99 XJ leak mystery

I have a leak under the rear axle. The fill plug in the rear diff looked to be leaking a bit before I wiped it away, but the "puddle" on the ground doesn't line up correctly. It looks like the splitter box for the brakes may be the culprit.

There's a black, almost chalky-gooey type substance on all 3 hoses and the little box itself, circled in red in the photo below. I've also included the rear diff plug and the "puddle" on the ground.

Is this something to be concerned about? A new splitter box? And finally should that plug be leaking anything at all? It's not much and I figured with 142K on her, it's not bad, but wanted to check with the experts first.

Thanks,
Andrew

http://i184.photobucket.com/albums/x268/rew70/axle_2.jpg
http://i184.photobucket.com/albums/x268/rew70/puddle.jpg
http://i184.photobucket.com/albums/x268/rew70/reardiff_2.jpg

After much searching, I can figure it's probably the rear brake junction box that sits on the axle. BTW, everything is stock, no mods. I found a post with this advice, is this the correct way to fix this?

Re: Rear axle oil leak through the breather line
I have had a couple of stock XJ's do this. My response to the problem was to pull the vent out of the axle, and then trim off the material hanging below the threaded part that screws into the axle tube. Now, no more leak ( at least with the stock thickness brake line junction block).

And where can I buy the junction box if I need to replace it?

Thanks again.

that splitter block is part of the flexible line that comes down from the body.. if you are leaking from the breather it may just be seeping around the threads.. sealing the threads with some sealant might help. i dont see how trimming the tube would make any difference since its not down as far as the level. ive seen those tubes "burp" a little oil after wheeling probably from off-camber situation sending all the oil into that side of the axle and a little bubble of oil getting into the tube and seeping out.. is this a new leak or has it been going for a while?

It's been going on for a couple of weeks at least. That's when I started noticing the drainage on the ground. The stuff on the ground doesn't really look or smell like oil. It's more clear than anything, though it's hard to tell really. But the spots line up right under that junction, and it's got black stuff where all 3 hoses converge.

Take a sheet of white paper and put it under where you think the leak is a couple of rocks around the edges will hold it down. Let it sit over night and check the paper in the morning. If it is a sort of clear fluid I would suspect brake fluid darker I would look at the rear end.

That junction is where your brake lines tie in it is a easy fix you can also look under the hood and see if the level is low with 142K I would suspect a line might be going which is causing the leak

I will try that tomorrow and post back. Thanks for the help.

if that junction is leaking, those should be double reverse flares... they might just be able to be tightened up. the thread sealer should not work unless the flare fittings have been shot. These can be very tricky to get off w/o breaking. a little PB blaster and a lot of time will help but try to snug them first. If the metal inside tube starts to turn, you will probably have to replace the metal brake line w new.

Well, I haven't seen anymore of the spots on the ground since putting down a couple of pieces of cardboard. I left it under there only for a couple of hours. I have them back under there and will check in morning to see if time makes a difference.

I did see that the fluid under the hood is right at the top of the dot marked ADD. So maybe a line is going?? What's the best way to diagnose that? And would that have anything to do with the heep pulling left when braking hard?

I know that could also be rotors or calipers but wonder if this contributes. May be time for a brake overhaul...thanks again for any and all help.

If it's stock, check your brake lines - My '97 had lines that were swiss cheese when I bought it, ended up replacing all the hard lines under the vehicle. The materials are cheap, you can get the flare tools from inline tube. You'll need a metric bubble flare tool to do the junction on the line to the rear brakes on the firewall, and a double flare tool for the rest. Also invest in a bender, it makes stuff go easier. Inline tube also has the spring guard to protect the hard lines on the rear axle, and you can get a nice braided stainless hose for the flex hose to that leaky junction block on the axle to dress it out. The wheel cylinders will also need to be replaced as the flares are probably frozen into the back of them, or the bleed screws will snap off. While you're in there replace the pads and hardware.

For the tools and the spring guard go to www.inlinetube.com and do some surfing.

You've got a good weekend ahead of you.

Mark

Sounds that way. Thanks for the info, I will begin plotting everything out today.

if it is just the breather, a zip tie to tighten everything up may be all you need. also, make sure it goes up to the frame where it is supposed to go.

if it is your brakes, may be a good time to upgrade to an extended line