This question is for a 2008 stock JK.

My wife was driving my jeep and the brake light went on at a stop light. Figured a little low in brake fluid. When I went to check the reservoir, it was a little low. and it appeared a different fluid was in the reservoir.

I've had no issues with the brakes (no "hard" brakes, seizing of calipers, etc.), just occasional sponginess. Looks like the different fluid was just a top off, didn't fill the whole reservoir.

By now, I would have expected major brake problems, but there are none. I'm thinking maybe the less dense fluid has been floating on top of the reservoir.

Given no issues, do think it would be acceptable to siphon out the reservoir and flush the system before putting PROPER fluid back in?

 

Here's what I would do...

Siphon out what you can, then refill with brake fluid. Get a new cap. Don't flush the system with brake clean.
Take it to the dealer to do a complete flush, including the cycling of the ABS module with their scan tool.
I would also tell them what might be in the system.

Your concern going forward is the seals, especially those in the master cylinder.

 

Thanks i will do this. Anything I do in the future or periodically? I had the master cylinder replaced before this back in 2015, which may buy me a little time (fresh seals).

 

ide just siphon out the res then refill with brake fluid and then gravity bleed each caliper. after that top it off take it to a back road on some gravel and hit the brakes a few times to activate the abs and get the fluid to move through it then take it home rebleed / refill and call it good.

 

A thorough flush requires running the ABS pump.
He needs a thorough flush.

 

thats what stopping on the gravel does. it activates the abs and runs fluid through. it also works for for removing air bubbles sometimes.

 

I'm currently trying to siphon out the reservoir and it looks like there's a lot more I could get out from looking at the reservoir from outside, but when looking into the fill hole, I've bottomed out. I'm using a turkey baster. Is there something I'm missing as to how to get more of the fluid out?

 

Flexible hose on the turkey baster?
Remove what you can. Can't do any better than that.

 

I ended up using a thin flexible hose and sucking out what I could. There's still a bunch lying on the bottom of the reservoir, but I guess this will have to be good enough. I'll refill and take off a layer tomorrow once it's settled. Maybe some more of the power steering fluid will float to the top since it's less dense.

Really appreciate your help.

 

While you are waiting, put some of each fluid in a clear cup and see if it will actually separate into layers.