Will this present a problem?
 

My new wheels will not fit [front only] unless i remove the dust cap and that little brass spring plus adding a 5mm spacer. The spacer does'nt bother me, but removing the dust cap does.The problem is the center MB cap hits the large bolt holding the disc on. With the cap off and the spacer on all should fit.

That dust cap is what keeps the dirt,dust, crud and water out of your wheel bearings...you really might want to have it. Better off to find a set of rims with the proper offset for your application. Also, bear in mind that adding spacers will leave you with less lug bolt actually threaded into the hub, which could result in losing a complete wheel while tooling down the road.

But hey, it is your car.

Hay Mike: i just measured the lug bolt and added the 5mm. spacer,and without the dust cap there is .493 of thread left.If i leave the dust cap on i will need at least 3/8 spacer. Is 3/8 too much? I will get longer lug bolts from the company.

Anybody!

I'll try to more more blunt...you have to have the dust cap, lest you destroy your wheel bearings and spindles.

Any spacer is iffy and a 3/8" spacer is definitely too thick in my opinion, but you know what they say about those. Also, if you get longer lug bolts what is to keep the next tire shop from mixing and matching front to rear with the lugs? What you get then is destroyed parking brake assemblies.

"Dust cap" doesn't tell the full story. Wheel bearing grease is wonderful stuff. It's gooey and stays in place when you're working on it, and fluid enough to flow where it has to at operating temperature. Without a cap, you'd likely lose enough grease over time to ruin the front wheel bearings. And you'd have awfully messy wheels.

Sixto
95 S420
87 300SDL

Not only that but the wheel bearing housing is actually taking the load of the front wheel. In your case, the wheel is farther out, there is less load bearing area, the lug bolts are taking more load, the zero offset front suspension is no longer a zero offset front suspension and it's a really bad idea to just add small spacers. Better to get a proper spacer plate or the correct rims.

Failure could be disasterous.

I just had to say something about this, I see all kinds of Mercedes cars with wheels from who knows where. I would think that the wheel on a mercedes is engineered specifically for that car and therefore the the best wheel for that car. I would never drive a Mercedes very fast with some other kind of wheels on it. Some people are more interested in bling bling and getting attention than they are with safety and engineering. Keep the car the way it was designed. Mercedes Engineers have been doing this longer than I have been alive and I believe the wheels they put on my car are probably better than something I can pick up at a local tire shop.
Those shiny wheels are nice, those bigs wheels get attention, but I would rather have peace of mind that I am not causing undue stress on my suspension components and a potential hazard of a wheel flying off, I also have comfort in the fact that I would rather have money in the bank than pay to replace something that works perfectly fine already.
Keep the car a Mercedes!
Happy Benzing,
Brian

Be very, very, very carefull with spacers!!! You really should not use them on a Mercedes your wheels could fall off and kill you!!! The hub supports the wheel not the lug bolts, by putting spacers on their you are making the bolts take the load, they are not built for that and can share off. I went threw this with my SDL when I got the wrong wheels, they were to wide for the car. The only "safe spacers" to use are the H&R hub centric ones, their 40mm wide and extend the hub to support the rim. But the wheels will stick out and look stupid with them, not to mention their $150 a set so figure $300 for the whole car. Just buy the right wheels.