I have a Hitachi EX75UR. It only runs in slow travel. I cannot for the life of me find out how to switch it to fast travel. I have bought a manual and service manual. They refer to a travel mode switch, but I cannot find it on my digger. I have looked for the solenoid, but have no luck in finding it. I do not know if I have the Hitachi EX75UR -5 or Hitachi EX75UR-3. It does not say anywhere. Do anybody here know if these machines were sold without the fast travel speed option? Andreas Lyngstad
Good day According to my schematic, the speed of the motors relates to the pressure required to drive the motors. I suggest you count the lines going into the central joint > 4 large & one small drain line = no solenoid. An additional small line will connect to the solenoid if you have one which will be unlikely. Check that the lube is good in the transmissions and that the idlers - rollers are free to turn. Kind regards Uffex
Good day I have been corrected if you have a blade there will be two additional lines in the central joint. Kind regards Uffex
Hi Thank you for replying! Here is a image of the final drive. I think( hope) that the line in the middle is the speed mode line. The lines from both sides meet in the central joint as shown in this image This image is form the left of the cabin. There are electrical connectors that has nowhere to connect. Also there is angle joints where I know there is a 9 valve solenoid on my schematics I have found 7 lines on the central joint. I have a blade so i think it is travel left/right back/forward = 4 lines Blade up/down = 2 lines last one drain line or travel speed mode. There might be one more, but its hard to see without dismantle a lot of things Does this make any sense to you? If the last one is the drain, where do you think it is going? I hope that if the middle line on the final drive is controlling the speed, I could buy a solenoid valve and add a switch in the cabin for controlling the pressure on the speed line. I found the below picture of a final drive. The 2 speed is where the thin line is on mine. But, I also found images where this is the case drain. Confused! Andreas
Good day I suggest you measure how much pressure you are using to drive the crawlers. It may be that one motor refusing to change speed may well effect the other. see attached. Kind regards Uffex
Good afternoon! Thank you for taking you time to answer my newbe questions! Does not the schematics in your pdf suggest that there is no 2 speed on the excavator? It does crawl, but only at one speed. I was hoping that I could fix something that was there. I found a manual and schematics online. I am not sure if I have a EX75UR-3 or EX75UR-5. Maybe this manual is for a slightly different excavator. Any way, this manual got my hopes up. Do you think it is possible to retrofit speed control on my excavator or is it no point in barking up this tree?
By the way... There is no switch for changing the speed inside the cabin. There is however many signs of different alterations on the electrical system. So, I thought maybe the speed control was removed at some point.
Good day There are many excavators that work with the automatic speed control, even some with a switch control in the cabin. If the pressure required to drive the motors remains below a certain level the motors adopt a minimum displacement high speed as that pressure requirement increase so will the displacement slowing the motors. I suggest you lift each side and measure how many revolutions you get and compare with the manual. To convert is likely to be expensive, you should be able to achieve reasonable travel speed with what you have. Establish which model you have and compare the data. Kind regards Uffex
G'day mate, I've got a Ex75UR. The small line on your travel motor is the case drain. The travel speed is switched by activating the solenoid on the side of the main hyd pump. When the solenoid is activated it limits the swash plate angle of the pump and as a result lowers the output flow, resulting in low speed travel. When the solenoid is deactivated it allows the main pump swash plate to go to full stroke, increasing the output flow and resulting in high speed travel. I assume your machine will be the same. As for the switch to activate it, I'm not sure, still haven't found it in mine. Might be one of the joy stick switches?
Hi There are at least 3 different ex75ur models. It is the ex75ur, ex75ur-3 and ex75ur-5. The first one does not have two travel speeds. This is the one I have. This model also have wires form the blade stick to the hydraulic valves. I believe the two other models have two speeds, but I am not sure. I spent considerable time to find this conclusion. I do not believe I would get this time back by traveling fast in the excavator . Thanks for all of your replies! Andreas
Good day Converting a single speed to twin speed requires the replacement of motors and central passage if the port is missing.See attached example. Kind regards Uffex
This is one of the funniest lines ive read on this forum