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Discussion Starter #1
Alright... I will try to be as brief as possible. I paid a shop to rebuilding my entire rear end a little over 8 months ago. It leaked almost immediately from the pinion seal. After reading the FSM and other forum posts, I decided to tackle the change of the seal myself.

I started by marking the pinion nut in relation to the threaded pinion rod. I did not check the torque needed to rotate the assembly as I didn't have one to read that low. I recorded the torque needed to back the nut off (I used a steel plate tool I made to hold the flange steady). It took 90 ft/lbs to loosen.

I pulled the flange and the seal, cleaned the housing, and put a new seal in. I put RTV on the splines to be sure there would be no leaks and used red loctite on the threads of the nut. I tightened the nut to just past the original line I made (BTW, I counted the number of rotations of the nut to make sure it was in the exact same spot). I also recorded the torque it took to get the nut to the line (125 ft/lbs)

Fast forward, and there is still a leak. I decided to try another seal and a new flange. I did the same procedures as above, but now it only takes ~70ft/lbs to get the nut back to the line. I clean the pinion nuts threads before reinstall as I wanted to remove the old loctite. I can't see that making a ~55ft/lb torquing difference. I am concerned I crushed the collar somehow, and I am hosed.

I have ordered a 0-60 in/lb torque wrench to check the bearing pre-load. I have taken it apart again and plan on seeing how much effort it takes to get to the white line. I really hate to pull this all apart (the whole rear end). I plan to reassemble the flange and nut and carefully check the pre-load. If it's in spec, I guess I will let it ride.

Any tips or comments from the pros?
 

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Bringing Yellow Back
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did you put RTV on the part of the seal the contacts the housing or the splines of the pinion?

and im guessing you crushed the crush sleave a little
 

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Discussion Starter #3
did you put RTV on the part of the seal the contacts the housing or the splines of the pinion?

and im guessing you crushed the crush sleave a little
Yes, to the RTV on the seal and housing and the splines. The FSM says to lubricate the splines with diff fluid on install, but I could see it leaking these without RTV. I should have mentioned the leak after the first replacement came from the center section where the pinion flange rotates inside the seal. I bought a new flange to install as it does have wear marks from being used so long and could be warped I suppose.
 

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I recently did this and it sounds like the crush washer may be crushed from the last time you tightened the bolt. I probably wouldn't worry about it unless you hear some humming or other noises from the rear end.

Can't really help you on the leak as I simply removed the old seal and rtv'd around the new one before installing it and it's been good to go since. I didnt do anything with the splines other than place some grease.
 

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Discussion Starter #5
I recently did this and it sounds like the crush washer may be crushed from the last time you tightened the bolt. I probably wouldn't worry about it unless you hear some humming or other noises from the rear end.

Can't really help you on the leak as I simply removed the old seal and rtv'd around the new one before installing it and it's been good to go since. I didnt do anything with the splines other than place some grease.
I have read it takes ~160 ft/lbs to crush that sleeve, so I am not sure how I could have really crushed it all that much.
 

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yea the first time it takes that much to crush it, after that it is much easier
 

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Discussion Starter #7
I wish I knew more about how that theory worked. I would think you could keep crushing it to a point, and just maintain the same pinion preload somewhat. It would seem as though you just can't reduce preload by backing off b/c you have already created the slack by crushing the sleeve. I wish I knew how big the sleeve was or how far it could be crushed. Makes me think there is a lot of room for error/extra crush in one direction. I just need to keep tightening as I check the preload with my new torque wrench.
 

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Just to add:

It's impossible to check the bearing preload correctly with the rear end all assembled. Instead of just turning the pinion, you're going to be turning the entire assembly, which will give you a totally incorrect reading.

Your best bet would be to pull the rear end apart and replace the crush sleeve at this point, and then redo the bearing preload and then put everything back together. I know that's probably not what you want to hear, but that's the only way you're going to get the job done correctly at this point.
 

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This is one reason why I use pinion spacers whenever doing a rear end build I will use the crush washer to get it close, measure the washer then put i the correct spacer in. Never have to worry about crushing the crush washer any more when taking apart and putting back together
 

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Discussion Starter #10 (Edited)
Just to add:

It's impossible to check the bearing preload correctly with the rear end all assembled. Instead of just turning the pinion, you're going to be turning the entire assembly, which will give you a totally incorrect reading.

