Morris Minor Owners Club

Has anyone fitted a helicoil for a front damper mount, and who could give me some guidance?

Just noticed while checking the front suspension that I have a stripped thread on one of the damper bolts.

The thread on the bolt looks worn, with the edges of the thread worn down (see bottom pic). While a new bolt might do the trick, I'm inclined to think I will need to fit a helicoil. It's the upper bolt nearest to the LHS inner wing, so not the easiest to reach, but hopefully do-able with a flexible drill extension.

The bolt head is 1/4 Whitworth, so I'm guessing the thread is too - but I'm not sure. Nor do I know the size. Does anyone know? The head of the bolt is marked Ruben Owen 755 - 65.

And could anyone recommend where I could buy a decent make helicoil kit and inserts for this size?

Finally, any tips for a first-time helicoiler would be much appreciated!

Thanks all

Why not try a thread cleaner or tap through the nut first along with some new bolts.
The bolt doesn't look stripped , more worn than anything.

Hi

Those bolts are 5/16" BSF on my 1969 Traveller.

Phil

Which thread is stripped? Top or bottom hole?
Personally I wouldn’t helicoil it, I would drill and tap a flat piece of steel and cut a slot Underneath the Cross beam and feed it up, you will get more purchase on the tapped steel than a helicoil when you tighten it up. You could even weld the same size nut to the steel and run a tap through it to increase the thread depth.

The bolts are 5/16" BSF.
The bolts are quite soft compared to the captive nut
I would try a new bolt in the hole. Do not clean up the thread as the thread as is will hold the bolt better.
I also had the same problem on my Ser 2. Top outer hole. To overcome I cut a small slot in the inner wing at the end of the cross member and fitted a nut, spring washer and bolt. A flat ring is ideal for holding the nut through the slot. Cover the slot after fitting the nut and spring washer.
Good luck.
Phil

Thanks for the advice, everyone.

I like the idea of the bolt being sacrificial, and hope I can get away with just fitting a new one - I don't like the idea of cutting slots (I'm not sure it would be possible on my car because I think the bracket for the telescopic shock on the inner wing is welded across the end of the crossmember).

Fingers crossed!

Without going out to have a look do I remember a large hole at the back area of the cross member?
Enough to feed a nut/washer up.
Or have I got it wrong! (probably)

Alan

Alan
The hole is there but it is near impossible to get anything through it to repair the outer top damper fixing.
Phil

Thanks Phil - you were dead right!

I bought a new bolt and screwed it in with great trepidation, and was delighted to find it bit the internal theads and tightened properly.

Good thinking by BMC to make the bolts softer than the captive nuts!

I have just been faced with removing the bolt pictured below from captive threads.
Even with heat and plus gas it would not move but with gentle back and forth movement with a breaker bar and socket it eventually came free.
I cut off the excess threads so as to make removal easier. The 1/2" UNF male threads are as you can see shot but the female threads were ok.
So it cannot be assumed that because the male bolt threads are shot the female threads are shot also. In most instances the female threads will be ok.