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How to retro-fit the Mk8 rear suspension aero covers or stone guards to a Mk7 Golf.

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Disclaimer:- This info is for community usage. I am NOT affiliated to, or sponsored by, any company/individual to promote them or their products. Companies/individuals may NOT use my name, photos, or threads/technical guides, for financial or personal gain (fraudulent misrepresentation).

Part 1 of 5
Vehicle used in this guide
UK spec, 2014yr model, Mk7 Golf Estate (GSW), GT (Highline) trim, 1.4lt TSI (140PS) CHPA petrol engine, MQ250 6speed manual gearbox, multilink rear suspension.

Vehicles that this guide is applicable to

Any VAG (Audi/Seat/Skoda/VW) cars from circa 2003 (Mk5 Golf onwards) with the PQ35 (A5) or MQB platform, with the multi-link rear suspension, including AWD versions.

Introduction

This thread was originally written in 2015 as a section in the bigger "Aero/skid trays" thread & was solely about the Mk5/6/7 "Stone chip guards". I have now separated it out & re-written it to include the new (2020) Mk8 Golf "Splash guards" (Aero covers). Ever looked under the rear of the car & thought “those wishbones arms will get a beating from stones etc”, or "those arms look like air brakes & will adversely affect the underbody aero"? Guess what, so did VW, & they made parts for the job!
 
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golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Part 2 of 5
Research

Since the VAG (Audi/Seat/Skoda/VW) PQ35 (A5) platform, introduced on the Mk5 Golf in 2003, & continuing on the VAG MQB platform, all the rear lower multi-link suspension arms are virtually the same. They have two small holes (one either side of the spring seat) in the bottom face of the arm & a further four holes (two each side of the spring) in the top face of the arm. These holes are to enable you to fit the original stone chip guards & the new Mk8 Golf aero covers to the arm.

In Germany you can factory order the option of PR code 1SK “Additional engine and transmission guard and underbody stone guard”. The original Mk5/6/7 stone guards are the 1SL “Underbody stone guard” component of the full kit. These cover the front face & the front half of the underside of the rear lower main arm/wishbone on the multilink suspension. They protect it & the springs from stone chips/impacts most likely to occur on off-road trails etc.. This option was available on previous VAG cars under the PR code 2UB “Rough road design”.

The new Mk8 "Splash guards" cover the same frontal area as the stone guards, but with the additional coverage of the whole underside of the arm, & extending further rearwards to provide a trailing edge. Not only does this provide some impact protection to the arm & spring, but also provides a trailing edge for air passing under the arm to merge better with the air behind the arm, lessening the amount of turbulence. Similar designs to these Mk8 "Splash guards" have been used by VAG & other manufactures on high performance & "Eco" cars for many years as they smooth the air flow which is very turbulent around the rear lower arms on multilink suspension designs. VAG previously tried a similar engineering principal on the MK5 Golf, & Audi TT, by using a badly designed trim piece in front of the trailing arm, which had a tendency to be knocked off easily, so they discontinued it!

The original Mk5/6/7/8 Stone chip guards (5.2mm thick black rubber):-
Have the following PR codes:-
1SK = Additional engine & transmission guard & underbody stone guard
1SL = Underbody stone guard

The new Mk8 Splash guards (Aero covers) (2.25mm thick black plastic):-
Have the following PR codes:-
1SA = Without additional front underbody guard
1SB = Additional front underbody

P8141031-annotated.jpg
 
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golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Part 3 of 5
Parts required

VAG ETKA illustration for VW Golf Mk7 or Mk8/Rear Axle/No.511-002 to -007,

ETKA for the Mk8 still shows the exact same drawing as below, but with the additional new Mk8 Golf/Tiguan "Splash guards" listed at the side.

Parts list & approx. costs in UK £

Golf Mk5/6/7/8, Stone chip guards:-
Item No.22:- 5Q0 511 533A,
Stone chip guard left, black rubber, £26.92 (x1)
Item No.22:- 5Q0 511 534A, Stone chip guard right, black rubber, £26.92 (x1)

Golf Mk8, Splash guards (Aero covers):-
Item No.22:- 5Q0 501 733,
Mk8 Splash guard (Aero cover) left, black plastic, £11.07 (x1)
Item No.22:- 5Q0 501 734, Mk8 Splash guard (Aero cover) right, black plastic, £11.07 (x1)

To fit as per VAG all require:-
Item No.23:- N 909 203 01,
Rivet nut M6, £1.63 (x4)
Item No.24:- N 911 335 01, Hex head bolt M6x18mm with washer (22mm dia.), £0.96 (x4)
Item No.25:- 8E0 825 267, Plastic spreader rivet, £0.24 (x4)

Modified parts to fit Stone chip guards as per my way:-
The combi bolt/washer (Item No.24) is plain galvanised steel, & I prefer to fit marine grade A4 stainless steel if I can find it, & found the following fitted perfectly:-
M6x16mm, A4 grade stainless steel bolts (x4)
M6x25mmx1.5mm thick, A4 grade stainless steel "Penny" washers, (x4)
You could also substitute Item No.23:- N 909 203 01, Rivet nut M6, £1.63 (x4) with stainless steel versions.

