After advice on this forum I looked for a dedicated brush mower instead of converting a Hydro Ax feller/buncher to a brush mower. I found a 1992 621B with a 8' rotary ax mower as it came from the factory. I now need some help on the inspection. The machine is said to have about 5000 hrs with an overhaul 500 hrs ago on the 4-53 T Detroit Diesel. I plan on pulling engine and hydraulic oil samples, driving and working it under load during the inspection. My biggest concern is the condition of the drives and pumps. How can these be best evaluated in the field? Also, what have been the weak or problem areas of Hydro Ax in general? As I have not driven any type of wheel loader machine in the past, any help would be appreciated.
At 5,000 hours on the machine, I would expect the machine itself to be pretty tight if it had normal maintainance. My old 411B Hydro Ax has been good to date with 8800 hrs. Rebuilt the 4-53 at 5200 hrs before it got two worn. Occasional hose blow mostly due to trees catching something on the shearhead or rubbed a hole thru. That machine moves pretty slow with the rotary mowers while in operation. Other than a little lifting up and down occasionally on the loader arms the machine mainly runs the pumps on the mower. If the hyd oil samples come back good I would not be to concerned. I assume it has three pumps. If dirty they could all be contaminated. The head on the other hand takes a terrible beating if it has been used as most of them has. Check the bearing and shafts on the head. Look for bent and wobbly cutting assemblies. You can spend a ton of money there in a hurry.
Inspection Reply Thanks for the reply. The owner says he recently replaced the mower main shaft bearings and balanced the knives. Hopefully any damage to the shaft would have been addressed then if necessary. I guess I'll know a lot more next week.
A concern may be obsolescence of the hydro ax especially a B model. It has franklin axels. Ring and pinion parts will be available but housing and planetary parts could become a boneyard search mission. But I am with you on the purpose built mower . I have a 340 timber king buncher that I have considered doing the same thing to. It is basically a 470 hydro ax with a cat engine. Addition , just saw where my previous thread was linked.