From: jaxincalifornia@aol.com
Date: Sat Apr 20 2002 - 08:38:40 PDT
RE: TRACTOR, WHEELED, WAR MFD BY PSI MOBILE PRODUCTS INC. MOD: X3-WT REG# 86-F-932, S/N: G1W60612 (PSI is now called NMC Wollard Co., Eau Claire, Wisconsin.)
Hi Gang... went down to TRAVIS AFB to pick up my tractor-tug and the rear brakes (disk) have a lock down on them that serves as an emergency brake. We couldn't get it to disengage and the 5000 lb tug wasn't going to move without those rear wheels free! I did what I could on scene, but being totally unprepared for this I didn't do much, (see below).
Let me back up a bit and explain the situation. The tractor/tug had no ignition key and the engine compartment had a fire that burned up the carb, plastic top on the radiator and melted some top radiator hoses, also a couple of 14 gage wires. That last part was real minor, just barely melted the wire insulation and also the plastic tops of a couple of relays. Looks like the carb caught fire and flamed upwards away from most things thru the louvers in the top. Battery was slightly melted, of course it was dead too, but probably fire didn't do that.
Upon inspection of the engine compartment I found what looked like a standard electrical relay mounted on the left rear brake caliper, two wires came from it. I applied 12 volts of power to each wire, then both wires, trying to get the caliper piston to back off the disc. The relay for this was clicking... but the brake didn't release... hoping the brake piston isn't rusted tight! The disc was really rusty. Then I disconnected the main brake line hoping to back off the pressure...it lost a little fluid, but still there was no release to the rear brake.
I figured that on this tug when the brake pedal is depressed and then you activate a special pressure valve lock mounted inside brake caliper via an electrical (dash button) switch it closes this valve and that holds the piston inside the caliper against the brake pad and in turn against the disc. Least this was my deductive reasoning having never seen such a setup before.
I was able to remove a bleed nipple on the electrical switch mounted to a brass block on the caliper, but not actually in the caliper... still locked solid.
Unfortunately the two remaining bleed nipples on the caliper were not really accessable with my cresent wrench and I didn't want to strip the corners round with the wrong wrench... so there is sits, still at Travis AFB. I'm going back next week to see what I can do... any suggestions how to release the parking brake? I go back next Friday to try again.
Note: Failing to release the brake at the base I will try to rent a couple of wheel dollys from a tow service and put them under the rear wheels to move the thing up on my trailer. The front wheels are drum type and I think they are moving free.
I will e-mail/call the factory on Monday...but the original mfg. called "PSI" was sold early in the early 90's and now a company called Wollard owns them. The PSI brand is not advertised, so I'm not real confident about getting an answer there.
Any suggestions... ? Thanks in advance for any advice/help.
Jack Lee
(Chico) Northern California
Sale items:
I have what I think is a new tow bar for a deuce. Code says, "Yoke, towing" NSN 81100085662513. Has two halfs of a pintle yoke that overlap to form a V yoke.
Russian gas mask, NOS, circa 1950.
Also have 50 feet of high pressure hose, black rubber reinforced, about 1 inch inside diameter, about 3/8 thick wall.
Two tactical parachutes, square, ram air type, used by Rangers and SF.. shroud lines cut. Not torn up, one sky grey and one light brown.
3 BDU, xSmall Reg coats (fits most ladies), new.
Just make me a slightly unfair offer and I'll sell em! Pics available.
This is spring cleaning at the Lee house... lol
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