SLK R171 Rear number plate fixing problems

[Jack Ryan]

Just bought an R171 SLK 350 and decided to replace the number plates with some private ones from one of my other cars. Big problem as on the rear plate I couldn't shift 3 out of 4 retaining bolts. One eventually sheared leaving part of the bolt flush with the top of the fixing.
Anyone got any ideas on how to get the remaining bolts out and remove the sheared part?? Really stupid design Mercedes I have to say.
Can these fixings be replaced??

 

[grumpyoldgit]

Spray the broken one/s with penetrating oil, leave to penetrate for a day or so, occasionally applying more. (Plus gas or similar). (Not WD40, it's not penetrating oil).
Drill the bolt with a smaller diameter bit and use 'easy-out'. (Screw extractors).

Screw Extractor 5 Piece Set | Specialist Drill Bits & Accessories | Screwfix.com

Apply grease or Vaseline to new screws.

 

[optimusprime]

Grumpy you wont eaze it out .These are rivnuts and put in with a tool .I did just the same a few months back .Bolt sheared off leaving the base in the boot lid.You can get them from the dealers .To get them out ,drill it out with small drill and a pair of pliers twist it off but watch you boot lid.The hole thats left in the boot lid is star shaped Then use a plastic insert and screw to that .Just for one corner it will be just as good ,and no one will see it .Seen the rivenuts on ebay ,but they are shallow ones .I thougt it was a nut and bolt ,but its that tight behind the cavity , you wont get a nut on it.They are like a tube with a nut fitted in the end .The special tool squashes it up .Look on the bay for rivnuts ,you will see what i mean..Second thoughts be very careful, this brings it all back to me now.I went at it with a drill ,and guess what it broke off .You see the bolts are brass and the insert is alloy.It spins off the brass or metal ,so be extra careful .Good luck

 

[Richardjames]

Mine arn't rivinuts just regular bolts!!

 

[Jack Ryan]

Thanks guys, whatever you do with these rivenuts seems to be a pain in the backside. Did a bit more research and the favoured method seems to be try and get the bolts out without shearing them off but if they do break, just fix the number plate on with 5mm double sided foam tape and do away with the bolts altogether.
Would rather go down the original fixing route but hey.......if it doesn't work I'm willing to go for a sensible alternative.........

 

[paulshep69]

I had issues with changing my wifes numberplate on her Grand Vitara, it had something similar to what your describing, I tried fairly unsuccessfully with double sided foam tape.

Instead I centre punched the centre of the sheared bolt and drilled the bolt out in stages, 0.5mm at a time from 3mm, till there was very little bolt left, be very careful to get as close to the centre of the bolt as you can.

If it hasn't loosened its self with the heat of drilling and screwed its self through then drill it out to 5mm and tap it out to M6.

 

[Jack Ryan]

Tried to get the remaining bolts out after soaking overnight with penetrating oil........all of them sheared off. Didn't bother trying easy-outs as let's face it......if a socket wrench on one side and a pair of mole grips on the other didn't shift them an easy-out isn't going to work. Cleaned it all up and put the new plate on with 6mm double sided foam tape......works a treat and looks so much better than a plate with four rusty bolts through the corners.........job done.