Your best bet would be to pull the rear end apart and replace the crush sleeve at this point, and then redo the bearing preload and then put everything back together. I know that's probably not what you want to hear, but that's the only way you're going to get the job done correctly at this point.
Although I suspect you are right that the best thing to do is to start from scratch....

According to the FSM, the readings should be taken with the wheels and brakes disconnected. Not without axles or a center section, etc. No reason I can't remove those items and check the preload.

And, at the onset of all this, I felt how much force it takes to turn the assembly over with just the wheels and brakes removed. It took hardly any effort at all. Not even measurable with any torque wrench I had.
 

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That's not right.

They should be setup to around 25 in lbs of preload without the trac-lock even in the pumpkin. If it was not setup like this to begin with, then your pinion preload was incorrect to begin with, which would be the cause of your pinion seal leaking in the first place.
 

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That's not right.

They should be setup to around 25 in lbs of preload without the trac-lock even in the pumpkin. If it was not setup like this to begin with, then your pinion preload was incorrect to begin with, which would be the cause of your pinion seal leaking in the first place.
:withhomo
 

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Discussion Starter #13
That's not right.

They should be setup to around 25 in lbs of preload without the trac-lock even in the pumpkin. If it was not setup like this to begin with, then your pinion preload was incorrect to begin with, which would be the cause of your pinion seal leaking in the first place.
I appreciate the comments/help, and I am not arguing with you. But do you have an FSM? For the procedure for changing the pinion seal and checking preload, this is how it tells u to measure it.
 

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No, and honestly, I don't care what the FSM says. Not trying to be rude, but pinion bearing preload has been set in the same way and with the same preload since the 8.8 was put in the Mustang in 1987. Even if you follow the FSM, there's no guarantee that without pulling the entire rear apart that you are going to get the preload correct, no matter what that book says.

Have I ever replaced a pinion seal without pulling it all? Sure I have. Did they leak? Most didn't, but some still did. Once the crush sleeve is crushed, there's no way of getting it 100% perfect again.

What is the preload spec in the FSM with the rear end assembled?
 

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How long can the car be down? If you can wait a few days, I say get a new crush washer, they are cheap, get the preload set, take it back apart. get these Richmond Gear 04-0011-S Richmond Solid Pinion Bearing Spacer, Measure your washer and put in the corrisponding spacers. You might have to add or subtract a few shims but the crush washer will get you close to what you need
 

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when i rebuild a rear end, i usually buy a couple of crush washers because i know i'm gonna mess it up the first time. i usually don't even measure preload. i torque the pinioin nut until there's no play in the pinion and then check gear pattern afterwards. i've never had any trouble out of the four rear ends i've rebuilt doing it this way.

you need to take it apart and put a new crush washer in or go with what f8l is saying.
 

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How long can the car be down? If you can wait a few days, I say get a new crush washer, they are cheap, get the preload set, take it back apart. get these Richmond Gear 04-0011-S Richmond Solid Pinion Bearing Spacer, Measure your washer and put in the corrisponding spacers. You might have to add or subtract a few shims but the crush washer will get you close to what you need
lol funny you posted that because thats exactly what i was thinking about since i used this kit in my rearend a few days ago. Since he has really never set up a rear at ALL i would highly NOT recommend he buys a solid spacer. it is IMPOSSIBLE to crush and if he doesnt know how to setup the backlash and spacing then he will not have a clue how to use it. Just my .02
 

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Discussion Starter #18
Fortunately, the car can be down for as long as needed. It's great to have two vehicles. However, I am always impatient and prefer to drive the mustang. I can see the advantage of the solid spacer in initial setup. Changing the pinion seal would not longer affect preload. I am very close to convincing myself to pull this thing apart entirely.

I am going to install the new OEM gasket and pinion nut. I am going to see how much torque it takes to get back to the same exact spot. I am going to test the pre-load as per the FSM, and see where I am. Then make a decision. I don't know how many times I have to learn this lesson; don't let a shop do your work...
 

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we have done so many installs that we do preload by feel. and then check tool pattern. If you were closer I would come check it out and give you a hand
 

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we have done so many installs that we do preload by feel. and then check tool pattern. If you were closer I would come check it out and give you a hand
I made sure to get a feel for the rearend before I tore it apart initially. So if it's WAY off, I will be able to tell.
 
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