Disco 2 broken rocker shaft bolt

Well in this week's antics, 3 of the 6 rocker shaft bolts snapped leaving the threaded part in the cylinder head. I've had a little play with drill the first one but that's a terribly slow process and is hardly making a impression.

Using easy outs extractor type jobs will not work as the thread is too far down through the cam carrier..

Hmm, now I'm reading about left hand drill bits? Anyone used any and can recommend a certain jobber or anyone had this experience.. Cheers

you need to better drills and these type of extractors

Thankyou Jamesmartin.. do you know where I might get a set like that?

http://www.ridgidtoolsdirect.com/pr...rt=51e93886a2ce89950c1861920a0ad4ca#sku=35585
Link above. Not cheap but look good quality
Mark

Ill be re-installing my injectors in a couple of weeks, the rocker shaft bolts have already been "used" five times so after reading about your woes, Ill be replacing the bolts this time!
Mark
PS Bolts are LYG101510 from £.86 to £1.92 each (genuine LR)

henrytd5 said:

Well in this week's antics, 3 of the 6 rocker shaft bolts snapped leaving the threaded part in the cylinder head. I've had a little play with drill the first one but that's a terribly slow process and is hardly making a impression.

Using easy outs extractor type jobs will not work as the thread is too far down through the cam carrier..

Hmm, now I'm reading about left hand drill bits? Anyone used any and can recommend a certain jobber or anyone had this experience.. Cheers

Click to expand...

I had the same problem this week, if they snap on the way in you may be able to get the out with good quality left hand drill bits, if they snap on the way out you will end up taking the head off ! Mines off now and I'm putting my spare head on with all new bolts, gaskets, genuine seals etc ! Good luck

I've just done my injector seals and they were bloody tight. Didn't think about they might snap. Think if I do them again and I get them out I'll be changing them. Good luck getting them out.

Thankyou for the input on this one lads, shame it's getting towards winter and I only have weekends to work it over.

I had a feeling it may result in taking off the head, if so and I then split it away from the cam carrier section, would that help me get closer to broken bolts?
Also I've been looking at some new/used heads, but could really do without the expense!

I'm going to try a left hand drill bit and I've seen the deep style extractors, which I have a close eye..

Cheers

If there is nothing else wrong with your head, stick with the head you have, the broken studs can def be extracted and it will be a lot cheaper!
If you remove the head budget about £150 for bits, you must use the correct sealant between the cam shaft carrier and the head.
Small note for the future, if you break a bolt when installing it, dont carry on, it could mean your torque wrench is set wrong or faulty.
Mark

I would certainly suggest changing the bolts to anyone undertaking any work involving them. A bolt like that shouldn't break but they do

Well step one of the weekend, left hand drills. Got some engineering ones. So should be half right.
Step two, deep extractors, as in the pic on this thread.

If all above fails... take off the head.

The garage tried both methods on my snapped bolt to no avail, head was taken off and swapped for my spare head, even with the head off , the snapped bolt is being a pig to get out, I'm going get it on a milling machine to get it out the correct way. The bolts are hard as hell .

Evening lads, sorry for the time lapse, been at it again this weekend and here's the tale so far..

I tried left hand spiral drill bits, 3, 5 and 7 mm, 1 of the bolts back out no problem after drilling for only a few seconds. But the other 2 didn't budge.
I found it extremely hard to drill down the center of the bolt, the bit seemed to stray off to one side. Maybe due to the surface angle that it broke at.
I tried to packer the drill bit with tape to keep it central in the hole but still drilling off center.
Next I tried to drill the bolts out all together but as vizlauk said they are hard as hell.

Easy outs and extractors where no use without a good center hole.

An hour of research later.. I came to the idea of helicoiling/ thread repair insets.
I had a trip to machine mart and got a set of Clarke M10's.
I drilled the hole, tapped the threads and inserted the coils. Extremely easy to do. I did coat the drill bit and tap in grease to collect all the ally chips and bunged all holes and working areas with rags.

Now I'm just awaiting some suitable bolts before starting to reassemble.
Hopefully this works, there's only 2 of 6 holes been helicoiled so it should hold the rocker when I'm operational again.
For me this is the best option for me. Cheap and not so labour intense, as stripping the head would be.

I will post more when I get the bolts and start rebuilding.

Cheers

I managed to drill the broken rocker shaft bolt out of my spare head today with ease, I used a 3mm wurth drill bit through a guide, it drilled with ease, then went up to a 4mm, then filled the hole with some penetration oil, left it for ten minutes and it turned out with the easy out, so a good head will be going up for sale.

Good work viz! Good result also! Wish mine came out the easy.. I had put around 5-6 hours labour into trying to drill them out.

I think I got lucky, the snapped one in my previous head just wound out.

Damn you lucky people!

Might be a bit late but the usual way to get a snapped bolt out is with spark erosion (well actually to make it disappear). Unless you live in the back of beyond there's likely to be an engineering shop around who can do it. It's often used to remove snapped drills, taps etc.

eg http://www.sparkeroding.co.uk/

I did see a little thing about spark eroding on the Web whilst looking through my options. But then I've got the labour of stripping down and getting the cylinder head out, fitting kit and having the job done. All good and well and it's a brilliant thing if you got the time and cash. . I have not much of either at the min haha..

A 2 year olds Christmas presents are draining me...

jamesmartin said:

you need to better drills and these type of extractors

Click to expand...

Same guides that I used, very good indeed

vizlauk said:

Same guides that I used, very good indeed

Click to expand...

its rare i get a bolt they wont shift ,and drilling guides help