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4.9 water pump stripped bolt


lacseville

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that *smurf* that put my water pump on stripped out one of the small 10 mm bolts in the block, or broke the bolt in half. it turns but won't tighten, but it hasn't fallen out yet. anyhow, i obviously have a small leak coming from there. he won't fix it, say that the "wheel and tire guys probably poked a impact up in there and broke it off" :unsure: anyhow, is here any way to retap that bolt if it stripped? maybe just put a slightly larger bolt in there? this suck you guys...

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i have never had luck with aluinumm blocks, it can be done but the motor would probaly have to come out because there is not enough room for a tap . man if i were u id go after the guy that did the pump his story is bull thers no way to get to the pump from the tire well and no reason to do it in the first place btw i do have a air dame

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If you can get a staight shot at it thru the wheel well you might be able to drill it out and install a helicoil or retap. Otherwise maybe leave that bolt out and seal it with RTV. Maybe use RTV anyway. Just be sure it is perfectly clean and don't add coolant for 24 hrs while it cures. The next size larger bolt MIGHT work if all else fails but I'd still use the RTV. I'd take it back and raise hell but since he doesn't seem to stand behind his work he will probably just do some temporary fix to get you off his back and it will fail later.

One other thought, if it is a small leak maybe sealant tabs or Barsleak Gold will seal it up.

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In 125k on my last car ('92 Deville) I never had to do a water pump so I am not familiar with it. I thought it bolted into a hole that was tapped into the block. If a nut on the backside is possible that would be the way to go.

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i'm not understand what you mean by a nut on the backside? i tried the gold power barsleak. i thought the hole was small enuf that'd fix it, but it didn't. I'm not too familiar with RTV. What exactly is it, and how do you apply it. you said not to add coolant for 24 hrs, so does that mean I have to drain my cooling system? i really really rather not take the motor out, obviously!! thanks for your suggestions!

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You said it turns but does not tighten, if so remove the bolt and go to a hardware store and buy a self tapping bolt sligtly larger then the original bolt.This bolt has a point on it with course threads, and bolt it in.The same happened to me last year and its been one year and no leak since i replaced the original bolt with the self tapping one.

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If the bolt is actually broken off, it may be possible to extract it, if you have the room. Sears is one place, but many hardware/tool stores have extracters.

Essentially, you carefully drill a hole into the center of the bolt, then tap or screw in the extracter (there are a couple different approaches) that is set up to "grab" counterclockwise. If you can get enough grab, you can back out the portion of the bolt that is still in there. If that part is long enough, a new bolt might be able to grip the remaining threads since it sounds like the outer threads are toast.

If you got that out, there are a couple things you could do. Perhaps the factory threads run a bit deeper than the actual factory bolt. If you could obtain or make a bolt that is longer (but still wouldn't bottom out) you may be set.

Or, if you can find a factory length bolt, and can get it torqued sufficiently withouth stripping the remaining threads, perhaps a little bit of loctite would insure that it wouldn't back out again.

Its been awhile since I've looked at the water pump. If I recall, there were four or five large diameter bolts (some of which had torx heads) which go into the aluminum block and a lot of small nuts and/or bolts at the perimeter. Some of the perimeter fasteners actually attach to the timing cover (the nuts) so you may be able to remove that (no small job, but easier than removing the engine) if its one of those. The large bolts are what holds the pieces together at the pressurized areas going into the head so they're pretty important to get right.

One thing you might be able to do, if there is enough clearance is to fabricate a rigid piece that would span over the bad bolt hole and attach to the bolts on either side. The water pump flange is relatively thin stamped metal and will flex a little. If you could piggyback a rigid support , you might be able to get it to seal. If you had the pump off, you might be able to get something welded on, although that might distort the pump housing so much that it would be worse.

I only mention that as a last resort to prevent having to remove the block.

RTV is Room Temperature Vulcanizing sealant. It is typically marketed in tubes as gasket making material (sometimes called "form-a-gasket"). It can be used as an auxiliary seal, to hold gaskets in place for assembly, as a gasket repair, or to replace a gasket. One advantage it has over a gasket is that it will take up the space in less-than-flat assemblies where the mating surfaces are scratched, slightly corroded etc. The disadvantage is its a b*tch to get off compared to a paper gasket when you have to replace that part again down the road. Another disadvantage is it can get squeezed into places you don't want it to go so you have to use care. RTV is actually specified in the service manual for a couple of areas (the triangular intake manifold seals where the heads, block, and intake all come together, for example) so its not "snake oil", but it isn't appropriate everywhere.

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Pull the bolt and look at it. He may have put one there that is too short or they be be room for a longer one (to get at the good threads). If you try a longer bolt just be sure it tightens against the pump and not the end of the bolt.

Also when trying to fit a larger bolt, try a SAE size. the next size metric probably would be too big, but you might find a SAE size thats just a litlle bigger.

You can also try to insert a heli-coil. That should hold well enough for a water pump bolt. If you can get at the bolt to put it in there is likeky enough room to insert a heli-coil.

If you cant get at it to use a heli-coil there are also a lot of epoxy products out there made for repairing stripped threads. You just put them in there and then right away put the bolt back.

Try NAPA auto parts for these things.

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thanks for the ideas guys. i'm on my way to auto zone. i'm going to try to take the bolt, then try to put in a longer bolt of the same size, then try the SAE bolt with a nut on the outside, then maybe epoxy or RTV. this doesn't have to hold a lot of pressure, just make contac with the gasket a little better. (it must be a very small hole)

I'll let you know.

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man, i've been working on this pump since 1200. i tried a longer bolt... didn't work. i tried an SAE bolt slightly larger... didn't work. i just bought a slightly larger self tapping bolt. anybody know any reason i shouldn't put a self tapping screw in?

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Not sure about the self tapping bolt. I'd hate to give you bad info but I don't see why it wouldn't work if it was same threads but one size larger diameter.

RE: RTV, the mating surfaces MUST be perfectly clean and dry or it will not seal and you must let it cure for 24 hrs. before adding coolant back into the system or it will not cure and seal.

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should i coat the bolt with something before I tap it- thread locker or something? about the RTV again... how were you talking about using it? the pump is still on the car... i don't really understand where to put it!

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As i stated earlier it worked for me.I basically but some RTV in the hole and installed the self tapping bolt.What to watch out for is that the bolt is not longer or to large so that when you put it in it doesn't break.The bolt should go in with out to much effort since you are going into aluminium and don't overtighten.

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should i coat the bolt with something before I tap it- thread locker or something? about the RTV again... how were you talking about using it? the pump is still on the car... i don't really understand where to put it!

RTV is meant to be used on the mating surfaces like a gasket. When/if you remove the pump.

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A long set-screw, to use in place of the bolt(hex headed screw), might work if the tapped hole is blind( doesn't go through). Lock-tite it in. Hold the allen set screw still (with an allen wrench), while you tighten a lock nut and washer, to hold the pump tight. RTV is silicone sealer(form a gasket). I have used some made for thermostat housings, water pumps. It worked good, but needed 24 hours to cure.

rek

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that seems like a pretty good idea too. are these set screws pretty rigid? i got the entire original bolt out, but the block must be pretty stripped, so it'd take some torque to re-tap a bigger screw. also this way, if I ever had to take the water pump off again (hope it dies before I have to do that again!) it'd make it a lot easier.

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I haven't had any problem with them. Check the depth of the threaded hole, and see if the threads go all the way to the bottom. You might be able to tap new threads at the bottom, with a bottoming tap( less lead -in than a starting tap). If you go this way, easy does it. The chips have to be removed, so the tap can go down.

rek

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