Hey all, Just bought a 2008 CAT TH407 telehandler to do some ranch work with. I also bought a new grapple bucket for it. For starters, as soon as I recieved the machine, the AUX setup for running the grapple would hardly even let the grapple move at idle speed. Also, the hyd system seemed to have a "pulsing" when run at idle to just off idle with no load on the hydraulics. with some other problems present, I decided to take it to the dealer. they put in a new control unit and it took care of most of the problems. But, the grapple speed (aux imput) on this is still poor yet not as bad as before. I definatly still notice the pulsing although not as bad when I open or close the grapple. when it does this the engine surges up and down about 25-50 rpm. it's worse when the oil is cold than when it's hot. tonight I had my lights on, and I noticed that every time I'd boom full up, or full down my boom lights would flicker and eventually it blew a fuse. since the hyd controls have solenoids, could this possably indicate a bad ground issue? The speeds on the electronic control are turned up to the max, and if I bring up the rpms from idle to 1200 rpm, all of the sluggishness is gone, and the surge for the most part is too. This machine has 1200 hours on it, and the hyd fluid was recently changed as well as the filter while I had it in the shop. at times it almost acts as if the load sensing portion of the hyd pump is confused. because the speed will be fast for a moment, then slow, and then fast again. is there any adjustment for this? This is by far the worst performance I've ever seen out of a telehandler, but maybe I'm spoiled coming from a JD 3420. but, I'm stuck with it, so I'm going to try and make somthing good from it. I'm open for suggestions for my next telehandler since Deere no longer makes one... the JCB 541-70, and the Gehl CT 23 series looks good, but I have no experience with them. I'm just trying to figure out why we cant get a brand to stick around for more than a few years until they either sell out, or discontinue a line. Thanks for your imput. Adam
Who installed the grapple and what hoseing was used? Sometimes a hose has a defect inside that "flutters" on pressue, but is OK on return. This occurs in new factory OEM hoses and made up by user. As for speed try some larger hose (#8 vs #6). We used to get complaints of SLOW opening cotton bale clamps on forklifts. Swap out the hose size and WA LA ;slam bam, it was good. This in spite of tubing on the mast being the same for both size hoses. Clark C500-40 and 50's then.
The grapple was installed and the hosing was built at the place where the bucket and grapple are manfactured. all I had to do was plug it into the machine The speeds are only slow at idle or near idle. if I bring the rpm up to 1200 instead of 1000, problem is vanished. Just trying to figure out what this surging of the hydraulics means. and how to correct it.