Eagle

Nyuk, nyuk -- A 50/50 mix under 13 psi won't boil until 260 degrees with an open system, either. :D But -- different parts of the engine see different temperatures, and all it takes is one hot spot to create localized boiling, which then raises the pressure throughout the entire system and can cause boiling over even if the gauge doesn't show an overheating condition. Although I believe that spot on the back corner of the head was selected for the sender because it is normally one of the hottest parts of the engine.

Nope. A bad fan clutch would not result in that behavior. A bad fan clutch doesn't move enough air to remove the heat from the radiator. A vehicle moving at 25 or 35 MPH pushes air through the radiator and doesn't need the fan -- that's why we have fan clutches, to essentially make the fan NOT work when it isn't needed. Get serious. The Jeep temp gauge isn't calibrated in a linear scale, it's logarithmic. The low mark is 100, straight up is 210 (that's a delta of 110 degrees), and the top end is 260 (that's a delta from the mid-point on the gauge of only 50 degrees). Ain't nobody got any idea where on that scale 215 or 225 is. That's not turning on late, that's turning on when it's supposed to turn on. The aux fan isn't for normal cooling, it's to prevent OVERheating. It doesn't turn on until the temperature gets above the normal operating range.

No, he's asking if he should do that, or swap in the brakes from a non c-clip '88

The Renix system doesn't use sensors during initial warm-up. It's called "open loop mode" because the sensors are "out of the loop." It runs on a pre-set air/fuel map in the ECU until the engine temp sensor (the one low on the block, not the one on the back of the cylinder head) reaches the lower limit of the normal operating range, then it switches to "closed loop mode." On cold mornings, for me the switch occurs just about two miles down the road, on a level stretch where I'm at mostly neutral thottle, and there is a distinct sort of stutter-burp when it switches over. If yours doesn't idle cold, clean the idle air controller on the throttle body.

First, that's not the only difference between pipe and tube. Second, bending tube with a pipe bender hasn't ever worked for anyone else, so why are you so convinced it should work for you? Sorry to be brusque, but you came here with a question. The answer is that you're using the wrong equipment for the job. What you wish to do about that is your choice. There is a reason why tube benders cost so much more than pipe benders, and why Harbor Freight Tools doesn't sell tube benders.

Your problem is using the wrong tool. Pipe benders are for bending "pipe." For bending "tube," you need a tube bender. The difference is that steel tubing is measured by outside diameter. Pipe is measured/specified by inside diameter, so 1-1/4" pipe (for example) is close to 1-1/2" in outside diameter. Bending tube without kinks requires mandrels that fit the tube tightly, and it's pretty much impossible to use pipe mandrels because they just don't match up to the diameter of the tubing.

The bigger brakes go with the non c-clip axle, and I don't know quite how all the retainers, seals and such match up. For a permanent situation I would certainly choose the older, larger brakes but for a temporary band-aid, I think it'll be much easier to use the 9" stuff so you don't have to replace the backing plates and worry about trying to meld c-clip and non c-clip bits together.

The fan clutch should move *somewhat* easily when cold, and it should NOT move easily when hot. The simplest end-user test for the fan clutch is a traffic light. If the truck holds normal temperature when you are moving but starts to heat up when you stop at a long light -- then cools right back to normal when you start moving again ... the fan clutch isn't spinning the fan fast enough to be doing any work.

You can't use the ignition key for the doors on the early, two-key vehicles. I thought you could, too. I even had a so-called locksmith tell me he could do it, but I wasn't comfortable with the way he said it. Awhile later I was buying some locksets for the house from a REAL locksmith, so I asked him. He said the door keys use 5 tumblers and the ignition keys use 6 tumblers. They keys are the same length, so the pin spacing is different. He said he might be able to make an ignition key work in the door, but he'd never be able to make a door key work the ignition. And IF he got the ignition key to work the door, he guaranteed it would wear out the key and the locks within 6 months. I'll keep muddling along with my two keys ...

AutoZone and Advanced Auto had grommets -- they just didn't have body plugs.

Saving that tee fitting is potentially a huge mistake. You'll still be connected to two lines, doubling the possibility of a rust-through causing a loss of rear brakes. It's far better, whether you keep the MJ front metering block OR convert to an XJ front proportioning valve, to rip everything out and run one, new line from the front to the rear hose.

Somewhere in one of my FSMs there's a description of the official, factory measurement for correct ride height. Too late to look for it tonight, but I'll try to find it for you.

It can't flow any more into the bottle after you shut it off. The bottle should be filled to the halfway mark with the system cold. The coolant expands when hot and pretty much fills the bottle due to compression of the air in the bottle. What may be happening is that once you shut it off, the coolant isn't circulating so it gets hotter in a couple of places and raises the overall pressure in the system, which would compress the air even more. Once you've left it parked for awhile, does the coolant level in the bottle go back to the half-full mark? If so, there's no air trapped in the block. Does it overheat when you're moving, or only at traffic lights? If it runs okay but heats up when you're stopped and idling, you need a new fan clutch.

