U-Joint bad?
Thread Starter
Teching In
Joined: Dec 2002
Posts: 45
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From: Millersville TN
U-Joint bad? Quick Question #1:
If one of the U-Joints were bad, should I be able to feel any play in the driveshaft. I yanked back and forth and up and down on both ends of the drive shaft and could not feel any movement.
Quick Question #2:
If the front U-Joint were to need to be changed, how would it be done? It is more than just unbolting some U-bolts.
If one of the U-Joints were bad, should I be able to feel any play in the driveshaft. I yanked back and forth and up and down on both ends of the drive shaft and could not feel any movement.
Quick Question #2:
If the front U-Joint were to need to be changed, how would it be done? It is more than just unbolting some U-bolts.
TECH Veteran
Joined: Dec 2004
Posts: 4,012
Likes: 1
From: Beaumont, TX
Originally Posted by KevinTernes
If the front U-Joint were to need to be changed, how would it be done? It is more than just unbolting some U-bolts.
Disassembly Procedure
Tools Required
J 9522-3 U-Joint Bearing Separator
J 9522-5 U-Joint Bearing Spacer Remover
Notice: Never clamp propeller shaft tubing in a vise. Clamping propeller shaft tubing in a vise could dent or deform the tube causing an imbalance or unsafe condition. Always clamp on one of the yokes and support the shaft horizontally. Avoid damaging the slip yoke sealing surface. Nicks may damage the bushing or cut the lip seal.
Important: Nylon injected ring universal joints cannot be reassembled. Replace nylon injected ring universal joints with external snap ring universal joints.
When reassembling a propeller shaft, always install a complete propeller shaft universal joint service kit. This kit includes the following components:
One pregreased spider
Four service bearing caps with seals
One needle roller bearing
Delrin round washers
Delrin flat washers
Grease
Four retainer rings
Ensure that the seals are in place on the service bearing caps during handling. The seals will hold the needle roller bearings in place during handling.
Important: There are no bearing retainer grooves in production bearing caps. Production bearing caps cannot be reused.
1. Support the propeller shaft in a horizontal position that is aligned with the base plate of a press.
2. Place the universal joint so that the lower ear of the shaft yoke is supported on a 28.6 mm (1.125 in) socket.
3. Use the following procedure in order to remove the lower bearing cap from the yoke ear:
a. Place the J 9522-3 on the open horizontal bearing cap.
b. Press the lower bearing cap out of the yoke ear. This process shears the nylon injected ring on the lower bearing cap.
4. If the bearing cap is not completely removed, use the following steps in order to completely remove the bearing cap:
a. Lift the J 9522-3
b. Insert the J 9522-5 between the seal and the bearing cap.
c. Press the bearing cap out of the yoke.
5. Rotate the propeller shaft.
a. Repeat Step 3 in order to shear the opposite nylon injected ring.
b. Repeat Step 4 in order to remove the opposite bearing cap from the yoke.
6. If the front universal joint is being replaced, use the above procedure in order to remove the two bearing caps from the propeller shaft slip yoke.
7. Remove the spider from the yoke.
8. Clean the yoke in the area that will hold the retainer ring in order to ensure proper assembly.
9. Clean all of the sheared nylon from the universal joint cup bore.
Important: Do not loosen or damage the dust seals. If the dust seals are loose or damaged, replace the entire universal joint.
Important: These universal joints are designed for extended life and do not require periodic inspections or lubrication. When these joints are taken apart, repack the bearing. Lubricate the reservoir at the end of the trunnions with chassis lubricant or linkage joint lubricant.
10. Remove the U-joint spider bearing retainer rings. If the retainer ring does not snap readily out of the grooves, lightly tap the end of the bearing cap in order to relieve the pressure against the retainer ring. After relieving the pressure, remove the retainer ring.
11. Support the propeller shaft in a horizontal position that aligns with the base plate of a press.
12. Place the universal joint so the ear of the yoke is supported on a 28.6 mm (1.125 in) socket.
13. Use the following procedure in order to remove the lower bearing cap from the yoke ear:
a. Place the J 9522-3 on the open horizontal bearing cap.
b. Press the lower bearing cap out of the yoke ear.
