727 Transmission rear mount bolt hole stripped

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Goblinking
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727 Transmission rear mount bolt hole stripped

Post by Goblinking »

I was looking under my car and saw one of the transmission rear mount bolts was hanging out.
I took it out and saw the threads were full of crumbly dusty stuff,i went to put it back in and it wouldnt bite.
It looks like someone might of chemical metalled the bolt in.
Should i tap the hole or helicoil and if so,what size bolt do i use?

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MattH
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Re: 727 Transmission rear mount bolt hole stripped

Post by MattH »

Im sure a helicoil or similar will be ideal. Size wise, I am not sure but probably measure what you have then check some helicoil charts.
You may find metric stuff is more common, so be careful. I am sure there will be UNC helicoils.

There is another type, similar to helicoil, the name escapes me, but a local Alfa specialist fit them to all the fixing points on their aluminium heads where studs or bolts just go into the ali.
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ScottyDave
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Re: 727 Transmission rear mount bolt hole stripped

Post by ScottyDave »

I think possibly 3/8 UNC the transmisson mount threads on my 904 don't feel particularly good either, I was planning on using this
https://www.ebay.co.uk/itm/331514010047
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MrNorm
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Re: 727 Transmission rear mount bolt hole stripped

Post by MrNorm »

I did this years ago on my 727 for the same reason, I bought a helicoil kit for the right Unified size (can't remember offhand but could try to look ifneeded). It worked perfectly and was not difficult, I never had any issues
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Pete
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Re: 727 Transmission rear mount bolt hole stripped

Post by Pete »

It's bigger than 3/8 UNC.

The bolt head should be 5/8" so you can use that on a look up table for the correct shank size.
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mopar_mark
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Re: 727 Transmission rear mount bolt hole stripped

Post by mopar_mark »

Most likely 7/16” UNC
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Goblinking
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Re: 727 Transmission rear mount bolt hole stripped

Post by Goblinking »

I ended up helicoiling it and it worked a treat.Size M10.
Last edited by Goblinking on Wed Mar 31, 21 9:36 pm, edited 1 time in total.

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Pete
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Re: 727 Transmission rear mount bolt hole stripped

Post by Pete »

Well done! Sorted!
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Goblinking
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Re: 727 Transmission rear mount bolt hole stripped

Post by Goblinking »

Thank you,it was a relief it worked,its the first time i have ever used a helicoil.

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Pete
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Re: 727 Transmission rear mount bolt hole stripped

Post by Pete »

I had to helicoil the pump bolts, but had to trip the entire trans to do it!!!
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