A leak on the parking brake passenger side

[watuzi]

Hi folks,
I need help diagnosing a leak in my passenger side rear parking brake. I just recently changed my rear brakes and I noticed the rear passenger side parking brake was all wet with what I will assume as brake fluid. Both of the parking brakes on the passenger side were really wet. Is it safe to assume that the brake cylinder as the main cause of the leak? I'm very bad a diagnosing but good at replacing parts. Any help is greatly appreciated. Happy New Year to all!

 

[Scottydoggs]

im going with a bad axle seal, see if it stinks real bad, (the fluid) if it does its diff fluid.

if you have e brake pads that means you have a rotor, e brake is all cable driven, back to the axle seal.....

 

[HiHoeSilver]

im going with a bad axle seal, see if it stinks real bad, (the fluid) if it does its diff fluid.

if you have e brake pads that means you have a rotor, e brake is all cable driven, back to the axle seal.....

Yup. No fluid for them there e brakes.

 

[watuzi]

OK, thanks guy I'm gonna check Youtube if I can replace the axle seals myself if it's not too difficult.

 

[Scottydoggs]

its not a picnic but can be done in the driveway all diy style. lots of vids out there on how to get the axle out. once you get the brakes off you should be able see the leak. and confirm its the seal leaking.

 

[swathdiver]

Edmund, do you have disc or drum brakes back there? If you have drum brakes, there will be a wheel cylinder that can leak. To check for an axle seal leak, you'll need to look behind the axle shaft (plate with wheel studs) and see if it is wet back or under there. If so, you have to remove the differential cover, pull the differential pinion shaft, remove the c-clip and then pull the axle out so you can then remove and replace the seal. Obviously, you'll need new differential fluid and maybe a gasket if yours is worn.

There's photos and posts here and on youtube.

 

[watuzi]

Edmund, do you have disc or drum brakes back there? If you have drum brakes, there will be a wheel cylinder that can leak. To check for an axle seal leak, you'll need to look behind the axle shaft (plate with wheel studs) and see if it is wet back or under there. If so, you have to remove the differential cover, pull the differential pinion shaft, remove the c-clip and then pull the axle out so you can then remove and replace the seal. Obviously, you'll need new differential fluid and maybe a gasket if yours is worn.

There's photos and posts here and on youtube.

Yeah, I have an '04 4.8L 2WD Tahoe, it has disc brakes on all wheels. I read the Haynes manual and I don't if I can replace it myself. I will definitely have to watch several Youtube videos for sure. Thanks for all the help.

 

[SnowDrifter]

its not a picnic but can be done in the driveway all diy style. lots of vids out there on how to get the axle out. once you get the brakes off you should be able see the leak. and confirm its the seal leaking.

Axle seals are easy. Seriously. Don't be scares of it.

If you can change your rear diff cover gasket and do brakes then you can do your axle seals!

Jack the car up, pull the diff cover off. Whole that's draining, remove your rear brakes, rotors included. Ebrake hardware can stay there.

To back to the diff, put the car in neutral if you've not done so already, spin the diff until you can get to the 8mm bolt holding the center pin on place. Remove the bolt, push the center pin through, then set them aside.

From there, push your axles in towards the center of the vehicle and fish the c clip out with a magnet. You may need a bungie cord to hold it in as the seal can push the axle out just enough you can't release that clip.

If memory serves you don't need to fuss with the rear wheel speed sensors

From there, just pull the entire axle straight out. Pop the seal out with a screwdriver, minding that you don't gouge the axle tube.

It wouldn't be a bad idea to do rear wheel bearings too while you're here. Check seat depth with a micrometer then remove them with a blind hole puller. They're just lightly pressed in.

Install the bearing if you chose to go that route, noting the depth with that you measure before. Remember to apply some grease or diff oil to them so they're not dry until the differentials own lubricating system takes over.

Install the wheel seal with a seal driver or flat piece of wood.

Put your axle back in, reinstall the c clip, install the center pin, and install the retaining bolt with new loctite. Clean up the threads with brake clean or carb cleaner so the thread locker has a nice clean surface to work with.

Toss the brakes on, install the rear diff cover with gasket of choice, then fill your rear diff.

Drop the car, torque your wheels, then take a few hard left and right turns to splash some lube up there and you're good to go


While process start to finish should take your around 3 hours

 

[CountryBoy19]

Axle seals are easy. Seriously. Don't be scares of it.

