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jdemaris
05-23-2004 07:23:26
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Re: Pettibone mullikin brakes in reply to sam , 05-22-2004 20:20:22
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I've got the same machine, i.e. Pettibone Multihoe LDA. The air over hydraulic brakes is an optional setup. Standard was non-power brakes, with a separate brake pedal and master cylinder for each side - so you could brake each rear wheel independantly. I think I'd rather have the standard setup, but I don't. With the optional setup, there are still two brakes pedals, but either one brakes both wheels together, not separatetly. Only difference between the pedals is . . . one will engage brakes and do nothing else, whereas the other will engage brakes and disconnect the transmission at the same time. Reason for that is so, when your foot is on the brake, and the transmission is still in gear, you can rev the engine up (to make the loader go faster)and the machine won't try to move. It simply saves you the trouble of having to put the machine in neutral. So, the extra line from the brake valve goes to a transmission hydraulic disconnect valve near the back of the engine. If your gauges are working, you should see the transmssion pressure gauge go to zero when you stomp on one of the brake pedals, and not change at all when you stomp on the other. 80 psi is enough to run the brakes, but I don't remember exactly what pressure mine runs. Next time I use it I'll take a look at the gauge. I suspect your problem is in the air-brake valve. I think it's prone to getting moisture in in. Mine tends to get frozen solid in the winter, but works fine in the summer - so there has to be moisture in it. And, I drain my air tank every time I shut the machine down. The optional air over hydraulics came as a kit, part # 3227-S. It has a lot of parts. Basically, there is an engine driven air compressor that is liquid cooled and uses engine oil for lube. It hooks to an air tank/reversoir, and then hooks to the brake-air-valve, then to the air servo assisted hydraulic master cylinder,and the hydraulic lines to the brake wheel cylinders.
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