Uneven brake wear & other ?s from newbie DIYer

[aurore]

I've recently learned to love my car, most likely a direct result of having to drive my mother's pokey little car around for 2 months (after her open-heart surgery). I've not taken such great care of it in the past, often because I couldn't afford it. But I want to change that, and learning how to perform maintenance myself seems a good start.

Now before anyone assumes I'm an idiot for jumping into car care pretty much blind (and does it say somewhere that I'm 24/F? hmmm), I just want to point out that while applying to the air force 5 years ago, my test (asvab?) scores were all in the 99th percentile, with the highest in mechanics. They wanted me to work on jets, I wanted to go into linguistics, and hence we parted ways. But the point is that I am mechanically inclined and tend to have a sense for this sort of thing, so hopefully you'll cut me a little slack. So I'm a bit impulsive, ok, I give you that, but...

I'm currently halfway through relining (am I using the right term?) my front disc brakes. 1996 mitsubishi mirage DE coupe 1.5L, btw. And I had a lot of questions. I did the google thing and the search forum thing and answered many of them, but I'm having a hard time finding a few bits of info.

Mainly, my front passenger brake. Gone. Rotor horribly disfigured on the inside. My fault, of course, for waiting too long to service my brakes. But then there's the drivers side - still has tons of life left! Mirror-like rotor surface, inside and out, at least 50% of the pads to go. What the...??? I always knew my brakes had issues. They rarely go more than 18 months before screaming at me. My husband's 1994 Toyota Tacoma has thus far NEVER needed brake service (although, admittedly, it's likely that that damn truck will still be putting along just fine 50 years from now). But this is much more extreme than I realized. Why haven't any mechanics mentioned this before? What the heck is causing it? This can't be right... I realize inner pads wear faster than outer pads, but the passenger side brake turns to dust while the drivers brake still has another year or two? Is this a caliper thing (they are floating calipers, btw, thank you very much )? I've ruled out alignment issues... could it be the bearings? Still haven't figured out how to access those (I think I have to detach a pin at the end of the rod (is this still the axle?) that protrudes from the center of the rotor - yes I have some tech terms to learn) or whether or not to check them.

So that's my main concern, but in browsing the forum and the net (howstuffworks was great, and thanks for that link) I caught some talk of vented rotors and deduced that venting is standard and solid is not? My old rotors are vented, and the new ones I got at autozone are solid... should I be concerned? I have to admit that I was irritated at the lack of rotor choice. Because of my brakes' poor history, I chose to get the best (ie most expensive) parts when replacing. I spent a good deal on the pads (bendix - blue box - not fancy, but not generic either, it was the best they had) but only got one choice for rotors. Should I care?

Another query... service manuals. I looked through the autozone manual section... talk about generic. Can't I get an info-laden service manual specifically for my car's model and year? And if so, where? I really want to learn all I can, and maybe slowly work on getting my car back into shape and beyond. And I want to DIY as much as possible.

One last curiousity... the pads! I was so befuzzled when I was putting everything back together on the passenger side; I even took a look at the (as yet untouched) driver's side to confirm... nothing holds them away from the rotors. Although I've confirmed via howstuffworks that this isn't as strange as it seems, I still can't make sense of it. What keeps them from wearing constantly on the rotors? Air flow from the spinning rotor? But the rotors have to be spinning at a good rate for that, so what about starting up after stopping? It just seems weird.

Sorry for the long post, that's me for ya. Tomorrow daylight I'll be back at it, hopefully with some new knowledge, and will also be changing my oil for the first time... wish me luck.

Aurore

[public]

You have a sticking caliper. Most likely the passenger side is sticking and causing all the braking on that side to be done by the inside pad. As for the rotors, most people won't notice a difference. Solid is more prone to warpage due to excessive heat. If this becomes an issue you may be able to find vented if you check around but it is a Mitsu so parts availability is going to be more limited than a more popular vehicle. The dealer would have the originals but the usually cost a lot more. As for the manuals being kind of generic, thats because a lot of the repairs are the same on many cars from the same company. The Haynes or Chiltons books a good for most home mechanics. Either on will certainly get you through a brake job. They are easy to understand and have good photos and drawings. Any special proceedures required for your vehicle will be noted. Good Luck.

