Pickups and 4Runners (1979-1995)
I live in the heart of the Rust Belt. Here, the sides of Toyota pickup beds fall off, and 4Runner rear gates rust away to oblivion. Most rust issues with Toyotas are merely cosmetic; however, you're about to read of one that isn't and you may not have known about it before. For more information on the cosmetic rust issues, please click here. If you have experienced this same brake problem, please let me know via E-mail so I can show I'm not the only one (and I know I'm not).
Before I go any further, I want to stress a few things. First of all, rust here is extreme. For someone living in another area of the country, what I have experienced may not even apply. Better to be safe then sorry though. Second, I want to make an awareness of this potential problem--not create panic and sound the air raid sirens. I have owned 13 Toyota trucks and 4Runners myself and I stand by their quality. I will continue to buy more in the future. Third, I have seen brake problems happen on 3 different generations of Toyota trucks and 4Runners covering the years 1979 to 1995. Other years may be affected, but I don't know at this time and it's probably too soon for anything to happen to 1995 and newer models. What I recommend doing won't take much of your time. Please read on to learn about the potential brake failure, how to fix it, and how to prevent it.
Okay, here's the hazard. Two metal brake lines run to the rear axle of trucks and 4Runners. These two lines run on the inner side of the passenger side frame rail--not actually inside the frame itself but on the outside surface. The two brake lines are about ten feet long each and start at a line splitter resting near the passenger front wheel well. They both end where they enter the rear brake proportioning valve (the strange dohicky that is bolted to passenger side frame just above the rear axle). On their way to the rear brake proportioning valve , the brake lines pass between the gas tank and frame. Just below where the brake lines pass by the gas tank is a "lip" that runs all the way around the tank and is approximately 1 1/4 inches wide. Dirt, rocks, and other debris that get flung around while you drive fall on to the lip and stay put. There is hardly any space between the gas tank and frame, but just enough to trap debris real well. It's almost impossible to clean this area out with a garden hose too. If you try and look at the area I'm talking about, you'll see what I mean because it's difficult to see the section of brakeline here. The parking brake cable is often blocking your view too. I've dropped a few gas tanks before and have spilled up to a pound of debris trapped here.
As you may have figured out by now, the problem that occurs is the debris piles up around the brake lines and causes rust. Dangerous rust. Years worth of junk collects up there, and nobody ever thinks to clean it or barely can if they do think to. Rocks get wedged in real well between the brake lines and frame. Grass gets twisted around everything. Mud, dirt, and sand pile up to fill the voids.
Of friends and family who own Toyotas, a total of four vehicles have blown the rear brake lines. Out of 13 Toyota trucks and 4Runners I have owned personally, two have blown the brake lines in this spot. Yikes! Good thing I was only just pulling out of my garage in one incident ( 1987 Toyota 4x4) and traveling less than 20 mph in the other (1986 Toyota 4x4). My sister's 1990 4Runner had the brake lines replaced by the previous owner. A 1987 4Runner I sold a couple years ago blew its brakelines about a year after I sold it. This 4Runner was nearly rust-free underneath too! Keep in mind these are just examples of the vehicles in my own little world. I have heard on Internet bulletin boards of other people having the same problem. I haven't heard of anyone dying yet, but that is always a possibility.
When is the brake line likely to blow? Well, that depends. It might happen at any time during normal stopping. However, it is more likely to occur during the following two situations. The first is hard-braking or panic stopping. Normal braking may not have burst the lines yet, but the extra force applied during hard-braking might be enough to do it. A quick test of this in your garage or drive way (definately do not practice this while driving!) is to step very hard on the brakes and see what happens. If you feel the pedal suddenly "pop" loose and travel to the floor, you just blew the line.
The other likely situation to experience the loss of brakes is after adjusting the rear brake pads and/or fixing the parking brake. If the parking brake is broken or not used, the rear brake shoes do not self-adjust to compensate for pad wear over time. This results in you having to push the brake pedal further to the floor before the rear brakes engage. If you adjust the "star" wheel for the rear brake shoes to proper specifications, less pedal travel is needed to engage the rear brakes and the "mushiness" goes away being caused by this particular issue. How should you know when your rear brakes are adjusted properly? Well, keep in mind I am NOT a certified Toyota mechanic and I could be wrong. But I like to adjust the shoes so that there is slight drag on the rear wheels when you try to spin a rear tire (with both rear tires off the ground). Say, enough drag so the tire only spins once or a little less. You should also be able to hear the slight drag of the brakes as the tire spins. Just make sure you are doing it right if you decide to do this. Please don't blame me if you do it wrong. With the rear brake shoes properly adjusted and regardless of the parking brake being used or not, the shoes might not self-adust anyway. The "star" wheel adjusters can freeze up on their own.
The reason I mentioned the parking brake as being involved is because both times I blew lines in my own vehicles was immediately after freeing up the siezed parking brake armatures that run in to the rear brake drums. My original intent was just to get a nonfunctional parking brake working again, but I also fixed some mushiness in the brakes by adjusting the rear shoes. Even if you don't manually adjust the rear brake shoes, fixing the parking brake will. Pulling the parking brake handle pushes a little lever in the brake drum which in turn spins the "star" wheel a click (if needed).
How can you check your brake lines and how do you fix it? Well, before doing anything, you might notice the stain of brake fluid running down the frame next to the gas tank dripping on the ground. But if you can see this, you are probably already aware of the situation. You can also crawl underneath the truck and look between the frame rail and gas tank. You might see a solid wall of crud masking the brakelines from view. Otherwise, you have to drop the gas tank to really see anything. This can really be a pain if everything is rusty. The bolts holding the tank and skid plate up might be rusty and round off or snap. To replace the lines, you have to get two 10 foot sections of metric brake line (I don't recall the metric size). You'll have to custom bend them yourself which is not much fun. You can also buy factory lines too, but they are pricey. Of course, you can just have the dealer do the work and save yourself the headache. As an example, a local run-of-the-mill auto shop charged my sister about $200 to replace her two brake lines including both parts and labor.
What about preventative maintenance? First off, you can make the first visual inspection if you have never done that. If you can't see up in there, you may have to move the parking brake cable and shine a light up there (be careful if you have a gas leak). If your truck is pretty rusty underneath and there are great globs of dirt trapped up there preventing you from even seeing the lines, then you might want to consider dropping the tank (hose the area clean first to see if that helps). Try to include this area whenever you wash your vehicle. Squirt the hose right up there and clean it out good. You can even try to attack it from the top side of the frame rail. On 4Runners, this might be difficult due to the body contours though. Here's a tip that I like to use in addition to the cleaning. I like to "paint" on motor oil (preferrably over rubberized undercoating to help the oil stick) in the areas of concern. Motor oil is a good rust inhibitor (ever notice how that old oil stain still has nice paint under it, or that the inside of an engine or differentail are virtually rust free even on non-moving surfaces?) The oil is a bit drippy at first, but after driving down a dirt road the oil gets a coating of dust and stays put after that.
So, now that all is said and done... My intent is not to scare you from owning a Toyota truck or 4Runner, but to enlighten you of a new issue arising. I might be saying more than I need to here, but that is becuase brakes are nothing to cut corners on or ignore. Recall that I live in an area where rust much worse here than normal. Rust might not be an issue at all where you live. But I would never forgive myself if I heard of someone losing their life because of this and I didn't do anything to spread awareness.