Chevy Astro and GMC Safari Forum banner
1 - 10 of 10 Posts

·
Registered
2000 Lifted 4x4 Astro 92 V8-350 Shorty
Joined
·
6,133 Posts
Discussion Starter · #1 · (Edited)
Yesterday I replaced my front passenger-side axle seal.
It's a pretty involved job.

PREPARATION:

IMPORTANT first order of business is to take a photo of your cv-axle engagement into the differential axle tube. This is important as you will need to know EXACTLY how far it was engaged when you replace the axle.
Automotive tire Tire Bumper Automotive exterior Rim


BEGIN JOB:
  • Raise vehicle with jack under lower-control arm (toward outer end)
  • Place jack stand under sub-frame (side you're working on)
  • Pull TIRE
  • Pull brake caliper and rotor.. (move out of the way .. 3/8 hex)
  • Disconnect shock (at control arm)
  • Disconnect axle from hub (36mm)
  • Separate upper ball-joint (pickle fork)
  • Lower jack to lower control arm fully (allowing it to hang freely
If you wish, you can remove the cv-axle nut while vehicle is still on ground.
Otherwise, here is how I hold the hub while removing the nut (with 36mm socket)
Wood Gas Nut Machine Auto part


You should now be able to flex lower-arm far enough to pull cv-axle out of the hub.
(you do not need to separate lower-control arm)
Tire Wheel Car Vehicle Hood

Automotive lighting Vehicle brake Automotive tire Motor vehicle Bicycle part


Pry the cv-axle out of the axle tube.
I used a crow-bar between the lip of the tube and cv-axle.. it popped free without difficulty.

OLD SEAL REMOVAL:

I found I needed to pull the internal axle shaft out of the axle tube so I could get access to removing the seal. A large screw-driver against the c-clip groove with some leverage will pop it out easily.
Automotive tire Automotive fuel system Automotive exhaust Carbon Rim


I was also able to easily pop out the old seal using a flat blade screw-driver (to get it started) then a crow-bar. It's not hard to do, but there is limited leverage room. The crow-bar angled in nicely.
Hood Organism Boat Gesture Adaptation


Plan on catching some fluid.. but if you lean the vehicle away from you, the flow will be minimal.

NEW SEAL:
National seal #710491 ($12)

I lubed the new seal, and pounded it in using a 2x3 piece of wood.. flat and fit well.
I slightly rounded the edges of the wood for a perfect fit. It went in easy.
Hood Automotive tire Automotive lighting Automotive exterior Automotive design


When fully seated, the seal should be slightly recessed below the outer tube lip.
Also make sure it is squarely seated.
Automotive tire Automotive exhaust Camera accessory Exhaust system Carbon


Again make sure seal is clean and fully lubed.
Lube cv-axle outer yoke.

CV-AXLE INSTALLATION:

One of the more difficult aspects of this job is pounding the cv-axle back into the shaft.. fully seating it. There are identical c-clips on each end of the internal splined shaft. I tapped the shaft back into the housing first, then the cv-axle. I found it difficult first go around... but found that by positioning the open end of the c-clip downward it finally went in.

It is imperative that you suspend the cv-axle perfectly lateral with the axle shaft so when you hit it, the force drives it straight in. You also need it fully compressed so the cv-axle's spring loaded action does not absorb your hammer impacts. In other words.. you need a SOLID FIRM HIT straight in with a large sledge-hammer.
Automotive tire Vehicle brake Automotive lighting Automotive exhaust Automotive fuel system


I whacked on this thing quite a few times before it fully seated.
A this point, it is almost a 2 person job, unless you can get the shaft suspended tight and straight.

MISTAKE:

I made a serious mistake this time. It is well known to never hit the shaft directly with with a hammer.. the nut should be screwed on even with the end of the shaft.. even better with a disposable nut. Well I managed to hit it enough times to distort the nut, and the nut was extremely difficult to remove. I forgot that in the past I would place the socket over the nut and hit the socket, rather than the nut. Fortunately I still had a nut from a previous cv-axle which was un-damaged.

