Thanks to NIGE. So I finally got the customer to get the transmission rebuilt, and we got it back together and started today. Now I knew the parking brake would not hold before due to no hose going to the transmission to release the parking brake, started trouble shooting and ran into a couple issues. When I take the shift handle out of park there is no air going to the park brake, followed the lines and it appears the foot brake valve supplies air to the parking brake valve. The only way to get air to the parking brake is to move the lever to the neutral position and step on the foot brake then air goes to the parking brake. There is also a bit of air coming out of the relief port on the foot brake valve. So needs a foot brake valve replaced. Question #1, what is the pressure of the air going to release the parking brake, #2 anyone got pics or diagrams with the hose routing, other than what you get off SIS. Any help is appreciated.
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140H Parking Brake Problems
- Thread starter Jim Duke
- Start date
Nige
Senior Member
See where this gets you. The SysOp for the brake system.
Sir Thanks for the info, finally got back to it and figured it all out. Some idiot had it all hooked up incorrectly. Thanks again Sir.
Another question for you, replaced the valve in the shifter handle that sends air to release the parking brake (pn# 253-4347) it has a pin hole and it leaks air, when I move it out of the parked position it quits and the brakes release. When placed back into the park position it leaks air out of the pin hole again. I played around with the shifter handle thinking I needed to adjust it some but it is either in park leaking or brake released with no leak. Thanks
Nige
Senior Member
Are you sure the air lines are hooked up to the valve the right way.?
I’ll take a look at the valve internals to see if they show which way it should be connected.
I’ll take a look at the valve internals to see if they show which way it should be connected.
That I am not sure, replaced the way I took it apart. Have been finding things that other people have done that was not right and trying to get it all sorted out, before the trans went out, they were using it and rolled down a hill into a tree and smashed the ripper cause it had no brakes,
I swapped the air lines, same thing, before the manual air valve under the cab is a Parking Brake Solenoid, pn# 185-0008. It is 24V when you turn the key on, is this valve suppose to open and close with the key operation. When I turn off the key it looses voltage but air is still flowing out of the little pin hole and drains the air tank. Thanks
GEORGIOS198217
Well-Known Member
Maby you must clean the air line. Under transmission there is a plug in which give you access at another plug and when you put it out with full air you engage and disengage the park brake and all dirt is coming out
Nige
Senior Member
Yes it is. The solenoid valve should be activated and deactivated with the key switch on/off. I'll send you the electrical schematic. you might find it useful.
It shouldn't do that. You need to find out why. The power is coming and going with the ley switch but is the solenoid valve actually opening & closing.?
Attached the air lines layout for the parking brake so that you can get them correct.
Sir Thank You but this is a new rebuilt from Cat, They had crappy mechanics messing with everything before and I am stuck straightening things out for them. I was able to figure out what is going on. Thanks again.
Thanks NIGE, figured out the solenoid is bad, had power but not operating, same valve as the horn and has power but not operating. There is no air dryer on this thing, do you know if it suppose to? I heard some did some didn’t. There has been old moisture and crud in the different lines and valves I have found, The foot brake valve was the same way and the hoses were hooked up incorrectly. Thanks for the help up till now, still sorting out a few other things, they had some wanna be mechanics before and I am stuck helping sort it all out. They did finally get the trans rebuilt by cat and it works wonderful. Thanks again and I will hit you up if I need anything else.
Nige
Senior Member
The air dryer is an attachment (option) that is included as part of a Cold Weather package. CCA01223 was not built with that attachment. Not to say an air dryer couldn't be retrofitted but at this point I don't think that it would solve any of the contamination problems that you have found within the lines & valves.
Jim what George is referring to is the air supply line to the transmission to release the parking brake. On the transmission housing right next to where the air line connects should be a plug. If you remove that plug and put air through the parking brake release line it will blow all the dirt out of the line and anything that might have found its way into the parking brake cavity since everything was connected up after the transmission was installed.