The power of jb weld

I ran into the Ford F series truck water pump problem. I have a 1994 F150 with a 351W engine. One of the water pump/timing cover studs was so seized up that it broke before I could get it out. I tried an Easy-out, almost broke that. Probably because I drilled the pilot hole slightly off center. So I tried to enlarge the hole and get the bolt to collapse. No luck. During that process I caused the hole to be not only off center but off axis too (no longer perpendicular to engine block). Helicoil didn’t look like much of a solution (because of that hole), but I tried it anyway. No luck. JB weld time. I filled the hole and covered the end of allthread (same size of original bolt) and stuck the allthread into the hole. The allthread is being held in place by the power steering/ac condenser bracket (through which stud portion of the original bolt went). The original bolt is 5/16"-18TPI. The hole I drilled and tapped is 21/64". New allthread is same size as orginal bolt, I’m just planning on using a nut to secure the water pump and timing chain cover. Every thing in contact with the JB Weld was religiously cleaned with acetone.
Do you know if this is going to hold, or should I just call the welder to weld up the hole and give me another chance at drilling straight. Can that even be done? The engine block is thinwalled cast iron.

Thanks for reading!

JB weld won;t hold for long.

I’m having a hard time envisioning this, but it sounds like you might be able to thread and helicoil the 21/64" hole and accept a nonperpendicular bolt. You could use a washer under the bolt to better distribute the bolt’s load on the (I assume) cast bracket. I’m saying helicoil because 21/64" is slightly larger than 5/16", and I’m assuming that you’ll need a bit smaller bolt to go through the bracket hole.

I’m sorry for not being clear. The broken bolt went through the water pump and timing cover. That’s like 4 inches thick, so there is every little room for error. My nonperpendicular bolt is too non perpendicular. I considered filing the bolt holes on the timing cover and water pump, but the bolt is still too far off.

You need to back up and start over. Remove the grill, condenser and radiator to get access to set the timing cover and water pump in place and run a drill through them to get the drill properly lined up and oversize the hole so that it can be tapped oversize for a heli-coil.

IDK, but JB Weld done right is amazing stuff. I had a Toyota pickup that had a cylinder head with a couple of voids in it. When the voids let go, at about 275,000 miles, it mimicked a blown head gasket. I had taken the head to a machine shop for a tank, valve reseat, and a shave. Put it all together and it was shooting coolant out of a new void the tanking probably opened up in-between the exhaust ports for #1 and #2, just above the exhaust manifold. I cleaned it out as best I could, and packed it as full of JB Weld as I could with a popsicle stick. Found the original void causing all the problems after coolant was still burning out the tail pipe. It was at a coolant passage right at the #4 cylinder exhaust port, halfway to the valve. I did the same thing as the other void. That repair lasted until I sold the engine after the wreck, some 4 more years and with 325,000 miles on it.

Also, I broke off a bolt in an aluminum screw hole for the thermostat housing on my Toyota Supra. Drilling out the steel screw, I made a mess out of the surrounding aluminum. I packed that hole with JB Weld, then re-tapped it for a helicoil and used a M5 stud with lock-tight red. Holding strong 2-1/2 years later, no leaks.

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BustedKnuckles that is an amazing story.

I’ve made structural repairs with JB Weld including filling voids, drilling and tapping it. Coarse thread pitch is better than fine. I’d wait to see how your repair fares before I’d rip it apart.

I’m not a fan of JB Weld myself but it could work on something like this. What I might be concerned with is the timing chain cover which is cast aluminum. With age and old coolant these small block Ford covers were prone to leaking due to the aluminum rotting out where the coolant passages mate against the cast iron block. (Generally on the passenger side of the engine.)

I wouldn’t want to get too deep into fixes until it’s known that the cover is not going to be a problem and the entire shooting match all has to come apart again.
(The covers are enough of a problem that a local salvage yard here stocks new covers at about 40 bucks each.)

If the patch fails it would likely result in coolant leaking into the timing chain cover and contaminating the oil. That would very likely have some catastrophic results.

JB Weld is good but I don’t think it’s that good. I would not want to risk the life of my engine on it’s ability to hold things together.

I would add that the timing cover problem I mentioned not only can lead to an external leak and end up misinterpreted as a water pump leak, it can also leak coolant into the engine oil.

well, it’s all buttoned up with the one stud held with jb weld, we’ll see how it holds up. i’ll take her up mount diablo, and then do a pressure test. i’ll keep you all posted.