Fluid coming out of rear brake drum, brake fluid or diff fluid?

I have a 1995 Tacoma, ext cab v6, the other day I noticed that there wa fluid leaking out of my drivers side rear brake drum/wheel cylinder. I just got the time to take it off today and look at it and I found that the inside of my brake drum has a greasy type fluid all over the inside of it, but I'm having a hard time telling if it's brake fluid or diff fluid, it pretty much just smells like brake dust but I compared the smell to diff fluid and brake fluid and can't really tell which one it is. I was hoping maybe you guys to help me figure it out based on the pic. I'm definitely going to have to replace the brake shows because they're soaked

 

My first guess would be you have a leaking axle seal. Don't forget that when you fix the leak, you need to replace those brake shoes too. They are pretty much worthless at this point.

If you are worried about the wheel cylinder for the brakes, you can peel back the rubber boot on the cylinder and check for fluid in there. If it's wet it's leaking....l.

 

The underside of the brake cylinder (where the piston shaft exists the cylinder) is dry, so it doesn't appear to be brake fluid. Diff fluid (75W90 gear oil) is also thicker than brake fluid.

 

You'll be able to tell the difference in smell, and the feel of it in your fingers. Brake fluid will kind of feel dry, and your finger will probably not slide off each other real well. Diff fluid is super slick.

Check brake fluid and diff fluid levels...which is low? As long as you know where they used to be, that's also a decent indication. Brake fluid will drop quick. Diff will be more difficult to tell.

 

It definitely feels slick, so im guessing it must be diff fluid. I checked my diff fluid level and its not that low. My brake fluid levels are normal too

 

Leaking axle seal like stated before. Might as well replace the wheel bearing while its apart.

 

The seal is a half hour replacement. The wheel bearing is 3x that if you know what you're doing, and do it carefully. I wouldn't bother with the wheel bearing unless its toast.

 

Yup, if it aint brake fluid its a axle seal. Id tear it down and if the bearing looks good Id just do the seal and top off or better yet change the diff fluid

 

Alright, Im going to go get the parts today and get it taken care of, thanks for the help guys!

 

If you have an open diff the retaining clip should be an easy removal. There's no topping off of diff fluid because you have to drain it to replace the seal. Also be given the cost of a wheel cylinder (about $30 usually) might as well replace it while you're there. Unless it's bone dry under the boot wheel cylinders will inevitably leak. All you add is about a half hour labor time taken up mostly by bleeding the cylinder. Gravity bleeding will even shave some time off of it.
I will add that the amount and color that I see in your pic screams axle seal

 

I have the same problem. Im thinking this weekend my brother and i are going to take my wheel off and give it a look. If im going to fix the leak do i have to remove the bearing also? What kind of seal am i going to be dealing with? Like a gasket type seal or one thats pressed together like the wheel hubs are? Thanks

 

This thread has some good, and bad advice in it, old and new.

I agree with the possibility of it being the wheel cylinder. If it looks real old, I'd replace it regardless. I was able to replace mine without having to remove the shoes. You'll have to bleed the cylinder afterwards, but it wouldn't take much.

There are 2 seals, an inner (in the axle housing), and outer (next to the wheel bearing). The inner is the most likely culprit, and much easier to replace. It helps to have a seal remover, but you can use a large screwdriver to pry it out. Either way, removing the old seal completelydestroys it, so be sure to have the correct replacement on hand.

However, you really don't have to drain the diff, I've done this many times without draining it. When you jack up that side of the truck, jack it up by the axle tube, rather than the frame, so the axle is tilted up on the side you're working on. That way, gravity prevents any diff oil from getting to the working area.

 

Like others said, leak is likely the rear axle seal, a known Tacoma issue. It is a fairly simple replacement. There are some how-to video clips on YouTube. Most auto stores will loan or rent you a seal driver kit, or you may have a right sized piece of PVC pipe laying around that can do the job of tapping in the new seal.

One other thought: on most trucks with high mileage a leaking rear axle seal would lead one to suspect the axle bearing. As bearings wear they can lead to seal failure. You don't say how many miles are on your truck but with a '95 you may have some pretty high miles. If you replace the seal and it fails again within a short time, you may have worn bearings that need replacing.

