Rear Brake Drum Leak

[JoshuaDudee]

Hello everyone! So I had a leak in my brakes somewhere for a few weeks now and I finally got around to finding the leak. I filled it up and a week later it was low so I took it into action to find this ****er!

So I looked under the runner and seen my tire had brake fluid all over it..
Yay..


So then I took off the tire (clearly) and seen some brake fluid around the drum.


So I took off the drum to see if it was from the inside. (which i think it is.. You tell me..)


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But i also found some on the back by the spit valve and brake line so idk..


I seen it was dripping by the part I circled on the left but I don't know what that part is called to replace..
I found THIS online but I don't see the part I think is leaking.

 

[mattatata]

Hey! About the only thing that could leak back there if it is only brake fluid is the "drum brake wheel cylinder" peel that little rubber boot back if there is fluid inside replace that little brake wheel cylinder clean it all up, bleed the brakes and id probably go from there.

 

[frodiesel]

You need to replace your rear axle seals asap.

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[JoshuaDudee]

Hey! About the only thing that could leak back there if it is only brake fluid is the "drum brake wheel cylinder" peel that little rubber boot back if there is fluid inside replace that little brake wheel cylinder clean it all up, bleed the brakes and id probably go from there.

Do you think i should just replace the boot on that wheel cylinder? Cause it is brake fluid. It's bubbling up all my paint and stuff and feels like it. I'm pretty positive it is.

 

[JoshuaDudee]

You need to replace your rear axle seals asap.

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You think it's my axle seal even though my brake fluid is leaking??

 

[St Runner]

it could be both but you will not know until you get it cleaned up. First thing is to replace that rear cylinder (OEM) They are not expensive or difficult. Clean it up as best you can, brake fluid is nasty stuff and inspect it over the next couple weeks to see if you have any further leaks

 

[thegipper]

The reason why people are saying that it could be the axle seals is generally when we see this kind of leak in the area's you are showing, it is almost always the rear axle seals.

In your case, you said you "filled it up" and it leaked again so you had to add more. I'll assume you mean the brake fluid reservoir so in your case, it could just be brake fluid (which would be a good thing).

The other thing you can do is remove the abs sensor. You have a picture of it in your post, it's held on by one 10mm bolt. Be careful prying it out, they are expensive to replace. Remove it and take a look in there. You will see the abs ring and it should be dry. If it is coated in oil, then your axle seals are leaking.

It's probably just brake fluid given your description but I'd check anyways to be sure. Gear oil has a pretty distinct smell to it.

If you haven't done the extended rear differential breather mod already, do it. Even if it isn't your axle seals leaking, the mod is stupid cheap insurance for making your axles seals less prone to failing.

 

[19963.4lsr5]

If he had a axle seal leak he'd smell it when he took off the drum. Unless the OP doesn't know "that smell".

How does your brakes feel with that brake fluid leak?


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[JoshuaDudee]

If he had a axle seal leak he'd smell it when he took off the drum. Unless the OP doesn't know "that smell".

How does your brakes feel with that brake fluid leak?


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They feel soft they don't stop on a dime nor is it hard I'm close to the floor but still stop. I think I'll have to bleed them. And it has no smell at all not even a bit.


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[thegipper]

It's probably just brake fluid which is a good thing. Like I said, when pictures show up like this, it's usually an axle seal leak.

It still doesn't hurt to check the things I suggested and do the breather mod. The breather mod takes like 15 minutes and costs $20. Checking the abs ring for gear oil costs nothing.

 

[nevada]

yep, wheel cylinder is leaking.

to do that repair correctly, you would want to replace BOTH wheel cylinders, and the brake shoes. then have the drums cleaned, and resurfaced, and lastly bleed the brakes. don't forget to adjust the shoes up correctly.

you can opt for new hardware as well, but its not necessary. not a bad idea if its got higher miles though. the springs do lose tension over time.

 

[JoshuaDudee]

yep, wheel cylinder is leaking.

to do that repair correctly, you would want to replace BOTH wheel cylinders, and the brake shoes. then have the drums cleaned, and resurfaced, and lastly bleed the brakes. don't forget to adjust the shoes up correctly.

you can opt for new hardware as well, but its not necessary. not a bad idea if its got higher miles though. the springs do lose tension over time.

So replace the whole wheel cylinder or can I just replace the rubber boot around them?


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[JohnMc]

The whole wheel cylinder. The rubber seal on the outside is just to keep dust out of the cylinder. The 'real' seal is inside the cylinder on the inside end of the piston.

You can get seal kits - but generally replacing the whole wheel cylinder is just easier. Who knows why the old one is leaking, it could be corroded and rough inside, and it might just chew up a new seal.

 

[octanejunkie]

The whole wheel cylinder. The rubber seal on the outside is just to keep dust out of the cylinder. The 'real' seal is inside the cylinder on the inside end of the piston.

You can get seal kits - but generally replacing the whole wheel cylinder is just easier. Who knows why the old one is leaking, it could be corroded and rough inside, and it might just chew up a new seal.

Cylinder, not just the boot

While you are at it freshen up the braking system overall

 

[johnbyebye]

The whole cylinder is like 5 bucks on RockAuto. Lol.

 

[nevada]

like they said above, the part you can see is only a dust boot. the seal that is leaking is internal.

you could put a wheel cylinder kit in it(rebuild kit) however, I would recommend to just replace the entire unit. as I said above, do both wheel cylinders, and both shoes. they are saturated now, and will continue to cause you problems. usually they will grab or lock up.

 

[JoshuaDudee]

Alrighty tomorrow morning I'm buying all new and will put it all together. Thanks for your guys help.


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[19963.4lsr5]

Alrighty tomorrow morning I'm buying all new and will put it all together. Thanks for your guys help.


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It doesn't talk long to replace a wheel cylinder. Remove your brake hardware and brake loose the two bolts holding the wheel cylinder to the backing plate.

Fill your master cylinder to the full line. Remove the brake line from the old wheel cylinder and let it drip while you remove the cylinder from the backing plate.

Mount the new cylinder and open the brake bleeder. Then install the brake line to it. When you see a steady flow from the bleeder close it.

You can then bleed your brakes but you may be good with doing the above. It guarantees you have no or minimal air trapped in the system.


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[phattyduck]

A vacuum cap over the open brake line keeps the leaking to a minimum and makes sure the reservoir doesn't run out.

-Charlie

 

[JoshuaDudee]

Well $109 later I'm all finished.

(2) wheel cylinders
(2) cans of brake cleaner
(2) sets of shoes
(1) big bottle of dot 3 brake fluid
(2) rebuild kits

I did both sides and wow I'm glad I did I found a lot of mud from off-roading inside cause there wasn't plugs on the back side of either one but the rebuild kid had them. So now they're all clean and hopefully that was the leak. Took about a hour and a half. Not too bad.

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