R129 - rear underside struts

[R129mine]

I have the car up on axle stands at the moment and noticed the 2x rear struts could do with a tidy up

according to ilcats these are part numbers

32	A1295240347	1	STRUT
35	A1295240447	1	STRUT

one of the torx55 bolts is badly rusted and almost did not come out but WD40 and a large breaker bar did the trick

Will be cleaning up the discs and strut bars and do a rust treatment and respray

Hopefully MB parts department is open again for replacement screws

I cannot find the part number for the discs at the end. I think they are this part number

45

A1295240176

2

DISK

but not entirely sure as it seems to be for the front struts.

does anyone know? May be easier to get new ones rather than trying to de rust and clean them up

 

[R129mine]

First cleanup with axle grinder. Right one is badly pitted. Will try and remove most of it

have not had much luck with hammerite or jenolite in the past and don’t want to apply por15 or dinitrol on these parts.
What product do you recommend I apply before zinc priming it and spraying it black?

 

[R129mine]

The discs have been sanded down with the grinder

and are now enjoying their citric acid bath


one of the disc may be too rusty to be used again but will see what it looks like tomorrow

 

[Yogioes]

For the front pair, I wire brushed with the angle grinder, rust treatment and painted with Smoothrite. Refitted with new bobbin bushes as the old ones had separated.
For the rear pair .... I took the much easier option of taking them to the powder coaters.

It's only been about a year but the powder coated ones certainly look better.

 

[R129mine]

I have not had great results with various rust treatments and media blasting and powder coating gets the best results I agree. Although a part I had powder coated 2 years ago cracked a little bit and rust appeared underneath.

I am experimenting with various solutions and see how I get on.

• Grinding down with axle grinder
• deox gel or using citric acid which is basically the same thing
• And considering wet sand blasting with pressure washer but not tried yet
• Not sure on coating I will use. Por15 and dinitrol or good but finish is not always as nice

anyway will try some different finishes and see which ones work and which ones don’t and will see what it looks like in a years time.

 

[Eduardo]

I had done a full suspension and drive train rebuild in a pretty rusty '00 TT quattro, the chassis was good but all the suspension and drive train components were rusted (superficial, nothing structural).
Someone recommended me to send everything for powder coating, but this was a weekend hobby so I actually (power) brushed it till metal and used smooth hammerite on it, 2 layers. Two years on and very little rust appeared (mostly out of some chipping), so I believe with a 3rd layer it would have been completely sealed.

 

[millo777]

I always find powder coat tends to chip quite easily then rust starts again and gets underneath it and it all gradually flakes off.

The best solution I've found is using a heavy zinc primer and then a 2k epoxy paint. The Bilt Hamber electrox zinc primer followed by the Spray max 2k black epoxy primer in an aerosol are the most convenient without having to use compressors and spray guns.

I've done quite a front anti roll bars using these over the years and so far they've all held up really well.