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Grinding sound from rear end area when driving
#1
I have driven my bronco about 500 miles since I've had it. I have noticed that there are no leaks coming from the drums to suggest my seals are bad, but does that mean the bearings are still good? If that isn't the problem, think it could be from the pinion area, say the pinion bearing? Again no leaks are coming from the pinion seal. Heck for all I know the hothead could be low on oil. It's so dang difficult determining exactly where the noise is coming from when ur in the drivers seat! Any help on ruling potential problems out is most appreciative.
Matt
[SIZE="2"]77 project bronco w/ 5.0 & c4, Sagi PS, 2 hard tops, eyebrow grill [/SIZE]
WANTED: auto column, gas tank, front/ rear seats
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#2
thats tough...can u put it on jack stands and let it idle in gear to check the noise?
77 built 306,Trickflow Cam/Alum Heads/dome pistons/10:1comp,nv3550,duff long arms,3.5" lift,family cage,protofab rear bumper,twin sticked, and 35KM2'sG.D.I.
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#3
Guess I can put it on blocks this weekend. Just sounds scarey and stupid. Just right up my alley! Is the pinion bearing easy to fix?
[SIZE="2"]77 project bronco w/ 5.0 & c4, Sagi PS, 2 hard tops, eyebrow grill [/SIZE]
WANTED: auto column, gas tank, front/ rear seats
Reply
#4
not exactly...try to zero in on sound 1st-then we'll go from there
77 built 306,Trickflow Cam/Alum Heads/dome pistons/10:1comp,nv3550,duff long arms,3.5" lift,family cage,protofab rear bumper,twin sticked, and 35KM2'sG.D.I.
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#5
I agree with Chuck - jack it up and spin the wheels. Check the fluid in the diff. Does it differ with speed? Do you feel it or just hear it?
'74 Grocery Getter, '73 Project Buggy, '77 Parts Rig

[Image: Bannerpic.jpg]
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#6
I noticed it for the first time this weekend. It just sounds like the start of something big. Wanna take csre of it pronto. Will raise and turn wheels by hand to see if it repeats.
[SIZE="2"]77 project bronco w/ 5.0 & c4, Sagi PS, 2 hard tops, eyebrow grill [/SIZE]
WANTED: auto column, gas tank, front/ rear seats
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#7
Does it happen under power or during coast? In turns, straight, both? Is the sound constant? Does it sound like a train rolling on the railroad tracks? Is it rhythmic like coincident with wheel rotation? Need more details.

And HELL NO, your bearing aren't necessarily good just cuz there is not a leak. Oil breaks down over time and even faster when contaminated with moisture. NOTHING is impervious to moisture. If you have a vent, then each time that sucker heats up and cools off it is drawing moisture from the ambient air.

Do you know if it has a locker?
'77 351w- Explorer EFI, 4R70W, 4-link, lockers, 4.56, 35" MT/Rs with a severe rock addiction.Confusedmokin:
Roads? Where we're going, we don't need roads.

[Image: sig2.jpg]
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#8
I got off early from Drill today and jacked up the rear with motor off and in park. Once on blocks I released the emergency brake. At that point I turned the the driver tire in a clockwise direction, the passenger tire was going counter clockwise. The grinding noise Was coming from the passenger side wheel. The hothead, transfer case, and driver side was all fairly quiet. Guess its the bearings. Is this something I can do or should I get a pro? Will look around for tech articles.
[SIZE="2"]77 project bronco w/ 5.0 & c4, Sagi PS, 2 hard tops, eyebrow grill [/SIZE]
WANTED: auto column, gas tank, front/ rear seats
Reply
#9
there not too bad.
1.pull drum off
2.4 retaining bolts-remove
3. try pulling on hud and slide axle shaft out.(sometimes these can rust in place making it a pain to remove)
if thats the case, use a old rim(bare-no tire), bolt it one and use that as leverage, if that dont work..locate a axle slide hammer)

use angle grinder, and cut the outer race off...remove all thats left of the bearing and use a cutting wheel on grinder to gently remove inner race.

you will need a press to install new bearing and bearing retainer(retainer can be a pain!!! and take a lot of force to press)

and dont forget new axle seal in axle housing.

holler if ya have a problem
77 built 306,Trickflow Cam/Alum Heads/dome pistons/10:1comp,nv3550,duff long arms,3.5" lift,family cage,protofab rear bumper,twin sticked, and 35KM2'sG.D.I.
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#10
If ur going to need to press it on i would use the press to remove too. Both ways work but the grinding method is risky if u havent done it before. If u hit the shaft, it is going to make for hell getting the new bearing on. Use caution.

U can get an axle shaft puller for rent @ autozone and advanced. I know that sucker is gonna be glued in there so save yourself a lot of headache and spring for the puller from the get go.


Sent from my Droid using Tapatalk 2
'77 351w- Explorer EFI, 4R70W, 4-link, lockers, 4.56, 35" MT/Rs with a severe rock addiction.Confusedmokin:
Roads? Where we're going, we don't need roads.

[Image: sig2.jpg]
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