Screw broke off in primary hub

[alexdecker]

Hey all

So when trying to change the rubbers, I realised that one of the three screw in the hub of the primary drive was broken off inside the hub. Didn't realise this before trying to take it apart completely.

I have attached some pictures for reference. Both sides of the hub, and with the broken screw next to a new one for reference.

I don't have access to any special tools - only a handheld drill and a heatgun. Does anyone have any advice as to how I could get this little bit out without breaking the threads? Last repair needed before I can assemble the motor

[Johnwebley]

It might be better to take it to an engineering shop,

To get it ,removed/drilled out/helicoiled,

It's not a place to have loose screws,

Your hand tools may not be accurate enough for the job

Sent from my SM-A750FN using Tapatalk

[Oddjob]

I have at least one of those spare, you could have had it FOC if you weren't in Europe.

[McCabe-Thiele (Ted)]

You are having some bad luck with seized stuff Alex - a used item might be cheaper than an engineering shop.

[alexdecker]

I have at least one of those spare, you could have had it FOC if you weren't in Europe.

What a nice offer, thank you. If you’d be up for shipping it to me, I don’t think the whole England/Europe thing would be a problem. I’d reimburse shipping costs of course. But can totally understand if you don’t want the hassle. But if you wanna do it, throw me a PM!

[alexdecker]

You are having some bad luck with seized stuff Alex - a used item might be cheaper than an engineering shop.

Haha, I don’t know if it’s bad luck or normal. Probably also because I am inexperienced and things seem harder the first time around. This broken screw was very much bad luck though!

[Oddjob]

I’ll have at look at one of my spares, will check that it will come apart as you don’t want to find out another screw breaks on the replacement.

[alexdecker]

I’ll have at look at one of my spares, will check that it will come apart as you don’t want to find out another screw breaks on the replacement.

That would be much appreciated, thanks! This is all that stands between me and assembling the engine again (I sincerely hope  )

[Oddjob]

It's been many years since I've had to do this job. As such I didn't seem to recall how the primary drive housing came apart.

Can I ask Alex why you took it apart, of tried to take it apart is more descriptive.

The reason I ask is that to replace the primary drive damping rubbers you don't need to remove those 3 screws, they are for access to the starter gear rollers and springs, I'd forgotten that. It's the circlip on the other end which allows access to the damping rubbers.

Anyway, mines apart. Came apart with no problems even after 40 odd years being stuck in a box in a shed with a leaky roof.

[alexdecker]

It's been many years since I've had to do this job. As such I didn't seem to recall how the primary drive housing came apart.

Can I ask Alex why you took it apart, of tried to take it apart is more descriptive.

The reason I ask is that to replace the primary drive damping rubbers you don't need to remove those 3 screws, they are for access to the starter gear rollers and springs, I'd forgotten that. It's the circlip on the other end which allows access to the damping rubbers.

Anyway, mines apart. Came apart with no problems even after 40 odd years being stuck in a box in a shed with a leaky roof.

It was only because the gear comes apart from the hub automatically, and when that happen, one of the three screws in the hub just fell out. I felt like I had to make sure nothing fishy was going on (with only three screws in such a crucial spot in the engine, I figured they better all be tightened down), and then realised it had broken off.

Yesterday I took my handheld drill and went to town on it. I figured I might as well, as I'd either get a new one from you, or buy one. So couldn't hurt to try and mangle my own a little bit. But some great stroke of luck, I managed to hit the center of the screw with a 2mm drill, and drllled through the screw in a straight line! I did the same with larger and larger drills, and after having gone through the hole with a 5mm drill, the remaining of the screw just kind of came out in a small steel spiral. Not believing my luck, I found a new screw and checked the threads, and everything was in order, and I now have a screw free hub, ready for service and three new screws!

So while I really appreciate your offer, it would seem I don't need it anyways! Phew, about time I got some luck with this seized old engine anyways 

[Oddjob]

Good result. And good that the starter clutch fell apart so you spotted the broken screw. Don't forget to use thread lock on the screws when refitting.

[alexdecker]

Good result. And good that the starter clutch fell apart so you spotted the broken screw. Don't forget to use thread lock on the screws when refitting.

Yes. Using new stainless screws all around the engine as well. Was thinking of using Loctite 243 on everything. That should be okay, right?

[Oddjob]

Very rarely use Loctite on bolts except where it's needed. I'd do the screws on the primary drive hub though.

If using stainless around the engine use nickel grease on the threads or there is a chance the thread will gall and it's virtually welded together when that happens. I had a new stainless bottom hanger bolt made, put 2 new stainless nuts on it, went to undo it a few days later and it was solid. It was so stuck that the bolt sheared in half before the nut released. Rang the maker and he kindly made me a new one FOC and advised re the grease.