AZJeff

I have never seen duct tape that thick, but I am not an expert on that stuff. The idea behind the aluminum is to help keep the crack or hold from expanding, and the epoxy becomes the agent to bond/seal the aluminum to the existing resin HVAC case.

It’s actually probably “macro blend” which is a PC+ABS blend. And like I mentioned, it’s mineral filled to enhance rigidity. Depending on the type/length/location of the crack and/or hole, an added reinforcement of aluminum sheet about 0.025” thk. would be beneficial.

Can you send a picture of what the damage looks like? I can make a better suggestion on how to best repair it so that it's more or less permanent.

If we are talking about the actual heater box proper, it’s going to be of a resin that won’t deform under the temperatures seen around the heater core, which are going to be about 200*F. That rules about polypropylene or polyethylene. It might be ABS, but it’s also mineral filled, to increase its stiffness. Epoxy should work. If the damage is extensive (long crack or a hole), a piece of thin aluminum laid over the damage and bonded with the epoxy would be prudent. (A few “pop” rivets through the aluminum/plastic sandwich to help position the repair would also help. I have done this on other ABS parts such as old dashboards in the past with good success.

I don't quite understand your question. The timing cover is attached to the engine block with a bunch of small bolts that go around the perimeter of the cover and also join the cover to the oil pan. As long as these cover bolts are not loosened or removed, the cover's relationship with the crankshaft will remain untouched, and the concentricity of the balancer to the seal in the cover will be unchanged, thus insuring the seal will do it's job. It's only when someone removes or loosens the cover, and then does not realign it with the center of the crankshaft that we get into issues where the seal does not contact the surface of the balancer evenly, and it begins to leak oil.

I am building a new short block for my MJ, and have found a couple of variations between what engine is in the vehicle now, and the one I am assembling, and this made me wonder about these small differences. I wonder if any of you AMC gurus would know the reasons for these: 1. Cylinder Head Dowels my existing engine that I am replacing is from a 2000 XJ. The cylinder head is located to the block with two dowel pins. My replacement engine block is from 1992, and does not have the dowels nor the holes for dowels. Does any one know why they added the dowels on later engines (aside from the obvious convenience when installing the head)? 2. Timing Chain Types my existing engine has a "silent type" timing chain and sprockets. The new chain my engine machine shop recommended is a traditional "roller" type. I know that AMC used roller types in the past, but I don't know when Chrysler switched to the silent type. Does anyone have any comments? 3. Camshaft Thrust Control my new camshaft comes with a spring loaded plunger that fits into a new special bolt that retains the camshaft timing chain sprocket. This plunger pushes against the inside of the timing chain cover, and controls end movement of the camshaft. The old engine from the 2000XJ lacks this feature, and obviously has some other way to control thrust. Does anyone know when and why they made the change?

If you are JUST replacing the balancer, and have NOT loosened the timing chain cover, the new balancer will fit on the existing seal and be concentric enough to seal correctly. People get into trouble when the loosen/remove the timing chain cover, and then the cover needs to be recentered on the balancer snout before it is tightened to the front of the engine.

That's the little devil in question. Mine doesn't have any of the locking features any longer, as some previous owner/repair person broke them off. I don't like trusting a critical connector like this when it only uses friction to be retained, and it's facing downward where gravity is working on it all the time. I will secure one of those Custom Connectors. You are a hero. Out of curiosity, HOW did you know that was a APEX? I sort of searched around on the web, and didn't find that result. (And I worked in the electronics industry as an engineer for 40 years, but not automotive stuff, so I have "some" knowledge of connectors.)

That is the primary failure mode for a harmonic balancer. Fix it soon, or else the outer ring can "walk" rearward on the hub and begin chewing up the timing chain cover.

I am looking for the connector on the body half of the wiring harness for a 1996 or later XJ (my engine in my MJ is from a 2000 XJ, along with the wiring.) Does anyone have a line on one in good working order? (Wells Automotive makes a replacement, but it's FIFTY DOLLARS, and that's kinda steep for a silly connector.)

The engine builder who is making my new short block tells me that Pete (known here as "Cruiser54") has passed away. He will be missed for his insight into old MJ's and XJ's. I hope his "Cruisers Tips" is archived for posterity here. EDIT: address for if anyone would like to send a card to his widow. The Family of Peter Rushbrook 7255 N Spur Rd Prescott AZ 86305-8928 Funeral / Celebration of Life: - May 29 5pm, Upper Ramada @ Watson lake in Prescott, AZ

If worse comes to worse you can take the prop. valve out of the vehicle, disassemble it, and push the shuttle back into place from one end. (It might also be a good time to clean the whole valve to make sure any crud from within the valve assy.) Of course, this will require bleeding ALL the brakes, but that's not actually a bad thing, especially if the fluid is old.

