Removing a snapped injector bolt (Mercedes CDI)

[Lankytim]

Hi all.

 

The PT Cruiser suffered a leaking injector over the weekend, with the associated "black death" of carbon everywhere. I ordered a bolt and seal kit and set to work today. Everything went swimmingly but there was still a very slight escape of gas, only noticeable when I poured water around the injector. Anyway, like a twat I nipped up the injector clamp bolt to try and stop any leaks and it snapped inside the head, the injector shooting up under pressure and showering me with water and diesel. FFS!

 

How can I get the snapped bolt out? The local garage don't seem too keen on the job and I don't want to try and drill it out as I'll Deffo kill it

Help!

[Mally]

Not familiar with PT Cruiser, but if the bolt has not bottomed you may find it will extract by drilling with a LH drill. 

Centre punch exactly in the middle and use a drill about half the diameter of the bolt.

LH Drills are available on ebay.

Best to let someone brave do it who has done a few. Will be at your own risk though whoever does it

[New POD]

If it's a high tensile bolt, you might struggle to drill it with a normal drill. 

 

I imagine, that taking the head off, getting it to an engineering workshop/tool makers, getting them to clamp it in an/the appropriate machine, and machine it out properly before fitting helicoils in all the bolt holes, would be the right thing to do, but cost more than a second hand head.  

[Dead_E23]

How about buying a 2nd hand drill stand off Ebay (e.g. this) and modifying it to bolt to the camshaft holes?  

 

That would presumably increase the chances of drilling vertically and reduce the chance of snapping the drill bit. 

[Asimo]

Isn't there an entire cottage industry related to Mercedes injector and injector bolt issues?

I remember reading about it when I was convincing myself I didn't want a CLK 2.7. 

Probably involves removing head and taking to machine shop or drilling into screw yourself, breaking off a tap or stud remover, then taking the head to a more expensive machine shop for spark-erosion removal of broken hard tool.

[Lankytim]

I honestly cba to take the head off and staffing with cam chains and the like. Access to the snapped bolt looks good, it's right on top of the engine

[warren t claim]

Hammer a bigger injector over it?

[omegod]

Try tapping it round with a long thin punch, works surprisingly often if access is good 

[forddeliveryboy]

Left handed bit is something I'd try if the tapping with a punch doesn't work. Then if it doesn't unwind, you've a hole to screw an extractor into.

[New POD]

Try tapping it round with a long thin punch, works surprisingly often if access is good 

 Apply a bit of warm to head to make it expand a little.  

[Dave_Q]

They are notorious for it, there is a repair kit of some sort to put a helicoil in.

 

If you can't get the bolt out whole you'll have to drill it out and tap for the helicoil, actually I think its a Time-Sert that's normally used.

 

BTW the injector bolts are stretch bolts so single use, don't know if you've used a new one but you need to.

[Dead_E23]

Chuck the injector away and Araldite an ultrasonic dog whistle in its place.  Then dogs will enjoy your car too!

[Mally]

Trouble with tapping it round first is if it doesn't work its then difficult to find the exact centre.

Centre punch it in the middle first maybe.

What size is the bolt?

[Dave_Q]

http://www.MBClub.co.uk/forums/showthread.php?t=169126

[cort16]

weld a stud through the hole in the rocker cover.

[Dave_Q]

They're M6 so not exactly loads of meat to go at with a punch, this is also probably part of the reason for failure.

[billyboy406v6]

Try asking on some Merc forums, or google it, they are usually rather helpful ?

[Station]

What were Mercedes thinking?? Those Merc injector bolts were too thin to be torqued up properly twice, the best advice is drill all the holes out and tap for a larger bolt size. When I did mine I did it to the recommended torque amount and no more - they either strip the thread or snap the bolt. You have to clean out the holes of Black Death, which is probably what yours did and couldn't go further in.

 

They're not high tensile as the head is aluminium - get some decent drill bits and easi out set, it should come out easily with a small one. Proper pain in the arse as they ALWAYS leak.

[Station]

BTW I bought new bolts from Mercedes and accord seals from Honda.

[Lankytim]

I also suspect the black death in the bolt hole helped it snap, there's lots of info on this topic on the net so as people have said it's obviously a weak spot on these lumps. A new bolt and seal was used. 

 

Trying to hammer a groove into the snapped bolt with a screwdriver and unscrewing it failed to work, so I hit google and found a local guy who specialises in borked threads and snapped bolts. As soon as I mentioned the engine he interrupted me, "snapped injector bolt, aye, shit these are"

 

He's coming tomorrow morning with his van full of special drills and stuff and for £85 he's going to drill out the hole and tap it to 8mm rather than the poxy 6mm it already is. Not sure if he uses a helicoil or not. He's also going to drill out the injector clamp to fit, which as it's hardened steel is no mean feat apparently.

[Mally]

Bargain! If hes done it before he won't have a problem.

[Dave_Q]

Seems reasonable, I recall reading there are a few places/people that will do a full repair of "Black death" for about £500, on the Merc forums they were going on about this like it was good value.

 

I've been looking at Vitos and would definitely take on one with black death for a decent discount, all you really have to do is scrape off a load of shite and clean it up well, although the injectors can often take special toolz to get out.

 

£85 seems like a result anyway.

[The Moog]

Didn't Scooters (ex of this parish) basically set up a business doing just this?

[Lankytim]

It's the black death that sticks the injectors in and writes the engine off. FYI, I've been using biodiesel and it seems to melt black death away. My injector came out easy peasy

[Station]

Mine came out easy as well. Get some ceramic lubricant from Halfords to put the injectors back in, it supposedly does something that improves something or other. The MucOff bike chain oil in the pink box is the stuff. Also seal cutting tool off eBay for 15 quid.

 

You're supposed to tighten the bolt so the cheap plastic injectors seals properly but the screw size is too small to do it enough, it's ridiculous. 85 is cheap and will save you a lot of hassle.

[Joey spud]

I have a picture somewhere that i will post up of an E270 i went out to with a engine noise and fuel leak.

 

The injectors had been worked by a garage on the coast a few days previous and on inspection the 6mm bolt that held the injector had pulled the thread out of the head casting.

 

To make things worse the force of the injector popping out had put a sharp dent into the centre of the bonnet and to add insult to injury the old chap only had basic ten mile max recovery entitlement so it cost him another £160 to get the car back to the garage that carried out the work.

 

Did feel bad for the guy.

[garbaldy]

How did the injector manage to pop out and damage the bonnet was it not plummed up to the high pressure pipes ?

[Lankytim]

Mine was idling and shot the injector out, bending the pipe. I imagine a high speed clamp failure would result in quite a bang!

[garbaldy]

I ran the space ship upto temp numerous times without the clamp and couldn't get it to budge, strange how some pop out easier than others.

[Lankytim]

All done! The fella drilled the hole out an helicoiled it to take an 8mm bolt. Cleaned up the bottom of the injector hole with emery paper on a stick, stuck it together and fired it up!

 

No hissing or popping noises but a water test shows there's still a bit of blow by with lots of bubbles emanating from the base of the injector. BALLBAGZ.

 

HTF do I get this bastard to seal properly?