Oil leaking

[yoshi]

My 9" rear axle appears to be leaking from the u bolt that holds the prop in place

[Rude Dude]

Seal at the u bolt flange is damaged or gasket (o-ring) around that area needs replace.

Originally Posted by yoshi

My 9" rear axle appears to be leaking from the u bolt that holds the prop in place

[Rude Dude]

here is pic of ford nine

[Coupeguy2001]

Because there is a crush sleeve behind the prop yoke, If you take it apart, when you put it back together, you can't tighten it down to make the yoke tight.
You are going to have to make it just snug, or get another crush sleeve, and retorque it to factory specs.
The torque is way up there like 230 lbs foot.
Since the crush sleeve is of the proper crushed length, just tighten it back to firmly snug, and it should last a long time.

The part is identified on the IPC drawing above as a collapsible spacer.

[tmoble]

if you try to do this without replacing the crush sleeve first mark the pinion nut and the yoke with fine point scratch awl, use a little black magic marker if needed first. Then use a generous amount of Red Loctite on the nut and tighten it up so your marks line up like they did before plus a few degrees. You may need to get a large pipe wrench on the yoke and let it rest against the ground or a frame rail or something. The nominal torque to crush that sleeve is like 250 Lbs-ft.

[tmoble]

fall back and re-group. the u-bolts do not enter any area that holds oil and cannot leak. something else is leaking. it could be the pinion or yoke seal or it could just be a little grease from the u-joint itself. You'll be wanting to verify carefully before deciding to pull the yoke. That's to be avoided if possible.

[yoshi]

That exploded view looks helpful thanks. Not been able to get under there due to putting my back out, hopefully I'll be able to tonight & get some pics & clean it up to see where it's coming from. Got some oil on the drive that's what alerted me to it. Thanks all

[dsraven]

sometimes oil can track up the spline of the input yoke and come out behind the yoke nut. if it isn't the pinion seal then that could be the issue.
whenever you take the yoke off you should replace the crush sleeve. it isn't that tough if you don't think too much into it. put a little silicone on the splines when the yoke goes back on.

[dsraven]

post a pic before you clean it up. maybe we can give some insight.

[yoshi]

Ok will do

[yoshi]

Some pics before I touch anything

[yoshi]

Another

[dsraven]

that looks like gear oil that has worked it's way past the spline on the yoke. smell it to see if it smells like gear oil, if so, I would assume that you will find oil behind the nut/washer on the pinion when you take the driveshaft off. you could, at that point, simply clean the area well, then remove the pinion nut, again, clean the area behind the nut, place a small bead of silicone on the surface behind the nut and then install the nut and torque accordingly. remember that the bearing preload is achieved by crushing a small piece of pipe between the bearings called a "crush sleeve" and it has already been "crushed" so too much torque on the nut, past where the nut was positioned before, will crush it even more and the preload will be too much. the end result is failed pinion bearings. the proper way to repair this is to a) clean the area so no dirt gets inside. b) remove the driveshaft, pinion yoke and seal, pull the oil slinger "washer" out then the forward pinion bearing off the shaft. this will give you access to the crush sleeve, c) replace the sleeve and assemble the parts with a new seal. d)check the yoke for wear in the seal area. replace as required. e) place some silicone on the splines and slide the yoke onto the shaft. f) install a new nut and torque the nut down while monitoring the force required to turn the pinion shaft. it is not much rolling torque so do lots of checking while torqueing up the nut. you will feel the nut getting harder to turn as it bears down on the crush sleeve and starts to crush the sleeve. keep an eye on the end play of the bearing at this point and when the end play goes away watch the rolling toque of the pinion closely because you are getting really close to done, or, overdone. check the diff fluid level after. also check the diff vent because a plugged vent can cause pressure in the diff and then seals start to leak.

[yoshi]

So are you saying I need to replace seal 4676?

[dsraven]

I'm saying, if it was me, I would replace the seal because if you pull the yoke out to silicone the spline then you run the chance of marking the seal and a possible seal leak. if you are just gonna remove the nut, silicone the backside and install WITHOUT pulling the seal, then no worries other than ensuring the preload is not too tight from over tightening the nut. some Loctite is advised so the nut doesn't back off. of a new nut.

[ptc]

The only thing I would add is make sure it is not a "Daytona" style pinion support. They do not use crush washers.





Crush sleeves are used when setting up most 9 inch carriers to set bearing load,
but on the N case with Daytona pinion a non-crush solid spacer is used,
shown above are the two side by side (solid spacer on right).

[yoshi]

Ok, seal on order, silicone grease obtained, 3/4" drive torque wrench & sockets available when I'm ready