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    Results 1 to 6 of 6
    1. #1
      Join Date
      Oct 2012
      Posts
      38
      Country Flag: South Africa

      Welding on a unibody

      Hi guys, I was wondering if you can please help me with this. I have been searching all over but just can't seam to find the answer I'm looking for. I am looking into getting a old w108 Mercedes Benz as a project car so I'm doing some research into doing a rear end swap and replacing the swing arm rear end with IRS but that requires that I build a custom sub frame to mount the axle carrier to. Now I myself am not a fabricator but my friend is so he can help me fabricate,weld...etc. If you take a look at the picture I have attached you will see the rear end underside of the car I want to get,as you can see on the left hand side is a mounting point on the cars sub frame where one of the control arms mounts to. What I would like to know is can you weld your own sub frame to that sub frame as well as to the under side of the car? will it be structurally strong enough to mount an axle carrier too? not only that but in general can you attach your own sub frame to a car by weld your sub frame to the car's sub frame as well as the sheet metal of the body? From what I have read when weld to a unibody you are suppose to stitch weld, is that correct ?
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      Sorry if the question is a little confusing



    2. #2
      Join Date
      Mar 2004
      Location
      Mid-Michigan
      Posts
      2,764
      Country Flag: United States
      Not confusing at all. Look at some of the rear suspension kits that are offered for the early Camaro's. These use bolt in crossmembers that mount to the existing suspension pick up points. There is nothing different about your Mercedes that would not allow you to do the same thing. Get some very good measurements and design your new crossmember to fit. Adding doublers or bolt plates where needed to help carry the loads.
      Mark
      Mark:
      "Bad Ast" Astro Van. Just because I did it... Doesn't mean it's possible...
      This my Bad Ast thread...
      https://www.pro-touring.com/showthre...roject-Faze-II
      This is my Fotki album...
      http://astroracer.fotki.com/

    3. #3
      Join Date
      Oct 2012
      Posts
      38
      Country Flag: South Africa
      Quote Originally Posted by astroracer View Post
      Not confusing at all. Look at some of the rear suspension kits that are offered for the early Camaro's. These use bolt in crossmembers that mount to the existing suspension pick up points. There is nothing different about your Mercedes that would not allow you to do the same thing. Get some very good measurements and design your new crossmember to fit. Adding doublers or bolt plates where needed to help carry the loads.
      Mark
      Thank you, I was actually thinking of working from the pick up points and make cross member to fit but I think some of the cross member will need to be supported.
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      This is the axle carrier I was thinking of using but theres other options as well. Its the rear end of a bmw e39.
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      Here you can see the mercedes benz with the diff and one off the control arms.
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      This is from behind. It has a swing axle and only 3 mounting points, the 2 control arms and the mount the diff bolts to the body. I was thinking of building a cross member going from all the mounting points to make a frame for the axle carrier to bolt to on the 4 points on the axle carrier. But I was thinking I might have to weld the cross member to the under side of the body coming off the control arm mounting points. The other option is a tri 4 link rear end but I dont know if that will work and I would prefer the IRS of the bmw.

    4. #4
      Join Date
      Feb 2014
      Location
      Perth, Western Australia
      Posts
      2
      Country Flag: Australia
      Hi Loom,

      I've just joined this community myself as I'm very new to this form of vehicle modification.

      I too have just purchased a 1969 W108 280se. My intention is to run a Twin Turbo'd LS long block, 6 speed automatic and an appropriate tubbed rear end to take the abuse.

      Having looked at the rear end setup, I believe a custom irs setup can be achieved with the existing mounting points. As I will do in my scenario, approaching an engineer will help confirm any concerns you have
      with regard to building it to suit. The w108 is not a typical hot rodded chassis, with next to no information available. Forget the vintage MB forums, any discussion about modifying is usually met with elitist tunnel vision.

      Good luck :D

    5. #5
      Join Date
      Oct 2012
      Posts
      38
      Country Flag: South Africa
      Quote Originally Posted by Explicit View Post
      Hi Loom,

      I've just joined this community myself as I'm very new to this form of vehicle modification.

      I too have just purchased a 1969 W108 280se. My intention is to run a Twin Turbo'd LS long block, 6 speed automatic and an appropriate tubbed rear end to take the abuse.

      Having looked at the rear end setup, I believe a custom irs setup can be achieved with the existing mounting points. As I will do in my scenario, approaching an engineer will help confirm any concerns you have
      with regard to building it to suit. The w108 is not a typical hot rodded chassis, with next to no information available. Forget the vintage MB forums, any discussion about modifying is usually met with elitist tunnel vision.

      Good luck :D
      Hi Explicit,

      Welcome to the forum. Congratulation on your purchase, I'm still looking form the right w108 to buy, but I'm doing my homework while searching. It sounds like you want to put down some serious power, I myself was just looking into a bmw m50b25 engine with a 5 speed, it's a 2.5 liter straight 6 and can be boost to 400 - 450 hp on stock internals and will be enough for me for the moment. I hear you on the there's next to no information available and I have been on the MB vintage forums too,hahaha really cool to see someone else have the same vision as I do with this car. Good luck on your build and please keep us posted. ;)

    6. #6
      Join Date
      Dec 2010
      Location
      Germany
      Posts
      68
      Country Flag: Germany
      Hi, are there any news ?
      i have the same vision with an LS.........





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