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Curtis B.
Curtis B., Technician
Category: Construction and Road Equipment
Satisfied Customers: 1177
Experience:  Technican turned service manager with multiple lines of equipment and rental units.
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I have an Akerman H12blc excavator, made around 1987. When

Customer Question

I have an Akerman H12blc excavator, made around 1987. When I tensionsed a track to its 19.5 cm spec, it compressed the idler spring, and when I tried to run the excavator it would only go straight ahead or straight backward, it wouldn't turn (H12B's have a forward pedal and reverse pedal and hand lever for turns and contra rotation). I then let all the slack off the idler spring, but it still will only go straight forward or straight backward. When I apply the turn lever, it feels like its trying to do something but just goes forward or backward very slowly. Any ideas? Thanks!
Submitted: 2 years ago.
Category: Construction and Road Equipment
Expert:  catmastertech replied 2 years ago.
Hello, This sounds like a CAT control valve. Have you seen any part number on the valve?Do you know if this is a CAT undercarriage and what model it may be?
Customer: replied 2 years ago.
Hi Catmastertech,Akerman was a Swedish manufacturer founded in 1939 which was acquired by Volvo I think in the late 80's. I've heard people call Akerman the 'Rolls Royce of excavators' but production numbers were not very large and distribution in the US was limited. I think Volvo tried to use the Akerman technology and make it faster, but eventually bought Samsung in 1998 and shifted more toward that technology.Here's a little info on the Akerman machines and specs on the H12b excavators: I'm not sure how similar the undercarriage would be to CAT. I'm guessing the track, final drives and hydraulic motors are fairly similar to other excavators, but I haven't seen other excavators with a hand operated steering control. I could email you schematics on the final drive, hydraulic lines, and control lines, and whatever else you might think is relevant. What is your email address?Meanwhile, here's a few part numbers referenced in the owner's manual that might be relevant:
49578 Steering pressure valve for travel
236871 Directional 4-way valve for travel
211117 Hydraulic travel motor
12880 Travel brake inner disc
43070 Travel brake outer discPlease let me know what I can provide that would be helpful. Thanks!
Expert:  catmastertech replied 2 years ago.
All contact is limited to this site per policy. All information is open to the public and can be view by anyone, please do not post any personal information for this reason. If you can upload the image of the direction control valve (I assume this is the foot pedals and steering lever) I will see if it matches the CAT design. The part number you listed are not CAT so, I am not sure this will be the same. The edit features should have upload options for image files and pdf documents.

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