IMPORTANT TIP: Place socket over nut and shaft and hit the socket, rather than the nut

FINAL:

Confirmed the cv-axle was fully seated (as in the original photo)

--------------------------------------------

Closed it all up, tire on, lowered to ground. Topped off the differential with gear oil
The entire job should take about 4 hours (provided all tools are handy and ready)
This job is inexpensive, but labor intensive... I don't recommend it for everyone.
You'll need the right tools, a big hammer, and a strong arm.
Automotive parking light Automotive side marker light Wheel Tire Car


Fun time.. nice workout!
Last weekend it was the rear pinion seal, which was easier and worked out nicely.

No more oil drips!

Ready for my trip from South Florida to VA this week.
 

·
Registered
2003 Safari AWD
Joined
·
189 Posts
I just did this as well - nice write up and good tips. it is difficult holding the shaft straight and hit it with a big hammer. I ended up doing it like a reverse slide hammer.... pulled out on the shaft, then holding it perfectly straight slide it in forcefully as a hammer - back and forth a few times did the trick.
 

·
Registered
Joined
·
2,497 Posts
The FSM says in bright red text:
Rectangle Font Parallel Slope Number


I lubed mine the first time and they leaked -- didn't lube them the second time -- and they're bone dry 2 years later.

Not sure why -- but I'd posit GM wouldn't put that text in the FSM if it didn't matter.
 

·
Registered
2000 Lifted 4x4 Astro 92 V8-350 Shorty
Joined
·
6,133 Posts
Discussion Starter · #4 ·
I've seen that about "not" lubricating the seal.
I've also seen conflicting instructions
It doesn't make much sense.

I guess I'll find out in a couple years...
 

·
Registered
2000 Lifted 4x4 Astro 92 V8-350 Shorty
Joined
·
6,133 Posts
Discussion Starter · #8 ·
I think I have a leaking CV axle seal. I added a 2 inch body lift a few weeks ago, and I've noticed it since. I did NOT touch the torsion keys, so that's why I'm a little confused. Did your seals cause the differential to leak?
The seals ARE at each end of the differential (one side at end of axle tube)
Body lift has ZERO relation to cv-axles and differential.. it merely lifts the body.
(steering, alignment, and suspension remains unaltered)

You'll want to completely de-grease the entire area, then watch to see where leak starts.

Normally when I see drips on driver side, I suspect either hydroboost unit or leaking oil lines. Both will send leaks flowing downward, which will spread everywhere. It will "look" dark like oil, so it's almost impossible to tell the difference.

But ultimately, leaking front axle seals is not that uncommon.
 

·
Registered
Joined
·
11 Posts
The seals ARE at each end of the differential (one side at end of axle tube)
Body lift has ZERO relation to cv-axles and differential.. it merely lifts the body.
(steering, alignment, and suspension remains unaltered)

You'll want to completely de-grease the entire area, then watch to see where leak starts.

Normally when I see drips on driver side, I suspect either hydroboost unit or leaking oil lines. Both will send leaks flowing downward, which will spread everywhere. It will "look" dark like oil, so it's almost impossible to tell the difference.

But ultimately, leaking front axle seals is not that uncommon.
Thanks for the quick reply! The oil lines look good. I knew my hydroboost was wet, but it didn't even occur to me that it could be the culprit. I degreased everything last night, took it for a spin, and so far the CV looks dry. I'm starting to suspect hydroboost. Thanks for the tip!
 

·
Registered
2000 Lifted 4x4 Astro 92 V8-350 Shorty
Joined
·
6,133 Posts
Discussion Starter · #10 ·
You'll know almost instantly if it's the hydroboost.. just reach under the brake master cylinder and see if it is wet.
If leaking, you'll also see lines and stuff directly under it wet too.
 
1 - 10 of 10 Posts
Top