Did you bleed them according to the specific procedure in the link someone posted? If not -- then you wasted your time. There are TWO lines going from the front of your truck to the rear brakes. If you don't follow the exact procedure spelled out in the factory service manual, there's a good chance there's air in the other line and that's why you have no rear brakes.

Neither AutoZone nor Pep Boys nor Advanced Auto had body plugs -- or even knew that I was talking about. But ... AutoZone did have in the "HELP!" aisle a GM master cylinder cover gasket that looked like the right size. I bought it, hauled it home, and it IS the right size. For the first time in years, I am actually looking forward to the next rainy day. Dang, if this works I'll be psyched to put the correct transfer case shifter in and see about carpet. Woo-hoo!

Got good spark? Take a cup of gasoline and dribble a bit into the throttle body, then try starting it. It's no different than a lawn mower -- you can start it and even keep it running by pouring gas right down the throat. Just be careful -- you don't want to be holding an open container of gasline over it if there's a backfire.

You have asked two things in one thread. Do you want to bleed the rear brakes, or do you want to remove the rear proportioning valve? Personally, I blew up my rear proportioning valve so I had to remove it. But you should realize that if you remove it, when you slam on the brakes like in a panic stop, there's a good probability that your rear brakes will lock up before the fronts, and that usually results in a spin-out. Being the olde pharte that I am, I grew up learning to drive decades before cars had proportioning valves, so a bit of fishtailing in a panic stop is normal to me. To you younger folks, it's probably better avoided if you're not expecting it and ready to deal with it. Try adjusting your rear brakes and then bleeding according to the link provided. If that doesn't work, then consider removing the rear proportioning valve.

Not just for making this place possible. I bought the red '88 MJ in November of 1999 and put it on the road about a year later. It has ALWAYS had a leak -- the driver's footwell fills up with water any time it rains harder than a heavy fog. This probably explains why the carpet had been removed when I bought it and there was no floor on the driver's side. I've had no luck figuring out where the leak originated. I had pretty much convinced myself it must be the windshield -- except that the leak was obviously on-going, and I had to replace the cracked windshield when I registered the truck for the first time. The guys who did it have done multiple windshields for me, and they NEVER screw up. So as an experiment, during a heavy rain over the past weekend I put an old shower curtain over the cab, ran it down to the cowl and clamped it in place with the wiper arms. The windshield was completely protected ... and the footwell filled up with water. Pete has mentioned tracing leaks in one of his, and it sounded like a similar place so I've exchanged a couple of PMs with Pete about exactly where his leak was. He said something about "gaskets" where things go through the firewall. Hmmmm ... so this afternoon, I popped the hood on the MJ, and on the '88 XJ parked right alongside. And what to my wondering eyes did appear? Well, what did NOT appear before my wondering eyes is a body plug in a hole about 1" in diameter through the firewall right next to the clutch master cylinder. The hole is factory -- the XJ has it, too, but the XJ has a body plug in the hole. If Pete hadn't said the magic woid, I probably would have looked at that hole another hundred times, seen the rubber pad behind it, and assumed that's the way it's supposed to be. Now, I believe I've found my leak, and I'm about to head off to AutoZone to see if they have body plugs in that size (or in an assortment). If that's all that was causing 8 years of aggravation, I may just have to shoot myself.

Yeah, I don't know what it is, but I'm sure it's intended to reduce corrosion, and I also hope it works.

None of the measurements you have provided tell us anything, because any tire size other than "stock" (which could be any of several different sizes) means measurements to body parts will be affected even with no lift. If you don't want to cut the coils, what DO you want to do? Are you looking for advice on replacement springs to buy?

The lines I recently bought from Advance Auto have some kind of coating on them. I just put 'em in the MJ a couple of weeks ago so it's much too soon to know how well it will resist corrosion. Next winter will be a good test. Whatever the coating is, I made up my bends using a hand-held mandrel and the coating did not ship or crack at the bends.

And in "Monsters' Ball" Billy Bob Thornton gives an MJ to Halle Berry :drool:

Be careful. If you let the tool contact the glass and put pressure on the edge when twisting the tool to lift up the trim, you WILL crack the glass. We won't discuss how I know this ...

Do you still have the rear height-sensing proportioning valve? If so, there is a special procedure for bleeding the rear brakes. I posted it verbatim from the FSM a few months back. A search should turn it up -- I don't have it bookmarked or I'd give you a link to the post.

There's no point to putting it on the full length of the lines -- it won't stop rust where it's exposed. I always slide the fittings back and put Never-Seez on the tube in the area that the fitting covers and on the flare itself, and then I put it on the threads before I attach the line.