[xj] Re: Vibration

“Bob and Peni Kopicki” <@Robert_and_Peni_Kopi>

Hi list,

My vibration and noise saga continues. I have a rumble now to add to my
list of drivetrain noises. This rumble is VERY speed specific and occurs
from 10 to about 15 mph and 30 to 40 mph regardless of acceleration or
deceleration. I’m suspicious of the driveshaft bearing since I have checked
all of my u-joints and they appear tight. Anyone have a method of
determining if the driveshaft bearing is going kaput? How about
replacement, does replacement require any special tools or can I do this at
home in an afternoon?

Thanks as always,

Bob Kopicki
'85 XJ-6 Series III
72K miles
Canton,OH USA===================================================
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“DOUGLAS DWYER” <@Doug_Dwyer>

Bob,
You cannot check U-joints when they are on the car. The only time they will
“appear bad” is when then they are 99% destroyed. Anything less than 99%
destroyed and they’ll probably seem Ok until you take the driveshaft out.
So, take the driveshaft out and twist the u-joints. The movement should be
smooth as a baby’s bottom. If not, you can remove the joints and see that
the needle bearings are hammered and/or the bearing surfaces are
galled----but you’d never see or feel this while the driveshaft is still in
situ. Same, really, for the center bearing. IMHO you should change the
center bearing on GP as long as you are going thru all the effort. BTW, new
u-joints are inexpensively available at any parts house. It’s the same UJ
that works on about 75% of GM RWD cars. Spicer number is 513x if my memory
serves.

You can do this at home if you have a vice and a variety of sockets to push
the bearings caps thru. If there’s a rental yard nearby they may have a
u-joint installer which would be a plus. It is very important that you don’t
inadvertently put the caps into a bind when installing the new UJ’s. Make
sure to keep all the yokes and driveshafts properly oriented for
balance—best to mark them with paint.

Doug Dwyer
Longview, Washington USA

Hi list,

My vibration and noise saga continues. I have a rumble now to add to my
list of drivetrain noises. This rumble is VERY speed specific and occurs
from 10 to about 15 mph and 30 to 40 mph regardless of acceleration or
deceleration. I’m suspicious of the driveshaft bearing since I have
checked
all of my u-joints and they appear tight. Anyone have a method of
determining if the driveshaft bearing is going kaput? How about
replacement, does replacement require any special tools or can I do this
at----- Original Message -----
From: Bob and Peni Kopicki Emily1999@prodigy.net
home in an afternoon?

===================================================
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“Bob and Peni Kopicki” <@Robert_and_Peni_Kopi>

Doug,

Thanks for your help. What about the half shaft u-joints? I replaced a
trashed right outer one when I got the car 2 years ago (It WAS 99%
destroyed) If I had known about this list then, someone probably would have
recommended that I replace the inner while I was at it and that would have
saved me trouble down the road. Is there anyway to tell if its a driveshaft
u-joint vs a half shaft joint? The vibration seems to come from right under
the front seats - not the back or to a side. I ask because this is going
to be a lot of work to pull the driveshaft out as was the half shaft 2 years
ago - not one of my favorite jobs. Thanks again for your advice and help.

Bob Kopicki
85 XJ-6
Canton OH USA

“DOUGLAS DWYER” DWYERD@email.msn.com

Bob,
You cannot check U-joints when they are on the car. The only time they
will
“appear bad” is when then they are 99% destroyed. Anything less than 99%
destroyed and they’ll probably seem Ok until you take the driveshaft out.
So, take the driveshaft out and twist the u-joints. The movement should
be
smooth as a baby’s bottom. If not, you can remove the joints and see that
the needle bearings are hammered and/or the bearing surfaces are
galled----but you’d never see or feel this while the driveshaft is still
in
situ. Same, really, for the center bearing. IMHO you should change the
center bearing on GP as long as you are going thru all the effort. BTW,
new
u-joints are inexpensively available at any parts house. It’s the same UJ
that works on about 75% of GM RWD cars. Spicer number is 513x if my memory
serves.

You can do this at home if you have a vice and a variety of sockets to
push
the bearings caps thru. If there’s a rental yard nearby they may have a
u-joint installer which would be a plus. It is very important that you
don’t> inadvertently put the caps into a bind when installing the new UJ’s. Make
sure to keep all the yokes and driveshafts properly oriented for
balance—best to mark them with paint.

Doug Dwyer
Longview, Washington USA

===================================================
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