centralnc

Fantastic Build. I really like the color. This obviously took a lot of time and patience. Congratulations on MJOTM!!

I believe I am going to have some time today to pull that alternator. I would like to ask one more question about them. RockAuto and Advance both list options for higher amperage alternators. It seems the standard is 61 amps, but 85 and 100 amp alternators are available. The price is essentially the same for the higher amp alternators. Is there any advantage to having the larger alternator? I don't plan on adding extra lights or anything that would demand a higher draw. I think I am going to order the standard 61 amp alternator. Thoughts?

I appreciate all the advice. I guess I am used to doing things the old way and just taking off the cable. I put a voltmeter across the battery terminals to test the voltage. The battery voltage at rest was 12.45 V. The voltage at idle speed was 12.35V. I was expecting a voltage of around 14V with the engine at idle. The positive cable to the starter isn't in the best shape. I am going to replace it tomorrow. I will take the alternator off and test it if I have time. Did you know that Advance Auto is offering a $50 discount when you purchase $100 of parts online? A new alternator and a battery cable would qualify for the $100 and I would get a $50 coupon for the next $100 purchase. Not a bad deal for a Jeep owner. How many times do you go to the parts store and drop $100? I believe Advance is trying to promote their online purchasing system to compete with RockAuto. I am going to look in my Jeep Service manual...but does anyone know a test for determining if it is the alternator vs. the regulator? A quick test with the multimeter might save me from pulling a perfectly good alternator.

I am getting closer to getting the MJ back on the road. I believe I need a new alternator. I can crank it up, but if I remove the battery cable it dies immediately. I drained one new battery already just letting it idle and run. The MJ hadn't been cranked in 4 years, so I wanted the oil to circulate and lube the engine. Would you guys buy a new alternator (~$100) or try a used one from the JY ($30)?

I am planning to try my luck at replacing the RMS again this evening. I am going to use a Napa RMS this time. I have a question about the blue Felpro gasket. Should I attempt to reuse the gasket or should I buy a new one? I am worried that the RTV sealant I applied at the corners might not clean off. It typically adheres to the rubber gasket pretty tight. Would you guys re-use the 2 week old gasket or buy a new one? It is such a PITA to drop the oil pans that the cost of the gasket ~$20 doesn't seem significant vs. having to replace it. Thoughts?

I think I understand what I did wrong. I was reading an article on a website and it talked about not skinning any of the upper part of the seal during installation. I remember catch the edge of the seal on the lip of the channel when I had it about 1/2 way inserted. I skinned off a small piece of the seal that was about 1/8 - 1/4". I didn't realize what I had done until I read this article and I remembered doing it!! I guess this was enough to make it leak under pressure. I will pull it again and try to insert a new RMS. Should I get a new oil pan gasket as well? Would you guys use Felpro or get a RMS at the dealership? Thanks.

It took about 5 hours total, but I replaced the RMS. Drained the oil, dropped the pan and removed the RMS. There is no doubt that this was the original RMS. It was brittle and looked very worn. I cleaned the crud from the bottom of the oil pan. The hardest part was scraping the old gasket from the pan and bottom of the engine. I bought a Felpro RMS and a rubber Felpro oil pan gasket. I replaced the RMS and used sealant to bind the ends of the gasket together. I re-installed the oil pan with new gasket. I waited almost 24 hours and then fired up the truck!!! Of course....it still leaked. Not as much as before, but it still leaked a lot. A good drip every couple of seconds. I couldn't believe it. Any thoughts or comments on what I could have done wrong? Could it be something else beside the RMS? It is possible that the sealant I applied to the oil pan gasket was rubbed off while I was aligning the bolt holes, but I can't see this much oil leaking out because of the sealant. The engine is really running well with the new fuel pump, O-rings on the injectors and a short treatment of seafoam. I let the engine idle (and leak) for about 30 minutes while I cut the grass. I wanted the new oil to circulate and get the engine lubricated. I just caught the drip and let it go. What would you guys do next?

You guys aren't going to believe this. I found one today at the Pull-A-Part for $35. It was even the same color as my truck. Unbelievable!!

