Front Diff Bushing
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Burning Brakes
Joined: May 2005
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From: Pearl MS
Front Diff Bushing
I am putting the rear back together on my '79. I got the diff in and all bolted up and then got the front bushing in, I went with a new poly bushing - the old one was in pretty bad shape. I got new u-joints put into the d-shaft and 1/2 shafts. As I tighten the u-joint straps the d-shaft binds up in 2 spots. I have pulled it and put it back in 4 times with the same results, everything is good to go but it still binds???? My father-in-law (mechanic) says that I have the pinion angle off now because of the new bushing. Is there any certain way that I should have the washers set and a way that I can do this easily (without removing that D$%^*&^$M d-shaft again??
Is this problem really the pinion angle?
Is this problem really the pinion angle?
Race Director
Joined: Mar 2001
Posts: 11,322
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From: Living in the Hartland
Might try doing in rev order, half shafts first and then front bushing. Also might need weight on the tires to get the half shafts more in line, the will bind if you have the rear tires in the air and rotate them.
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
Originally Posted by Fevre
Might try doing in rev order, half shafts first and then front bushing. Also might need weight on the tires to get the half shafts more in line, the will bind if you have the rear tires in the air and rotate them.
It is hard to imagine the pinion angle being off so far that the driveshaft universal bind.
Thread Starter
Burning Brakes
Joined: May 2005
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From: Pearl MS
I got the bushing from Van Steel and refered to their diagram when I installed the bushing. Best I can tell, I have everythig where it is supposed to be but it still binds. I do not have the 1/2 shafts in yet or the strut rods or the spring fully installed. Upon installation, I pulled it apart and then put the small bushing & bolt (with the washers) through the top part of the frame, the big bushing in between the frame and flange on the diff and then the washer, lock washer & nut on the bottom of the flange on the diff. I did notice the the new bushing was "thicker" than the old one but the old one was worn out.
How much could a washer here or there (having it out of place) effect the pinion angle?
How much could a washer here or there (having it out of place) effect the pinion angle?
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Pinion angle would be really hard to totally screw up that bad. Check that the driveshaft isn't actually hitting the floor somewhere and then with the driveshaft out make sure the rearend turns over freely. What if the backlash is out and causing the gears to bind in a certain spot?
I measure pinion angle using a magnetic angle gage. I put it on the output yoke of the transmission. Take a reading and then put it on the pinion yoke and take another reading. The two readings should be equal but opposite, the transmission one is down and the pinion should be up. Adjust the shimming of the pinion to equal the transmission reading but again opposite in direction.
I measure pinion angle using a magnetic angle gage. I put it on the output yoke of the transmission. Take a reading and then put it on the pinion yoke and take another reading. The two readings should be equal but opposite, the transmission one is down and the pinion should be up. Adjust the shimming of the pinion to equal the transmission reading but again opposite in direction.
Thread Starter
Burning Brakes
Joined: May 2005
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From: Pearl MS
Cool, thanks.
With regards to everything turning freely - everything turns very freely when not connected to anything else. Everything still is very free when the front straps on the drive shaft are tight but loose on the diff side of the drive shaft. It only binds up (in 2 spots) when the rear straps are tightened on the drive shaft. Clearance is also good all the way around.
Could I simulate the car being on the ground by putting the floor jack under the diff and jacking there to see if the pinion angle changes. This may help compress the new bushing a little and then move the angle. The car is sitting on jack stands and the rear end is still very apart, that is why I would like to see if it is just the car sitting in the air that is causing my problem.
Thanks again for the help.
With regards to everything turning freely - everything turns very freely when not connected to anything else. Everything still is very free when the front straps on the drive shaft are tight but loose on the diff side of the drive shaft. It only binds up (in 2 spots) when the rear straps are tightened on the drive shaft. Clearance is also good all the way around.
Could I simulate the car being on the ground by putting the floor jack under the diff and jacking there to see if the pinion angle changes. This may help compress the new bushing a little and then move the angle. The car is sitting on jack stands and the rear end is still very apart, that is why I would like to see if it is just the car sitting in the air that is causing my problem.
Thanks again for the help.
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Melting Slicks
Joined: Jul 2002
Posts: 3,000
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From: Boulder Creek California
I had no problems with this type of bushing, but didn't have it disassembled this far.
Is it possible that something is bent that would cause the needle-bearings to be locking up in the U-joints? Do the U-joint-ends turn easily when they're out?
-Chris
Is it possible that something is bent that would cause the needle-bearings to be locking up in the U-joints? Do the U-joint-ends turn easily when they're out?
-Chris
Racer
Joined: Mar 2005
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From: WAY SOUTH OF HEAVEN inebriated
hope i dont run into that problem ill be installing mine this weekend and its been a while since i took everything apart so ive completely forgoten how the bushings and washers were set up hopefully the order in witch you say is acurate and thanks for saving me an embarassing post.
Thread Starter
Burning Brakes
Joined: May 2005
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From: Pearl MS
When it first started binding - the needle bearings inside the caps were the first thing that I thought of. I pulled it and checked and all was good inside the caps. Put it back in and it still bound up. Pulled the shaft again and rotated it 180° on the pinion and it still bound up. Tried several more times with no luck.
I tried to get under "the car" (I am mad at it now and it is now "the car") last night but got side tracked with work and did not have a chance. I will try again tonight.
I will let ya'll know what I find out when I find it.
I tried to get under "the car" (I am mad at it now and it is now "the car") last night but got side tracked with work and did not have a chance. I will try again tonight.
I will let ya'll know what I find out when I find it.
Race Director
Joined: Jul 2002
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From: Clayton NC
To simulate ride height you can use two jacks place one under each shock mount and lift the trailing arm until the halfshafts are level. I really think as someone else said that it's currently just the halfshafts binding up... Dave...
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Burning Brakes
Joined: May 2005
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From: Pearl MS
It cannot be the 1/2 shafts binding up, they are not in the car, I wish it was that easy.
The only thing in there is the drive shaft and the rear end. That was why I asked about the ride height - I do not think that it will change when I "put a load" on the rear end but I am gonna try it.
Thanks for the help anyway.
The only thing in there is the drive shaft and the rear end. That was why I asked about the ride height - I do not think that it will change when I "put a load" on the rear end but I am gonna try it.
Thanks for the help anyway.
Race Director
Joined: Jul 2002
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From: Clayton NC
Sorry man I musta missed in all the posts that the half-shafts were not in.. Did you say your diff was completely rebuilt? Did they replace the front yoke? Mine new one required a little massaging to get my u-joint to fit in the new front yoke...Dave..
Thread Starter
Burning Brakes
Joined: May 2005
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From: Pearl MS
No - the diff was in good shape. I took it over to a local shop (that I trust) and they gave it a clean bill of health except for a c-clip that held the left yoke in and a hole in the rear cover from a spring bolt that was too long. Both of those have been fixed and I was now in the installation prcess while I was having my wheel bearings done. Other than that there has been nothing new to effect the pinion angle.