main and rod bearing relacement
Professional
Joined: Nov 2010
Posts: 115
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From: rhode island
its not very hard to do in chassis.mains can be done easily loosen all the caps do 1 set at a time .i have a small flexible plastic putty knife i use to push the top bearing around so it can be removed the hardest is the rear main they can be tough .rods are simple .just make sure your puttin the same size bearing in that you took out unless youve had a knock in that case remove the motor and fix it right.you could also use plasti gauge to check your clearances but you dont have to. if your just slappin bearings just because you wanna, go for it your motor may live a little longer.thats my opinion anyway.ive done rods and mains on almost every piece of crap ive owned all of them in the car/truck with exception of my wifes blazer.some needed it some didnt but i felt better about the vehicle after.
Registered User
Joined: Sep 2014
Posts: 2
Likes: 0
Related question/scenario:
Vehicle is a 1989 Dodge B250, 5.9L engine, TBI, 727 trans, limited-slip rear. Have owned it since 2004 or 5. Bought it with 122k on it, purportedly. It looked clean enough and drove well enough that I was inclined to accept that mileage. Tried to run a computer check, but PA hadn't been keeping records that early.
After the first oil change -- a week or so after I bought it -- I noticed that the oil pressure was dropping at idle, causing the engine to begin to falter. Keeping a foot barely on the pedal was adequate to keep the pressure up, and I got it right into the shop. After replacing the oil pressure sensor, then the gauge, then the oil pump, we concluded it was bearings. I filled it with 20W50, and all was well. Again, that was 9 years ago.
My first inclination was to assume it had 222k on it, but everything about it seemed too tight, and there was no evidence of it having been meticulously maintained.
As suggested by the mileage/year figure, it spends most of its life sitting. Most of the time I just ran it to bring a ton of bagged coal twice each winter, or to pick up an appliance or lumber. Nevertheless, it's been 100% reliable. In one instance, after sitting for 8 months, I drove it 900 miles round trip, one way pulling a car carrier, the other, the car carrier with a Grand Cherokee. Never gave it a second thought, and I would wouldn't hesitate to do it again on a moment's notice.
So, here's the question: Replace the bearings? Or "if it works, don't fix it"?
Again, it runs perfectly, otherwise.
My reason for asking is that with my wife and I recently retired, we've been considering doing some traveling with it, possibly pulling a modest trailer. While HERE, I have a friend/mechanic with a lift, and the expertise to help me get it done while I do most of the hour-burning prep work. He indicates that it's not all that difficult to replace even the main bearings without removing the crank. Of course, if I had to pay someone out on the road somewhere to do it, it would be prohibitively costly.
Years ago I had another friend, also a top-drawer mechanic, who insisted it was far better to have loose bearings than tight ones, and so long as you control your oil pressure, he'd never replace bearings without cutting the crankshaft, and would prefer to replace the crank with one that hasn't been cut undersize.
Were it not for the toll of Northeastern rust, I wouldn't give a second thought to pulling the engine and doing a proper rebuild, but the body isn't good enough at this point to justify that kind of expense.
Now, what I'd LOVE to find is a solid body in search of a new drivetrain...
Vehicle is a 1989 Dodge B250, 5.9L engine, TBI, 727 trans, limited-slip rear. Have owned it since 2004 or 5. Bought it with 122k on it, purportedly. It looked clean enough and drove well enough that I was inclined to accept that mileage. Tried to run a computer check, but PA hadn't been keeping records that early.
After the first oil change -- a week or so after I bought it -- I noticed that the oil pressure was dropping at idle, causing the engine to begin to falter. Keeping a foot barely on the pedal was adequate to keep the pressure up, and I got it right into the shop. After replacing the oil pressure sensor, then the gauge, then the oil pump, we concluded it was bearings. I filled it with 20W50, and all was well. Again, that was 9 years ago.
