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Hydraulic Brakes on Cat 970F

3rdGenDslWrench

Well-Known Member
Joined
Jan 9, 2011
Messages
86
Location
MD
Occupation
Heavy Equipment Field Mechanic/ Truck Mechanic/Aut
Two weeks ago we had a line blow going from the accumulator charging valve to the brake valve. No problem got the line off, made one up and everything was fine. Last friday got a call saying another hydraulic leak. Get out to the maching and find that there's another leak right near the original one from 2weeks ago. Pull all the panels out and its the other line going from the charging valve to the brake valve. So thinking there may be another problem, I change the line and pull the machine into the shop to start checking pressures. The accumulators are set at about 960psi, the two pressures for the charging valve are right....1450 cut in and 2100 cut out. Depending on how fast or hard you punch the brake pedal sometimes it'll drop down to the cut in pressure. So far everything looks good. The actual brake pressure to the axles are 1000 for the front and 1050 for the rear.....normal. The only thing that I thought was odd was that the accumulator charging pressure fluctuated....slowly but constantly but maintained the cut-in and cut-out specs.
So being a little miffed by this and not being able to tell if this is right from the book I went out and checked a 950F charging pressure and it did the same thing.
Long story short of what I'm trying to ask is...Has anybody ever had this happen before? Or knows something maybe I'm missing?:beatsme
 

3rdGenDslWrench

Well-Known Member
Joined
Jan 9, 2011
Messages
86
Location
MD
Occupation
Heavy Equipment Field Mechanic/ Truck Mechanic/Aut
I couldnt really tell you how long they were on there Nige. I work for a shipping terminal that stock piles salt and other materials so nothing really lasts to long in that environment. But both hoses didn't really blow out like you would expect from a larger line, one kinda broke some of the wires in the hose itself. The last hose I changed looked just like someone jabbed it with a O-Rick pick.
 
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