Identifying Leak

[danw77]

I just bought a 2015 Yukon XL SLT and I noticed this leak coming from behind the rear wheel on the drivers side. It looks to be oil coming from a plastic line that connects to the rear axle tube. Can anyone help me identify what this is? I’ve look for parts diagrams and I can’t find anything. Thanks in advance.

 

[Larryjb]

I could be wrong, but I believe that "plastic pipe" is a sensor wire for the ABS, so the wire itself shouldn't be leaking. I suspect it's differential fluid leaking through the axle seals, and through the sensor itself?

 

[Doubeleive]

that's kind of unusual, I would take that wheel off and get a closer look with a flashlight, there shouldn't be any axle grease coming from the abs sensor but I suppose it is possible, if it is axle grease you can tell real easy by the smell, if it has no odor it could "maybe" somehow be the brake caliper leaking, if it is coming from the edge of the abs sensor see if the bolt is loose or you can replace it easy they run about $20-25

 

[swathdiver]

Won't be grease, it will be hydraulic oil, either from the axle tube or the shock. Does not appear to be coming from the axle seal area in that photo. Were the brakes bled recently?

 

[danw77]

Won't be grease, it will be hydraulic oil, either from the axle tube or the shock. Does not appear to be coming from the axle seal area in that photo. Were the brakes bled recently?

Ahhh... that may be it. It was very thin oil. My first thought was that it was brake fluid, but there's no brake line right there. The vehicle was serviced and inspected before I picked it up. That would be a simple explanation and makes me feel a little stupid for not thinking of that. I cleaned the area up with brake cleaner. I'll check in a day or two to see if there's any additional leaks.

 

[Doubeleive]

Won't be grease, it will be hydraulic oil, either from the axle tube or the shock. Does not appear to be coming from the axle seal area in that photo. Were the brakes bled recently?

I didn't think of the brakes being bled but it does look like brake fluid, when my rear axle seal went out on my 00 it always smelled like grease if you got anywhere near it

 

[magua]

blown air shock

 

[91RS]

That does not look like anything is leaking from your truck. It looks like either something got ran over or maybe if you did just have a brake flush done they made a little mess.