My first inclination was to assume it had 222k on it, but everything about it seemed too tight, and there was no evidence of it having been meticulously maintained.
As suggested by the mileage/year figure, it spends most of its life sitting. Most of the time I just ran it to bring a ton of bagged coal twice each winter, or to pick up an appliance or lumber. Nevertheless, it's been 100% reliable. In one instance, after sitting for 8 months, I drove it 900 miles round trip, one way pulling a car carrier, the other, the car carrier with a Grand Cherokee. Never gave it a second thought, and I would wouldn't hesitate to do it again on a moment's notice.
So, here's the question: Replace the bearings? Or "if it works, don't fix it"?
Again, it runs perfectly, otherwise.
My reason for asking is that with my wife and I recently retired, we've been considering doing some traveling with it, possibly pulling a modest trailer. While HERE, I have a friend/mechanic with a lift, and the expertise to help me get it done while I do most of the hour-burning prep work. He indicates that it's not all that difficult to replace even the main bearings without removing the crank. Of course, if I had to pay someone out on the road somewhere to do it, it would be prohibitively costly.
Years ago I had another friend, also a top-drawer mechanic, who insisted it was far better to have loose bearings than tight ones, and so long as you control your oil pressure, he'd never replace bearings without cutting the crankshaft, and would prefer to replace the crank with one that hasn't been cut undersize.
Were it not for the toll of Northeastern rust, I wouldn't give a second thought to pulling the engine and doing a proper rebuild, but the body isn't good enough at this point to justify that kind of expense.
Now, what I'd LOVE to find is a solid body in search of a new drivetrain...
Champion
Joined: Sep 2012
Posts: 4,869
Likes: 434
From: Central VA
I'd suggest that you pull the motor and rebuild it being that its high mileage with low oil PSI. You can certainly install both main and rod bearings with the motor in the truck without removing the crank, but to get it right and feel comfy when traveling long distances, I would certainly pull the motor and rebuild it for peace of mind.
Administrator
Joined: Apr 2010
Posts: 87,465
Likes: 4,220
From: Clayton MI
Drop the pan, and plasti-gage a few of your bearings. See what clearances look like at the moment.
Do a compression test. Dry/Wet. Or, cylinder leakdown test, see what kind of shape things are in.
Decide from there what you need to do.
Do a compression test. Dry/Wet. Or, cylinder leakdown test, see what kind of shape things are in.
Decide from there what you need to do.
Registered User
Joined: Sep 2014
Posts: 2
Likes: 0
Thanks!
Actually, we did a compression test when we first spotted the pressure problem, and they were all even and where they should be -- don't recall the readings. That was one of the things that confused me. My inclination was to figure, okay, it had 200k on it rather than 100k -- won't be the first time I got screwed, but everything else about it was consistent with the lower mileage. At this point, of course, the body has gotten pretty rusty, though the undercarriage is still solid, which is why I'm hesitant to go to a lot of trouble with it. Leaning toward trying to sell it and grab and older short-wheelbase B-100 with the slant-6 and 4-speed manual. Had one before and it was incredible, but I digress...
Agreed about the plasti-gauge -- would have to be the first step regardless.
This is it, btw:
http://scranton.craigslist.org/cto/4669649309.html
Actually, we did a compression test when we first spotted the pressure problem, and they were all even and where they should be -- don't recall the readings. That was one of the things that confused me. My inclination was to figure, okay, it had 200k on it rather than 100k -- won't be the first time I got screwed, but everything else about it was consistent with the lower mileage. At this point, of course, the body has gotten pretty rusty, though the undercarriage is still solid, which is why I'm hesitant to go to a lot of trouble with it. Leaning toward trying to sell it and grab and older short-wheelbase B-100 with the slant-6 and 4-speed manual. Had one before and it was incredible, but I digress...
Agreed about the plasti-gauge -- would have to be the first step regardless.
This is it, btw:
http://scranton.craigslist.org/cto/4669649309.html