Good afternoon,

I have a 1999 4Runner and I'm about to hit the 200,000 mile mark. I'm having 2 different problems.

First is one with the brakes. Over the winter (Chicago suburbs, IL) I had a few times when I was driving that I hit the brakes and the pedal got hard and I it felt like I had no brakes. Almost causing me to get into a few accidents. Took it into a ditch to avoid an accident. Most of the time it was when I first started up my car and immediately started driving. Had the brakes checked and found out that I had a bad axle seal and that was leaking on my brakes. After replacing both front rotors and pads and rear axle seals, bearings, rear brakes I had another instant where the brakes did the same thing. My mechanic drove it around and felt the change in the brakes. One moment it seems fine and the next the pedal gets hard and it takes a lot of extra force to make it stop. Any suggestions on what could be wrong???

Second problem is more of just a pain. In warm weather the locks on my car act up. Mostly after the car has been sitting in the sun and gets warm/hot when I go to unlock the doors with my remote only some of the doors unlock. Usually only the passenger side unlocks. The driver side locks go up a little but not enough to disengage the lock. Had this problem all last summer but it went away with the colder weather. It also effects the rear trunk lock as well. Now that summer is approaching its starting to do it on a regular basis again. Also if I drive it around and cool it off (driving with windows down or using AC) when I go to lock it, it works perfectly but as soon as it heats up again it starts being fickle. Any suggestions???

Well I guess I have one more problem. I have noticed that I have an oily substance on my rear differential and I have notice a few small fresh oil spots on my driveway where I park it. I have cleaned off the dif/ axle with brake cleaner and seen/ and felt that it is dry/ no oily substance. First thought it could have been oil from adding dif oil after doing bearing and axle seals. But it keeps coming back. I have cleaned it off 3 times now and can not pinpoint the cause. My mechanic thought it might be the breather valve. If it was clogged or if it was not working would it allow dif fluid come out of it??? We have checked the brake line and the brakes are not leaking. We did notice that I have a lot of rust on the axle. Have you ever heard of a dif leaking a little from it being rusted through? Or could it be rusted through where the mount for the brake line is? I'm kinda at a loss because it seems to be leaking from the top of the dif. It also is not leaking a ton but enough that I want to find out what the problem is.

Thanks in advance for your help...

still learning the runners, but anyway....the brake issue sounds more like you are losing power assist am I correct? Does it only happen in the winter? A leaking seal- fluid onto the rotors will not make the pedal hard up top, the pedal travel will remain the same, you just wont stop...Happens like that on Audis when techs forget to remove the gew they are sealed in...

The electrical issue sounds like a contact or circuit is opening due to heat expansion. I have seen cases where door seals and other gaskets, even metals expand causing (usually to close the circuit) the contact points to open. I am not familiar with the receiving "lense" or module on the 4runner so I do not know how that reacts to temperature. Guess I cant help too much on that.....

For the last question I think the first thing to do is to find out which type of fluid it is- engine oil, diff oil, or brake fluid and go from there....also make sure no one else is parking their leaking car there