, freezing the bushes and lots of grease.

gr J

 

[keviwal]

Hi,
i have access to a full machine shop and i,m willing to make a bespoke puller etc for the job,the boss won't mind coz thats me .
It is a job that sooner or later i will have to do on my MW as it has 110k on the clock.
So if anyone is willing to measure the bush diameter, the length and i take the rest of the sizes off my MW.
it might be a possiblity that if it is really slick you might nearly be able to do it situ ie just drop it off the bushes to be replaced.
I am guessing that it would have to be hydraulic which in itself wouyld be no problem as you could use an ""enerpac" ram and pump.
It could then be passed round to whoever is doing the job next, what do people think to that?
i,m all for helping folk out , like so many others on here.
I guess i could machine the bushes as well if we could decide on the actual interference fit. I,m guessing that if the bush is around 75mm diameter that .05mm would be more than enough.
So guys i will look forward to your thoughts and ideas

Cheers for now

Kev W

 

[Deckchair5]

That's extremely generous and very interesting.


My thoughts are that if the bushes outside diameter are reduced so they are no more than a slight interfeence fit then no heavy installation gear would be required. I see no reason for them to be so tight.


If not needing so much force to install the bushes then hydaulic power wouldn't be so required, enough force being easily possible with a screw in pusher tool. That would make access room easier and it might even be possible to do the job in situ without removing the whole rear frame. That would save damaging seized hydraulic pipes etc and could make the job make less time consuming

Paulf said
I have just measured the metal sleeve and found that it is tapered towards the shoulder. It is 67.17mm and 67.35mm. the sleeve is 61mm between these distances and there is a2mm lip just before the shoulder, this is 67.41mm in diameter.


So a light interference fit on 61mm would be all that is required.
Paulf said
The shells measured between 0.15 and 0.2mm smaller than the new bush and the shell is oval by 0.1mm
So that's a ridiculous interference fit and it would easy to improve that so much by reducing the outside diameter of the bushes that nothing extraordinary would be required to install them


I would guess that the bushes are destroyed when the outer flexi material witholding the fluid type bearing becomes hardened with age but most of all when the bush cente bolt corrodes and seizes to the bush and can no longer rotate within the bush. This will tear the bush apart on suspension rotational movement. Most people have found that the centre bolt is corroded to the bush when they replace them

 

[keviwal]

Hi Decks,

thanks for the post and pics!
I have been giving this one some thought which has now changed due to seeing a picture of a bush . I just assumed that the bushes were headless ie like what you would find on a shock absorber. .
I am thinking that a screw type puller/claw setup might do the job. This will be dependant on how bigger threaded bar you can get up through the centre.
To be honest you can get tons of pressure just with a thread if you use the correct material by that i mean when you start swinging on it the thread wont pick up/strip or the rest of it collaspe. Looks like it is an ideal canditate to make it from a material called en 24, total git to machine but very tough.
I shall start doing a few drawings and put my ideas into reality!!

Kind regards,


kev walker

 

[Deckchair5]

I am thinking that a screw type puller/claw setup might do the job
That should do the job admirably

The bolt through the centre of bush is a [FONT=&quot]140mm x M12 so that would be a good diameter of screw to go in there

[/FONT]
[FONT=&quot] The slots in the end cap of the bush must go back in the same relative positon apparently so that will need consideration




[/FONT]

 

[yellowstilo]

Originally posted by Dechchair:
"I would guess that the bushes are destroyed when the outer flexi material witholding the fluid type bearing becomes hardened with age but most of all when the bush cente bolt corrodes and seizes to the bush and can no longer rotate within the bush. This will tear the bush apart on suspension rotational movement. Most people have found that the centre bolt is corroded to the bush when they replace them "


I think the bolt doesn't rotate in the bush - the inner tube of the bush is tightened by the bolt when the rear axle is in it's neutral position (carrying the car's weight without extra load) , the rubber and glycol fluid inside the bushes will act as a flexible joint and damper.
That's why the bushes are press-fitted, if they fit too easy the bush would start rotating inside the axle opening...
Please correct me if i'm wrong.....

 

[Muppet1]

I have just had a idea but not sure if its a good one, How about a solid polyurethane bush like you used to use on suspensions back in the 80's instead of the rubber filled one. I remember changing the leaf spring ends on a mk2 escort and it made a hell of a difference.

Might be a silly idea, I guessing the ride might be a bit harder but i dont see it would make much difference. Maybe somebody like Superflex might have something on the shelf????

 

[Deckchair5]

I'm not going to correct you yellowstilo as I haven't got a clue


What I do know is that these fluid resilient bushes are a very smart design and aren't just a bag filled with fluid but have some clever internal passages which make them act very similar to a fluid shock absorber in that fluid is passed from one chamber to another through small orifices and channels which dampen forces and vibrations. They also have an internal bump stop where solid rubber to rubber prevents excessive damaging force or movement in certain directions.

I don't think rotation forms a major part of what they do so a really tight fit of the outer sleeve isn't necessary to prevent rotation as they may only move +/- 10 degrees at most


What I'm guessing may be important though is that the mount brackets rotate fairly freely around the fluid/ rubber mount. If they seize by the centre bolt corroding and welding itself to the mount inner sleeve and the car starts to sag on old suspension springs then I'm guessing some undesigned rotational loads on the fluid bearing are going to be created. If all the bushes are the same throughout the Stilo range then there has to be a reason why MWagons suffer so much from rear bush failures.

To Muppet
Then yes, solid rubber bearings from the likes of Superflex might well do the job. Whether it would tighten up the feel too much or even improve the tautness feel of the back end is anybody's guess

 

[Davren]

If the bushes weren't such a tight fit in the housings, then this might work. With the current fit though, the central screw doesn't look man enough for the job.

 

[T14086]

from memory, depending on year bushes are available also only 2 bushes can be fitted per side before it needs replaced.

 

[roy lovelock]

well that was a fun day spent.....
it all came apart easily enough, but two bolts that hold the axel in place to the chassis were wrong, they were two short and narrow, they were doing nothing - first warning....
then i got the axel on the ground, hmmm, the bushes are not home correctly, both had around 1/4 inch before home.
anyways i pressed out the failed on first - the date on the bush stamp, 09.....
same on the other.
both bushes were replaced last year!!!! but had been fitted incorrectly.
so be aware if your not going to get the bushes home expect to replace them again!!
the press was completely useless tbh, it got the bush in so far but needs a holder or something to allow the bottom part of the bush to pass though, i managed to get the first bush though using some jiggy pokerery - then oil every where aggghhhh, back to the old way grinder and club hammer, took of loads on the outside of the bush housing (make sure you keep it cool though).
the previous owner had got the bushes replaced ive found in the service history by a garage he had used for years, this same garage charged the previous owner for zenon bulbs at £120 each (the car has standard halogen bulbs), and he was charged £700 for this complete bodge done on the rear axel.
the car now does feel tigher on the rear, but i think next time i may just get a new axel to save doing this poxy job for a third time.
roy

 

[sixpotman]

Anyone got an ball point figure of how much a new axle
costs? without fitting

John

 

[Deckchair5]

Sounds like a mighty botched job done previously. With the wrong, too short mount bolts then that was stupidly dangerous of the garage.

Ready to put your feet up then Roy

 

[Davren]

Anyone got an ball point figure of how much a new axle
costs? without fitting

John

February 2010 price was £913.54 incl. VAT or £769.97 incl. VAT if you have original gas HID headlamps.