Wow....your truck is fantastic. I really like that picture of it 1/2 way up that rock shelf. I like to see the shots of how the MJ changed with time. It is amazing to see some of the talent of the people on CClub. You never know what is possible until you see the imagination of other people combined with the mechanical skill to make those dreams reality!! I really enjoyed reading and seeing this MJOTM!! Great truck and Great Build!! :cheers:

Thanks for the advice on the brake cleaner. Spraying it like that probably does not make sense. I am going to try to get that main seal out today and get it replaced. Question: A new RMS from the dealership is about $25. Has any tried the fluorelastomer RMS? It is suppose to last much longer. Of course it is 2-3x more expensive. thanks.

This one didn't happen to be New London did it? If it is, I went and looked at it and can tell you about it. I actually didn't realize that one was for sale in New London. The one I was looking at was in VA. The guy who was suppose to be selling me the 87 Comanche sold it on Friday!!! I thought we had a deal, but he obviously did not. I checked out your build thread. You did a really good job on your Comanche!!

I am going to change the emission hoses to make sure the ventilation is working adequately. The big hose was actually cut off and plugged. I am going to take the valve cover off again and clean those ports mentioned in the article. Good advice.

I appreciate all of the advice and comments. I was able to get the oil pan off yesterday. It didn't take long to get the bolts out, but getting the oil pan to release was pretty tough. It has had 22 years to bond. It is going to be tough to get the seal off the pan and bottom of the block. I didn't get the rear main seal out. My wife and kids came home before I got that far. The oil pick-up screen had some pretty harsh carbon deposits on it. I am going to take some brake clean to the bottom of the engine. I didn't get home today in time for any work, but I am going to buy the oil pan gasket and a couple of rear main seals tomorrow. Thanks for the links and comments. I really appreciate it.

Ok...I feel like a horses @$$!! :dunce: My Haynes and Chilton manuals both say that the transmission needs to be pulled before replacing the RMS. I Googled "Replace jeep rear main seal" and got 1/2 threads with pics. All of them show how to replace it without pulling the trans. I got a quote from a local mechanic and it was $500 - $700 for the job. It might be possible to do it myself for < $50. I guess it pays to Google!!! Feel free to send any links to good repair threads. :cheers: I might even take some pictures as I go!!!

As you have probably noticed I bought bought an 88 MJ almost 2 weeks ago. It did not run, so I hauled it home from SC. The truck had not been cranked in about 4 years, so I expect a few problems. I got more than I expected. The paint is faded, but the truck has very little rust. Both floor pans will need replacing and the gauges / electrical will need some work. It is the major mechanical issues that I was hoping to avoid. Aside from a new batter and new battery cable, the first problem was that the fuel pump was shot. I ordered one from RockAuto and installed it on Friday. The pump worked and the truck cranked. That was when I discovered that the O-rings on the fuel injectors were shot. Gas leaked like crazy. I also discovered the valve cover gasket leaked badly. I spent a couple of hours this morning installing a new valve cover gasket and O-rings on the injectors. There was a lot of build-up under the valve cover, but I cleaned most of it out and lubed everything with oil from the top. The new O-rings worked well. I put 5-7 gallons of gas in the tank plus 1/2 can of Seafoam. I put the other 1/2 can in the oil. I fired it up and let it run. That is when I discovered the leak at the back of the engine. It isn't a drip every minute or two. It is a constant fast drip that leaks so much oil that I had to put a pan underneath it. I just let the truck set and idle for 30 minutes. I would cut it off, let it set for 15 min and then let it idle again for 30-45 minutes. I just wanted to make sure that oil was getting to the critical parts. I will say that the idle and engine response was much improved. There is very little hesitation. The big problem is that darn oil leak at the back of the engine!!!! After looking for a Comanche for 2 months, finding one in SC with very little rust (and paying too much), hauling back to NC and tinkering with it for 2 weeks.....now the RMS appears to be shot. :fs1: I found another MJ that appears to be in much better shape (87 4WD that actually runs) and I plan on buying it on Monday. Should I consider the '88 dead and just park it in the pasture for parts? Should I sell it to someone who can change the RMS themselves and wants a MJ for a project? What would you guys do? Needless to say I really like these trucks, but at some point a person needs to cut their losses on a project and move on. I have about $1800 in the truck now and I can't drive it. :dunce: I will try to post some pics later tonight. Any advice or comments would be appreciated!! I will say that I learned this lesson.....Never pay too much for a truck that doesn't run!! Never pay more than a near-salvage price!! There is just too much risk involved.