For a while now I have been hearing an intermittent “popping” sound during acceleration which was getting steadily worse but was still intermittent….in other words sometimes I heard nothing but when I did hear something the “something” was getting louder.

Well to make a long story short – using the wonderful resources here on CF - I determined that the problem was most likely bad u-joints in the rear axles.

Now my car is an 89 coupe with 64k miles on it…so low miles but all original. I should also admit at this point that I bought this car unbeknownst to me, with, I swear, every common C4 problem so far from head gaskets to heater core. No matter, as I tick each one off the car gets better and better. By the time I get through this car I will be a C4 subject matter expert but I digress…

The suspected u-joint noise was coming from the LH side of the car…this I was sure of. I even had someone else drive while I listened to the RH side so I could be sure.

Well yesterday I decided it was go-time on the u-joints so I jacked the rear of the car up and proceeded to tear into it using this article from a CF member Vader86 as a guide.

http://temp.corvetteforum.net/c4/vad...orpujoint.html

Fist off, I’d like to say thank you to Vader 86 for taking the time to take pictures of this and do this write up. It was extremely helpful.

I would like to add a couple of my own observations.

1. I didn’t remove the camber bolts as shown in the write up. Instead I removed the lower control arm at the outboard knuckle. This provided plenty of clearance to remove the shaft and maintained the camber settings.
2. I didn’t have a big enough bench vise to press the u-joints out. Mine is apparently the Playschool model. I called a local mechanic who does a lot of Corvette work and he recommended using a ball joint press tool which is available from Autozone’s loaner tool program.* He emphasized to me that I needed to ensure their was no deflection in the driveshaft yolk area and this tool allowed me to press one end while supporting the other side. The hole was just big enough for the u-joint cap to pass through. Perfect and free. Got all 4 out in about 10 min.
3. Spend the money and buy a pair of needle nose pliers preferably the kind with the 90 degree bend for the installation of the new snap rigs. The old ones were easy to pop out but my attempts to install the new one without this tool resulted in a screwdriver – thumb interference that I cannot recommend. $10 well spent here.


I did the LH side first and sure enough the inboard u-joint had noticeable play in it. I was proud of myself for correctly diagnosing the problem. So much so that I contemplated replacing the LH u-joints and calling it a day. I say I contemplated it but knew this was probably a bad idea since the RH side couldn’t be expected to last too much longer right?

I went ahead and pulled the RH side shaft and the inboard u-joint DISINTEGRATED as I took it loose. It was 100% trashed. I was wrong in my assumptions, this was the one I had been hearing.

Both outboard joints seemed pretty solid. This kind of makes sense given the degree of deflection required of the inboard joints. They are all new now and the car feels great.

Hope this is useful to some of you. If anyone has any questions about doing this repair let me know.

Dave


*I forgot to mention...the "experts" at autozone were reluctant to "loan" me the ball joint tool since there was "no way it was going to work" and I was going to "screw up my drive shaft". They even called their manager over who just shook his head in agreement. I told them that the tip came from an experienced Corvette mechanic who's been in business for 30+ years. I also figured my own professional experience (20+ yrs as mfg/ind engineer in aerospace field) might allow me to see something "outside the box".

 

Currently preparing to undertake this operation and wondering
if anyone can add the Spicer Part Numbers for the 4 U-Joints.

Considering that the most likely stock based service will
specify the greasable units, those part numbers will
probably be the most readily and cross-reference available,
however if anyone has the Part Numbers for the Heavy Duty,
High Horsepower Non-Greasable units, those numbers would
be greatly appreciated also as they will be the ones used in
my application.

Considering the excellent usefulness of this topic, the
addition of appropriate Part Numbers will only add to
this thread's value as a single source reference for future use,
so once again, thanks to any and all Forum contributors that
make this such a practical, helpful support community.

 

From: www.dennysdriveshalf.com

Everything you need to rebuild your existing 1984-1996 Corvette 1310 series
Aluminum Main Driveshaft and 1350 series Aluminum Half Shafts. Will fit original
equipment and aftermarket aluminum 1310 series Main Driveshaft and 1350
series aluminum Half Shafts.

Spicer maintenance free solid body u-joints are a super strong high mileage
universal joint ready to install. No greasy mess from these to splatter all
over your meticulously maintained or restored car.