If you put new brake shoes and wheel cylinders on right away, you risk fouling the new pads if it is a bearing issue. I am not recommending this mind you, but I do know guys take brake fluid cleaner and spray the heck out of the entire brake shoes, backing plate, drum, etc. That will clean them up okay - not perfect, but okay for most driving situations. That would give you a couple months to see if the seal holds, then you could do a full brake job on that rear axle.

 

Well judging by the amount if fluid I have on my tire and wheel it's probably pretty low. So I might as well go ahead and change the fluid. I'll be honest, I'm not too mechanically inclined but I'm learning. What are you referring to as the wheel cylinder? Is that different from the wheel hub? And yeah I was told a big flat head screwdriver will work. Thanks for the advice

 

My truck has a 110,000 miles on it. and yeah im waiting to replace my drums after i fix my axle leak. its messy in there so i didnt want to ruin new drums. So the axle bearing? meaning the wheel hubs, or is there another bearing coming from my axle to my wheel? And yes, i imagine ill look up a video on youtube. i tried finding a DIY on here but i had no luck.

 

Ah, nevermind. Now i know what a wheel cylinder is.

 

You r right Rick. Just realized it was my dodge van.

 

Wow, low miles - nice. Your wheel bearings are probably fine at that age. These little trucks don't usually get the heavy load abuse that full size trucks get on the rear axle, so you are probably just looking at the seal at this point.

The rear axle comes out easily. IIRC you just need to remove the parking brake cable assembly from the back of the brake backing plate (two bolts), as well as four bolts that hold the axle shaft to the brake backing plate. Pull the axle shaft out as straight as you can. You do not want to bang up the splines on the end of the shaft. Your brake shoes and even the drum can remain in place when you pull the shaft. Just remember to drain some of the rear differential fluid ahead of time, or raise the axle on that side as Tan4x4 suggested. I recommend you set that axle aside where the end splines won't get damaged by tools or kids. There is also an outer axle seal - really just a dust seal that seals the joint where the axle base mates to the brake backing plate. Looks like a large rubber O-ring. I just clean and reuse that outer seal if it's in good shape.

Once the axle shaft is out, the seal you want to replace is just a few inches inside the axle housing. There is a rubber inner lip (seal) you can see and feel that the axle shaft slides through. Whatever you use to pull that seal, make sure not to scratch the inside surface of the axle housing. I use a seal puller carefully and tape the end tip to help prevent any scoring.

Get yourself a couple new seals when you stop by your dealer parts counter (I bought mine at Toyota, not sure about auto parts stores availability). IIRC they are about $6 each. You can bunger those seals easily when you tap them in so is nice to have a spare on hand for that. Use an appropriate sized seal driver or similar and you should be fine.

There is a write up on a 3rd gen 4runner site on replacing this axle seal that might be helpful- shows some pictures of the seal in the axle housing: http://www.yotatech.com/f128/replacing-rear-axle-seals-3rd-gen-4runner-76339/

 

Had to change mine last summer hardest part was the damn abs magnet kept pulling on the seal when first putting it in. Other than that its a pretty quick straight forward job. AlSO.. I had to replace o rings that are on axle housing.

 

Yeah I had a pretty good find with my truck I think. Minor body dings and a scratch on the tailgate. But the miles surprised me when I called on it. Plus it's red, which is what I wanted. It was a match made in Toyota heaven. Lol. So I ended up finding a video on how to do it on YouTube. The guy did a good job with the camera so I was able to see everything he was doing. He ended up re-doing his bearing on both sides and went and got them pressed. I don't have any leads on where I could do that if I choose to do my bearings. However, when I was going to do my rear brakes we spun that tire and heard a scratch noise every rotation. Assuming that's my wheel bearing. I guess auto zone or O'Reilly should have a seal tool. Glad to hear the seals are cheap though. I probably will go buy them at Toyota. Rather those than auto stores brands. I had another question too, when I put my axle back in, how do I know the splines are lined up on the inside with my differential?