My brake pedal was getting a little long in the travel which means it is time to bleed the system. I try to bleed the brakes annually but I’m sure it’s been over a year since my last bleed.
In my opinion, the easiest way to bleed brakes is with a Motive Power Bleeder.
There is no more need to have an unwilling person pump the pedal to bleed the brakes. You just fill up the tank, pump it up and crack a bleeder valve open and watch the fluid flow.
As for brake fluid, I have had great results with Pentosin Super Dot 4 fluid. It is available locally and it seems to hold up to multiple mountain runs without fade. I have tried Valvoline Dot 3/4 fluid before and it doesn’t seem to hold up for nearly as long. I can usually get about one good mountain run from the Valvoline before I need to change it.
This time I thought I would try Pentosin Dot 4 LV (low viscosity) brake fluid primarily because it looked exactly the same as Super Dot 4 fluid; it was the only Pentosin on the shelf and I didn’t realize it was different until I after I bled my system with it.
After a quick google search I found that the low viscosity fluid is ok to run and my brakes won’t explode.
Low viscosity brake fluid can be used in vehicles that do not require a low viscosity fluid; however, standard DOT 3 or 4 brake fluid should not be used for top off in vehicles that require a low viscosity brake fluid. This action will reduce the low temperature properties and decrease the safety performance of the fluid.
Source: http://www.pentosin.net/f_brakefluid.asp
To bleed the brakes with the Motive Brake Bleeder, all you need to do is add brake fluid to the container and attach the line to the master cylinder reservoir.
Then pump up the Power Bleeder to approximately 15 psi, but no higher than 20 psi.
You should see brake fluid moving through the line once the line is pressurized. Gaps of fluid in the bends of the hose is ok; the fluid is moving down the sides of the tubing.
If there are no leaks, then the system is ready to be bled.
For very dirty fluid (very dark) – siphon out the fluid from the master cylinder reservoir. Then bleed the fluid from the closest valve to the master cylinder; go to the next closest valve and so on. The thought process behind this method is to limit the amount of dirty fluid you run through the whole system.
For a routine bled, start with the caliper furthest away from the master cylinder, passenger side rear caliper. Attach a line to the bleeder valve and crack open the bleeder until fluid begins to run through the lines.
Once the fluid turns clear and there are no more bubbles in the line you can close the valve and move on to the next caliper. Check the pressure and fluid level on the Motive Power Bleeder in between calipers.
TIP: If the hose is loose on the bleeder, use a small zip tie to snug it down.
Also, expect to go through quite a bit of fluid. For the two rear calipers, I filled up about a catch bottle and half. In total, I think I used 1.5 liters of brake fluid.
In the rear, I didn’t notice too many bubbles but there were a ton of bubbles coming from the front calipers.
Once you are done bleeding, remove pressure from the Power Bleeder by unscrewing the pump; then detach it from the master cylinder; then empty the remaining brake fluid from the bleeder.
Test the brake pedal and check for leaks before going for a drive.
In my case, the brake pedal is firmer and has far less travel in it. The car stops a lot easier as well. It’s not anything amazing, I think I need to add stainless lines for a much firmer pedal, but it is a definite improvement.
Cheers!
B.黒曜石 