R129 rust help

[Sdemon]

Dear all

Recently had my front 2 wings re done due to rust.

I noticed that unfortunately a lot of the suspension parts are now showing rust: drive shafts, control arms even the surface of the differential.

Unfortunately I didn’t get a chance to take any photos when it was on a ramp but my question is and to avoid replacing parts which are expensive or do not exist anymore from Merc could I:

1) use a steel wire on all surfaces to remove as much of the rust as I can?
2) using something to treat the rust without taking things apart
3) rust preventions/ coating option/ painting

I have read a number of articles of using agents such a por 15, bilt hamber, hammerite etc but tbh I’m lost about the whole situation.

I would prefer to be honest an expert to do this sort of thing as I’m short for time so if anyone could suggest someone in the region of London I would greatly appreciate it. Just don’t want to get taken for a ride.

Many thanks in advance

 

[LostKiwi]

Without pictures it's not possible to say whether it's an issue or not.
129s are not particularly known for any issues on the components you mentioned so I would suspect it's nothing more than surface rust.

 

[Sdemon]

Right. Let me get to the ramp and get those photos for your review.

Thanks

 

[Frontstep]

Selfie stick ?

 

[mioba]

The locations you mention would be surface rust, so your 1-3 seems logical.

Its the rot rust that you need to be weary about on eg the chassis, frames, wings etc that needs care (metal cutting out and replacing). I note you had the wings done, be prepared that it will come back in a few years unless it [the rust] was cut out out and new metal put in or you replaced the wings.

 

[Sdemon]

 

[Sdemon]

Here are some photos.

Many thanks

 

[LostKiwi]

Not pretty but most of those wouldn't be overly concerning. The second from last would bear a closer look as there appears to be a hole.

 

[mioba]

WHS above.

If your handy and concerned, wire brush and waxoyl.

If not you can ask a bodyworks place to do it.

nothing overly concerning there

 

[Sdemon]

Many thanks for your review and will get it checked out.

Could you advise me on these options if at all they are appropriate and make sense ( from other posts about rust)

Step 1) wire brush it
Step 2) options: rust ceasing. eg bilt hamber deox gel or rust curing eg hammerirte kurust
Step 3) zinc primer
Step 4) black paint eg: VHT chassis and roll paint

Within all this: waxoyl, dinitrole has been mentioned but was not sure if that works with these specific steering and suspension parts.

Just trying to find what the best method would be

Probably give it to a body shop guy to do as am time poor at the moment.

Thanks for your help

 

[charlysays]

Many thanks for your review and will get it checked out.

Could you advise me on these options if at all they are appropriate and make sense ( from other posts about rust)

Step 1) wire brush it
Step 2) options: rust ceasing. eg bilt hamber deox gel or rust curing eg hammerirte kurust
Step 3) zinc primer
Step 4) black paint eg: VHT chassis and roll paint

Within all this: waxoyl, dinitrole has been mentioned but was not sure if that works with these specific steering and suspension parts.

Just trying to find what the best method would be

Probably give it to a body shop guy to do as am time poor at the moment.

Thanks for your help

For suspension parts which are replaceable and made of thick metal, you just need to arrest corrosion and seal it. So start with a thorough degreasing, bilthamber surfex hd for example. Once dry wire brush. Straight bristle wire wheels on a drill will safe you a lot of elbow grease but you'll need an array of various size hand wire brushes to get into awkward areas and shapes. Then use a good rust converter like the dinitrol epoxy based one. Hydrate 80 from bilt hamber is a close second.
Then just apply a chassis black paint. Don't bother with zinc primer. It is not surface tolerant (needs an almost rust free surface plus a coarse scratch pattern to work well i.e much more prep than just wire brushing) and if you have used a rust killer/barrier like hydate 80 it won't be in contact with the steel anyway.
I would finish off with a coat of lanoguard topped up yearly, or more cost effective is bilt hamber dynax UC. Just a thin coat before winter on everything after a clean down will stop this kind of running gear rust.
This will keep the running gear looking good and protected for a long time.

For bodywork you probably need a more professional approach which is time consuming, the reason being the bodywork isn't easily replaceable and is often thinner metal. For underbody areas remove rust to atleast st2 surface prep spec, ideally st3, scratch it up good with abrasives, make sure it's thoroughly degreased (use BH surfex before starting prep then panel wipe before applying coating) then apply two coats of epoxy mastic. I prefer jotun 90 alu winter grade but bilt hamber epoxy mastic is very good if a little pricey.

One thing to note with panel corrosion on wheel arches etc is that it can be permanently cured without cutting it out but it requires meticulous use of rust removers like deox gel.

 

[charlysays]

The locations you mention would be surface rust, so your 1-3 seems logical.

Its the rot rust that you need to be weary about on eg the chassis, frames, wings etc that needs care (metal cutting out and replacing). I note you had the wings done, be prepared that it will come back in a few years unless it [the rust] was cut out out and new metal put in or you replaced the wings.

With the way most body shops deal with surface corrosion, I agree with you. But if you are a DIYer with a bit of know how and some time and perhaps a spare car you can use for a few days, permanent fixes of merc surface corrosion are possible without getting the welder out.
The key is turning the rust into an island, taking away a margin of sound paint around it. Then use power tools (wire wheels, needle guns, DA sander with coarse pads, grinder with flap wheel etc) to remove the bulk of the surface rust without attempting to grind away good metal to get at the rust in the craters. Then use bilt hamber deox gel (or if you want to go cheap, buy 45% phosphoric acid and mix with scolacell cellulose powder until it forms a thick gel which will cling to vertical surfaces). After a few days and 1-3 applications there will be no rust left whatsoever, even in the bottom of deep craters. All you need to do then is ensure its thoroughly degreased and scratched up with 40-80grit scratches and then epoxy prime with lechler 29107 or even an epoxy mastic.

about 10 years ago I used this method (except I used bilt hamber electrox 1k primer) on a pair of W202 wings which were badly pitted and pinholed in places. One of the wings got accident damaged but the other one has just been painted a different colour and fitted to my current W202, still no recurrence of rust after 10 yrs and tens of thousands of miles in all weathers, salt etc and this would have been labelled a scrap wing by most body shops.