Definitive 250 gearbox mount solution?

Discussion in 'Mechanical - Engine, Gearbox, Exhaust etc' started by dale.groves, May 9, 2016.

  1. -Jamie-

    -Jamie- RSM Moderator

    I may still have my old mount.


    Also, I seen it mentioned somewhere, I can't remember where. That the later lower mounts(FL 265's/275s/Trophy-R) are already drilled and actually use an M12 bolt, Different part numbers for the bolts and lower mounts. Think it was the French RS site, with photos to back it up. Worth mentioning
     
  2. Is it possible to get some part number for those later units?


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  3. -Jamie-

    -Jamie- RSM Moderator

    Send Paul at RPD a message, Tell him what part you want and quote a registration plate from a Trophy-R, he'll supply you the part number
     
  4. I changed the bolt on mine today. Not changed the mount as yet, mine looked ok though. I drilled it out with a 10.5mm drill bit first then started with an M12 x 1.5 tap but after about 5 - 10 mm depth I realised all I was doing was making the hole bigger and leaving no thread. Meh!

    Ended up using the replacement bolt itself to tap it out instead. Re-aligning the two parts of the mount to put it all back together was a bit fiddly. Removing the battery tray was quite possibly the worst bit of it all. What a PITA!
     
  5. And do you feel anything different in driving, stiffer or better gear change etc.?


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  6. Nothing at all. I suppose I feel a little more confident that it's less likely to fail now, with a heavier duty bolt. To be fair the original bolt looked fine when I took it out though. Paranoia made me change it.
     
  7. ianplymouth

    ianplymouth RSM Club Member

    yes please Jamie if you can find it :sunglasses:
     
    mrbull likes this.
  8. I have over 120k miles on the clock and still on the original bolt from the factory, last time i checked it, it was totally fine.


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  9. I totally get that. However, based on people on this very forum having had it suddenly go on them, for the effort it took, it's worth it for the peace of mind.
     
  10. -Jamie-

    -Jamie- RSM Moderator

    You can't tell by looking at it if it's gonna suddenly give up though, mine went at 35k IIRC
     
  11. which one is the new part? can i just use the old M10 bolt with the new mount?



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  12. The new style mount is the one on the left but the part that is known to fail is the bolt not the mount. Considering the bolt is the weak link, if you replace the mount then you should replace the existing M10 bolt with an M12 12.9 grade bolt. You probably could use the old bolt but I don't see why you would take that risk
     
    mrbull likes this.
  13. The new part is smaller and actually looks similar to the first model in my 250, PN 112200014r.
    d9574b67d5f46cabc7d1634e5fc6ab9b.jpg

    I was just thinking that the bolt failed probably due to the failed lower torque link or split rubber on the gearbox mount, which caused big movement of the engine...
     
  14. Had the bolt fail on my Megane as well, and just had it replaced (no time/room to deal with fitting an M12 bolt). For reference: my car has done about 71kkm (44k miles), no track usage, bolt snapped coming of a small roundabout while doing like 10mph.

    I was informed that the lower mount has been updated as well, 11.25.354.75R is the part number. Not sure what's different and wether you'd benefit from it if you're gonna drill it out to fit an M12 bolt anyway. :smile:

    Partnumber for the original (M10) bolt is 77.03.602.318.
     
  15. Mircea and maXX_CZ like this.
  16. Really good post with pictures and part numbers, cant go wrong.


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  17. -Jamie-

    -Jamie- RSM Moderator

    I dont think its quite accurate though, the info and stuff I've seen is that the 275 lower mount is different to the others and it already M12.
     
  18. Only info I was able to find using this online parts catalogue was this:

    112535475R BRACKET-GEARBOX Vehicle fabrication number >= 121024
    112530012R Vehicle fabrication number < 121024

    Appears that 112535475R is the newer lower mount, as I was told. Both use the same 7703602318 bolt, and that's M10. However that parts catalogue doesn't allow you to specifically select the 275...
     
