* Improper Installation: This is the most common cause. The seal needs to be seated perfectly and evenly into its housing. If it's even slightly crooked or damaged during installation, it won't seal properly. The housing itself may also be damaged, preventing a good seal. Make sure you're using the correct tools and techniques. A seal driver is essential to avoid damaging the seal lip.
* Damaged Housing: Inspect the axle housing bore where the seal sits. Look for any scoring, pitting, or rust. Even minor damage can prevent a good seal. If the housing is damaged, it may need to be machined or replaced.
* Incorrect Seal: While you mentioned new parts, double-check that you have the correct seal for your specific axle. There are different seals for different axle shafts and applications. An incorrect seal will not fit properly.
* Excessive Pressure: If you're using excessive force during installation, you could be distorting the seal or the housing.
* Contamination: Dirt, grease, or other debris in the housing can prevent the seal from seating correctly. Ensure the housing is thoroughly cleaned and degreased before installation.
* Worn Axle Shaft: The axle shaft itself might be worn or damaged, preventing the seal from making a proper contact. Inspect the shaft for scoring or wear.
Troubleshooting Steps:
1. Clean Everything: Thoroughly clean the axle housing bore and the axle shaft. Use a suitable degreaser and clean rags or compressed air.
2. Inspect the Housing: Carefully examine the housing bore for any damage. A straight edge can help detect even small imperfections.
3. Verify the Seal: Make sure you have the correct seal for your vehicle and that it's not damaged.
4. Proper Installation: Use a seal installer (the right size for your seal) to install the seal correctly and evenly. Avoid hammering directly on the seal.
5. Lubricate: A light coat of compatible grease on the seal lip can help with installation and prevent damage.
6. Re-Inspect: After installation, visually inspect the seal to ensure it's fully seated and flush with the housing.
If you've followed these steps and the seal still won't stay in, it's likely a problem with the axle housing or axle shaft requiring professional attention. You might need to have the housing machined or replaced. A mechanic specializing in rear-end work will be able to diagnose and fix the underlying issue more accurately.
