Pinion seal replacement

[Macman45]

Doing the pinion seal on a leaky 2007 GT with 95k miles. I bought a new Ford pinion seal, I plan to reuse the flange (oil slinger) as well as the pinion nut. Any tips? I know its not the proper way of going through the diff etc. but should be fine. Will mark nut w.r.t. flange and check both nut torque and in-lbs preload of pinion.

 

[JC SSP]

I always thought the pinion nut was one time use?

 

[GlassTop09]

Doing the pinion seal on a leaky 2007 GT with 95k miles. I bought a new Ford pinion seal, I plan to reuse the flange (oil slinger) as well as the pinion nut. Any tips? I know its not the proper way of going through the diff etc. but should be fine. Will mark nut w.r.t. flange and check both nut torque and in-lbs preload of pinion.

I've done this myself at times past back in the day w\o issue..............just make sure that you use a good quality red Loctite on the pinion nut & pinion shaft threads to help prevent nut backoff once retorqued............if you can't afford to replace this nut w\ a new one.

 

[GlassTop09]

I always thought the pinion nut was one time use?

Yes, you're correct.......they're designed to be used 1 time only due to the way the top threads are cut into the nut to help bite into the pinion shaft threads when initially tightened.........but w\ some care, you can sometimes get away w\ using a pinion nut at least 1 more time after initially using it the 1st time when in a pinch.........but you can't keep on thinking this can always be done reliably w\o reaping the consequences sooner or later.......like playing Russian roulette...........

This same thing can also be said concerning the reuse of some TTY bolts more than 1 time depending on what the TTY bolts are specifically being used to attach to\hold............but you really shouldn't be doing this as a matter of practice.

I've done this myself but ONLY on my own vehicles back in the day when money was much tighter........not on somebody else's vehicles.

 

[Macman45]

The thought process of reusing the nut is so you can achieve the same pinion preload. A new nut would not return to the same spot. I’ve done both.

 

[Macman45]

I can gladly put a fresh nut on but fear I’ll affect preload and damage bearings

 

[Midlife Crises]

You can reuse the pinion nut if you clean it well and use red lock tite and carefully tighten it back to a similar feel. I have got away with it more than once. You cannot set the pinion bearing preload with in-lb torque wrench while the pinion is in contact with the ring gear. Try to put it back where it was plus a tiny little bit.

 

[GriffX]

I reused the nut also with no problems, but added some Loctite.
Regarding the torque, I used a pinion spacer which has a torque spec for the nut of 175 Nm, it is far below the torque for crushing the sleeve, but enough to tight the nut.

PS: Back in the days, the driveshaft bolts were out of production, so I re-used them too.

 

[lwarrior1016]

If you have an in lbs swing or dial type torque wrench, pull the wheels, brakes, and driveshaft off. Then take a preload reading before disassembling anything. It’ll be a total rotating preload so it won’t match factory pinion preload specs, but if you install a new nut and put it back to that same preload, it will be very close.

 

[Mustang Terlingua]

Old Ford Tech here. That said, Do Not Never reuse pinon nut. They are cheap compared to the cost if it backs off. Always pull rear cover to check for metal to see Why the seal failed. Usually with 95K miles I woulds suspect pinon bearings failed. Ford used crappy Koyo bearings. I have fixed a lot of Mustangs 8' 9" 8,8 7 10.25 diffs after somebody tried the easy cheap way & then spent way more $ after. Read the shop manual & follow the directions they wrote it for a reason.

 

[GlassTop09]

Ford used crappy Koyo bearings

I've noticed this myself lately, but do you know when Ford switched to Koyo's?

I ask this due to me buying a full Ford Performance 3.73 gear set back in 2018 that came w\ all Timken bearings........which I was happy about & never had an issue w\ the gear set install at all for some 3 yrs.

But I've bought a Ford Performance M-4210-B2 Ford 8.8" Ring & Pinion Bearing kit last summer to replace all the diff bearings in my car's rear axle that I knew were Koyo bearings (had bought a Motive Gear Ford 8.8" Ring & Pinion Bearing kit which were all Koyo's when I also bought a set of Richmond EXCEL 3.90 gears--3.89 actual 9 pinion\35 ring.......fall of 2021.....shop install which didn't go very well......heavy gear whining......but I learned a lot of things I also didn't know concerning this Ford 8.8" axle. Switched to a set of Motive Gear F888390 gears--3.91 actual 11 pinion\43 ring........summer of 2022......self-install that fixed the gear set whining issues but made the mistake of reusing those Koyo bearings, even though they only had <1,500 mi on them........developed some light whine on decel between 40-45 MPH only so swapped out those Koyo bearings summer of 2023......found carrier bearing races pitted & out of round) thinking I was getting Timken's........but found they also were made by Koyo.......even the Hi TQ inner pinion bearing.

No issues so far (just put 2,000+ mi on them last month) but am a little concerned due to this fact that they are Koyo manuf'd bearings & not Timken since my experience so far w\ Koyo bearings hasn't been a good one.

You know if\where you can still get these Ford 8.8" bearing kits w\ Timken manuf'd bearings? If so, please do share.

 

[Derf08]

Old Ford Tech here. That said, Do Not Never reuse pinon nut. They are cheap compared to the cost if it backs off. Always pull rear cover to check for metal to see Why the seal failed. Usually with 95K miles I woulds suspect pinon bearings failed. Ford used crappy Koyo bearings. I have fixed a lot of Mustangs 8' 9" 8,8 7 10.25 diffs after somebody tried the easy cheap way & then spent way more $ after. Read the shop manual & follow the directions they wrote it for a reason.

Not knocking your experience but being that the car is 16-17 years old would be a significant contributing factor to a seal failure. Seals get get brittle over time and will simply fail. Agreed about the pinion nut and inspection though. That will also mean the fluid will be replaced which should be done with any seal replacement.

 

[Macman45]

Not knocking your experience but being that the car is 16-17 years old would be a significant contributing factor to a seal failure. Seals get get brittle over time and will simply fail. Agreed about the pinion nut and inspection though. That will also mean the fluid will be replaced which should be done with any seal replacement.

Agreed. There’s no metal. In fact, the leak is so small nothing even makes it to the ground. Just a light film. Seal was quite brittle from our heat cycles. I did put a new nut on and did the trick above with a dial Torque wrench to compare.

 

[JC SSP]

I agree with Derf08 and I am not a Ford Tech, just an average guy who has owned, modified and raced mustangs since 1986.

8.8 is a strong rear end and with quality parts and proper set up will last a very long time.

I subscribe to doing it right the first time so I don’t have to worry about it in the future. This is the way…

 

[GlassTop09]

Seals get get brittle over time and will simply fail

Agree w\ this...................is why I only will use National Oil Seals 3604 Ford 8.8" pinion seals for replacements\builds as these are rated for 400*F+ operation........the front pinion bearing is THE hottest running bearing in this axle & this seal is the highest temp rated pinion seal out there I could find for a Ford 8.8" axle.........

Hope this helps.

 

[GriffX]

My OEM Koyo bearings from 2007 lastet 20kMi and the Ford Racing kit had Timken inside. I had 2 new nuts and in the end I needed one more which I didn't have. To order a nut would have been 5 days and shipping overseas. Even to get a bolt from Mercedes would be 20 Mi driving and one day waiting. Workshop manuals are written for workshops where they have a stock pile and the customer pays. I never had issues with re-using parts in more than 15 years of DIY on my own cars.