Modified parts to fit Splash guards (Aero covers) as per other forum members:-
If you do not have a rivet nut installation tool, ignore Items No.23 & 24, & just order another 4 of the plastic spreader rivet (Item No.25.) making a total of 8 quantity of Item No.25 to purchase. Forum member "Reggie Enchilada" has used this on his car & done 140mph with no problems!

ETKA-rear-wishbone-stone-guard-cover.jpg
 
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golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Part 4 of 5
Fitting


This applies to both versions:-

Jack up & support the whole rear of the car, or do one side at a time. Remove the wheel on the side you are doing to improve access. Because the wishbones are the same item, (but just reversed for one side) it is easy to get these rubber stone guards/aero covers fitted to the wrong wishbone! I suggest you start on the passenger side UK (drivers side NAR) as this wishbone has the levelling sensor for the DCC & headlights etc. Make certain it fits around the levelling sensor bracket & that the four holes (two top, two bottom) in the stone guard/aero cover align with the same holes on the wishbone.

Now if you are fitting it using all the VW parts as listed then you require a rivet gun which will do M6 rivet “nuts”. These (Item No.23) are required to be riveted into place in the correct holes in the bottom part of the wishbone. This allows the bolts (Item No.24) to then bolt through the guard/cover into the rivet-nut & hold the guard/cover in place.

Golf Mk5/6/7/8, Stone chip guards:-
Once you have fitted the rivet-nuts, re-fit the guard & fit the bolts (Item No.24), torque spec of 8Nm (5.9lbft), & use some medium strength thread Loctite (blue). Then push the plastic spreader rivets (Item No.25) through the two holes in the guard, into the corresponding holes in the wishbone, & then gently tap/push the central stem fully in/flush. The guard should be secure & feel firm.

Golf Mk8, Splash guards (Aero covers):-
When fitting the plastic "Aero covers" don't torque the bolts up to 8Nm (6lbft) as I reckon you will split the plastic. I just put some blue Loctite (medium strength) & did the bolts up "snug/firm", & make certain you centre the hole in the plastic around the rivet-nut flange when you tighten up the bolts.

Further considerations on fitting

Due to a mix up (brain fart) on my part I initially installed the metal rivet nuts in the top of the wishbone & the plastic push rivets in the bottom of the wishbone (opposite to the correct way). The plastic push rivets (Item No.25) held for 2yrs all ok, no problems. The only reason I can see for having metal fixings in the bottom part is to stop the covers being totally ripped off by driving over a large stone. So if you do not have access to a rivet gun that can do nuts, then I suggest you order a further x4 of Item No.25 (total of x8), & fit the covers using these only! Forum member "Reggie Enchilada" has done this on his car & drive at 140mph with no problems!

If you using the lower metal fixings, I strongly suggest that you use at least A2 grade stainless steel bolts & washers for a more corrosion resistant finish. Using A4 marine grade stainless steel for the bolts, washers & also the rivet nuts would be the best!

Rear-stone-guard-mod.jpg
 
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golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Part 5 of 5
Results


The Mk5/6/7/8, Stone chip guards:-

This protects the front facing part of the rear lower wishbones & springs from all impact damage by stones, & off-roading etc.. It is worthwhile as part of a “rough road package” & to reduce the noise from stones hitting the lower arm, but not for aerodynamics, as I doubt it has any advantages!

The Mk8, Splash guards (Aero covers):-
This provides complete coverage of the underside of the arm compared to above, & also provides for less air turbulence due to a longer rear trailing edge!
Having done numerous 32+mile trips I know well, I note the following:-
1. on quiet sections of tarmac with little tyre noise, these aero covers have decreased (about 10-20%) the wind noise coming from the rear seats area.
2. the rear of the car generally feels more "squat/flat" & stable.
3. on a nice mid-speed (30-40mph) off-camber left turn I know, the rear inside wheel has more grip & feels more in contact with the road.
4. MPG on the trip was 50.5MPG (UK) more than I would usually get, allowing 1MPG for other factors... I would normally expect to get 46.4MPG to a max of 48MPG in these traffic conditions.

