757c boom problem

BR1 · Apr 15, 2009

I have searched and possibly come up with an idea. this is on an 01 tc35da, 400 babied hours. the boom function doesn't seem to have any power. when trying to dig and go straight down, it will just stop and have no dig power. the curl and dipper work great, as do left and right. the stabilizers will lift the tractor off the ground just enough to spin the rear tires, but not much more than that. fluid level is good, about halfway up the checked area on the dipstick. i had it in the driveway tonight and positioned the bucket so it was level with ground, and tried to lift the tractor via the boom extending, and it goes to resistance, but then does nothing, with no resistance on it, it works properly, so i'm thinking its a pressure issue not flow. therefore, i'm leaning toward a leaking cylinder. i am going to take the control cover off tomorrow evening and swap a line to see if that works, i'm almost hoping it doesn't, as wouldn't that pinpoint a leaking cylinder packing? how far off the ground should the stabilizers lift the tractor off? the top spool valve was replaced under warranty already, and i read a thread about someone having this done and it not being calibrated correctly. i don't think this is an issue as all of the other functions work pretty well. any help is appreciated.

GATC35 · Apr 16, 2009

Your stabilizers should lift your rear tires completely off the ground by 6 to 8 inches. Sounds like you have more problems than just the boom. Has this hoe worked normally on this tractor before? Have you recently changed any plumbing? Does FEL and 3 pt. work normally?

Sounds like it could be a PB ( power beyond ) problem coming from the FEL valve.

The first thing I would do is disconnect and re-connect all my hydraulic connections and make sure they are seating properly.

I also have a 757-C and have never had one problem with it.

If you decide to swap lines you will have to swap 2 lines on each cylinder, 4 total.

On edit: BTW Welcome..just noticed this is your first post. We have allot of knowledgeable people on the class three boomers: "jinman" and "have blue" are excellent.

Flatheadyoungin · Apr 16, 2009

i have loaded tires and it's all mine wants to lift the rear off of the ground....i usually have to help it with the backhoe arm....

mine's a 758c....any different??

BR1 · Apr 16, 2009

well, i just went out and swapped 4 lines, thanks for that advice, i was only expecting 2, but it makes sense. the boom now lifts it right off the ground with no issues whatsoever and has plenty of power. what would be the problem? are there replaceable parts in those sections of the entire valve assembly? does each one have a pressure relief valve? this pleases me, because i dont' usually need a whole lot of power for left and right swing, so until i get this figgered out, i can still use it. jsut have to remember the controls arent' the same.