14. If the bearing cap is not completely removed, use the following steps in order to completely remove the bearing cap:
a. Lift the J 9522-3 .
b. Insert the J 9522-5 between the seal and the bearing cap.
c. Press the bearing cap out of the yoke.
15. Rotate the propeller shaft.
16. Press the opposite bearing cap out of the yoke.
17. Remove the spider from the yoke.
Assembly Procedure
1. Install one bearing cap partially into one side of the yoke.
2. Rotate the yoke so that this yoke ear is on the bottom.
3. Insert the J 9522-3 in order to seat the trunnion in the bearing cap.
4. Repeat Steps 1 and 2 in order to partially install the opposite bearing cap.
5. Inspect both trunnions in order to ensure their straight positioning into the bearing caps (1).
6. Press against the two opposite bearing caps while working the spider in order to ensure free movement of the trunnions in the bearings.
7. Inspect the needle roller bearing for binding. If binding exists, one or more of the needle roller bearings may have tipped under the end of the relevant trunnion.
8. Stop pressing on the bearing caps when one bearing retainer groove clears inside of the yoke.
9. Press the U-joint spider bearing retainer ring into place.
10. Continue pressing on the retainer ring until the opposite side of the ring can be snapped into place. If necessary, strike the yoke with a hammer in order to facilitate seating of the retainer rings. (Striking the yoke with a hammer slightly springs the yoke ears.)
11. Repeat the above procedure for the other half of the universal joint.
TECH Veteran
Joined: Dec 2004
Posts: 4,012
Likes: 1
From: Beaumont, TX
'Bad u-joint' symptoms: 
http://www.cartalk.com/content/colum...tember/11.html
http://autorepair.about.com/cs/doity.../aa102602a.htm
http://mgaguru.com/mgtech/propshaft/ps102.htm
http://dodgeram.org/tech/repair/U_joint/repair.htm
http://www.cartalk.com/content/colum...tember/11.html
How do you tell when a particular U-joint is bad?
...
Tom: You really can't tell with the driveshaft still installed. You have to take it out and flex the joints, Roland. That's often the only way to tell whether a U-joint is bad.
Ray: A universal joint (U-joint) is a connector that allows the driveshaft (or anything else) to operate at a variety of different angles. And to do that, it has to flex in two different directions.
Tom: And there are two ways U-joints usually fail. Over time, the little needle bearings can wear out, in which case the joint will loosen up and get too much "slop" in it. That usually causes a high-speed vibration, or a clanking noise when you shift from Drive to Reverse.
Ray: U-Joints can also fail by seizing. That happens when water gets into the joint and displaces the grease. And then the needle bearings rust, and the joint stops moving in one or both directions.
Tom: If a joint has failed due to slop, you often CAN tell by prying at it with a screwdriver. But if it's seized, the only way to tell is by removing the driveshaft and flexing it to see if it bends smoothly in each direction.
Ray: Two other suggestions, Roland. Once you have the driveshaft out, you might as well replace all three joints. If you're doing it yourself, they only cost about 10 bucks apiece, and it'll save you the trouble of removing the drive shaft again NEXT weekend.
Tom: And also, see if you can buy replacement joints with grease fittings. Some of them allow you to grease the joint, and that grease pushes the water out and makes the joint less likely to seize again.
...
Tom: You really can't tell with the driveshaft still installed. You have to take it out and flex the joints, Roland. That's often the only way to tell whether a U-joint is bad.
Ray: A universal joint (U-joint) is a connector that allows the driveshaft (or anything else) to operate at a variety of different angles. And to do that, it has to flex in two different directions.
Tom: And there are two ways U-joints usually fail. Over time, the little needle bearings can wear out, in which case the joint will loosen up and get too much "slop" in it. That usually causes a high-speed vibration, or a clanking noise when you shift from Drive to Reverse.
Ray: U-Joints can also fail by seizing. That happens when water gets into the joint and displaces the grease. And then the needle bearings rust, and the joint stops moving in one or both directions.
Tom: If a joint has failed due to slop, you often CAN tell by prying at it with a screwdriver. But if it's seized, the only way to tell is by removing the driveshaft and flexing it to see if it bends smoothly in each direction.
Ray: Two other suggestions, Roland. Once you have the driveshaft out, you might as well replace all three joints. If you're doing it yourself, they only cost about 10 bucks apiece, and it'll save you the trouble of removing the drive shaft again NEXT weekend.