If you can change your rear diff cover gasket and do brakes then you can do your axle seals!

Jack the car up, pull the diff cover off. Whole that's draining, remove your rear brakes, rotors included. Ebrake hardware can stay there.

To back to the diff, put the car in neutral if you've not done so already, spin the diff until you can get to the 8mm bolt holding the center pin on place. Remove the bolt, push the center pin through, then set them aside.

From there, push your axles in towards the center of the vehicle and fish the c clip out with a magnet. You may need a bungie cord to hold it in as the seal can push the axle out just enough you can't release that clip.

If memory serves you don't need to fuss with the rear wheel speed sensors

From there, just pull the entire axle straight out. Pop the seal out with a screwdriver, minding that you don't gouge the axle tube.

It wouldn't be a bad idea to do rear wheel bearings too while you're here. Check seat depth with a micrometer then remove them with a blind hole puller. They're just lightly pressed in.

Install the bearing if you chose to go that route, noting the depth with that you measure before. Remember to apply some grease or diff oil to them so they're not dry until the differentials own lubricating system takes over.

Install the wheel seal with a seal driver or flat piece of wood.

Put your axle back in, reinstall the c clip, install the center pin, and install the retaining bolt with new loctite. Clean up the threads with brake clean or carb cleaner so the thread locker has a nice clean surface to work with.

Toss the brakes on, install the rear diff cover with gasket of choice, then fill your rear diff.

Drop the car, torque your wheels, then take a few hard left and right turns to splash some lube up there and you're good to go


While process start to finish should take your around 3 hours

Only a couple things to add:

Don't grease the bearings, after installing bearings (if you do new bearings) squirt some gear lube in the bearings and the space behind them just prior to putting the axles back. I'm not convinced sharp turns will splash lube out to the end of the axles. The carrier bearings mostly block the oil path; it has to slowly work out there over time so lube those parts well before installing axles just to be sure. Note: the only recommended way I can think of to get that oil out there is to tilt the car to one side for several hours then to the other side for several hours.

The OE brake dust shields are 1-piece and require axle removal to replace. If yours are starting to disintegrate just replace them while the axles are out. It does add a bit more work bc you have to tear the e-brake apart but its easier to do it now with the axles out.

 

[watuzi]

Axle seals are easy. Seriously. Don't be scares of it.

If you can change your rear diff cover gasket and do brakes then you can do your axle seals!

Jack the car up, pull the diff cover off. Whole that's draining, remove your rear brakes, rotors included. Ebrake hardware can stay there.

To back to the diff, put the car in neutral if you've not done so already, spin the diff until you can get to the 8mm bolt holding the center pin on place. Remove the bolt, push the center pin through, then set them aside.

From there, push your axles in towards the center of the vehicle and fish the c clip out with a magnet. You may need a bungie cord to hold it in as the seal can push the axle out just enough you can't release that clip.

If memory serves you don't need to fuss with the rear wheel speed sensors

From there, just pull the entire axle straight out. Pop the seal out with a screwdriver, minding that you don't gouge the axle tube.

It wouldn't be a bad idea to do rear wheel bearings too while you're here. Check seat depth with a micrometer then remove them with a blind hole puller. They're just lightly pressed in.

Install the bearing if you chose to go that route, noting the depth with that you measure before. Remember to apply some grease or diff oil to them so they're not dry until the differentials own lubricating system takes over.

Install the wheel seal with a seal driver or flat piece of wood.

Put your axle back in, reinstall the c clip, install the center pin, and install the retaining bolt with new loctite. Clean up the threads with brake clean or carb cleaner so the thread locker has a nice clean surface to work with.

Toss the brakes on, install the rear diff cover with gasket of choice, then fill your rear diff.

Drop the car, torque your wheels, then take a few hard left and right turns to splash some lube up there and you're good to go


While process start to finish should take your around 3 hours

Thanks for the detailed steps. You can do it in three hours, but it will probably take me the whole weekend to do it.

 

[watuzi]

Only a couple things to add:

Don't grease the bearings, after installing bearings (if you do new bearings) squirt some gear lube in the bearings and the space behind them just prior to putting the axles back. I'm not convinced sharp turns will splash lube out to the end of the axles. The carrier bearings mostly block the oil path; it has to slowly work out there over time so lube those parts well before installing axles just to be sure. Note: the only recommended way I can think of to get that oil out there is to tilt the car to one side for several hours then to the other side for several hours.

