Subaru front axle seal replacement! No need for more leaks, the media has plenty..
With all the leaks out there from newest tech devices, Liveleaks and various other media stories, let’s try to keep our Subarus from doing the same, i.e leaking all over the place. With four axles on every Subaru, except the Brz and older fwd Subarus, you have quite a few chances to end up with a leaky seal.
The signs of the a leaky seal are pretty straightforward with a burning smell on the as the fluid splatters the exhaust. A low level on the differential dip stick and lastly a spot on the driveway. With these clues you can track down the location of the leak and prepare your plan of action.
What happens to cause this issue? If you overfill the diff it can overwhelm the seal and cause a leak. When replacing Cv axles you can drag it across the seal and tear it or a poorly designed Cv axle can have rough spots where the seal rides can become worn and allow fluid to bypass.
This repair can take upwards of a an hour or two, With the right tools and practice this takes me around thirty minutes. Once again rust and the previous time all these parts have been removed will have the largest effect on your completion time. If things are rusty and seized the time can start to add up quickly.
Our typical array of tools will be on this list with a few specialty tools
Grey Pneumatic 3/8th socket set: These will start off the list. You will need your 12, 14, 17 and 19mm sockets will help get this job going.
Mayhew 5 piece pry bar set.. Helping you pop that pesky axle out of the diff. These are also great to have around for many jobs.
Hammer(s). It’s hammer time, hub bearings usually don’t just fall out, this will give it the persuasion that is necessary. Proto antivibe hammer is my choice hammer. A deadblow hammer is very helpful to put the cv axle back into the diff, as the c clip needs a bit of suggestion to seat in properly.. Atd deadblow hammer set.
32mm axle nut socket. Without this big boy you aren’t getting anywhere. This is needed to pop that axle nut off.
Powerbuilt seal driver/installer set. There are many things that can be substituted for these seals but having a set makes many jobs easier and less frustrated.
Lisle seal puller. With the right tool a job becomes that much easier. This guy should take care of this job no problem. Can be used for many other seals you may want to replace.
Today we will be working on a Subaru 5 speed manual but these also fit the Subaru 6 speed trans too. The driver’s side seal part number is 806735290
With the vehicle lifted and supported properly we can begin with removing the wheel. The next steps will be to remove the axle, we can start with the axle nut (32mm socket) and then move to the lower strut mount.
At this time you can choose whether to remove the ball joint not or bolt that hods the lower ball joint in to the knuckle to swing the knuckle away from the car. I prefer the lower strut bolts as they generally are easier to do but either technique works, we will follow along to the strut bolt removal. We will touch on the lower ball joint removal too.
Now we can mark the upper cam bolt before proceeding with the removal of the strut bolts. Both of these are 19mm and once removed the strut and knuckle may attempt to separate. If not you can use a small pry bar or screwdriver to pull the knuckle towards the outside of the car.
If your vehicle is equipped with Abs you will need to remove it from the strut, the same is true about the brake line.
Having the knuckle separated from the strut will now allow the axle to be removed from the hub. You may find that you need to apply downward pressure on the lower control to allow the axle to free itself. Once it is free find a safe place for the outer boot to rest.
We will now work our way to the transmission/differential to remove the axle. There is a c-clip on the axle stub at holds it in place, we need to apply enough force to pop that out. The most basic removal method is using a pry bar on the cup to knock it free or prying against the diff and axle to pop it free. Another specialty tool for it i a large C shaped adapter for a slide hammer. I reserve that tool to the very stubborn axles.
You may want to set a drip pan down before removing your axle, it is common to have a bit that flows over the seal and out. Having removed all of your obstacles and parts you can now pull out the axle seal. Subaru does have a different seal for each side, so make sure you have the proper side before tearing your old seal out. Once again there are many specialty style tools for this, I have used a standard seal puller but have also had good luck with a very small pry bar or large screwdriver. Taping off the tip of the utensil will protect the area where the seal sits. Damaging this area could easily cause a leak after your fix, and nobody wants that.
A quick note, you can also remove the entire seal area referred to as the differential Sundial bearing carrier. Thought this actually unloads the differential, which if you aren’t how to apply the proper preload to it, this should be avoided. Many will mark the sundial and transmission and then count the turns, I have never used this procedure but it is an option.
With the seal removed you will most likely have more fluid dripping out. When the fluid stops leaking we can clean the seal area for a proper seal of the new unit. It is also a great time to clean the surrounding area to be able to verify the seal isn’t leaking again. Given which side you are replacing you will need a seal driver kit or an object that is the same inner diameter of the seal but a slightly larger out diameter to keep it from being knocked right into the diff. Apply a very light amount of oil to the exterior of the seal to help it slide in.
Having the right seal driver in hand we can softly tap and check our progress. The goal being a seal that sits flush with diff housing. When you are happy with your seal placement I like to take a bit of diff fluid from my pan and dampen up the inner seal where the cv axle slides in. This will help avoid tearing seal when installing.
Next up is putting the axle back in. Being careful to not nick or tear the new seal we will slide it into the diff. Once it is engaged we need to hold it as straight as possible and give it a good couple of taps with a rubber mallet/deadblow hammer. This will allow the c-clip to engage the transmission, holding everything in place.
Completing those steps now brings you to backtracking your removal procedure. Replace the axle back into the hub and knuckle assembly. Then pushing the knuckle back into the strut and securing your abs and brake lines. Then applying a new axle nut and torquing it. Back on with the wheel and some further torquing. If you lost a lot of fluid, now would be the time to double check that fluid level on a very flat driveway, add if necessary. Then we bring the car back off the jack stands or lift and check that you are able to move back and forth.
Congratz! You have completed a less than fun job of replacing an axle seal! If your vehicle is tall enough you can double check periodically to make sure the seal has sealed.
Amazon Part Links
Subaru driver’s side seal 806735290
Subaru Passenger’s side seal 806735300.
. Subaru transmission seal kit. Both sides