W124 E320 coupe rust on jacking points

[grantmackay80]

Hi there, I have just bought a 1994 E320 coupe and need to repair the rusty jacking points, all 4 need to be cut out and replaced. Can anyone tell me if there is a kit available to assist me is doing this. Thanks Grant

 

[GP801]

Dont think so. Its usually cosmetic on the sills around the jacking points. The actual structure that takes the weight is normally ok.

 

[grantmackay80]

Thanks for your swift reply, I think your right as I can see the structure and it looks good so I think I might turn some stainless tubes and replace the rusty one and replace the rotten sill are. Thanks Grant

 

[WDB124066]

Are you going to weld the stainless tube to the body...??

 

[kth286]

I do believe the tubes are available from Merc - do a forum search.

 

[grantmackay80]

I have a lathe and a welder so was planning on replicating the tubes the jack inserts into and replacing the rusty existing tubes then using sheet stainless 316 to repair the sills. If any of you kind fellows knows of a reason not to please let me know. Thanks Grant

 

[hotrodder]

Stainless to mild can make the mild steel side of the joint rust more quickly. This dissimilar weld can also produce some funky metallurgy... the weld itself will be a mixture of stainless and mild steel (i.e. very low carbon and high chromium diluted into relatively high carbon and no chromium) and the result can be a martensitic microstructure. Martensite is hard, it's what happens when carbon steel is quenched in knife making for example. Hard = brittle which is why knives etc are tempered to balance the hardness against ductility
There are specific stainless alloys for such dissimilar welds ('overalloyed' to account for dilution) like 309L, more usually 309LSi for MIG wire. Strictly speaking the usual MIG gases contain too much CO2 for welding stainless (too oxidising as CO2 is dissociated in the arc) but i wouldn't worry about that for letting some fresh metal into a car

Mild steel followed by cavity wax when finished is a better approach IMO

a2016160247 is a jacking point repair panel for the outer sill sheet metal. Dunno if they still are but used to be cheaper than making it from scratch even for such a simple panel

 

[WDB124066]

^ Correct.

 

[MCFastybloke]

"a2016160247"

Is this a part no for Merc dealer?

 

[hotrodder]

Yep. Useless descriptions from inchcape but sticking it into google and clicking images fixes that

 

[del320]

I have a lathe and a welder so was planning on replicating the tubes the jack inserts into and replacing the rusty existing tubes then using sheet stainless 316 to repair the sills. If any of you kind fellows knows of a reason not to please let me know. Thanks Grant

Great theory but the tubes are the least of your worries. Being quite substantial, I doubt rust will have much effect on their integrity - the problem is all the surrounding metalwork which will be weakened.

 

[grantmackay80]

Thanks

Thanks This helps a lot. Cheers

 

[bolide]

I was thinking about this the other day. I think you'd need a nice big chunk of Meroganny (as they call it in Hove) with a curve to match the profile of the sill, with a hole with a bevelled edge

Attach mild steel to wooden former, bash to shape, drill a pilot hole and swage the steel into the recess round the hole to fit the jacking tube

Voila - one custom sill repair panel!

Nick Froome

 

[hotrodder]

^^ Commonly known as 'hammer forming'. As long as there's no sharp corners you can get dozens of parts out of a hardwood former provided you work the metal down gradually to avoid large tucks forming. Even MDF can be good enough for a few before the edges break down

 

[grantmackay80]

Hi there, I ordered the replacement repair patches from Mercedes for a remarkable £6 each so very pleased. Thanks for the part number

 

[bolide]

Didn't know there was a repair section - time to order a few!

Nick Froome