Splitting a JD 644J loader question!!

Hi guys this is my first time posting a question on the form's as I've have read a ton of stuff on here. Here it goes!!, I have a JD 644J loader that I'm in he process of splitting it for the repair of the lower center pin. Upper pin seems in good condition, but the lower one is toast on the coast. The 6 bolts are broken off in the frame as well as the upper hole is so wallared out it need to be line bored. I have split a 544 and 524 but this one seems to not allow me to roll the rear engine and frame section?. Is there an accumulator for the rear brakes that I missed? Hydraulic lines and drive line are removed, steering cylinder pins removed, Both upper and lower pin removed. I set heavy duty stands under the front frame section, and tried to move the rear section with my crane but it wont budge??? So what am I missing??. Any help would be most appreciated!!!. Thanks in advance...........Allan

Just guessing here could a center pin bushing have slipped so now it is stuck between two holes?

Bls repair said:

Just guessing here could a center pin bushing have slipped so now it is stuck between two holes?

Click to expand...

When I had the rear counterweight attached to the crane, I could telescope in and out and wiggle the back half from side to side and view the center section on both top and bottom with at least 2 to 3 inches of clearance. It didn't appear to be on a bind from the center, only the rear wheels were not moving. I know the park brake is in the front half of the machine. I'm just wondering if there is a brake valve somewhere in the back half preventing me from releasing the inboard brakes??

I think the 644 might have the park brake in the trans? I know 544 have a seperate brake in the front driveshaft but I think the 644 is internal to the trans.

Nathaniel Rat said:

I think the 644 might have the park brake in the trans? I know 544 have a seperate brake in the front driveshaft but I think the 644 is internal to the trans.

Click to expand...

Well that would certainly make since, but I believe it also has a brake parking on the front half. I read on the frame a notice to not over fill the park brake reservoir

I guess you can pull the sun gears and try it

Looks to me it would be better to block up the back end and pull the front forwards

You have a lot of gear reduction between the wheels and back output of the transmission. Did you leave the drive line between the tranny and rear differential hooked up? The machines I've done in the past, it wasn't an issue but I'm just brain storming. I also note that the rear of the machine sits on a bolster and can tilt side ways on the rear axle. It can be exciting when the back tips over almost to the tire. We used to put bottle jacks between the frame and the top of the axle just inside of the tires. It makes it a lot easier to line up the center joint holes when you are putting it back together again as well.

Bls repair said:

View attachment 228945 Looks to me it would be better to block up the back end and pull the front forwards

Click to expand...

Bls your right it would be much easier but hind sight is always 20/20. I found this out after I removed the pins and undid a few hydraulic lines. My problem now is space. I have limited space in front as I have a 1070 case tractor that's disabled. So I got to pull it from the rear.

John C. said:

You have a lot of gear reduction between the wheels and back output of the transmission. Did you leave the drive line between the tranny and rear differential hooked up? The machines I've done in the past, it wasn't an issue but I'm just brain storming. I also note that the rear of the machine sits on a bolster and can tilt side ways on the rear axle. It can be exciting when the back tips over almost to the tire. We used to put bottle jacks between the frame and the top of the axle just inside of the tires. It makes it a lot easier to line up the center joint holes when you are putting it back together again as well.

Click to expand...

John the drive line is still coupled in the rear to the trans. I think my problem is POWER!!!. I'm using my crane to lift up the counter weight and swing the rear half of the machine as well. I think it's to much for the crane to do at 1 time. It was suggested to me that I need a vehicle in back as well as the crane to pull it from the rear??.

This is the service truck I'm presently using to pull it apart. The knuckle boom is rated @ 11K but the swing power isn't designed to move that kind of weight. I believe this is my problem?. Your guy's thoughts??

you could hook up a come along and pull it back are you on concrete of in the field

I just did a A-30 Volvo off road truck and used my shop fork lift it worked great