Spicer 1350 Series MAINTENANCE FREE U-Joint for Half Shafts
1350 series measures
3.625 inches wide in both directions
All 4 bearing caps are 1.187 inch diameter
Outside snap rings

(Part Number: 5-1350X
Manufacturer: Spicer
Manufacturer Part No: 5-1350X
Fits 1350 Series applications. Non-greasable, outside snap ring u-joint.
Same ujoint as the old Spicer part number 5-799X)

For those that want the Greasable U-Joints:

Part Number: 5-178X
Manufacturer: Spicer
Manufacturer Part No: 5-178X
Fits 1350 Series applications.
Greasable, outside snap ring u-joint.


Spicer 1310 Series MAINTENANCE FREE U-Joint for Main Driveshaft
1310 series measures
3.219 inches wide in both directions
All 4 bearing caps are 1.0625 inch diameter
Outside snap rings
Spicer 1350 series Strap and Bolt set for Half Shafts
Each set comes with (2) Straps and (4) METRIC Bolts to replace that old
stretched out original set with a new one.
Spicer 1310 series Strap and bolt set for Main Driveshaft
Set comes with (2) Straps and (4) Bolts to replace that old stretched
out original set with a new one.

Please note: We do not sell universal joints based on year, make and model.
Too many mistakes are made this way because too many vehicles are modified.
Instead we sell them based on actual dimensions so that you get the right u-joint
when you receive it. To order you must measure how wide your u-joint is in
both directions and the bearing cap diameters of all 4 caps. This must be
done at each end of your driveshaft.


.

 

Update:

Before you go to all the effort of removing your
Rear axle half shafts for universal joint replacement,
or rear wheel bearing replacement, try this basic 15
minute per side utility check first.

A loose rear axle nut will mimic many of the
symptoms of a bad universal joint or rear wheel
bearing, however, if the nut has not been loose
for an extended period of time, it can be retightened
very quickly and you may solve all your "Issues"
without a time consuming and potentially
un-necessary disassembly.

Verify axle nut tightness first by inspecting one side
at a time. Loosen wheel nuts of the rear corner you
want to look at first, perhaps the side you think the
noise is coming from, then jack the corner up
and remove the wheel. Remove the cotter pin
from the nut locker, pull the nut locker off and
get out your 40 mm socket and torque wrench to
check.

The rear axle nut torque specification for all C-4's
is 164 Ft/Lbs.

In my case the nut was basically un-torqued. It was not
loose enough to be turned by hand, but it turned aprox.
3/4 of complete turn to bring to spec. and the rotating
noise that was there before is now completely gone.

I'm keeping the Spicer U-Joints and I'll replace them
in future, either when actually needed, or proactively
as a winter project.





.

 

More than once l've done and seen ujoints changed with a hammer sockets and a 2x4

JS

 

Wonder if that is the issue with my 96, but mine is not a popping sound. It's more of a tinging sound. I only hear it when taking off from a dead stop and it's intermittent as well.

 

The rotating noise the loose axle nut caused was
rather like, and for lack of better descriptives....

"Scritch", "Scritch", "Scritch"...(fast jogging pace,
downslope coast, engine off) with sort of a dry,
rubbery overtone and it was almost identical to
the sound my buddy's '90 C-4 made when he changed
the bearing as the correction. It was only on the way
back together when he decided to check the axle nut
and found it similar to mine... loose, which lead him
to doubt the bearing change.

It might not be unreasonable to associate
at least a side to side differentiation in audible
noise emissions from a loose axle nut while turning.
Either weighting or unweighting the loose side
as turning would do, could theoretically produce
more or less noise depending on weighting/un-weighting
forces??? Could you hypothesize further that noises
could change due to heat and expansion from cold to
hot as things "warm up", particularly if the axle nut
was partially tight???

Anyway, knock-on-wood, this one is quiet for now, but all
our C-4's are old enough that almost anything could change
tomorrow.

I was just thankful that the all-day chore anticipated
turned into 20 minutes and I spent the rest of the day
cruising to a regional club event I thought I'd be missing.


.

 

It's time for me to get into this endeavor and I clicked on the link in your post and an error message came up. Is there any other way you can guide me to the info in CF member vader86's post? I would appreciate any help that I can get. Thanks.

 

It's on a different forum, but still useful:http://www.digitalcorvettes.com/foru...d.php?t=144562

It goes through doing the hubs, so only go as far as you needed. I used it with mine and worked out well.