Would value the opinion of anyone who wants to weigh in...'cause I don't know my driveshaft from a hole in the ground

[nemosis]

So, Everything is smooth up until a certain speed range.  Then relatively severe shaking/rumbling coming from underneath and behind drivers seat, just about where top of drive shaft meets u-joint (near as I can reckon. )  Doesn't feel or sound like front end. Feels very much like worn bearing.  Starts about the bottom of 3rd gear, continues in 4th as long as in speed range (about 25-35 (goes away between 35-40)), then smooths out.  Can start to feel it in second (?), but  I am afraid to over-rev it far enough to tell. Only seems to occur when under load (throttle neutral or accelerating, within aforementioned speed range).

 

So what do you think?  Loose U-joint, worn bushings, out-of-balance drive shaft, none of the above? It also has started to have to be "worked through" a couple of gears, before going from N to 1st after complete stop (Clutch seems good, tho)?  How screwed am I?

 

Thank you for the responses,

[hobospyder]

Crawl under the truck, grab the drive shafts and move it around while looking at the carrier bearing. If you see daylight through it it's bad and needs replaced. If good, check u-joints

[hobospyder]

Have you lowered it recently? If yes how much and check your pinion angle. The u-joints need to be at the same angle

[flatcat19]

Carrier. U-joints. Wheel balance(unlikely given your description.)

[nemosis]

Yeah tires are wearing evenly as crap. Was underneath earlier today, tried yo wiggle shaft, about 2/3 way up to u-joint (but i'm not big, only bout a buck-30). Grabbed the ujoint, and got a lot more wiggle...Can you link me with pix of carrier bearing?..I've only ever messed with engine, electrical, suspension, and braking...

[nemosis]

Not lowered, stock.

 

Or describe carrier bearing?

 

Not finding it in the repair guides?

 

Wheel balance doesnt seem to be an issue, tho it does seem to be rotational. But with the shaft and not the wheels.

 

Repair guides=haynes and chilton...wish there was a sterling guide, like with the vdub

 

So, im looking north of the u-joint where it attaches to frame? Is that carrier?

[hobospyder]

There should be a round rubber thing above a cross member. Don't have any pictures of any of mine that I can find easily, under the back half of the cab (guessing, I have 620s) I don't know how to describe it, I know what it looks like and that's the best I can come up with sorry

[hobospyder]

But it sounds like you get a lot of wiggle out of the u-joints when you grabbed them, maybe pull the drive shafts and replace those, get the carrier bearing while you're at it too.

[hobospyder]

 

The thing lined up almost dead nuts to the wheel well on the drive shafts near the ujoints, that's the carrier bearing.

[hobospyder]

I'm guessing the red line on the long part of the drive shafts is the cab/bed split. Again, 620 not 521 but I'm sure yours is similar

[G-Duax]

There was just another multi-page thread on this.

Just go back a few days.

 

Found it:

http://community.ratsun.net/topic/70195-one-piece-driveshaft/

 

The last few pages has parts drawings, and info.

[nemosis]

Thank you all...just got off the phone with a friend who was mechanic for 20+, and had a few dats (bluebird, neone?)..and between y'all and him, i think im oriented right..at least for now..i have to say, this is one of the least drama/most forthcoming and helpful forum sites that i've ever been on..you guys rock!..there must be something in the make/model/water...thank you all, again!

[datzenmike]

The rubber isolator is a rubber ring gripping the outer shell of the carrier bearing which is stationery, while the driveshaft spins inside it. The outer side of the rubber grips a roughly triangular ring which is clamped to the body. The isolator just supports the driveshaft in place and is flexible but firm.

 

 

Rear side

 

 

 

Front side

 

 

If torn or rotted out, the driveshaft is free to wobble about and this will vibrate.

 

 

I had this problem and wrapped the driveshaft with a rubber belt enough times so that it could be clamped back in place. Took a couple of tries but it worked so well that 2 years later I stopped looking for a replacement.

[nemosis]

And thats why i love my dub, and now my datsun..."oem parts?!...we dont need no stinkeen oem parts/badgers!...just wrap a leather belt around it, itll be just as fine as anything else..lol..y'all are awesome..

[nemosis]

And thanks for the pics, datzenmike, etal..was hoping youd weigh in..so tell me a story about a sixties bluebird?

[nemosis]

Looks like im gonna be dropping that this weekend..*sigh*

[datzenmike]

Actually it was a strip cut from a rubber conveyor belt. Has to be snug when the metal band is tightened down so it doesn't fall out.
 
Think....
 

 
 
And just so y'all know ... you can put two or more sentences in a post. :lol:



 

And thanks for the pics, datzenmike, etal..was hoping youd weigh in..so tell me a story about a sixties bluebird?

My first Datsun was a $50 Canadian '68 510 that was 7 years old. It was actually blue, too. Had the amber rear turn signal lights. When 'done with it' I left it out in the field behind the barn. Few years later I was doing a 'hone and ring' rebuild on my 521 but the main bearing were so bad I couldn't use them. I pulled the L16 out of the 510, stripped the mains out of it and put them in. They were slightly better.

[nemosis]

Dont cry for me argentina..i knew what i was signing on for..

 

Lol..you must be like the "crepekeeper"..

 

 

I hope thats not gluten free..

 

 

Sure dont look it

[nemosis]

Pretty sure you dont want to invite me to string more than one sentence atatimetogether...king of the runonsentence...diarrhea of the brain...try to keep it in check...

[nemosis]

Counting to ten, deep cleansing breaths..

[nemosis]

Oom...

[nemosis]

But seriously, i appreciate how serious you all take this stuff, and how willing you are to share with mda

[hobospyder]

Out of mana?

 

 

This ain't wow dude, it's just a truck

[hobospyder]

Also, give us some pictures, I'm getting itchy over here and need my fix

[nemosis]

Mda=my dumb "aorta"/"donkey"

 

Manna=from heaven..