The OE brake dust shields are 1-piece and require axle removal to replace. If yours are starting to disintegrate just replace them while the axles are out. It does add a bit more work bc you have to tear the e-brake apart but its easier to do it now with the axles out.

Yep, thanks for the tip. I guess might as well replace the bearings and e-brake while the axle is out. I love my Tahoe, but man, she's starting to show her age.

 

[SnowDrifter]

Thanks for the detailed steps. You can do it in three hours, but it will probably take me the whole weekend to do it.

Lmao you'll be fine. It only takes me 45 mins to an hour but I work pretty quick and have access to air tools. Biggest thing is make sure you have enough space to actually pull the axle out!

Only a couple things to add:

Don't grease the bearings, after installing bearings (if you do new bearings) squirt some gear lube in the bearings and the space behind them just prior to putting the axles back. I'm not convinced sharp turns will splash lube out to the end of the axles. The carrier bearings mostly block the oil path; it has to slowly work out there over time so lube those parts well before installing axles just to be sure. Note: the only recommended way I can think of to get that oil out there is to tilt the car to one side for several hours then to the other side for several hours.

The OE brake dust shields are 1-piece and require axle removal to replace. If yours are starting to disintegrate just replace them while the axles are out. It does add a bit more work bc you have to tear the e-brake apart but its easier to do it now with the axles out.

The way the differential lubricates is it depends on the ring gear to carry oil. The shape of the rear diff cover 'wraps' around the ring gear intentionally. Its designed to create a lubrication channel to carry the diff fluid up to the top. From there it goes a few different places. Most of it goes to the pinion and by extension, the pinion bearing. A smaller portion goes to the side bearings, and a smaller portion still trickles down the axle tubes to make its way to the wheel bearings - which essentially are only kept wet and don't need active oil flow for cooling.

Turning side to side aids this process in getting started. Go in a tight circle a few times at a moderate speed, then do the same thing in the opposite direction. The side bearings are just bearings, not a seal. From a fluid pump perspective they're porous. Lube will make it by without issue.

Now whether you need to do this step is up for debate. But functionally it works as intended. I always have as sort of a covering my own ass type thing


P. S. The differential cover shape and fluid pump dynamics are why you never want to get one of those fancy covers with just a square chamber milled out. Make sure the inside is milled to the appropriate shape. Think about it for a moment and you'll understand why

 

[CountryBoy19]

Lmao you'll be fine. It only takes me 45 mins to an hour but I work pretty quick and have access to air tools. Biggest thing is make sure you have enough space to actually pull the axle out!




The way the differential lubricates is it depends on the ring gear to carry oil. The shape of the rear diff cover 'wraps' around the ring gear intentionally. Its designed to create a lubrication channel to carry the diff fluid up to the top. From there it goes a few different places. Most of it goes to the pinion and by extension, the pinion bearing. A smaller portion goes to the side bearings, and a smaller portion still trickles down the axle tubes to make its way to the wheel bearings - which essentially are only kept wet and don't need active oil flow for cooling.

Turning side to side aids this process in getting started. Go in a tight circle a few times at a moderate speed, then do the same thing in the opposite direction. The side bearings are just bearings, not a seal. From a fluid pump perspective they're porous. Lube will make it by without issue.

Now whether you need to do this step is up for debate. But functionally it works as intended. I always have as sort of a covering my own ass type thing


P. S. The differential cover shape and fluid pump dynamics are why you never want to get one of those fancy covers with just a square chamber milled out. Make sure the inside is milled to the appropriate shape. Think about it for a moment and you'll understand why

I'm mostly in agreement with you but only 1 contention. Yes, the ring gear "pumps" the oil and you definitely want a std curved cover bc that is a critical component to the pumping action. The part I disagree with is your proposed means of getting oil to the ends. I realize the bearings aren't seals and fluid can flow through them. The bearings, while spinning, actually act as a somewhat effective barrier to fluid flow. That's not to say none is getting through, it's just very little.

What exactly does the going in circles do? It's not like the fluid is sloshing up against the bearings. It's definitely not aiding the "pumping" action. Is the turning in circles just supposed to help the "trickle" of fluid get to the ends faster? All that, while you're driving without that fluid already there?

IMHO, waste of time, just squirt a bunch in the end right before sliding the axle in, it's a much more efficient use of your time.