It really should not take much force. I use a small pick and kind of try to drag the shuttle back to the center. It should also have an angled surface on it that actuates the switch plunger, and that surface is easier to use to actually push the shuttle along. (That angled surface might be out of view through the switch port, but some slight coaxing might make the edge of the surface show up in the switch hole. Once that surface is visible, it's easy to push it along the rest of the way towards center.)

The emergency shuttle often does NOT reset by itself. Years of gunk (and never normally moving) make it stick in place. It is possible to move the shuttle to the center by sticking a small pick or similar down in the hole where the switch plunger threads into the valve body, and I have done this in the past. Just be gentle with the pick on the shuttle, since it's usually made out of aluminum.

There were no robots on the assembly line when the XJ or MJ were in production, at least nothing like what we see today. However, the use of Torx fasteners allows the power driver bits to last longer on the production line.

For those who may not have studied the shape of a Torx bolt: the “star” shape you see is actually an “involute spline” tooth pattern. This is similar to gear teeth and to splines on things line drive shafts. this shape of “tooth” will transmit torque MUCH more evenly across the driving surface of the fastener. This results in less tool wear on repeated driving of fasteners, and less wear on the fastener head when removed/installed repeatedly.

The only bed bolts I ever messed with were bolts with separate nuts. if ALL of the bed bolts are that type, 3/8 grade 8 bolts with self locking nuts would substitute quite nicely.

'jdog' is correct. The starter relay is merely a distribution point for the power from the battery. The wires attached to the threaded stud on the relay are the wires that distribute the power to the various circuits in the vehicle. Finding which circuit is the one that is "bleeding" the electrical system when the vehicle is turned off involves identifying the circuit by process of elimination. Start by removing ONE of the wires attached to the threaded stud, and leave the vehicle sit overnight with the battery cut-off switch left in the "ON" position. If the battery is not drained by this action, then reconnect that wire, and pull another one, and repeat the overnight test. Once you have the wire that has the bleeding identified, now you can begin searching for the specific source of the issue. By the way, I assume you have performed all of Cruiser54's tips on improving your electrical system. If you have not, do that first, before anything else.

This is another good point. If you try to start pulling the new balancer on with the threads of the regular attaching bolt, it’s quite possible to STRIP THE THREADS IN THE CRANKSHAFT! What I always do is to polish the end of the crank with fine emery cloth to remove rust and varnish. Then clean the crank with brake cleaner or the like. Also clean the inside of the hub of the new balancer with brake cleaner as well. Then use some clean motor oil on the snout of the crank and the inside of the balancer hub. Tap the balancer on to the hub to make sure it is started evenly. I find that light taps with a hammer should get the balancer on far enough that the retaining bolt with thread in at least 4-5 turns. omce the bolt is that deep (or more) the chance of stripping the threads is very low, and the bolt can draw the balancer on the rest of the way.

That is a VERY good tip. Most guys who have never pulled a balancer don't know about the big washer under the bolt.

So a search on Helicoil on the web, and you will find they come in virtually every standard thread size/pitch, both SAE and Metric.

You might want to define "pretty snug" and "super tight" a bit more to instill more confidence here.

You are going to have to make your own brake lines to connect the MC to the prop. valve. The best thing to do is to take the MC to the auto parts store to match up the correct kinds of flare and thread. On a WJ, they might be using ISO “bubble” flares, and it is easier to buy the tubing with those flares pre-made. For the other end that connects to the prop. valve, be prepared to cut and bend the tube to create the custom lines you need and flare the ends with the traditional flare that attaches to the prop. valve. (You can reuse the regular flare nuts from your old tubes on the ends that connect to the prop. valve)

It’s back together with a stripped bolt hole?😳 That might not be a very good idea.

I stripped a caliper bolt in my MJ (but my bolts don't' look like yours) and I fixed it using a "Helicoil" thread repair kit. There is also another type of thread repair called a "Keensert", but they seem to be less widely available. Compared to Helicoils, Keenserts are for higher strength applications, as explained here: https://blog.mfsupply.com/2020/02/21/heli-coils-vs-keenserts-3-differences-you-must-know-part-1-of-2/ In your situation, the application you have does not place any real load on the pins, as there is no real tension on the threads once they are tightened. The threads only keep the pin from falling out. That means a Helicoil, if installed correctly, should be more than adequate for the job.