brake fluid

[42GPW]

What type of brake fluid do i use on the 151?

Matt R

[gpready]

DOT-5 or "silicone brake fluid" is what was used...but you can use conventional DOT-3/4 fluid BUT.. before you do...you must flush the system.

Check out these other posts concerning brake fluid, etc....

http://www.g838.org/viewtopic.php?f=2&t ... t+5#p12575

http://www.g838.org/viewtopic.php?f=2&t ... t+5#p13102

http://www.g838.org/viewtopic.php?f=3&t ... t+5#p19486

Joe

[raymond]

To tell if you have the older DOT 3 or the newer silicone DOT 5 brake fluid, you can draw out a small sample and mix it with a little bit of water and shake. The DOT 3 will absorb at least a small amount of water. The DOT 5 silicone fluid will not absorb any water and the 2 will form something like vinegar and oil salad dressing when it is shook up. It will soon seperate back into its component parts. Once you have established which you have, I would recommend sticking with it unless you plan on replacing most of the components of the brake system. There are valid arguments in favor of each type of brake fluid and asking which is the best is like asking whether Pepsi or Coke is superior to the other. One argument in favor of silicone is that it will not abosrb any water and thus will not rust up the interior of the entire brake system if left in too long. However, the brake system is vented and you will still get some condensation in the brake system. Water, being heavier than silicone brake fluid will accumulate in the low points, i.e. the bottom of the brake cylinders at the wheels and cause rust there. Ask Rick about this. I prefer DOT 3. Every couple of years I take a meat baster with a hose attached and suck all the fluid I can get out of the master cylinder and refill with fresh DOT 3. I then prime all the brakes with the fresh fluid. Then I retop the master cylinder. I know some old brake fluid will still remain, but I figure I got at least 75 percent of the old out.

[rickf]

Yup, What Raymond said. With silicone the water that does get in will settle to the lowest point and sit there and rust. That lowest point is the wheel cylinders.

Rick

[Ralph Fuller]

Rick: If that is the case about the wheel cylinders...would it behoove me to bleed the brake cylinders once a year or so?

[rickf]

Ralph, The only way to get water out of the wheel cylinder is to disassemble it. You pop the caps off, push out the cups, clean it up and put it back together. Unless you have reason to believe you have gotten water in there I would not worry about it.


Rick

[42GPW]

I think ill flush the brakes and put dot-3 in.

Matt R

[rickf]

Matt, If you have DOT-5 in there now you will also have to disassemble the wheel cylinders to get all of the dot five out before putting in the DOT 3. Since the bleeder is on top of the wheel cylinder you will not be able to remove what is in the bottom of the wheel cylinder just by flushing. What I would do is to remove the wheel cylinders and clean them or replace them. Empty the master cylinder and them pump the brakes until nothing comes out of the lines at the still removed wheel cylinders. Then add a little DOT 3 to the master cylinder and pump the brakes to run that all the way through and out the ends of the lines. Then put the wheel cylinders back on and fill as usual with DOT 3. Now you know there is nothing but DOT-3 in the system.


Rick

[Fil Bonica]

Remember the old addage : If it ain't broke don't fix it !
If it were mine I would check the brakes and adjust , Determine what kind of brake fluid and top off,and then leave it alone.
The idea of flushing the system completely seems like a lot of work for little gain. Save that project for a complete brake rebuild.

Fil Bonica

[42GPW]

Well so far i have no brake pressure. There is zero fluid in the lines. So i'll go with the more accesable Dot-3. Tommorrows project.

Matt R

[Flyboy740]

Don't give up too soon. You can go to any auto part store and get DOT 5.

[Ralph Fuller]

Rick: Thanks for the reply to my question.

[42GPW]

Well for some reason my brakes are working and great. When i drove it last i pulled up in the drive way as a normal habit i applied the brakes. I noticed a little pressure at the bottom. so i shut it off and pumped the crap out of them. Nothing. Not even pressure. So i got to thinking hydrollic brake fluid ????? So i started it up. And started pumping the brakes. Now i have great brake pressure. All 4 brakes engage at the same time. I got out on the road and was up to 45mph. Threw it into neautral and hit the brakes. all 4 engage evenly. No pulling to the left or right. My plan is to still bleed the brakes.

Matt R

[rickf]

Your master cylinder is going bad. Keep that e-brake adjusted!


Rick

[Rainman]

What Rick said, and wear hard sole shoes in case you need that Fred Flintstone effect foot brake. I've got a new and a rebuild in the parts room if you can't find one, but they are usually on ebay or available at the parts dealers. I don't know of any test other than pumping and holding the brake while sensing for any minor drop of the pedal. Anything else to narrow that down to the master cylinder Rick?