Driveshaft/Parts general
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Joined: Aug 2004
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From: Calgary
Driveshaft/Parts general
Good evening,
I am a driveline mechanic and have been for 11 years. I lengthen, shorten, balance, weld, and machine all parts to any kind of driveshaft and pto from pickups to kenworths.
The 3 main failures in driveshafts are
1) bent / dented
2) U joints
3) steady bearings
A bent driveshaft will shake and pull itself in the direction of the bend. Like spinning a nut on a string, the faster it goes the harder it will pull sideways. This will destroy your u joints, transmission tail bushing, and eventualy your diff. A bent shaft can be re tubed (cut out weld yokes and weld in a new tube) or can be heated red on the high spot of the bend and cooled to make the tube run straight. I have had "W" shaped tubes and heated them straight and re balanced them. A dent will cause an imbalance due to steel not being where it used to be, a bend, and will sacrifice the structural integrity of the tube as torque is distributed unevenly.
U joints will fail due to
a) lack of grease
b) water and dirt getting inside
c) too much torque
d) a vibration (bearing, axle, other u joint, bent shaft, bad tail bushing, etc.)
e) poor insalation
Steady bearings will fail due to
a) water washing out the grease
b) inner race was pounded on over a lump or burr
c) vibration in shaft
d) ran out of grease due to age and natural wear
I will talk about Ford quality parts in my next post in a few minutes as it is too much to say here
I will talk about instaling new parts and diagnosing problems in another post as it is too much to say here.
Do NOT go to driveline shops and ask for very heavy wall tubing and a larger size of u joints and the partnering yokes for your tranny or diff and try to "beef up" your driveshaft. The driveshaft and all of it's components are designed to shear at certain amounts of torque. This means that if you build an invincible driveshaft, you will break your diff or tranny or something else that is a lot harder to take out and put back in, and will cost a whole lot more money. A driveshaft is a shear pin that is designed to break.
Driveshafts must be cared for and inspected often. The 92 and newer came with non greasable joints. They are a godsend from Spicer. not only are they stronger and have much tighter tollerances than the old greasables, but people are too dumb to grease driveshafts now compared to days of old. The seals are better now, the needle bearings in the caps are harder, and they fit tighter than the old ones.
Inspections of your driveshaft will solve vibrations that will tear up all your moving parts in your driveline. One joint running badly, or one steady bearing running loose for 6 months can add 5 years of damage to your entire driveline and truck.
Think about it. an impact gun is easy to handle and puts very little torque on your wrist . Adding vibration while spinning will trist off half inch thick bolts (with a good gun). Trying to do that by hand will require tremendous strength and pulling compared to gently holding the impact gun. Vibrations KILL moving parts and spread throughout your entire driveline.
Rob
I am a driveline mechanic and have been for 11 years. I lengthen, shorten, balance, weld, and machine all parts to any kind of driveshaft and pto from pickups to kenworths.
The 3 main failures in driveshafts are
1) bent / dented
2) U joints
3) steady bearings
A bent driveshaft will shake and pull itself in the direction of the bend. Like spinning a nut on a string, the faster it goes the harder it will pull sideways. This will destroy your u joints, transmission tail bushing, and eventualy your diff. A bent shaft can be re tubed (cut out weld yokes and weld in a new tube) or can be heated red on the high spot of the bend and cooled to make the tube run straight. I have had "W" shaped tubes and heated them straight and re balanced them. A dent will cause an imbalance due to steel not being where it used to be, a bend, and will sacrifice the structural integrity of the tube as torque is distributed unevenly.
U joints will fail due to
a) lack of grease
b) water and dirt getting inside
c) too much torque
d) a vibration (bearing, axle, other u joint, bent shaft, bad tail bushing, etc.)
e) poor insalation
Steady bearings will fail due to
a) water washing out the grease
b) inner race was pounded on over a lump or burr
c) vibration in shaft
d) ran out of grease due to age and natural wear
I will talk about Ford quality parts in my next post in a few minutes as it is too much to say here
I will talk about instaling new parts and diagnosing problems in another post as it is too much to say here.
Do NOT go to driveline shops and ask for very heavy wall tubing and a larger size of u joints and the partnering yokes for your tranny or diff and try to "beef up" your driveshaft. The driveshaft and all of it's components are designed to shear at certain amounts of torque. This means that if you build an invincible driveshaft, you will break your diff or tranny or something else that is a lot harder to take out and put back in, and will cost a whole lot more money. A driveshaft is a shear pin that is designed to break.
Driveshafts must be cared for and inspected often. The 92 and newer came with non greasable joints. They are a godsend from Spicer. not only are they stronger and have much tighter tollerances than the old greasables, but people are too dumb to grease driveshafts now compared to days of old. The seals are better now, the needle bearings in the caps are harder, and they fit tighter than the old ones.
Inspections of your driveshaft will solve vibrations that will tear up all your moving parts in your driveline. One joint running badly, or one steady bearing running loose for 6 months can add 5 years of damage to your entire driveline and truck.
Think about it. an impact gun is easy to handle and puts very little torque on your wrist . Adding vibration while spinning will trist off half inch thick bolts (with a good gun). Trying to do that by hand will require tremendous strength and pulling compared to gently holding the impact gun. Vibrations KILL moving parts and spread throughout your entire driveline.
Rob