SN 493113A, TB42 LP
Help!
About a year ago I took on a new customer that owns this machine. The prior forklift service had quoted but never fixed an existing low brake pedal problem.
I am a little hazy on all the details at the beginning but I remember that after bleeding the left wheel cylinder (never the right one!) the pedal would be great. This would usually last about a week and then a low pedal again. I discovered the hydraulic tank oil was foaming (machine has a hydraulic brake valve, not a master cylinder). The source was a worn hydraulic pump, cavitating the oil. Replaced the pump, oil was milky from a leaking wiper ring on one lift cylinder, resealed this, new filter and oil, inspected and cleaned the pump suction screen. Worked great about 2 months.
Problem returned. Bled once a month or so a couple of times until a shop repair where I replaced the wheel cylinder. Just trying something. Worked great a couple of months the problem returned. I bled it again today- air only on left side, great pedal again.
These guys are a great customer and I suppose I can swing by once a month and crack the bleeder but I would REALLY like to solve this problem. Any ideas??
Showing items 1 - 7 of 7 results.
I recall a problem like this several years back on a Komatsu with the Hydraulic supplied brakes. Truck was sent to the shop. They rigged up something where they pressurized the hydrualic system with air and found a leak in the suction side of the hydraulic system somewhere.
Whenever I find one bad wheel cylinder I do both (unless it's replacing a faulty new part). When you replace the first, the second is sure to follow shortly.
Update
It is the RIGHT wheel cylinder that has air now- I had to go by again today. I had thought it was the left I was bleeding lately- and I checked our records and it was the LEFT cylinder that I replaced around February. So I ordered a new right wheel cylinder and will follow up with a new brake line if needed. Thanks for thr replys.
Try replacing the brake line on that side, maybe it's rubbed through somewhere or the flare is damaged. Just a guess.
Thanks for the response. You are correct, as soon as I crack that wheel cylinder the air comes out. Problem is that I changed the wheel cylinder and it seemed to help for a long time- then the air returned. You wouldn't think you could get air inside without getting fluid outside- but it MUST be happening.
I had a problem like this with a Nissan that used conventional brake fluid in it. The petal would fade lower after about a week. There was air in the left side. Bleed it and it would do the same thing a week later. A new master cylinder didn't help. I noticed that when I bled it the air was right there in the left wheel cylinder and came out as soon as the bleeded was cracked open. A new wheel cylinder fixed it. That's when I learned air can get in through a wheel cylinder.
Do you notice the air come out as soon as the wheel cylinder is cracked open? If so, I would think that is where it's getting in and not up top through the valve and hoses.
Hey guys- just wanted to throw this back on top for another look.
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