Driveshaft support bearing replacement

Dealing with all subsystems specific to the diesel powered Datsun-Nissan 720 pickup trucks.

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claybodie
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Location: Corvallis, OR

Driveshaft support bearing replacement

#1

Post by claybodie »

Hi,
I have an '82 720 king cab that has a shredded center bearing. All I've found so far is the whole driveline (with a cracked but solid center bearing) for a regular cab model.
The question is, are they the same length? It seems to indicate they are in the shop manual, although the specs show different body and wheel base lengths.
It may also be helpful to know which bodies are the same (I thought the 81-86 are roughly the same, right?).
It seems like it would be easier to just switch out the whole driveline than replace the center bearing... special tool needed?

I could use some input on this. It would be appreciated.
Thanks,
Clayton
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asavage
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#2

Post by asavage »

The driveline carrier brg can be replaced without special tools. It only looks hard. In the worst case, you might need an impact wrench to remove the companion flange nut, and a std gear/jaw puller to pull the flange off the driveshaft, but the last one I did did not require either of those. You will need the correct size socket for the companion flange nut. I don't recall its size; probably 27mm or 30mm, but that's only a guess.

The carrier brg is readily available, though not particulary cheap. Ebay = under $50, over-the-counter it can go for up to well over $100, but shopping around is worth your time.

I can't answer your Q about the possibility of driveshaft length variation.

The 720 PU was discontinued in North America in 1986-1/2, replaced by the D21 ("Hardbody"). The diesel engine option was dropped for the US then, but was apparently continued for the D21 series in Canada into 1987.

I'm not certain, but I think the 720 replaced the 620 in 1981. I seem to have a hard time remembering where the 1980 MY falls.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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philip
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Re: Center bearing fun/Replacing driveline? Comments needed

#3

Post by philip »

claybodie wrote:Hi,
I have an '82 720 king cab that has a shredded center bearing. All I've found so far is the whole driveline (with a cracked but solid center bearing) for a regular cab model.
The question is, are they the same length? It seems to indicate they are in the shop manual, although the specs show different body and wheel base lengths. SNIP
Clayton
The King Cab model has a two piece driveshaft. The often overlooked problem when replacing a worn center support bearing is ... checking both shafts for runout. When this condition is present (as it was in mine), there will be a driveline vibration present in the 48-53 mph range when there is power applied. In this case, the FSM calls out for replacement of the entire driveline which includes the center support bearing as a MATCHED set.

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Last edited by philip 17 years ago, edited 1 time in total.
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"
claybodie
Posts: 51
Joined: 17 years ago
Location: Corvallis, OR

#4

Post by claybodie »

Yep, that's exactly what mine looks like. I will check the runout and see how things look. If it looks good it would be a good idea to just change the center bearing? I haven't seen one on ebay - I think the cheapest I've seen is around $60.
If I can't replace the center bearing it seems like it will be difficult to find another driveline for my vehicle. The town junkyard has I think an '80 regular cab driveline that's 2 piece, but I can't figure out which models are compatible (I have the shop manual, but I need a little clarification). I have an '82 king cab...


Clayton
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philip
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#5

Post by philip »

claybodie wrote:SNIP
If I can't replace the center bearing it seems like it will be difficult to find another driveline for my vehicle. The town junkyard has I think an '80 regular cab driveline that's 2 piece, but I can't figure out which models are compatible (I have the shop manual, but I need a little clarification). I have an '82 king cab...


Clayton
When I did mine, I took the shaft to a local auto jobber store (has machine shop) to have the bearing pressed off / on. I also took the rear shaft. It was the bow in the rear shaft that escalated the repair to complete shaft assembly replacement. Yes, there was driveline vibration present at 48-53 mph.

No problem getting a replacement assembly. MANY times, a "driveline specialty" shop will simply manufacture a new assembly from raw materials. It will be balanced and straight with ALL new parts.

DO be SURE to mark/index each flange and the slip yoke before you disassemble otherwise, you may well get driveline vibration when you had none before.

Buying a used propeller shaft assembly is a waste of money. This is one of those areas where cheapskating will cost you. The only exception would be if you found one that was obviously a recent replacement.
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"
ocd
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#6

Post by ocd »

I just found the rubber completely gone on my carrier bearing too. Is it a west coast thing?
-Noah

i deliver blends of biodiesel -no more!.

82 datsun 720 KC w/sd22
85 volvo 760gle sedan turbo diesel
85 peugeot 505s wagon turbo diesel & parts car
83 chevy k20 suburban silverado 6.2 n/a diesel
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asavage
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#7

Post by asavage »

No, it's a 25-yr-old-rubber thing. Ground-level ozone.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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philip
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Location: Southern California, USA

#8

Post by philip »

asavage wrote:No, it's a 25-yr-old-rubber thing. Ground-level ozone.
:wink: Were it a British made part, it would have lasted about 5 yrs. :wink:
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"
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asavage
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#9

Post by asavage »

I've got British rubber parts that are in perfect condition after 50 yrs.

OTOH, my Husky's windshield seal was shot after 20 yrs -- and a replacement was made of unobtainium.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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philip
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Posts: 1494
Joined: 18 years ago
Location: Southern California, USA

#10

Post by philip »

asavage wrote:I've got British rubber parts that are in perfect condition after 50 yrs. SNIP
The exception doesn't disprove the rule. Out here in arid, ozone/smoggy southern CA, British rubber was notoriously shortlived, windshield seals and door molding being the most often cited offenders.

Now having said that, you probably know I'm reaching back to the MGs and Triumphs of the 1950-60s. :wink:
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"
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kassim503
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Location: Stony Brook, NY

#11

Post by kassim503 »

philip wrote:......
Now having said that, you probably know I'm reaching back to the MGs and Triumphs of the 1950-60s. :wink:
I know! I had a 1960 MGA, everything that was rubber- trunk, door, windsheild, convertable top- everything leaked! The car was only 15-20 years old when I drove it around.
'83 maxima sedan, l24e, a/t, black

227K SOLD 6/7/2012
claybodie
Posts: 51
Joined: 17 years ago
Location: Corvallis, OR

#12

Post by claybodie »

So I just checked the runout, and it looks fine to me. It was <= 0.5mm as near as I could measure. It isn't the easiest thing to measure with household tools...
Does anyone know a good supplier for center bearings? I know RockAuto has them and sometimes they show up on ebay.

Clayton
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asavage
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#13

Post by asavage »

Chinese bearings are what you are going to get if you price shop. Quality does vary. But this bearing is not stressed much; as you can see, it's the supporting rubber that dies first.

Have you considered buying it from the dealer? Many OEM parts are quite reasonably priced.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
claybodie
Posts: 51
Joined: 17 years ago
Location: Corvallis, OR

#14

Post by claybodie »

You know, I'm actually don't know where to 'buy from the dealer.' I just figured that the datsun is so old they wouldn't sell parts for it. Where would I find a dealer?

Clayton
1982 Datsun 720 w/ sd22 running on B100.
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kassim503
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Location: Stony Brook, NY

#15

Post by kassim503 »

Nissan dealerships still carry parts for the datsuns, some parts cost alot, some dont. Still you definitley do not want to run any chinese made parts, they really are more of a "patch" than a fix.
'83 maxima sedan, l24e, a/t, black

227K SOLD 6/7/2012
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