V12 water pump replacement - stuck bolts / studs

hi guys
during my damper pulley replacement,

I noticed some leaks from the bottom of the water pump, and someone had a heavy hand on RTV

and one of the stud has some leaking too

I checked the bearing and it’s smooth and noiseless, so it seems to be time to re-seal the pump to the block

hence I need to get it off first to remove the old gaskets and goo, and restart from new

after some struggle, I got most of the fixings free, but3 of them are stuck

on the right side of the pump, the upper stud, and the 2 lower bolts

I stopped before breaking one, and sprayed some de ruster, and will come back to them, may be with an impact gun if I can get a shorter one than mine.

As those bolts and studs seem to be available, I may sacrifice them, but I’m afraid of being stuck with the remains stuck deep in the block

The bold next to them had been replaced by an7/32 allen haed , and the thread seems to have rusted badly :

would an induction heater be of any use ?
I 've been thinking about one for a while, so this could be the decision time

Never tried them but they seem to work very well.

I bought an induction heater and use it often; works well. Still need patience and lots of penetrating spray, though.


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induction heater ordered, and I’ll spray some more penetrating oil
I’ll try spraying in the triangular opening for the output hose , in the hope the fluid could reach the 2 lower bolts : I fear shearing them as they seem very long, and totally stuck :sweat:

Impact wrench might be a better solution than brute force, as it should stress less the bolt while breaking the crud and rust

I managed to borrow a small impact wrench, but it did not make any difference to the 2 lower bolts (I don’t have an impact socket long enough to get at the stud)

As I received the induction heater (200€ Amazon special),

I had a go at heating the 2 lower bolts, before hittingthen with the impact wrench
I used the heater for about 45s, without result, then had another go for 1mn,

result ; one of the bolt got free, but still no luck for the other one

I added some more penetrating fluid, and will have another go tomorrow

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new session today, with induction heater and impact wrench :
success for a second bolt, which now leave me facing the upper stud

the choices are cutting the stud and replace it, or getting a deep impact socket

I’ll probably get new bolts all around, at least for those which are available

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Yes, use new bolts and studs, and use anti-seize on the threads so they will come out easily next time. You don’t want those bolts to break when you try to remove them.


those 5/16 bolts seem to be hard to find even is USA :
McMaster car only shows some stainless, and not in the required 1’3/8 length

getting 1’1/2 could be risky as they could bottom out before getting tight

I’ll dig more as I found some in UK

I’ll wait to order until I 've removed the pivot stud, in order to double check the available length for each hole

You can always cut the longer bolts, they will not rust :slight_smile:
If you go stainless, put some grease to avoid electrolytic corrosion.

SNG Barratt seems to have some of the bolts

I cut the additional length of the pivot stud, applied heat and got it loose with the impact wrench
lots of black deposit on the bolt, either RTV or boiled coolant (orange arrow)

all studs/ bolts are now loose but still grabbed by thread-lock or RTV from the previous fitting

solution was 2 folds :
per Doug suggestion, induction heater,

and small impact wrench (no need for very high torque as you don’t want to shear one of the fixings)
the one I borrowed is only 1/4 , so needed an adapter to fit proper 3/8 impact sockets , which made it a bit long / bulky to get though the pipes / hoses to reach the bolys

I ordered min with 1/2 square drive to be more compact

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