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Rusty Rear Subframe/Suspension - A Few Questions

24K views 57 replies 15 participants last post by  Pete Mac  
#1 ·
This weekend I disassembled the whole of the rear suspension, all went surprisingly well with only two badly corroded bolts to cut out.

The rust is only surface to both suspension and underboot floor area so nothing too nasty, but unsightly none the less, a few bushes look due for changing so I believe I have caught this at just the right time.

I am now in a dilemma as how to tackle the next stages, which I have broken down into three possible options.

1 - Replace all parts (other than subframe - that will be shot blasted and painted/powder coated) with new V.A.G parts - that's bolts, bushes, arms, shocks etc estimated cost?? Would be around ÂŁ1000 plus

The reality of this is that it's not cost effective and so will probably not happen

2 - Replace all parts (other than subframe - that will be shot blasted and painted/powder coated) with new after market parts - that's bolts, bushes, arms, shocks etc I have been trawling eBay/buycarparts etc and it seems the parts could be around
ÂŁ500 ish including the cost of the sub frame refurb (estimate about ÂŁ100)

This seems a good option, but I am concerned about using pattern parts, although after some initial research amongst friends and online it seems that the standard of parts from sone manufacturers is to a very high O.E.M standard, it's just getting used to the names...Febi, Lemforder, Mapco amongst many.

Funnily enough, from my initial fears I have discovered that one of the above mention brands are O.E.M suppliers to ahigh end German car maker! :p

Another good thing about using this option is that it will cut my physical input down allowing me to get on with the boot floor.

3 - Renovate all metal parts - Subframe, arms and metal components at a local shot/sand blasting company and replace bolts/bushes/shocks with new. I am unsure of price but would probably end up costing more than option 2 in terms of time and money.

The big advantage would be that the suspension arm pressings would all be original, but does this really matter? Some parts after all would be pitted from the rust even after blast cleaning and recoating.

I would need to drop the metal work off without any bushes, that's fine as I intend to replace them anyway, but it's a 40 mike trip to a garage I use to remove and then replace once the metal work has been cleaned and coated.

So my questions are:-

Is using original/genuine V.A.G parts important?

Anyone have any aftermarket horror stories regards suspension components?

What brands to avoid?

Should I consider using updated bushes like Powerflex?

Any input will be greatfully received.

For a laugh/gasp of horror, a picture of the task ahead.... :p
 

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#2 ·
Looks a great job you are doing here.

As far as bushes go, my thought would be to go for powerflex, as they are poly bushes not rubber, therefore they are a fit once and forget item, and if you are going to all this trouble, why not go for the upgrade, and come away with a better handling car as a result!

Mine is going to get the complete bush kit done as part of the chassis upgrade, thankfully mine is rust free already!

Richard
 
#3 ·
Funnily enough I spoke to a fella at a local garage and he said that some of the bushes were not available separately, this put a spanner in the spokes...

I then went to the powder coaters and he said why not use powerflex bushes, an added bonus is that you don't need a press to pop them in, I will do a little research.
 
#4 ·
r_turner01 said:
they are poly bushes not rubber, therefore they are a fit once and forget item
while I agree that poly bushes are a performance improvement, and probably the best choice here, they're hardly a "fit and forget" replacement... poly bushings deform plastically over time, compacting under compression and eventually requiring a refresh. look at most poly engine mounts after 10-15k miles you'll see these effects, provided they aren't of a molar-jarring durometer rating. same goes for the front control arm bushing that people frequently replace with poly. I expect that they'd last much longer in the rear suspension than front, but would still be wise to inspect more frequently than rubber.
 
#6 · (Edited by Moderator)
On the subject of non-Audi parts, remember that VAG do not make all the parts of your car, they buy in many parts from a huge range of suppliers / manufacturers. If you buy a bought in part from Audi you will be paying the price the OEM charged Audi plus Audi's markup. If you an buy it direct from the suppliers then you are getting exactly the same part for significantly less money.

The car manufacturers mark-up is/was so big that it became commercially viable for third party firms to buy parts from the OEMs and then sell them on to the general public. This is how Euro Car Parts and German & Swedish started business. The problem is of course sorting out the real OEM part from the cheap copies. Many traders are a bit economical with the truth when they claim that they are selling OEM parts. Often what they are saying is that company X supplies at least one part to Audi so therefore everything that company makes is an OEM Audi part.

Personally I would hardly ever buy a 'genuine' suspension part. I'm new to Audis but have owned various BMWs for many years and have had good success with Lemforder, Febi(Bilstein) and Meyle. Some genuine pats are not as good as they could be and occasionally third party companies produce parts that are better than the originals e.g. Powerflex and Meyle.

I have used poly bushes on several cars previously and they do seem to last well, however they can be significantly stiffer than the originals with a consequential impact on the ride. For me the big advantage is that they can be fitted without a press. Carefully saw the old one out and no press required. I do have one horror story about them though. I replaced the inner wishbone bushes on my MGF with Poly ones but they were so tight that they prevented the wishbone turning as the suspension moved, instead the wishbone flexed when I hit a bump. The eventual out come is shown below.

IMG_20161025_183522932.jpg


IMG_20161025_183634438.jpg
 

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#7 ·
Hi John

Some great advice there, thank you.

