If you ask a professional bodyman to do it, and he doesn't refuse, you probably need to find someone else.

There's a reason that car bodies aren't welded solid at all the seams.

So what would be the best way to strengthen it? If you rip the perches out and put in the new ones, you still have to weld it.

Answer
 

Grind clean the old spot weld, spot weld five points on the new perch, clean and seal all possible corrosion access to the new spot weld.

Extreme cleaning, before/during and after welding.
Extreme attention to sealing any possible corrosion access.



Have a great day.

The old perch's don't just fail, rust has to get at them. The 4 spot welds will hold it on for the life of the car provided they don't rust.

I almost wonder if it would be better to scrape all the undercoating away, and then just spray it with that wax undercoating and keep an eye on it. That stupid rubber undercoating is what's causing these problems. MB didn't use much on the W210, they cheaped out. Unlike the undersides of the W140/W126 ect which are liberaly coated in the stuff.

Is there a way to strengthen the existing one without removing it?

This is related to why spot-welds are used in the first place. The engineers do finite-element analysis to approximate the flex in the body parts, to determine and mitigate the effects of flex in the parts. The flex itself cannot be eliminated.

If you make the perch stiffer than it is supposed to be, or change how it's welded to the body, you may break something else after enough flex cycles.

Answer
 

NO, sorry for the negative answer, however I have looked for any alternative for years and found none.

Very few (in Michigan roughly one in four) show any obvious rust.

My automatic reaction to a W210 coming in for service is to measure the curb height, check the mount angle of the perch, and look for broken spring coils.

What a coincidence. I just saw a 210 at the shop getting the perch done. Here is what happened. The driver heard a "bang" sound and had issues with steering at slow speeds. Anyways, they usually take it to the body shop but somehow they did it at the service facility today.

The didn't weld it on. They riveted it.

Holy cheesy repair method Batman!:eek: I could understand the possible use of stainless hardware such as M10 or M12 bolts as secondary mounting devices to the welds, but rivets? I'm glad that wasn't my E320 you observed sitting up on that rack.:(

Chris

What is wrong with those rivets? Do you know how it is done? The broke 3 industrial riveters doing it. Then they borrowed the Body Shop's electric gun and it worked but it had to be recharged very often. Those are thick heavy rivets not the small ones you get at Home Depot.

They are not doing any more till they get another rivet gun that is hydraucually actuated.

Hi guys, I know I don't check up on tech stuff anymore, but a suggestion I thought I did make awhile back, and maybe Hunter can follow up on it. The 210 4Matic does have a reinforcement brace over the tower or perch, maybe this could be retrofitted to a 2wd (2Matic?) 210 perch???
Anyone ever see a 4Matic perch break???
Gilly

I would be very apprehensive about employing rivets on this particular type of repair because of the low amount of surface area that they rely on and their tendency to work loose from impacts and vibration over time. One must wonder if the engineers that originally designed the vehicle would approve of such techniques.

Chris

The procedure in WIS says to use rivets. One can only assume that the engineers thought it was a better solution than spot-welds, which aren't much harder to apply than rivets.

The perch is removed and the area sanded down. Then they will use the new perches which have a larger mounting area and a bunch of rivets that are thick.,

Curiousity forced me to make a trip out to the garage to see how other automakers secure their spring perches to the subframe. Upon inspection of my 1990 Mustang GT I found that Ford both riveted and welded the upper section that supports the front coils springs. Our BMW was only welded though.

Let's hope (for that owner's sake) that those rivets hold up better than the original spot welds did!

Chris