 

[SnowDrifter]

We will have to agree to disagree on that one. Fluid absolutely does make its way around in turns. And a fair bit of it too. Those bearings don't turn any where near fast enough to block fluid flow.

Not sure I'm glad to have the experience card on this one cause it was a ******* mess. But anyways... Had a vehicle in the shop a few years ago with a leaky axle seal. Customer wasn't interested so I went ahead and topped to the fluid just to stop it from blowing up on them. Turns out that little leak was a seal that decided one day it was going to up and leave. And that small leak was a result of having nothing left in it. First turn left a nice trail of fluid all the way to the parking spot.

 

[CountryBoy19]

We will have to agree to disagree on that one. Fluid absolutely does make its way around in turns. And a fair bit of it too. Those bearings don't turn any where near fast enough to block fluid flow.

Not sure I'm glad to have the experience card on this one cause it was a ******* mess. But anyways... Had a vehicle in the shop a few years ago with a leaky axle seal. Customer wasn't interested so I went ahead and topped to the fluid just to stop it from blowing up on them. Turns out that little leak was a seal that decided one day it was going to up and leave. And that small leak was a result of having nothing left in it. First turn left a nice trail of fluid all the way to the parking spot.

So by your own admission turning in circles isn't needed? If just driving pumps that much fluid then by the time you get it out of your garage it's already filled the tubes up... so save the time wasted doing circles.

FWIW, I'm not agreeing with you, I don't know the circumstances of the axle you did the repair on but different rear ends are designed differently. This one does not pump any oil to the tubes, only what can seep through the spaces in the carrier bearings. We'll agree to disagree at this point. Still not a bad idea to squirt the bearing and space behind it full before sliding the axles in. It costs a couple seconds and adds a pretty healthy insurance policy of making sure the bearings are lubed good.

 

[swathdiver]

Mark and Chris, have you fellas watched Banks' videos on this subject? Pretty cool and I for one am anxiously waiting for his next video on the topic!

https://www.youtube.com/user/bankspowerinsider/videos

 

[SnowDrifter]

So by your own admission turning in circles isn't needed? If just driving pumps that much fluid then by the time you get it out of your garage it's already filled the tubes up... so save the time wasted doing circles.

FWIW, I'm not agreeing with you, I don't know the circumstances of the axle you did the repair on but different rear ends are designed differently. This one does not pump any oil to the tubes, only what can seep through the spaces in the carrier bearings. We'll agree to disagree at this point. Still not a bad idea to squirt the bearing and space behind it full before sliding the axles in. It costs a couple seconds and adds a pretty healthy insurance policy of making sure the bearings are lubed good.

I feel as if we've reached the point of playing word games with eachother. The point I was trying to make was that yes, oil makes it into the axle tubes on turns. And that was interpreted as my saying you don't need to drive in circles?


Regardless.... All info on this has been shared. It's up to OP what he chooses to do with the info. . I'll do my little circle drive - it takes 30 seconds and it's easy insurance when doing this sort of stuff.

 

[CountryBoy19]

Mark and Chris, have you fellas watched Banks' videos on this subject? Pretty cool and I for one am anxiously waiting for his next video on the topic!

https://www.youtube.com/user/bankspowerinsider/videos

I've watched every one of them since the first... lots of good info in them. Just rewatched to be sure I'm not missing something, from what I saw he didn't quantify in any way how much fluild gets out through the bearings. Maybe the F150 he's testing on has a separate "splash channel" for fluid to move through, but the GM 8.6" does not, it must make it's way through the bearing. It may happen in 100 feet, it may happen in 5 miles, I don't know for sure, but I can be sure of one thing, squirting lube into the wheel bearing and the void behind it (where the ABS reluctor is) only adds extra insurance that the bearings are properly lubed from the start instead of waiting for the lube to makes it's way out through the bearings into the tubes.

Plus, for me to drive circles would require me driving to a place that I could drive in circles. Closest place is almost 5 miles away. My driveway alone is almost a mile long...

 

[Scottydoggs]

with the fill hole in the cover being higher then the axle tube id think there some fluid in the tubes at all times. even once the diff is spinning and washing fluid around the ring gear.

 

[89Suburban]

Thanks for the detailed steps. You can do it in three hours, but it will probably take me the whole weekend to do it.

If it's any consolation i have to do mine to so your not alone.