I have been looking at the (apparently) sister company to Euro Car Parts - Buy Car Parts and have been getting prices for the parts needed from Lenforder/Sachs/Mapco. I was unsure of Meyle, but it seems they are ok? Mapco seem to be a big brand but I know nothing of them, I read that Lemforder are O.E.M for some parts for Porsche, so that's good enough for me! :p

In the past I have used Powerflex bushes on a few cars cars - Ford XRs/RSs etc with great success, can't believe how much they have gone up! :eek: This car is a weekender for two old biddys (Wife & I) so a harsh ride is something I really don't want, life can be bad enough.... :p

I see you mention an MGF, I once had a TF160, was you a member of the MG-Rover website?

Update

I have been running around getting ideas and prices and at the moment it's looking like the most cost/time effective way to deal with this project is to buy all new suspension components from Buy Car Parts, Lemforder are my top choice at present.

The upper/lower wishbones, tie rods, trailing arms, drop links are coming in at around ÂŁ270.

I went to the powder coaters and they gave me a price for the subframe, anti roll bar and all the parts mentioned above (and in the picture in the initial post) of around ÂŁ200. But if I do buy new parts that will have to be adjusted as I will only be getting the subframe, trailing arm/chassis connector boxes, anti roll bar and springs ( noticed a tiny amount of rust on each one when removed) shot blasted and powder coated.

Bushes are working out around ÂŁ60 for the dozen or so needed, I was told by a fella at a garage that it's cheaper, in the long run, to simply replace the whole assembly rather than re-bush, he's sort of right. Cost wise new is dearer, but not by much, but there is time running around dropping off and picking up to be added. I would still like to go this way, my heart says yes, my head says no... :p

New bolts (Lemforder) are coming in at around ÂŁ60

On a quick inspection of the boot floor it does need a little tickle up here and there, but it's not worth getting over animated about it, I will know/see more once I have steam cleaned it. I have seen much worse corrosion, but NEVER on a 9 year old car! My opinion of Audi quality is a little shell shocked at the moment...
 
#8 ·
happychappy said:
I did a little research and they are way too expensive for me, a rough estimate is nearly ÂŁ500 just for the rear!
Would be worth speaking to Awesome GTi, ask for Stephen he really knows his stuff. They are also UK suppliers of all things powerflex.

I am not affiliated with them in any way but I will be having the full kit myself from them along with some other work hopefully not to long from now!

Rich
 
#9 ·
To be honest after some considered thought I am going for the standard bushes, from memory the Powerflex bushes made one of my cars very harsh, maybe the compound has been changed?

Anyway the cost far exceeds what I am willing to pay, I would rather that money go to other things that I will be tackling soon.
 
#10 ·
Dare to post a pic of the trunk floor area without the suspension blocking the view? Even though these mk2 are mostly aluminium but the rear section is steel and can rust. My car has been dailydriven for the 12 years (and almost 270k km) of service in harsh finnish weather. Though what I have seen pictures of undercarriages on uk cars we can't compete, you guys have a serious problem with rust because of the climate.

The trunk floor area from below on my car looks like it could use a little cleanup and I might aswell do something similar to it next summer when I have my summer car on the road. To keep it from getting worse. Suspension parts look fine on mine, just dirty.
 
#13 ·
Totally agree Tev.

I am so glad I caught it sooner rather than later!

There are many saying that their car is fine, I thought this until I delved a little deeper....

There is minimal protection paint and wax in this steel boot area and unless you know where to look you may well pass yur car off as fine, however, as a rule of thumb, if your subframe/wishbones/shocks are rusty then next time it's up on a ramp have a good look past the suspension components towards the boot floor/fuel tank area, it may be only a little surface rust at the moment, but that will soon escalate.

Hopefully people will read this and make themselves aware of what may well be going on in the deepest darkest Bowles of their cars. :p
 
#20 ·
happychappy said:
Hoggy said:
cancellara27 said:
Is there anything recommended to put on the steel to prevent it from rusting?
Hi, Waxoyl, ACF 50 etc.
Waxoyl would be my preference.
Hoggy. :D
Would you paint before the Waxoyl?
Hi, Definately not, waxoyl won't be able to treat the corrosion if you paint it.
Put the waxoyl can (not aerosol) in a bucket of hot water & spray it on, after removing any loose rust.
Hoggy. :D
 
#21 ·
Aha, I am trying to prevent future corrosion with the wax, not cure what's there now.

The underside does have some kind of wax, mainly around the box sections, but no where near enough to prevent what's happened.

It's this kind of O.E.M finish I am trying to achieve so that the underside looks as original as possible.
 
#22 · (Edited by Moderator)
happychappy said:
Aha, I am trying to prevent future corrosion with the wax, not cure what's there now.

The underside does have some kind of wax, mainly around the box sections, but no where near enough to prevent what's happened.

It's this kind of O.E.M finish I am trying to achieve so that the underside looks as original as possible.
Hi, Still spray it straight on to the metal. No good having original rusty & corroded. Original wasn't painted :?
My Front & rear suspension is treated with Waxoyl. Pic of the rear.
SANY0276.JPG

Hoggy. :D
 

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#24 ·
That's where an attack with a wire wheel, a coating of Krust (or similar) then finish with a top coat of Hammerite (or similar) comes in.

Think we may be a little at crossed purposes, the boot floor does have some paint on it, looks like a smooth primer, but no topcoat.

The waxoyl will be used in the box sections and a mist over the suspension,boot floor and surrounding nooks and crannies.