Re: Cherokee w/AT-Tow in D or LOW gear?
Auto trans already do all the shifting for you. You never actually start out in third gear. When you down shift you hold the gear, which is helpful on hills up and down because stomping on the gas to down shift is already stressful enough, without a boat. If you have an OD overdrive, i would keep it out of that unless the car manual says you can run on 4th gear.
Slowing down and down shipfting to second will help slow the speed of the vehicle and help reduce braking. Dont pump the brakes periodically to slow yourself down. Nice steady pressure. Take your time. Everything takes longer. Speedup and slowdown. Turning, merging, etc.
By the way, do you guys know what happens to old brake fluid with 2% water by volume? It lowers the boiling point of the brake fluid. It boils, which forms air bubbles and your brakes are useless.
I think you can buy test strips to check the fluid, its worth asking. Tests have been done. Open a bottle of fluid and leave it on the shelf. In a couple days, it will have too much water in it.
If you need to bleed the system, its easy to do. Buy 2-3 pints of fluid for your vehicle usually dot 3 or 4 which is most common now. 5 is reserved for vettes and a few special cars.
Get 1/4 inch I.D. clear plastic tubing to connect to the bleed screw. Most parts guys will know that, and some may have it. Otherwise go to a hardware store. If you need 3/16 inch tubing, dont shoot me. The hex could be anywhere from 6-9 mm but dont use visegrips. A small cresent wrench will open those not old and rusty. Get at least two feet. More will do more wheels at the same time.
The tube goes into the bottom of a jar or coffee cup you dont need.
Before you open the bleed screw.......
You can prep the master cylinder resevoir CAREFULLY (brake fluid eats paint) hense a spray bottle with soapy water may save the day.
Suck out about Half the fluid in the res. and Not below the brake line tubes coming out. refill with new fluid. All brake fluid is water soluable. When you open it, just punch a pen hole into the foil. Just one hole. Go slowly. Splash prevention is appropriate. Put the cap back on immediately when done. watch for dripping Hense you need paper towel. A large syringe or turkey baister [sp] is what you need to remove excess old fluid. Its not critical, it just saves a lot of time.
Start with the front, the shorter lines.
Open the bleed screw. Your brakes are hooked up in an X pattern. Front left, and right rear. Its a long way to the back. Open the bleed screw so it will drain on its own. Gravity will do the job, but you need to keep filling the res.
leaving the cap off for the moment is not going to hurt, but if it will drain with the cap on then do that. Dont do this project in the rain.
Do not pump the brake pedal unless you have fluid in the bottom of the jar, covering the tube. Air will just slow down the process. If you pump the brakes, DO NOT push to the floor. You are pushing a piston in the master cylinder that will go past its normal operation range and the seals will be damaged by crud in the master cylinder. Then it will leak down the firewall and it may not be cheap. They could be a 1000-3000 for a master cylinder now days. Computers are everywhere. Antilock, etc.
You can do more than one wheel at a time, but you really have to watch the resevoir level. Air from the master cylinder will take a long time. So if you are not confident, dont suck out the old fluid, just let it runs through the lines. When it comes out clear, you are done with that line. If you have to stop and leave its ok as long as everything is buttoned up and you did not add air to the system. The brake pedal will pump up or be spungy, if you have air in the system.
Many shops use a power bleeder system and it pumps new fluid in and pressurizes the lines so they just open the screws until its clear.
If they dont, and they do it manually they probably dont have high quality techs either. Ive seen masters bleeding down the firewall after brake jobs.
