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MG TD TF 1500 - Heli Coil Kit 1/2' BSF

The mounting holes of the TF front bumper were stripped by the PO. The bolt size is 1/2"-16 BSF (thanks Dave Dubois). I'd hate to buy a HeliCoil kit (~$100) just for this one-time use. Does anyone have a used kit they would like to sell? (I already have a couple of metric HeliCoil kits leftover from the engine rebuild (M12 and M8), I'll probably never use again).

thanks,
Tyler
Tyler Irwin

Tyler,

I can imagine there is a lot of force on the mounting bolts. I would suggest, therefore, that a Helicoil may not be the strongest solution. Rather, I would suggest that you weld up the hole, redrill, and retap.
Lew Palmer

Tyler, are you saying the holes in the front of the chassis were threaded, one on each side? There s no evidence of threads ever being in mine. Could someone confirm this. PJ
Paul S Jennings

A helicoil repair is as strong, if not stronger than the original thread. That said, $100 for a single repair is rather steep. Have you considered drilling the original hole out and just using a plain bolt and nut as Paul is suggesting? Cheers - Dave
D W DuBois

Tyler if the threads have been simply stripped and not drilled out a M14 tap will probably give you a good thread. You can then use easilly obtainable stainless bolts. No one will ever know apart from the lack of rust. Much, much cheaper than buying a Helicoil or Wurth kit.
Paul if there are no threads in your chassis how is the bumper attached? Have you got nuts and bolts? If so do you have access to the nuts?

Jan T
J Targosz


1. Paul: Yes, there are remnants of threads in the frame horns where large bolts once threaded into, and I have the original bolts(see photo).
2. Paul: Yes, drilling out the holes and installing nuts & bolts is possible IF there's enough access to fit a nut and lock washer on the bolt from behind.
3. Jan: The M14 Helicoil kit is an option (~$50), but I might as well spring for the BSF HeliCoil kit (~$100) if I'm going to buy a kit, since I already have the BSF bolts.

Drilling out the holes is the cheapest way to go, and probably the strongest support, but I have my druthers about screwing with the original design.

Any more thoughts? I appreciate the advice.

thanks,
Tyler

Tyler Irwin

Hi Tyler,

There is no need to Helicoil to M14, you can run a M14 tap down a worn 1/2" BSF with little trouble and end up with a good thread. A full set i.e. plug/taper/bottoming taps on eBay costs £6 and a pair of stainless bolt £4. If you try the Helicoil or nut and bolt route you will have to redrill to oversize 1/2" and I don't know if you have an electric drill of this capacity. Ones in the UK are virtually always 1/2" max.

Jan T
J Targosz

I didn't pay any $100 bucks for my helicoil I got at Napa!
efh Haskell

The $100 is for a 1/2"BSF HeliCoil kit from British Fasteners (not available at NAPA), but I think I'll go with tapping a M14 into the stripped holes.Fast, reasonable, semi acceptable.

thanks, Tyler
Tyler Irwin

My front bumper is held on with two 1/2 inch bolts and lock nuts. Bit of a pain to tighten up, but once tightened up, there's no way the bumper will ever move. Had I thought of it earlier, I would have tack welded the nuts in place. To do that now I'd have to pull the rad and grill off, no way I'd weld anywhere close to the new grill. PJ
Paul S Jennings

This thread was discussed between 18/12/2014 and 19/12/2014

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