That's at least a 2.5MPG gain & possibly a 4.1MPG gain!!, which is a 5.2% to 8.62% gain!!

Conclusions

Here in the UK (& other countries) we cannot order the German factory option of 1SK “Additional engine and transmission guard and underbody stone guard”. Our UK cars come from the same German factory, so why not offer the same options? Market demand is the answer, well at least this allows you to add the stone guard back onto the car!!

The benefits of aero covers like the Mk8 Golf "splash guards" have been known about for years. VW should have designed & used these from the beginning on the Mk5/6/7 Golfs to get better MPG instead of rigging the software that ended up in the "Diesel-gate" scandal. To make these covers & fit to every VW car would have been far cheaper than the software fix, buy-back schemes, legal actions etc., etc.!!

Yet again penny-pinching bean counters ignoring basic aerodynamic engineering!!!...IDIOTS!!....
 
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Faceman

Drag Racing Champion
Location
Long Island
Car(s)
'17 GSW 4Mo
Have the parts, will hopefully install them soon. Thanks!
 

Railman

New member
Location
United Kingdom
Car(s)
Golf GTI
This is the first I have seen of the stone guards / splash guards and has come at a good time as I'm about to order various underbody panels from the excellent aero thread. Very comprehensive write-up and thanks for your time and making my wallet, initially, lighter.

So I understand correctly, the stone guards have been removed in favour of the aero/splash guards?
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
So I understand correctly, the stone guards have been removed in favour of the aero/splash guards?

Yep..I wrote the thread originally (5yrs ago) on the stone guards as part of the much bigger "aero trays" how to guide......& then when the MK8 Golf came out this year I notice the new aero covers....which is what I just fitted after removing the stone guards......I haven't re-written the thread yet as the fitment is the same..but I hope to post photos up later.
 

Railman

New member
Location
United Kingdom
Car(s)
Golf GTI
Thanks, it would be great to see a comparison over the stone guards.

If there is a a 10 to 20% reduction in noise then it's well worth doing. These cars are quite noisy inside at speed.
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Are there same type of new stone guard in Mk8 for torsion beam rear axles too?

Yes there are MK7 parts to cover the MK7 torsion beam near the spring seats..also MK8 Golf/Polo part to cover the main cross piece section of the MK7 beam..

from the main aero trays how to guide I did:-

Rear lower arm stone guard/aerodynamic trim for Twist-Beam Rear Suspension.

http://www.partsbase.org/vw/golf-var...hock-absorber/
Item No. 17:- 5Q0 501 559 "C" or "D", Stone chip guard for under side of trailing arm left side.
Item No. 17:- 5Q0 501 560 "C" or "D", Stone chip guard for underside of trailing right side.
Item No. 18:- 5Q0 501 561, Stone chip guard for top side of trailing arm left side.
Item No. 18:- 5Q0 501 562, Stone chip guard for top side of trailing arm right side.
Item No. ??:- 8E0 825 257, 8mm spreader rivet. Unknown quantity required.

These items I have not actually seen or fitted, but they appear on ETKA for the MK7 Golf with the Twist-beam rear suspension, so should fit & cover the trailing arm part of the rear twist beam.
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Thanks, it would be great to see a comparison over the stone guards.

If there is a a 10 to 20% reduction in noise then it's well worth doing. These cars are quite noisy inside at speed.

Pictures done above in edited early post....

I notice a reducing in noise on quiet tarmac so no tyre noise...the fact that sat in the front I notice less noise from the rear means it has to be 10% minimum reduction...20% is maybe an overestimate on my part..but it gives you a range..

Also I have the estate which has a bigger void where the rear suspension is as the spare wheel well is more rearward & after the suspension. The hatch has less of a void as the spare wheel well sits on top of the rear suspension..
 

Nifa

New member
Location
Finland
Car(s)
Skoda Octavia
Yes there are MK7 parts to cover the MK7 torsion beam near the spring seats..also MK8 Golf/Polo part to cover the main cross piece section of the MK7 beam..

from the main aero trays how to guide I did:-

Yeah I have noticed those from your topics. :) But what I ment was is there an upgraded version like those in Mk8 versus Mk7 ones.
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Yeah I have noticed those from your topics. :) But what I ment was is there an upgraded version like those in Mk8 versus Mk7 ones.

Possibly....just info is hard to get due the current situation ....
 
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