[measuretwice]

It isn't likely, but there is also a chance that there is damage to one of the hard lines to the brake. If the line were mashed or kinked, the brake fluid would build pressure on the caliper when you pressed the brake, but have trouble relieving that pressure when you took your foot off. So, as you should any time you have a brake problem, check all the lines for damage and leaks.

[woofhaven]

For most cars, you can purchase a make-model-year specific manual from the parts department at the dealership. They are very pricey, but they are very detailed and the reference standard -- these are the manuals that the mechanics at the dealer use. Every time I buy a car, I go straight to the parts department and get the manufacturer's shop manual for it. These days, they tend to me multi-volume and hundreds of dollars, but they are fantastic, especially if you are new to this sort of thing -- no step is left out.

[fallingrock71]

Another very good possibility is that the brake hose going to that caliper is bad. I know, if it isn't leaking how can it be bad? When you step on the brake pedal, fluid is forced in only one direction. When you let off the brake pedal the pressure is released. Over countless thousands of these cycles the inside of the hose can form "fish scales"(for lack of a better term). These "fish scales" act as a one-way check valve and will not let the fluid return from the caliper. Hence uneven wear, lots of heat and eventually a warped rotor. A bad hose or sticking caliper is likely the culprit. Probably goes without saying, but anytime you change a hose or otherwise open the brake system you will need to bleed the brakes. If your car has ABS check a repair manual because it will likely call for a specific bleeding sequence. Hope this helps.

[aurore]

Thanks for all the replies, very helpful! I got the brakes done, and it was quite simple, although I went slow on the first one just to be sure I was doing everything right. The cleaning was the worst part, especially since my car tends to retain a lot of brake dust, a fact confirmed by a Jiffy Lube employee who used to work for Mitsubishi. I clean my hubcabs, and they're black again within a month.

Sound like I should go ahead and replace my calipers. And I suppose I ought to replace the hoses while I'm at it. Not looking forward to the whole 'bleeding' process. Any tips on making it go as smoothly as possible? Sounds rather labor intensive.

I'm getting some rattling from the driver's side wheel, which I believe is the brake pads. The outer pads have clips but the inner pads just sorta sit there, loosely. The old pads had shims, but the new pads came with none. I wonder if I should buy shims... might this alleviate the rattling? It makes me nervous.

I also may possibly have made a mistake in starting the car before pumping the brake. After the car was started I pumped a few times (the pedal went loosely to the floor the first time and built up pressure after 4-5 pumps) and got a horrible loud bang/snap sound. Any idea what this might have been?

Seems to be driving just fine, though I get a squeak on the passenger side that's in sync with the rotation speed. I imagine it's related to the axle?

Also, I re-lubed the caliper pins with brake pad lubricant (the kind in the little packet). Read something later about using only non-petroleum lube on the pins. Any problems?

And yes, on those manuals, I did look at the general repair manuals for my model and did not find them satisfactory in the least. Parts vary widely from model to model and year to year, and as a newbie I find it too difficult to work with vague instructions and diagrams that don't match the parts I'm working on. I need more detail, better pictures, and more repair info. Found some factory repair manuals on Ebay for my specific year, make, and model and I think I'll go with those.

One last thing... a few years ago my air stopped working consistently (would stay cold for three seconds and go warm for the next ten) and caused a water leak under the passenger dash. My mechanic told me it was something behind the dash, something regulating pressure or some such, and the part wasn't expensive but the labor was, so I decided to tough it out until I had more money. The next summer my air was working OK again, but I plan on getting the calipers from my dad, who owns a garage, and thought I'd get that part from him while I'm at it. Anybody know what it's called?

Thanks guys, for all the help! This is fun.

[woofhaven]

Originally Posted by aurore

Not looking forward to the whole 'bleeding' process. Any tips on making it go as smoothly as possible? Sounds rather labor intensive.

I recommend getting a brake bleed kit with a vacuum pump. Makes the bleeding process go much, much faster.

A "bleed kit" will have a plastic cup with a lid and two hose fittings. The first hose fitting goes to the bleed screw on the brake caliper, and on the inside of the cup, a short hose runs from the bottom of that fitting to the bottom of the cup, which you partially fill with brake fluid.

Connect the vacuum pump to the second fitting on the lid and suck the brake fluid (and air) out of the line. The whole process goes much, much easier than the old fashioned way.