My son just sent me pics of said brake. It IS on drive line and DOES provide for adjustment. Now maybe we can accomplish something!
Jim
Sent pics to MIchelle - hope she will post them for me. next for me to learn is how those shoes are activated. Operators manual tells me to shift to neutral, hold service pedal down and flip switch to set brake.
Jim
Son just was under chassis again. We thought hydrolics pushed levers down to set but he watched as grandson flipped switch and he said lever went UP during set.(Brake must have been set during pics We talked a bit and recalled coach had been driven a few miles with switch in set position and that the PO had reminded us to not do that - wonder how he knew? Maybe all we need is a new set of shoes!? Sorta like the episode I had recently in learning my fuel tank was empty!! Grandson says shoes look to be about 1/4 in. thick.
Jim
With movement when switch is operated, things must be working up front of brake pedal?
CCC_Email <fcccservice@daimler.com>
To:Jim Sizemore
Oct 11 at 9:58 PM
There are no manuals that we can give you for the Oshkosh units. They closed there publications in 1995. The park brake is simple. It allows hyd fluid from the tw11 valve, when applied, to go to the park brake canister near the drive shaft. This canister then will fill and activate a piston that will apply the brakes to the driveshaft.
Sincerely,
Glenn Hoops
Representative
Case = 87089
Jim
I could not understand having to depress service brake to set park brake. Now we know...
If you drove "a few miles" with the brake set, the pads (shoes) might be glazed. If you can figure out how to remove them, they would probably clean up with a bit of work. Degrease with brake cleaner, then use emery cloth to scuff them up. (at least that's the way I've seen it done).
Drive shaft parking brake I thought was spring applied? You have to have hydraulic pressure from the motor or aux pump to release it. Fails on. Not off
That is how I recall. I had a 1988 Winnebago on a 1987 John Deere (later became Oshkosh) chassis, front engine Ford 460 gas. It had the Bendix parking brake and service brake system. It used hydraulic pressure from a second power steering pump to power both the service brakes and release the parking brake. Placing the shift lever in Park applied the parking brake via spring action. Pulling the release knob with the engine running and shifted you of Park would start the hydraulic pump, releasing the brake. I do recall the service brake needed to be applied for something, as an interlock.
For what it's worth, I have a failure within the warranty period. The hydraulic fitting to the parking brake was cross threaded, and let loose, draining all the hydraulic fluid used for the parking brake and power brakes. I was able to stop with the electric motor backup system on the service brakes, but the parking brake was toast. It tried to engage while I was driving, and needed to be replaced.
Grandson just moved the coach. Noticed that park brake tension changed with pressure on svs pedal, Not much, but perceptable. Looks like brake fluid will go from master cyl. to the valve mentioned by freightliner on its to the back of the coach. Will post more about this when I learn more.
Jim
Does the spring application only apply with air brake systems??
Jim
Jim,
No, that method of application (spring applied) and either air or hydraulic pressure released is common. It addresses the basic requirement-- fail-safe is, the brake is ON.
So is freightliner correct that mine is set byservice brake pressure thru the TW11 valve. If so, how does it remain set when pedal pressure is stopped(and it does!)I thought freightliner straightened me out - but now I am confused again...
Jim
Look up "line Lock" or "tow truck brake" . Small electric solenoid that keeps the line pressure on until button is pushed.
Sounds like you could use one in place of the system you have now.
I'm still confused. Mine sets when I apply svs brake and releases when I apply pedal and turn switch(valve?) off. Just doesn't seem to hold like my '68 Travco. I'm probably chasing a ghost as I've heard this complaint from others?
Jim
Thanks, Michelle,
Good pictures of the drive line brake itself.
But, follow the cable "up" to see what activates it.
Said another way, that cable could be "powered" by a straight mechanical linkage, hydraulic pressure or air pressure. I know of coaches with each of those choices. Not necessarily better/worse, just different.
It looks like the adjustment rod has been run down quite a ways. Probably need to have the shoes religned.
I have not been under there but both my son and grandson say that that rod comes thru a rubber boot from a tank/ container with what looks to be a hydraulic line feeding it. This follows the info from freightliner. I'm still having trouble understanding what keeps pressure there after svs. pedal is released. That valve on the dash has what I was using for a switch toggle but it is a lever. Must hold the valve so pressure can not go back thru it? I'll try to look myself tomorrow. We have backed the coach up onto a concrete slab to make getting under easier. That could explain having to depress svs. pedal before switching to set?? Still just guessing...Thanks again , Michelle
Jim