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Post by stevem on Jul 16, 2006 12:59:12 GMT
The water pump on My P5B Coupe is completely shot with lots of play in the bearing and water leaking. It looks as if its been on the car since the year dot. On trying to remove it, despite all the usual tricks, 3 of the long bolts have sheared and also one of the short bolts. I assume that the casting that is the back of the water pump is the cover for the timing chain etc. and the whole lot has to come off to get at whats left of the threads. If all this lot has to come off, is the engine oil level below this? i.e. I don't have to drain the engine. When eventually i get to put it back together, what should be applied to the threads to stop this happening again?
Steve M
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Post by Phil Nottingham on Jul 16, 2006 16:46:13 GMT
Its very common for them to seize and shear off - if you are very lucky they can be driiled out and retapped otherwise its a lengthy process to remove the timing cover - oil draining should not be necessary. Undoing the pulley nut is hardest
Stainless steel bolts and anti seize Copaslip helps a lot but even this goes off after many years
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Post by Deleted on Jul 16, 2006 20:26:05 GMT
I just got my origianl water pump off last week, I only sheard one short one off, as there is a bit of thread left I'm going to heat it and try to get it out with mole grips. If not 1 won't matter as long as I use a bit of gasket sealant. I just got a new pump from JR Wadhams, the casting is bloody terrible arbeit the inpeller is a revised design.
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Post by Smallfry on Jul 16, 2006 21:42:30 GMT
The long bolts go all the way through to the cylinder block. When you have removed the timing gear housing/oil pump assy, the sump will be exposed. Make sure no swarf/crud goes into it.
In any case, I would advise removing the sump anyway to prevent this happening. You will no doubt ruin the sump gasket anyway, or never be able to get an oil tight seal, so replacement is probably a good idea.
Hope it doesnt end up like mine, and require another cylinder block !
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Post by stevem on Jul 17, 2006 15:35:24 GMT
Wasn't planning to have to fit a new cylinder block. Are you saying the studs are difficult to drill out and this sometimes wrecks the block?
Is it not possible to pack the gap into the sump with cloth to prevent ingress of swarf etc.
I'm begining to fear the worst. Seems like changing the water pump could be a nightmare.
Steve M
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Post by Phil Nottingham on Jul 17, 2006 16:20:17 GMT
Its only a worse case scenario! You can pack the gap if you have to remove the timing cover
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Post by Smallfry on Jul 18, 2006 0:09:05 GMT
For sure you can pack out or mask off the sump to prevent anything going in there, but I have always found that when you remove the timing cover, the sump gasket breaks, especially if it has been on there for a good few years. I only suggest replacing it to save disappointment later !
With regards to the studs, if there is a little bit sticking out of the hole, try to grind or file it off square before marking it with a center punch, this way, finding the center of the stud is much easier. Start off with a small hole first and make it bigger.
If whats left is flush with the surface, and the bolt has broken as a result of corrosion, NEVER, EVER, try to use an "easyout" to remove it, because they expand the broken thread, actually making it tighter, and if you are unlucky enough to snap it off in situ, it cannot be drilled, and will then most likely require specialist attention.
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Post by stevem on Jul 18, 2006 15:14:16 GMT
Presumably if an extractor will make the remains of the thread tighter i will need to drill to the correct size and re-tap using a taper tap. Any idea of the thread size so i can get the correct tap?
Steve M
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Post by Phil Nottingham on Jul 18, 2006 16:27:03 GMT
1/4" and from memory UNC.
I think the screw in extractors are fairly useless and as Smallfry says can make matters worse.
Having said that the ONLY time they worked was getting out a V8 cylinder head bolt that stretched and sheared off on tighten up (at 20Ftlbs!)
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Post by Smallfry on Jul 18, 2006 20:45:13 GMT
Actually I think you will find that they are 5/16 UNC. There are two smaller short bolts that are 1/4(I think ) but they don't normally snap off. I have heard about some straight fluted easyouts too.....looks similar to a Torx bit.......that you hammer in, and then unscrew, but I dont like the sound of that either. I think on larger diameter bolts you can get away with it, but for me, 5/16 and under usually goes wrong !
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Post by stevem on Jul 18, 2006 20:58:22 GMT
You are right about the bolts that snapped off being the larger ones. Two out of the three have snapped off flush and the other protrudes slightly. The long bolt that came out without breaking released water/antifreeze, so the tapped hole in the block must extend into the waterway. Do you know if all four tapped holes adjacent to the waterways should be drilled right through into the waterway?? This would obviously make them easier to drill out and re-tap.
Thanks Steve M
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Post by Smallfry on Jul 20, 2006 0:03:24 GMT
I do not have a P5B block to look at, but I have got a 1988 block in the garage, and none of the holes in that go into the water jacket, however, one does go through into the block proper.........where the engine internals are .......so you dont want to be drilling through that one, unless you remove the sump to clear the swarf. When you say some protrodes, have you removed the timing cover/oil pump, or is it still on there ?
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Post by stevem on Jul 20, 2006 16:34:16 GMT
Timing cover and oil pump etc. are all removed. The bolts that have sheared off are all adjacent to the waterways to and from the water pump. I spoke to Holly at RPI and he says that on some blocks the tapped holes go through the block and into the waterway and on others not. He said it didn't matter if the drilling goes through into the waterway as long as the drill does not go right into the cylinder liner (obviously). The thread that's left proud of the block will not budge. I've tried stilsons, mole grips etc. and tonight I will file flats on it and try a spanner so I can watch it break off in front of my eyes! Steve M
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