Removing brake fluid from pads

[Rikk]

Not kart or car related.

We have an old Schaeff forklift at work and I was sick of paying the local company to come out and not fix the problem.

Original problem was found on a 6 month PM check. The brake cylinder, (which resides on top of each drive motor and is only for the dead-man pedal that stops the truck if the operator lifts his foot) was leaking and a new cylinder was going to be almost $2k, so they managed to find an aftermarket rebuild kit and rebuilt it.

About 5-7 hours of use after they did this, the right brake would grab when going slow in reverse. They came out 2-3 times and couldn't figure it out. So I found a factory manual on ebay and decided to have a looksee myself. Turns out that when the seal was leaking, it soaked the upper brake pads. There is an upper pad set, that reminds me sort of like an old tractor clutch disk then a floating rotor then an upper pad set, all in a vertical position. They replaced the lower pad set, but the upper set can only be purchased as part of the new cylinder. I tried soaking them in brake cleaner and sandblasting them to remove the oil, and it worked, but after a day of almost continuous use, the heat caused the oil to seep from deep in the pad, coat the disc and now it's grabbing again. And the pads are a metallic type compound.

I need to clean the pads, but good. Here's what I am thinking about doing, but I will take any ideas that anyone knows to work.

We have a 200 degree ultrasonic cleaner that has a good industrial cleaner (Blue Gold) in it, I am going to run it in there for an hour or so and follow it up by baking them @ around 300 degrees for another hour or two with the pads facing down so the oil will hopefully seep out and drip away.

What do you guys think?

 

[Krakkergreg]

I will bleed my brakes when I change pads cause it looks bad dark brown boy it makes a mess but the water hose washes it right off the concrete

 

[paulkish]

"but the upper set can only be purchased as part of the new cylinder"

Are the pads riveted on or glued on? Somewhere someone must make and sell pad material, which you could use in house to remove the old pad material and replace with new. You can't purchase the whole shoe, but you only need to replace the pad. Might be some requirements doing it if it contains asbestos thought. Could the shoes be removed and the pad material removed and replaced inside a sand blast cabinet? You would have to come up with a procedure to do it that works inside the cabinet, but once you learn to do it, saving 2k is saving 2k.

Can you remove the shoes or what ever they are mounted to from the cylinder and have the shoes sent out for pad replacement?

If the pads are asbestos, could you burn the oil out of them with a torch.

Try soaking the pads in alcohol and even baking them while soaking or pre heating them.

_______________________

I also just did a Duck on it.

In the below:

http://en.wikipedia.org/wiki/Isopropyl_alcohol

It says " Isopropyl alcohol is also used to remove brake fluid traces from hydraulic braking systems, so that the brake fluid (usually DOT 3, DOT 4, or mineral oil) does not contaminate the brake pads, which would result in poor braking."

Looks like my research says to soak the pads in Isopropyl alcohol and bake them to draw out the oil.

hummm... which would be the least likely to explode, baking them with alcohol in a gas oven or an electric oven... or maybe a kart tire hot box with hot air heating?

 

[Rikk]

"but the upper set can only be purchased as part of the new cylinder"

Are the pads riveted on or glued on? Somewhere someone must make and sell pad material, which you could use in house to remove the old pad material and replace with new. You can't purchase the whole shoe, but you only need to replace the pad. Might be some requirements doing it if it contains asbestos thought. Could the shoes be removed and the pad material removed and replaced inside a sand blast cabinet? You would have to come up with a procedure to do it that works inside the cabinet, but once you learn to do it, saving 2k is saving 2k.

Can you remove the shoes or what ever they are mounted to from the cylinder and have the shoes sent out for pad replacement?

If the pads are asbestos, could you burn the oil out of them with a torch.

Try soaking the pads in alcohol and even baking them while soaking or pre heating them.

They are riveted on Paul, that's a good point, I never thought about re-lining them. I'm sure I can get the material from someplace that re-lines brakes or clutches. Great idea, thanks!!
Fortunately, they are easy to remove, so if I can't clean/bake them clean, it's not a big deal to pull them off to reline them.

 

[NAPA28]

Relining is your only choise. brake fluid is some nasty stuff. New drums "may" be needed also. JMO

 

[Rikk]

The thing is, the brake pads just barely ride on the disc when the pedal is pushed. The pedal must be stood on for he truck to operate. The only time the brake is ever used is when the operator gets off the truck. It's a fail safe to stop the truck should the driver be knocked off the truck. The braking when the truck is in use, is electronic regenerative motor braking and doesn't involve the disc brake at all. It's a stand up type truck.

What is happening is, when the truck is used continuously, the heat from the drive motor rises up to the brake and heats the pads. Once they are warm, some of the fluid weeps out onto the disk and when going very slow, it tends to grab a little. It's not noticeable, but when you are backing up very slowly with the mast lifted and a load on the forks, the grabbing brake causes the truck to jerk and while it doesn't do anything to effect the operation, it's unnerving as hell when the forks are 12 feet in the air. I found material to reline them, I will pull it apart tomorow and see how easy it will be to make new pads and determine if I will bake them or reline them.