Tplane37
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Brake System
Okay, after researching this site, Google, and the TM's, I managed to figure out the plumbing for the hydraulic system side of the brakes. I found several pictures of the individual components and then the text identifying where the components were located. I took my 4 pages of notes back out to the barn and followed things around. This time, I remembered that this was a dump truck and lifted the bed up and set her down on the safety stop (which is thankfully present and solid!). The guy I bought this from told me that when he was bleeding the brakes, brake fluid leaked out of the lines like a sieve, and the master cyl. is empty... but I do not see any build-up of dirt, dust, or anything line that on any of the lines that one would typically associate with a hole or leak in a hydraulic line.
It would appear that my best option at this point is to waste some brake fluid. Like I said, the Master completely empty (but not dry, if that makes sense). As I mentioned in my last post, I am uncertain of which fluid to use in this truck (I am not asking for anyone's opinion on whether DOT 3/4 or DOT 5 is a better choice, what belongs in this truck). Without knowing (a) what brake fluid the City used in this truck when they were using it prior to 2007, (b) what brake fluid the seller put into the truck between 2007 and last weekend), and (c) what some knucklehead may have put in the system at any point in this truck's 60 years of existence.... with all that potential for a screw up, and since the Master Cyl. is currently empty, I think it is a good time to flush the system, but how?
In theory, I should be able to pull the rubber lines off of each wheel, put each of them into a bucket, fill the Master Cyl. up and pump away (engine off, e.g. "Manual Bleed") anything in Master Cyl, Air-to-Hyd. Cyl, Slave Cyl. and the lines, then hook the hoses back up and pump out the Wheel Cyl. But with what? If I use DOT 3/4 or DOT 5, and any residue of the other type remains in the system, I risk a chemical reaction creating more work and more money out the window.
Is there a non-petroleum-based fluid that is compatible with both DOT 3/4 and DOT 5 that will work to flush the hydraulic service brake system without damaging any components? Should I blow through the system with compressed air first (all the disconnects from above disconnected first) and will that be enough to remove enough residue to prevent that wonderful slime? And once more, what fluid is supposed to be in this truck? I presume DOT 5, but I do not know when DOT 5 became available to the military or civilians... I just know I have been running it in my 1964 Chevy Panel truck since 1999 after a complete brake system replacement.
Okay, after researching this site, Google, and the TM's, I managed to figure out the plumbing for the hydraulic system side of the brakes. I found several pictures of the individual components and then the text identifying where the components were located. I took my 4 pages of notes back out to the barn and followed things around. This time, I remembered that this was a dump truck and lifted the bed up and set her down on the safety stop (which is thankfully present and solid!). The guy I bought this from told me that when he was bleeding the brakes, brake fluid leaked out of the lines like a sieve, and the master cyl. is empty... but I do not see any build-up of dirt, dust, or anything line that on any of the lines that one would typically associate with a hole or leak in a hydraulic line.
It would appear that my best option at this point is to waste some brake fluid. Like I said, the Master completely empty (but not dry, if that makes sense). As I mentioned in my last post, I am uncertain of which fluid to use in this truck (I am not asking for anyone's opinion on whether DOT 3/4 or DOT 5 is a better choice, what belongs in this truck). Without knowing (a) what brake fluid the City used in this truck when they were using it prior to 2007, (b) what brake fluid the seller put into the truck between 2007 and last weekend), and (c) what some knucklehead may have put in the system at any point in this truck's 60 years of existence.... with all that potential for a screw up, and since the Master Cyl. is currently empty, I think it is a good time to flush the system, but how?
In theory, I should be able to pull the rubber lines off of each wheel, put each of them into a bucket, fill the Master Cyl. up and pump away (engine off, e.g. "Manual Bleed") anything in Master Cyl, Air-to-Hyd. Cyl, Slave Cyl. and the lines, then hook the hoses back up and pump out the Wheel Cyl. But with what? If I use DOT 3/4 or DOT 5, and any residue of the other type remains in the system, I risk a chemical reaction creating more work and more money out the window.
Is there a non-petroleum-based fluid that is compatible with both DOT 3/4 and DOT 5 that will work to flush the hydraulic service brake system without damaging any components? Should I blow through the system with compressed air first (all the disconnects from above disconnected first) and will that be enough to remove enough residue to prevent that wonderful slime? And once more, what fluid is supposed to be in this truck? I presume DOT 5, but I do not know when DOT 5 became available to the military or civilians... I just know I have been running it in my 1964 Chevy Panel truck since 1999 after a complete brake system replacement.