  19. Great thread this.. I'm going to upgrade the bolt as a preventative measure.

    Can anyone tell me if my mount has already been replaced with the new style? Car is a 2010 Megane 250 CUP
     

    Attached Files:

  20. That does look like the new style mount idd!
     
  21. it is actually the earliest version mount. same as mine with PN 112200014R. It does look the same as the new style mount.

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  22. Hi all, I'm going to fit the later style mount 112212065R and tap the hole in the support to accept an M12 bolt. I don't have any larger metal drill-bits than 10mm, what size would I need to then tap a 12mm hole?

    I do have a 12mm tap, but its 1.75 whereas the thread above says 1.5, is this correct, or do I need to buy a 12mm 1.5 tap as well? Presumably the bolt is then M12 1.5.
     
  23. All the M12 50mm Grade 12.9 bolts I can find have a 1.75 thread.

    And apparently a 10.5-10.7 drill bit should be used for then tapping a 12mm hole.
     
  24. For the sake of clarification - the latest version of the gearbox mount is 112212065R and the gearbox bracket that the mount sits on is: 112535475R.

    I can confirm the mount is definitely still M10 and the updated reference bolt to go with it is: 7703602318.

    The bolt is also still M10 (obviously!) and the same 10.9 grade and the same 50mm length so not sure if there actually is any difference.

    And as I previously mentioned all M12 50mm bolts are 1.75 thread, rather than 1.5 as advised above in the guide.

    All the guides I found on t'web said to use a 10.5 or 10.7 bit to drill a hole to then tap to 12mm, but having done it I personally think this was a touch too large and 10mm would be better.
     
    Jon Birkett and MartijnGizmo like this.
  25. How does changing this mount differ to changing the stabiliser mount to an uprated version like the Vibratechnics or K-tec option like this: http://www.k-tecracing.com/show_product.asp?id=5086&appid=20

    Should I do both to be on the safe side? Any opinions on whether to go Vibratechnics or K-tec? Both the same money and do the same thing I guess!
     
  26. That is to replace the lower mount, people are changing the upper gearbox mount, and upgrading to an m12/14 bolt
     
  27. Thanks @Mikeyjp. Which mount is it that people have problems with it breaking, is it this upper mount or the lower one?
     
  28. The upper one like I said lol
     
    Somnambulist likes this.
  29. They don't do the same thing at all mate, one limits the engine moving under load, and the other stops the engine falling out of the car....

    Just follow the guide and you will be fine.


    I've replaced the top gearbox mount, upgraded the bolt, fitted a vibra pendulum mount, and powerflex'd the engine side mount, such an improvement over OE. Particularly worn OE!
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    Somnambulist likes this.
  30. Mines in on Thursday for the same things

     
    Last edited: May 8, 2017
  31. Has anyone's mount snapped? Did you still out the bolt? Or buy new bottom mount?
     
  32. Guess it would depend if it did any other damage
     
  33. Bolt snapped. So the bolt remains in thread.

    Silly design tbh.

    But it's £80.00 for lower bracket which is ridiculous.
     
  34. Here is a solution we made for a friend in Bulgaria with RS3 Trophy who snapped the mount. CAD designed, CNC machined, polyurethane inside.
     

    Attached Files:

  35. That looks like a very well engineered piece of kit! So the lower-bracket is held up onto the upper-mount by a nut, rather than by a bolt?
     
  36. A stud fixed to lower bracket with stop screw, a nyloc nut on upper bracket, polyurethane between the two.
     

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  37. Again, looks a very well engineered! Out of interest what's to stop the stud failing like the standard bolt? Are you thinking of producing these for retail?
     
  38. Stop screw through the stud, can not fall. It is on the road and track several months already. Can produce on order, yes.
     
  39. Please don’t think I’m being argumentative because I don’t mean to be – I am just genuinely interested. The failing point for the old bracket to mount was the relatively small diameter (and hardness) 10mm bolt, my question is why wouldn’t the new stud fail? Is it thicker/harder or just the design?? Magic question – what’s the retail cost?
     

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