victorgallas Posted August 14, 2016 Share Posted August 14, 2016 Has anyone have experience on replacing the main bearings in the car? I can get to them, but the one in question is on the 2.5l engine. The rear main seal is put from the flywheel side, so will removing the last bearig block, while keeping the others in place, will it dislodge the seal out of place? Trying to avoid having to pull the trans again. Any advice guys? Also, what best place to.source the bearings? Link to comment Share on other sites More sharing options...
johnj92131 Posted August 15, 2016 Share Posted August 15, 2016 My first questions is WHY do you need to replace the main bearings? Have you pulled a bearing and found an issue? If so, what issue did you find? Do you even know what size bearing you need to buy? Link to comment Share on other sites More sharing options...
victorgallas Posted August 15, 2016 Author Share Posted August 15, 2016 Yes, they all have rubbing damage, I first saw glitter in the oil which prompted me to drop the pan and check. I removed the bearing caps and could see the scored bearings. They are all 0.02 for the main and 0.01 for the connecting rods. I plan on using plastigauge after putting the new bearings to check the clearance. But because I can't measure the diameter, I am just gonna have to measure the clearance with the plastigauge then pick another bearing if need be. Does anyone know a good way to deal with the least main cap and the rear main seal? I would like to do that bearing, but if I drop the cap off, I could upset the rear main seal and require to drop the trans to put a new one :-( Link to comment Share on other sites More sharing options...
Jtrux Posted August 15, 2016 Share Posted August 15, 2016 Main bearings are in pairs. Top and bottom. You will need to pull the crank to get to the other one. The flywheel is attached to the crank. In order to get the flywheel off, you will be moving the tranny back at the very least. I did this to an old CJ years ago. I had the crank turned and installed oversized bearings. But like I said, you will be moving the tranny out or back in order to do it. Pulling the engine will be easier. Link to comment Share on other sites More sharing options...
Jtrux Posted August 15, 2016 Share Posted August 15, 2016 If you absolutely must do this in the truck, do not knock the pistons up too far when you pull the crank. You will have to pull the head to push them back down if you end up moving the pistons too far. Link to comment Share on other sites More sharing options...
Eagle Posted August 16, 2016 Share Posted August 16, 2016 It is NOT necessary to pull the crankshaft in order to replace main bearings. The upper bearing can be pushed out and the new bearing pushed in. Unfortunately, I don't know enough about the 2.5L to answer the original question. Link to comment Share on other sites More sharing options...
victorgallas Posted August 16, 2016 Author Share Posted August 16, 2016 Thanks everyone. I was able to push the top main bearings out with the crank in place. Just the last one I am a little hesitant about, as I don't want to mess the rear main seal. I already ordered a new set of bearings, so once it's in I'll see what I can do. Worse case, I'll have to slide the tranny out, but I really don't want to :-( Link to comment Share on other sites More sharing options...
victorgallas Posted August 22, 2016 Author Share Posted August 22, 2016 Hey everyone, just to report back that I was able to replace the main bearings and connecting rod bearings in the car, dropped a new oil pump while at it and now the engine sounds great and runs great. Finishing the AC retrofit to r134 then off to the road it goes. It's been quite a trip this process for sure. Link to comment Share on other sites More sharing options...
Eagle Posted August 22, 2016 Share Posted August 22, 2016 Good news. Thanks for the update. Link to comment Share on other sites More sharing options...
MJanky Posted August 22, 2016 Share Posted August 22, 2016 So what happened with the rear main seal? Did you have to drop the trans? Link to comment Share on other sites More sharing options...
victorgallas Posted August 23, 2016 Author Share Posted August 23, 2016 Nope,just didn't touch that last one. The lower main bearings had a little bit of damage at near cylinder 1. The one right next to cyl 4 seemed OK, so I left the last one alone since I didn't want to risk it. I put the sema bearings size to those I took off. So far is running smooth, quiet and way better oil pressures than ever. :-) Link to comment Share on other sites More sharing options...
johnj92131 Posted August 23, 2016 Share Posted August 23, 2016 Nope,just didn't touch that last one. The lower main bearings had a little bit of damage at near cylinder 1. The one right next to cyl 4 seemed OK, so I left the last one alone since I didn't want to risk it. I put the sema bearings size to those I took off. So far is running smooth, quiet and way better oil pressures than ever. :-) Just wondering what clearances you had when you plastigauged the new bearings? Link to comment Share on other sites More sharing options...
victorgallas Posted August 27, 2016 Author Share Posted August 27, 2016 Most of them where giving me around 0.002 for what I recall. Essentially right on spot for oil clearance on what I could find on the manuals. The first main bearing was a little on the tight side, but I am just gonna let it break in lol. Link to comment Share on other sites More sharing options...
victorgallas Posted August 29, 2016 Author Share Posted August 29, 2016 For those wondering. This is how the bearings came out of the car. Glad I replaced them. https://www.dropbox.com/s/zmoe4ysuk4mmj3f/IMG_20160828_154738765_HDR.jpg?dl=0 Link to comment Share on other sites More sharing options...
87Warrior Posted August 31, 2016 Share Posted August 31, 2016 You made the right choice to leave #4 alone. The 2.5 has a one piece rear main unlike the two piece found in the 4.0. If you dropped the cap and crank, I don't think you could have gotten the seal to fit squarely when putting it back together. Link to comment Share on other sites More sharing options...
victorgallas Posted September 1, 2016 Author Share Posted September 1, 2016 Yeah, that's what I figured. The engine is running so smooth and quiet, it's awesome. Pretty happy with it. Just gonna enjoy it as is. Should something come up later that prompts and engine tear down, then I'll revisit that last one. Link to comment Share on other sites More sharing options...
victorgallas Posted September 1, 2016 Author Share Posted September 1, 2016 Let me clarify, when I did the procedure, I did not remove the crank, since it was attached to the transmission. I had to rotate the crank with a small cotter pin in the oil passage to rotate the upper bearing out. It work well. Link to comment Share on other sites More sharing options...
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