rear suspension coilspring lower bush - should there be one?

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veteran
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rear suspension coilspring lower bush - should there be one?

Post by veteran »

Can anyone here with access to published VW workshop procedures tell me if, on the Polo 6C, there exists on the rear suspension a rubber bush - occasionally referred to in other literature as an 'insulator' - between the bottom of the coilspring and the large, cup-like metallic seat for supporting the entire spring? If one is shown in a workshop diagram, can you find a part no. for it?

It's commonplace to have a rubber or plastic bush of some sort there to prevent direct metal-to-metal contact of the coilspring with the seat and so therefore avoid the grinding of the two together whenever the car moves. It would also reduce the amount of roadnoise, travelling up from the roadwheels, getting on to the coil.

I recently noticed that the rear suspension on my 1.2 TSI does not have this bush. There was certainly one included on Mk5 Polos and before. Also, Golfs have always had one, as far as I'm aware.
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Re: rear suspension coilspring lower bush - should there be one?

Post by iichel »

Top should have a rubber bearing, lower part just a metal ring.
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Re: rear suspension coilspring lower bush - should there be one?

Post by veteran »

By that, do you mean that the lower end of the spring should have a 'bearing' on it but that the bearing is not rubber but instead takes the form of a metal ring? Just like to get that clearly understood. I can't see a 'ring' on mine at all.

Here's what my rear coilspring setup looks like:

susp-2.JPG
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Re: rear suspension coilspring lower bush - should there be one?

Post by RUM4MO »

I have not checked the parts listing, but certainly in earlier models way back to the start of 9N type back in 2001> there has always been an aluminium ring in there. Typically it will not be possible to see this - though maybe on your car veteran as it is still newish and low milage, if you look up in through the hole on the lower spring cup, you might just make out the edge of that aluminium ring - or be able to spot some white dust as that ring “disolves” !

Edit:- it could be that that is showing grey/silver at the base of the spring in your picture.
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Re: rear suspension coilspring lower bush - should there be one?

Post by iichel »

Your spring assembly looks allright to me veteran ;)
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Re: rear suspension coilspring lower bush - should there be one?

Post by veteran »

Before posting that pic I magnified it to max to look for any remote sign of a separate ring of any kind. But there's nothing obvious there. That whitish annulus you mention, RUM, is more likely to be, in my case, just dried remnants of contaminants.

I'll be getting underneath the rear of the car probably during the coming weekend, weather permitting, and I'll try looking at the 'seat' from a different angle. Maybe there is a ring or a very thin bush of some kind there but that it's almost wholly covered over by the coil end?

You suggest that it's likely to be made of aluminium and, as you say, RUM, allowing aluminium to mate directly with steel is, from the standpoint of corrosion pertaining to different base metals, normally a complete no-no, especially for surfaces that will be moving against each other. In this particular case, it would lead to disintegration of the aluminium component (but obviously not as rapidly as inferred by the young age of my Polo!).

I'll in due course post some further pics of the bottom end of the spring, so do return to this posting over the forthcoming days and week.

It strikes me that VW might just as well have interposed a substantial rubber bush there, something maybe 10mm thick. Even 5mm would have been beneficial. That would have had some specific advantages over any sort of metallic bush or ring, and probably would have added negligible height to the rear end, since I guess that's determined more by the specification of the coilspring than anything else. But clearly, VW in their great wisdom decided otherwise. They maybe wanted to save a few more pennies and also lessen the weight of the vehicle by a tad. I'm not convinced they've done the right thing.

If you happen to have a Haynes manual for the Mk5 Polo (2009 - 2014) to hand, take a look at bottom-right of p.10-11, and top-left of p.10-12, as you might find that of interest.
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Re: rear suspension coilspring lower bush - should there be one?

Post by RUM4MO »

I've checked up on what Haynes shows in that area, I agree it shows nothing, but if you consider that Haynes seem to have been using a Polo 6R that had quite a few miles under its belt, and when you consider that I've already said that that ring washer is made of aluminium, and surrounded on both faces with steel - okay initially painted steel, then I'd guess that on that car that was the subject of the Haynes manual, that that ring washer had "left the scene" - turned into the white dust I was referring to.

I might just be wrong here, but I think if you ask anyone that has replaced rear springs on a Fabia/Polo/Ibiza that was roughly 8+years old, they will not have spotted any ring washer in that location - and I'd guess that most of them do not believe that there was ever a ring washer in there - but there was at one time.

If you look at your picture zoomed - and you consider that the hole on the lower spring cup has raised sides to help locate the spring, looking that the end of the spring you will see silvery/greyish showing, as I said, that is the aluminium ring washer, P/N 1J0512109 and called UNDERLAY, so this part has been in use on VW Group cars for quite a long time, maybe even initially on a Golf!
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Re: rear suspension coilspring lower bush - should there be one?

