560sel water pump bolt shearing

[ATLD]

Good evening all. Here's one for the experienced techs.

Was removing the water pump from my 86' 560 sel (harmonic balancer and all) and ended up shearing one bolt (my worst fear) that secires the pump in the process. I've had hard times with some thermostat housing cover or pump bolts before so I liberally PB-blastered these well in advance, but one, just one gave me trouble and broke (and I knew it was going to break, I just had no other choice; had to get the pump off).

There is still 1/4" stud sticking out of the valve cover case. Any suggestions as to how I should proceed or anyone experienced this before on this engine? Attempt to extract? Drill out? Weld male stud?

Normally, I would drill it out but I really don't want to since it's adjacent to the water jacket and a 1.5" long 8.8 bolt in an aluminum case...I can't ensure my drill will be on track. Any thoughts?

Adam

[BamaMB]

Don't know if this will work in your situation, but I remeber reading a thread about stuck bolts. The trick used was bee wax or candle wax. Heat the bolt and allow the wax to weep into the threads to free the bolt.

[Ferdman]

Adam, I would drill the center of the bolt with a drill bit large enough to use an EZ-Out bolt extractor ... pick a drill size that will allow some margin for error if the hole is slightly off center, but large enough that a suitable size EZ-Out can be used to remove the bolt stub. You certainly want to avoid breaking off the EZ-Out so apply PB Blaster liberally before attempting to remove the bolt stub.

[ATLD]

This bolt is really quite stuck. Knowing how much force it took to shear the bolt even after liberal use of PB blaster, I will not attempt an ez-out. They break-off too easily and then I can't drill it.

I read about the wax trick and think I will try it too. My concern with the wax or penetrating oil is the lenght of the bolt; there's at least an inch of bolt before we even get to the threads. This will make heating less effective as well.

In either way, I will be heating very soon to try and loosen it. May try cycling heat and dry-ice cooling but I worry about the allum cover's proximity...

last resort before I drill is to weld a nut to the stud. Some folks say the concentrated heat from welding can loosen the bolt, and I'll have the nut to turn the fastener; but arc-welding on the engine is a difficult affair with the ECM etc...

I hate when this happends...

Thanks.

Adam

[david s poole]

are there enough threads left to use a stud extractor?

[ATLD]

there's only about 1/4". Do you know of a stud extractor tool for small diameter studs that is designed for that small stud height? All the extractors I have are either too big, or require a stud at least 1 inch.

[ATLD]

another thing; has anybody arc-welded on this engine? Did you disconnect the ECMs?

[david s poole]

can i assume that you have tried vice grips after heating it up with a propane torch[this will tend to break the grip of the corrosion between the aluminum and steel?

[heespaul]

Sorry to hear about your problem. Getting bolts out depend on several things. They range from access to the bolt to the ability to put heat on the area with nothing being damaged. If you can drill out the bolt, then I think this is a way to go about it. It is good to have either a small angle grinder or a Dremel type tool for easier access. First, file/grind the top of the bolt/stud flat. Then center punch the top dead on center making a deep punch so that your drill bit will not wander about. Using a extractor takes patience. If you can apply some heat using a torch around the immediate area then this will help . If so heat the area around the bolt, making sure to get everything out of the way so nothing catches fire.Do not heat the bolt itself. What I do is heat and then use some WD -40. I have not had good luck with PB. Do this several times, so the WD can get into the threads and the heat will expand the area around the bolt.Then try using the extractor. It should come out. If not and if you can drill the thing out, then you may end up just drilling and re-tapping the hole to a slightly bigger bolt size. This may require you drilling the hole in the water pump the same size.If you are keeping the car make sure to use some Permatex thread compound on every bolt. Threads should be oiled at minimum to get the right torque reading unless you are using thread locker. One last thing, before you do anything, tap the end of the bolt with a small all peen hammer with a nice direct hit. Not to hard but steady and firm. Do this several times. If you can do this when you use the extractor then do so. This helps. Next time you experience a bolt that will not cooperate tap the end of the bolt /wrench with a hammer as you twist. I have found this will help tremendously helpful with stubborn bolts/studs. Good luck Paul

[ATLD]

Thanks for the good thoughts. Yes, I've had at the bolt with propane and vice-grips etc. I need more drastic measures and I'm cautious about going to hotter flames because of the alluminum.

Would you heat the allum timing cover with Oxy/A? I would think it would get too hot. Plus I'd have to heat from the back side toward the fuel distributor which worries me.

Yes, the pump is off; I did all the tricks I knew when removing the bolt, but after all that; I decided it was more important to get the pump off than to wait it out. The failed bolt is the second to the bottom, lower left hand side. It is the one behind the thermostat cover. It's one of the shorter ones, but it's still about 2.5" total. 2" of the bolt is still in the cover, only the last 0.25" peeks out.

Is it a lot more work to remove the timing cover at this stage? If removing the cover meant I could get a better grip at the bolt and a clear shot at the threads with a penetrating oil, then I'm sure I could get the thing out mechanically but that's a lot more work than I intended. I assume I'd have to remove the distributor, hydraulic pump etc???

If I get really lazy or in a bind, I'm going to weld a stainless steel stud to the bold head and just secure the pump with a nut; but I'm worried about arc-welding on the engine while sharing the ECM's ground.

[jhodg5ck]

I've done well with Mapp gas..Oxy is too hot..

The last time this happened to me I heated and then cooled w/ CRC freeze off repeatedly..the thermal shock of going from 600 to -what ever degrees was enough to get the bolt to loosen up and come out w/ a set of vice grips.

I would pull any modules you can prior to arc welding.

Jonathan

[Robert Squires]

* This broken bolt shaft is probably seized by the aluminum hole rather than by the steel threads in the block. If you could break the shaft loose from the timing cover hole, you could likely turn the threaded part out easily.
* So I agree with 2 ideas which have already been offered. First, try to heat the timing cover, around the bolt shaft, to expand the hole a little. I wouldn't try to heat the bolt shaft directly although the alum will expand more than the steel anyway. Then use whatever works to get a bite on that 1/4in.
* If heat doesn't work, then drilling would be my next choice. Needless to say, start with some new, high quality bits. Then mark the bit with a little piece of tape or such to control your drill depth. Being off center in the aluminum probably wouldn't be as bad as drilling too far and chewing up block threads.
* EZ Outs are, in my experience, anything but easy. By the time you've drilled out an 8mm shaft enough to take an EZ Out, tightening the EZ Out will expand the shaft and make it a tighter fit in the cover, exactly where it's stuck. Only a small chance of working if your seizure was in the threads. You'll either spin the EZ Out or break it off. If it breaks you're in for a good ride. The only thing (sensibly priced for the DIYer) that will remove a broken EZ Out is a stone in a high-speed grinding tool (experience with broken 3.8 head bolts and EZ Outs).