Advice please on dealing with a sheared manifold bolt

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OakleyPilot

New Member
Posts
75
Location
Hampshire, UK
Hi folks,

In fitting the EGR mod on my discovery 2, I have managed to shear off the right side bolt to the exhaust manifold. Despite trying to be careful, I had given the bolts two days worth of repeat WD40 treatment and had the socket square onto the bolt. The left side came out fine, but the right sheared with only normal pressure.

The following photos show the issue:

Untitled | Flickr - Photo Sharing!

Untitled | Flickr - Photo Sharing!

The bolt is sheared flush with the surface of the manifold. I have drained the coolant and moved the cooling hose from just above to get more access to the bolt. However no drill I have can fit between the radiator/fan and the offending bolt. I possess a fairly modest array of tools, but not yet the viscous fan landrover spanners (ordered a set from eBay). So at the moment I can not get the fan off.

I have never removed a sheared bolt before and understand there are several ways of doing it. I am probably best described as a willing amateur at DIY mechanics.

Therefore I am looking for some advice as too how to proceed. The way I see it is I can give this a go myself but risk making the situation far worse than it already is. Alternatively find a mechanic locally who has the necessary tools and knowledge on how to fix this.

I am based just outside Basingstoke, anyone have any recommendations of local professionals?
 
I did exactly the same the other day. Although my manifold was off at the time.

Centre punch then drill, mine didn't want to go straight so ended up a little to one side. Drilled bigger and tapped out to M8.

You could try and get a angle drill which will allow you to work in the confined space.

Viscous fans are usually easily removed spanner on and give it a whack.
 
It wouldn't satisfy the engineering purists, but as it's the outer lug you could drill straight through and put a nut on the other side. Oh, and it's worth investing in some moderately expensive drill bits to do it with, as those socket head bolts are made of something tough. The tips of bog standard DIY store drills will rapidly burn off, in my experience.
 
Yes not quite sure how to proceed, my concern is if I try and drill in situ it will be hard to keep the drill bit straight. However if I remove the exhaust manifold entirely I could be faced with more studs in the cylinder head shearing off. Bit of a dilema..

If I do go ahead myself then I will either need the tools, I guess a tap set, a reasonable sized vice and a pillar drill.. none of which I presently own. Or perhaps get a whole new manifold, which I suspect might be cheaper!
 
It wouldn't satisfy the engineering purists, but as it's the outer lug you could drill straight through and put a nut on the other side. Oh, and it's worth investing in some moderately expensive drill bits to do it with, as those socket head bolts are made of something tough. The tips of bog standard DIY store drills will rapidly burn off, in my experience.

Thanks for the advice, I will look at some drill bits tonight to find the toughest SDS I can find, I am quite happy with any form of fix, like you suggest perhaps going all the way through with a size 6 bit and putting in a new M6 bolt and nut.

If it was you, would you leave in situ and drill that way? Or remove the manifold?
 
I'm not familiar with the td5 or the positioning of said stud but would a set of easy outs not do the job? Got to be worth a try?

I have no experience of removing any stud, but reading around the web it seems a lot of people state never to use easy outs as they regularly break off and create a far worse problem as they are impossible to drill.
 
I think as long as you go careful with them they're... if you can get an angled chock then drilling out in confined spaces will be a lot easier, screwfix should do them
 
Thanks for the advice, I will look at some drill bits tonight to find the toughest SDS I can find, I am quite happy with any form of fix, like you suggest perhaps going all the way through with a size 6 bit and putting in a new M6 bolt and nut.

If it was you, would you leave in situ and drill that way? Or remove the manifold?

SDS bits are for masonry surely? You won't have much joy with those. I tend to find those HSS titanium plated ones (they're usually a sort of yellow colour) are best for drilling bolts out especially when the bolts are high tensile, as most socket head ones tend to be. Before dismantling further I'd try and see if I could get a drill on it without getting the manifold off, perhaps by getting the fan and the radiator hose out of the way. To get the manifold off, you'll probably need to take the turbo off and the exhaust off too, all of which are held on by bolts and nuts likely to be rusted solid, as well as the manifold studs themselves, all of which could break, so let's try and keep that to a minimum!
 
Those titanium coated bits are a con, they have the thinnest coating possible on them which scratches off the moment it hits the workpiece.
A properly sharpened hss bit will do just as well, or else get a set of cobalt steel drill bits.
 
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