Rear dif leak repair advise/write up? anyone?

[03snake03]

I need to replace the gasket on my rear dif cover. It's been leaking ever since the shop install my BF brace. How difficult is it with the IRS on these cobra's? Anyone have a write up or how to do this or what all is involved? Know it sounds like a easy job for most of you but I've never done much work on these cobra's.

Thx

 

[85FourEyedGT]

Hmm, If i were you , I would get under there and check it out, mine leaked after I did my irs brace too, Turns out the side where the brace was not on was quite a bit loose

So what I did was blast away all the crud with some brake cleaner , once its clean Check ALL the bolts and retighten them to about 23lbs, I coulndt fit a torque wrench so I just used a small wrench and tightened as much as i could, then I cleaned everything again and put some sealant around the Leaky areas of the cover, worked for me!

 

[03snake03]

It's not a bad leak, just a few drops every few months. My car sits alot so I think that' s why it leaks so much. I have already went under the car and tried to tighten them and they are tight. I fear that from what I've read on this site is that the pumpkin has to come off to properly re-seal the cover. Maybe I'll just do a gear change etc all at one time, because I have a feeling it's not going to be cheap or easy to drop the pumpkin.

 

[bubblehead93]

somewhat a PIA but not too bad - more tedious than hard.

1. Get car on jackstands, recommend stands put under rear lower control arm.

2. Remove cat-back exhaust

3. Remove wheels

4. Disconnect parking brake cable and unbolt/remove rear caliper and bracket as single unit, zip tie to rear subframe mount bracket. unbolt the parking brake cable from the lower control arm and feed it out of the retaining loop which is on the inside of the rear knuckle - just get it out of the way. remove brake disc.

5. Mark upper cam bolts - many use a sharpie, however, if your rear is aligned and you like the setup, take a small cold chisel/hammer and place match marks on the edge of the eccentric and the adjacent surface of the upper control arm.

6. Place match marks on pinion companion flange and driveshaft, unbolt and remove, leave in back of transmission, tie wrap to available bracket in transmission tunnel.

7. Unbolt rear tie rod ends at the knuckle. unbolt the shocks at the lower control arm.

8. With pry bar, pry between rear end housing and half-shaft to free from differential, should not have to pry hard - do not pry on the abs ring. Unbolt upper and lower bolts holding the knuckle to the control arms. Support the differential side of the half-shaft and remove half-shaft/knuckle/hub as a single assembly. Take care not to place weight of half-shaft on oil seals in side of differential housing and damaging them (inspect and replace if necessary though).

9. Unbolt the abs sensors from each side of the differential - it is a torx bolt though you can get a box wrench on it as well. zip tie them out of the way.

10. Break loose but do not remove the front and rear differential bolts from the subframe - two in front, either side of the pinion snout and the two in rear, upper/lower cross-wise.

11. Support differential with jack

12. On both sides, remove nut from the front most lower control arm frame bolt and tap bolt forward enough so that 1/2" to 3/4" still protrudes - the goal here is to create anough clearance so you can remover the front cross-member which supports the front of the differential - CAUTION - hitting the bolt to far affects the integrity of the lower control arm which is supporting the weight of the car, if really concerned - just add additional jackstands under the car frame.

13. Remove front and rear differential to sub-frame bolts and the front support bracket and lower differential from car.

14. Repair leak and re-install - torque cover bolts to 25 ft-lb. While you have the cover off I would stud the main bearing caps in the differential - SME-85101-1 or TFS-85101-1 which I think are just repackaging of the FRPP kit - about $35.

15. Re-install is the reverse. The upper and lower knuckle to control arm bolts are 66 and 85 ft-lb respectively. the shock to lower control arm bolt is 95 ft-lbs or so. I forget the differential to subframe torque values and pinion companion flange to driveshaft values. I'll look them up and edit my post when I get home.

Hope this helps - hope I did'nt leave anything out.

 

[ZZR]

+1 on the above but would ad that I'm seeing zero leaks since switching to Threebond instead of silicone. Similar results when I resealed the trans.

 

[bubblehead93]

I would also add that if you plan on seriously launching your car at the strip, especially with slicks, that while you have the differential out you replace the crush collar on the pinion with a solid spacer and shims. most of these cars produce enough power that this becomes a real issue on the strip. while many might not feel comfortable pulling the pinion out and shimming it, it is quite easy when you already have a set of gears already set-up. the only unusual tool is a small in-lb beam type torque wrench to measure running torque as you shim it - though you can do without it - calibrated touch - lol.

 

[03mgtermi]

http://www.svtperformance.com/forums/terminator-talk-229/675978-please-help-cant-get-diff-cover-off.html

my trials and tribulations.......some pretty good responses here if interested

 

[1 bad bullitt]

Check the obvious, after I installed mine, about 6 month later, I noticed spots in the garage, well I finally got around to putting the back up in the air, and several of the bolts had backed out. Now, I had used the factory sealant from Ford and torqued every bolt to spec and every thing and they were still backed out. Anyho, I went under and German Torqued tham and never had a issue again.

 

[Badd Asp]

it is absolutely doable without dropping the diff out I just did it and installed the LPW diff cover wasnt really bad at all however i was not changing anything but cover

 

[bubblehead93]

i'm sure it is possible to do it without dropping the differential, alot of the interference is the same though - driveshaft, exhaust. i'm not sure if it is any faster that way and it sure is easy working on the differential in a fixture mounted on a bench. also if you use a cold chisel or scribe to match mark your upper cam bolt vice a sharpie I am confident you can do it without an alignment afterward (assuming it was lined up to begin with). Finally I think if your going to go through the trouble of pulling the cover, inspect the gears and bearings, especially if your running more than stock power. JMHO.

 

[99 KOBRA]

I have a diff. leak also. The shop I us doesn't drop the diff. to repair. Goes in next week for repair.

 

[bubblehead93]

lol - work smarter not harder. however, if your paying someone else to do it, the labor charge is likely less leaving it in place (leaving tires, brakes, and halfshafts all in place). i'd be curious what a shop charges to do it this way. Good luck with the repair.

 

[boost by u]

was told by a few ford dealer ships to just seal with rtv silicone thats all they do works better then a gasket the metal on metal seals better any advise fixing my buddys tonight please comment

 

[boost by u]

Anyone????????

 

[P49Y-CY]

that is correct - seems like the generally accepted method nowadays is to seal with silicone (no gasket needed)

the driveline shop who just installed my tru-trac said the same thing. they only used grey rtv sealant with my lpw cover.

 

[greengt88]

Gray sealant and lpw cover on my fox for 2+ years and no leaks.

 

[boost by u]

thanks fellas

 

[99 KOBRA]

JBA Performance fixed my leaking diff. with gray or black sealant, and installed a Steeda IRS diff. brace. I was out the door for under $400.00 (I supplied the brace).

 

[99 KOBRA]

lol - work smarter not harder. however, if your paying someone else to do it, the labor charge is likely less leaving it in place (leaving tires, brakes, and halfshafts all in place). i'd be curious what a shop charges to do it this way. Good luck with the repair.

See my post for price.

 

[Bdubbs]

I'm use to foxbodies, but I've always ditched the gasket idea, and used high-temp gray sealent, never had problems.

Now a BF brace I would like to install, I've seen a write up on this and it seemed like alot of work! Is this true?