Left side differential seal leaking again a month after replacement. (2 Viewers)

[Kamran Khan]

I have replaced left side differential seal a month ago and it was holding up fine, yesterday after inspection, I found it leaking again. What are your thoughts on it?
How far in the oil seal need to go inside the differential tube, I was jacking up the car on the right side to replace some bushing, could it be tilting that cause the diff oil to come out on the left side?

 

[excessive]

are you using OEM parts?

 

[Kamran Khan]

are you using OEM parts?

Seal is genuine, bought it from partsouq. I am thinking maybe the diff breather is clogged but I haven't inspected that yet.

 

[OEMGUY0720]

Leak/weep after seal replacement is ‘usually’ due to installation error. Other factor cam be bent axle which I hope is not the case. And yes a clogged differential breather can create pressure in the axle housing that can lead to seal failure.

 

[Kamran Khan]

These are the pictures of the old oil seal. I believe the older oil seal wasn't seated properly that's why it was leaking and maybe I have made the same mistake when installing new seal. I wasn't sure how far in I need to push the seal.

 

[excessive]

that does look too far "pushed in", but I haven't done this job in a while.
another thing is there could be a wear mark on the shaft itself, where the old seal was sitting. you could try to install a new seal slightly less deep so the seal rides on a different part of the shaft

 

[baltistyle]

Seal is genuine, bought it from partsouq. I am thinking maybe the diff breather is clogged but I haven't inspected that yet.

Definitely check this out, the breather. It should always be the first point of inspection for a diff leak, imo.

 

[Kamran Khan]

I believe I have finally figured out the problem. I installed the new oil seal too deep into the differential tube and that caused the leak. Took picture of the new seal and added captions to it. It may help someone in future doing this job.

 

[rmspider16]

I believe I have finally figured out the problem. I installed the new oil seal too deep into the differential tube and that caused the leak. Took picture of the new seal and added captions to it. It may help someone in future doing this job.
View attachment 3929636View attachment 3929637View attachment 3929634View attachment 3929635

This is why I love this forum. Members always provide great updates to these threads, so future searchers will have the answer. Thank you much for taking the time to do this!

 

[2001LC]

Some tips:
Scrape clean, inner ledge, seal seats flush with.
Lube inner area of diffs seal seat area and outer area of seal, with gear lube. Helps seal fits easy, without binding.

Seal seats, level with inner ledge.
Do not seat seal any deeper.

This place outer extended lip of seal, flush with outer tube housing (good) or slightly proud (best).

Add grease to inner area of seal, where axle of front drive shaft (AKA: FDS, AKA: CV) rides/seals. Also add some to lip of area where seal rides on axle

I use grease, to hold snap ring, "open end down". I "DO NOT" reuse snap ring.

Use care when install axle of FDS, so that seal is not knocked out of position.

 

[nissanh]

Continous strikes to the metal frame of the seal can deform the perfect circular shape. I use a heavy hammer to strike the seal with an appropriate adapter.

 

[scubadoober]

This seal continues to give people fits. I am a firm believer if it isn't leaking before the CV swap leave it alone. As often as our CV's need replacing you will be back in there soon enough, but this is the fourth or fifth thread in 2025 alone.

 

[2001LC]

It's a 50/50 shot, old seal will leak with a new FDS.

In the countless diff side seals, I've replaced. Not one has leaked.

 

[nissanh]

I see a lot use a hammer and socket extension to tap 4 corners of the seal which dents the frame causing the lip to be non linear. If you use the oil seal on the new seal, a solid wood black that covers the entire (old) seal and tap right in the middle with a heavy hammer like sledge hammer is the key to success!

 

[BnvS]

I have a rear differential seal that I tried replacing twice that is now leaking again. These seals are tricky to get right. Probably 3rd time is a charm. Hopefully.