After doing some investigation...I decided that I really needed to change the brake fluid in my truck. Its probably still the same fluid it came with from the factory. Its now recommended that the fluid get changed every couple of years or so...or around 30k miles. Brake fluid absorbs water...which keeps the inside of the brake lines from rusting...but it begins to lower the boiling point of the brake fluid. It may get to the point where in a panic stop you hit the brakes...the water in the fluid turns to steam...steam compresses...and suddenly you have no brakes. Not good.
I found all sorts information on the net about changing the fluid...but nobody had pictures or provided information like wrench size...tubing size...etc. So...thats what this thread will include.
The first thing I did was crawl under the truck and spray some WD-40 on all the bleeder valves. I didn't want to run the risk of breaking any of them when I tried to loosen them. You can see where the bleeder valve is here
. This is the right rear caliper. The tubing that I used had an ID of 3/16" and an OD of 5/16". You will need a 10mm box end 6 point wrench to loosen up the valve. I used a 6 pt 10mm socket because I didn't have the wrench. Once loosened...a 10mm open wrench works fine.
I also picked up 2 bottles of Valvoline synthetic brake fluid. It exceeds Dot 3 & 4 requirements. This stuff has a dry boiling point of 480 degrees F and a mimimun wet boiling point of 330 degrees F. My Advance Auto had it on sale for $5 for 32 ounces. DO NOT use DOT 5 stuff in our brake system!!!
First things first. I used a vet syringe to draw the old fluid out of the master cylinder. This
is how it looks. I figure I drew out 22 to 24 ounces of old brake fluid. This
is a side by side comparison of old fluid to new fluid. Yuck!!
Once that was done...it was time to enlist the help of my wife. I needed someone to pump the brake pedal to build pressure...then hold the brake pedal about 1/2 way down while I bled the brake system. You start at the right rear...then go to the left rear...then the right front...and finsh with the left front. This
was my 'el cheapo collection system. You need clean fluid in the bottom of your collection bottle...just in case you don't close the bleeder fast enough and vacuum draws the fluid back up. I had 3 feet of tubing...which was a bit too long. 2.5 feet would have worked better. I had the wife pump the brakes...hold pressure...then I cracked open the bleeder valve with the 10mm open wrench...counted to 5...then closed it and had the wife release pressure. You repeat this cycle over and over until the clear brake fluid runs out of the bleeder valve. The right rear took the longest...obviously...to get clear fluid to run out.
It took about 50 minutes total to get through all the brakes. I'm guessing that it also took around 45 ounces to get the clean fluid through the entire system.
After seeing my old fluid...I am really glad that I got this done when I did. I tow a bit heavy with the camper...and now know that my fluid is up to the task.
On edit...Got a chance to drive the truck. Brake pedal definately has a more firm feel to it. And...my truck used to "bunny hop" when slowing down from highway speeds. About 75% of that is now gone. I was always chocking it up to warped rotors...but maybe the brake fluid was just getting to old.