Post by cheba »

I cannot remember seeing any kind of bushing or ring when I removed my rear springs when changing to a Bilstein B14 kit last year on my Polo (built late 2013).
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Re: rear suspension coilspring lower bush - should there be one?

Post by Mike Austin »

This is my lower coil fitting (Blue GT 2017). Looks like something very thin there at the interface.
Image
I have been having trouble with noise that I suspect is coming from here.
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Re: rear suspension coilspring lower bush - should there be one?

Post by RUM4MO »

cheba wrote: Sat May 26, 2018 5:33 pm I cannot remember seeing any kind of bushing or ring when I removed my rear springs when changing to a Bilstein B14 kit last year on my Polo (built late 2013).
I think that your car's "UNDERLAY" (the word VW use in the parts listing) had already disolved due to the action of water + salt + dissimilar metals being in contact with each other.

It will have had that part fitted during initial assembly.

Edit:- cheba, I'd think that not seeing/finding a washer in there would not surprise me as you like me at the time, were not expecting to find one there, it was only after trying to work out why there was white dusty deposits there that I looked up the parts listing and discovered that there is meant to be a washer in there. As my car had just failed its MOT test for 10>15mm missing off the end of one rear spring, my urgent action that day was to buy two new springs and fit them - and after passing the MOT getting round to investigating any other issues like ordering in 2 new bottom bolts and 2 new washers (UNDERLAY in VW language).
Last edited by RUM4MO on Sat May 26, 2018 9:54 pm, edited 1 time in total.
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Re: rear suspension coilspring lower bush - should there be one?

Post by RUM4MO »

Mike Austin wrote: Sat May 26, 2018 6:53 pm This is my lower coil fitting (Blue GT 2017). Looks like something very thin there at the interface.
** image removed**. I have been having trouble with noise that I suspect is coming from here.
I agree that is what you can see there, in case I missed reading any other postings you have made wrt this, what sort of noises are you hearing and under what conditions?
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Re: rear suspension coilspring lower bush - should there be one?

Post by Mike Austin »

RUM4MO wrote: Sat May 26, 2018 9:46 pm
Mike Austin wrote: Sat May 26, 2018 6:53 pm This is my lower coil fitting (Blue GT 2017). Looks like something very thin there at the interface. I have been having trouble with noise that I suspect is coming from here.
I agree that is what you can see there, in case I missed reading any other postings you have made wrt this, what sort of noises are you hearing and under what conditions?
The thread is https://uk-polos.net/viewtopic.php?f=56&t=71336.
It is a noise that begins very quietly at about 10mph and seems to be loud at 20mph and 40mph. I have posted a sound clip here: http://www.towerhouse.me.uk/NoiseInCabin.mp3.
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Re: rear suspension coilspring lower bush - should there be one?

Post by RUM4MO »

Ah right, I have been reading that thread, I'm still thinking about taking action about noises in my wife's August 2015 Polo 1.2TSI 110PS SEL 5 Door - it emits noises when load changes, ie sounds very much like power train mounting systems though nothing rubbery has been torn as far as I can see. Trouble is when driving the car the sound either comes from the area where the gearbox and the engine rearmost mountings are located, though sometimes sounds like it is coming from further back which I'm sure it can't be.

Much has been put into print about VW Group accepting that the clutch action in their newer small cars is not as quiet as it could be, this started with the Up etc and seem to be present in some Fabias maybe with the same powertrain, ie 1.0MPI engine and 5 speed gearbox - so VW Group has tried to roll out a blanket "they all do that sir" to fend off spending money on warranty repairs it seems, I don't want to get stuffed into that position, it only started making this noise after its 2nd birthday or so.
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Re: rear suspension coilspring lower bush - should there be one?

Post by Mike Austin »

RUM4MO wrote: Sat May 26, 2018 10:06 pm Ah right, I have been reading that thread, I'm still thinking about taking action about noises in my wife's August 2015 Polo 1.2TSI 110PS SEL 5 Door - it emits noises when load changes, ie sounds very much like power train mounting systems though nothing rubbery has been torn as far as I can see. Trouble is when driving the car the sound either comes from the area where the gearbox and the engine rearmost mountings are located, though sometimes sounds like it is coming from further back which I'm sure it can't be.
I find the frequency remains the same but the level can change with speed. I have not found any dependence on load. Thus I feel it has little to do with rotating components. Rather, it is some standing waves being excited in something 'static' - hence the investigation into springs and their mountings.
...it only started making this noise after its 2nd birthday or so.
Mine was making the noise at 5,870 miles, when I bought it.
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Re: rear suspension coilspring lower bush - should there be one?

Post by iichel »

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