Sheared bolts on sump guard. What's easiest?

[Rob Cowell]

I know I'm not the first person to do this. Have always done my front diff oil every 20,000 miles. The time I leave it 30,000 miles and of course the bolts are seized solid. Got half out with the blow torch, but still managed to shear the other half.

I've drilled and tapped bolts before and it was a ball-ache, and these will need to be done laying on my back. Was thinking rivnuts, but then I'm guessing I need to get rid of the captive nuts first? How? What's likely to be the easiest fix?

Ta

 

[goodoldboy]

I can't really see any alternative to drilling and tapping Rob hopefully someone will have a better idea.

 

[Rob Cowell]

Oh well. At least I changed 1.3 litres of lovely clean EP90 for 1.3 litres of lovely clean EP90.

 

[goodoldboy]

I've no idea of where it bolts onto exactly but could you drill and tap nearby ? might be easier ?

 

[Rob Cowell]

Yes, probably could. It's certainly hit a lot over the years looking at it, so whatever I do it'll have to be soon.

 

[Tractionman]

Im sure you know Rob, but here goes anyway. Rivnuts or similar are for cavities and have a collar on the front that protrudes slightly and the rear is squeezed up inside the cavity with a tool or a bolt nut and a spacer. If so I cant see that it will take the place of a captive nut, or have I understood you completely wrong. Sorry if that's the case.

 

[karl2000]

Which bolts are the problem? Front or back?

 

[Rob Cowell]

One at the front, one at the back.

 

[Rob Cowell]

I haven't used rivnuts before. Rivets, yes. And I assume the principle is similar in fitting them. If I understand them they would be an alternative to a captive nut, but wouldn't work if a captive nut was in place because they wouldn't be able to expand in the cavity?

 

[Tractionman]

Yes, correct as I see it. As for 're tapping elsewhere, there wouldn't be enough thickness for thread would there, hence captive nuts. After all that, still no further forward. Bu@@er !

 

[Rob Cowell]

But I should be able to drill a hole in a new location and use a rivnut, shouldn't I ?

 

[karl2000]

It might be worth considering an aftertmarket bash plate? I know some of them have their own brackets that attach to the factory holes, then the plates attach to the new brackets.

Just thinking you could drill the snapped bolt out and possibly just use a nut on the other side to attach the bracket, which would be OK as you won't be removing it ever again....

Not sure you can attach a rivnut to something that thick, but I might be wrong.

 

[TonyP]

Drill and tap from my perspective, but what a ball ache

 

[Tractionman]

Rob, yes, and as well as different diameters/ thread size, they come in different lengths.
I am in the process of fitting some to my chassis rails.
There are alloy, plated steel and s/s with different weight strengths for different applications

 

[flint]

Not infallible, but sometimes a good soaking of Plus Gas and a left handed drill bit does the trick.

 

[Jon Wildsmith]

weld a nut onto the bolt shaft. Takes a bit of practice and can be tricky but works every time for me. Much easier than drilling and tapping imho.

 

[Tractionman]

Yes, with the drill in reverse, it could wind it out if it gets a grip.

 

[bones]

You can get left hand drill bits . A few cycles of heat can help, to be honest I wouldn't fit rivnuts. You could drill it out and fit a threaded insert, like a helicoil.