what is this?

[Vacdaddyt]

I have been working on this 91 for a few months now and I'm getting down to the things that are mysterious to me. I get a small spot of oil on the floor a few times a month, not steady. Last time it was a couple of months ago and I crawled under the Ex to look. Near as I can tell there is a block mounted on the frame near the front end drivers side that has brake lines going to it and one wire that is leaking oil. I topped the master off a month ago and it has not changed until yesterday when I noticed a spot again.What does this do? Is it something that should be replaced quickly? The brakes occasionally feel like they are not releasing in the morning. The rotors I believe are new and the pads were changed shortly before I got the Ex in April.
Also I have changed out the motor and have not yet got the air out of the cooling system, or at least the temp gauge swings a long ways some mornings. I put a new thermostat in it and the water level does not change. i have put a thousand miles on it since and it does not feel right.
Any ideas or comments are greatly appreciated.

 

[DeRocha]

If you have ABS then the master cylinder will have brake lines going to the HCU (Hydraulic Control Unit). This part is responsible for pulsing the brakes when the ABS computer detects a wheel is in a lock up condition. If any of the lines are rusted and leaking they should be replaced (sooner than later). The longer you wait the more problems you're going to have. At the least you will be adding more and more brake fluid as the leak gets bigger and bigger. At the most it could cause the line to blow out causing a complete failure for either the entire front or rear brakes (whichever the bad line supplies). The line would then need to be repaired and the Master cylinder, HCU bleed to remove any air introduced to the system.

 

[Vacdaddyt]

This device appears to be about 3/4 inch wide by 2 1/2 inch tall and 3 inches long. The leak is not at the lines but at fitting/port towards the bottom away from the lines. This I believe has rear antilocs, I'll have to get it on a lift to see it better as it is up in an out of the way spot and check it again. i think you are probably correct though.

 

[DeRocha]

That's most likely the RABS valve. (Rear Antilock Brake system), Its the only box like think in the frame rail that a brake line goes to. If the part is leaking then I would personally just remove it and replace it with a brake line. You won't have anti lock brakes anymore, but it'll save you $$$ as that part is pricey.

 

[Vacdaddyt]

Not to mention the Chiltons says you need special tools to bleed it so I probably would end up in a shop with it. I suppose it got worse because I found a nice minimum maintenance road to wheel on during the week end and went down it several times to play. 1st gear, brakes on all the way down at 5 mph, about a mile and a half of 6 inch rocks and diversion mounds to get water off the road.