Alternator with stripped thread!

XP29 · Post by **XP29** » Tue Jul 28, 15 5:55 pm

Hi, the belt on my alt needed adjusting as it had come loose coming home from Nats. Had a proper look today and the wrong bolt had been put in as it had stripped the threads. Looked to be 8mm ish but imperial, I tried a stainless 8mm that just stripped it further. When I pulled the bits of thread out I can get a 10mm in but it won't hold. The alternator is quite new (guessing bought last year). Is there a way of repairing this?

Pete · Post by **Pete** » Tue Jul 28, 15 6:05 pm

Can you post up a picture?

Can you just use a nut and bolt - is there enough clearance to get a nut on the back?

Normally the head size is 7/16" spanner...I think that may be 1/4" or 5/16th" - more learned people than me can tell you........

Mick70RR · Post by **Mick70RR** » Tue Jul 28, 15 6:40 pm

It's a 5/16" UNC. Same thing happened to mine and I fitted a helicoil.

XP29 · Post by **XP29** » Tue Jul 28, 15 6:44 pm

Got a couple of close ups. First is looking into the hole that the bolt needs to thread into

2nd is side on view of that part. There does not seem to be enough room to get a bolt head in there. The wire is plastic coated but guess it's bad if it's touching an earthed bolt?

XP29 · Post by **XP29** » Tue Jul 28, 15 6:46 pm

Mick70RR wrote:It's a 5/16" UNC. Same thing happened to mine and I fitted a helicoil.

How do I go about fitting a helicoil?

John · Post by **John** » Tue Jul 28, 15 6:51 pm

You can buy the kit on ebay where you drill and tap the existing hole then simply screw the new helicoil in which is basically a sleave that has the corect size thread internally for the bolt you need to use.

If you dont want to do that Ashpoles in Stortford have a chap that will come and do it for around £20 I think

XP29 · Post by **XP29** » Tue Jul 28, 15 7:00 pm

Cheers John. Just looking at Google at Helicoil and it looks like my alternator had one as there was a chewed up piece same as in the kits. So I need a new one putting in and a new bolt as that is chewed up also.

Pete · Post by **Pete** » Tue Jul 28, 15 7:01 pm

John wrote: ....If you dont want to do that Ashpoles in Stortford have a chap that will come and do it for around £20 I think

Well worth knowing, John

I bought a set off eBay and helicoiled the head exhaust manifold stud, also included the correct drill.............

aussie pete · Post by **aussie pete** » Tue Jul 28, 15 7:01 pm

http://pages.ebay.com/link/?nav=item.vi ... 1677426254

XP29 · Post by **XP29** » Tue Jul 28, 15 7:06 pm

Cheers guys, ordered one. But cutting it fine for getting it in time for the weekend.

Blue · Post by **Blue** » Tue Jul 28, 15 7:17 pm

I've got a 5 /16" UNC helicoil kit here you could borrow if you come unstuck, could no doubt find a bolt as well.

XP29 · Post by **XP29** » Tue Jul 28, 15 8:42 pm

Thanks Blue, I have ordered the 5/16 kit in the link above, also a generic mixed metric sizes one. Thinking handy to have in, plus as I think mine has had one in before the thread may need to go up a size to hold.

cadboy · Post by **cadboy** » Mon Aug 03, 15 7:02 am

I put in a helicoil in my alternator recently too used the M8 one and seems fine.

latil · Post by **latil** » Mon Aug 03, 15 7:52 am

We've used http://www.tracytools.com/ for years. Fast service and have just about everything thread-wise.

Captain Chaos · Post by **Captain Chaos** » Mon Aug 03, 15 9:08 am

If you are unsuccessful with a repair I have a new Alternator that I'd be prepared to sell,cost me £120 would take £60.