Tom: And also, see if you can buy replacement joints with grease fittings. Some of them allow you to grease the joint, and that grease pushes the water out and makes the joint less likely to seize again.
A bad U-joint can most commonly be detected by a metallic clunking sound when the vehicle is placed in gear. This indicates play in the U-joint and should be investigated as soon as possible. Other symptoms of a failing U-joint are vibrations from the drive shaft, noticeable especially between 25 and 35 mph; shudder on acceleration and/or squeaking noises.
To check a Universal Joint for play, raise the vehicle and support the rear axle with jack stands. Place the vehicle in neutral and set the parking brake. Now rotate the drive shaft back and forth by hand, checking the joint for any play if any play is detected, the U-joint will have to be replaced. Also look for signs of rust. This usually means a U-joint that has no grease and is ready to be replaced soon.
To check a Universal Joint for play, raise the vehicle and support the rear axle with jack stands. Place the vehicle in neutral and set the parking brake. Now rotate the drive shaft back and forth by hand, checking the joint for any play if any play is detected, the U-joint will have to be replaced. Also look for signs of rust. This usually means a U-joint that has no grease and is ready to be replaced soon.
An attentive driver might identify a bad universal joint in the propshaft by the vibration it creates in the car when driving at highway speed. It may vibrate more under light throttle, and vibrate less (maybe) when you take your foot off the go pedal. A bad front U-joint may cause the shift lever to vibrate in your hand. A bad rear U-joint may vibrate the chassis of the car a bit with little or no noticeable vibration at the shift lever. But when the problem is bad enough to be noticeable while driving, this is indication that the maintenance has been neglected. The worn u-joint should be detected much sooner by inspection during regular periodic maintenance of the vehicle.
...
There should be absolutely no free rotation (backlash) at all in a u-joint. When they they look like the picture above, they are life threatening, .... and it vibrates with a vengence at speed. Shortly thereafter the propshaft falls off in the street while you're driving, and if you're lucky, maybe nobody gets killed.
When you find a loose U-joint you should replace it immediately. Once a u-joint is worn to the point of having noticeable (detectable) freeplay, all the grease in the world isn't going to help it much. With sloppy internal parts the U-joint will proceed to self destruct with additional driving. From the time it has only a miniscule amount of detectable freeplay to the time when you can feel a noticeable vibration at highway speed (slight latteral freeplay) might be a few thousand miles (which is why it should be detected during normal maintenance).
However, from the time when you can first feel a noticeable vibration at highway speed to the time of immenent drive failure (like in the picture) may be as little as a few hundred miles.
...
...
There should be absolutely no free rotation (backlash) at all in a u-joint. When they they look like the picture above, they are life threatening, .... and it vibrates with a vengence at speed. Shortly thereafter the propshaft falls off in the street while you're driving, and if you're lucky, maybe nobody gets killed.
When you find a loose U-joint you should replace it immediately. Once a u-joint is worn to the point of having noticeable (detectable) freeplay, all the grease in the world isn't going to help it much. With sloppy internal parts the U-joint will proceed to self destruct with additional driving. From the time it has only a miniscule amount of detectable freeplay to the time when you can feel a noticeable vibration at highway speed (slight latteral freeplay) might be a few thousand miles (which is why it should be detected during normal maintenance).
However, from the time when you can first feel a noticeable vibration at highway speed to the time of immenent drive failure (like in the picture) may be as little as a few hundred miles.
...
I can hear it at low speed, a scraping squeak as ...coasts to a stop. As I take off again, there is a clunk from under the truck. At cruising speed something doesn't sound right, and I can feel a vibration. On my back under the truck, the U-Joints appear to be fine, but one of the front driveshaft u-joints is loose when I wiggle the driveshaft by hand. It is time to get out the tools!
The photos at the right are an example of a bad u-joint. The needle bearings had fallen out of the cup and the cross was using the cup as a bearing. Total failure of the cross, u-bolt, or yoke is likely if it is run for long in this condition.
The photos at the right are an example of a bad u-joint. The needle bearings had fallen out of the cup and the cross was using the cup as a bearing. Total failure of the cross, u-bolt, or yoke is likely if it is run for long in this condition.
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