JD 4630 hydraulic problems

[rolsen05]

I bought a 4630 and didn’t realize there were some welds on top of the rocker arm cover. Please see pictures. The last two years it’s been leaking from that area and increasingly worse hydraulics. It’s to the point now it’s struggling to lift the three point with my 4 bottom plow. Also struggling to open the Baller door.

I’m guessing most of these problems are due to the Weld, however, do you suggest anything else I could check?
I have checked the pressure on the front pump last year with help of the local farmer/friend. The pressure was fine on that.
I have also changed the hydraulic fluid in the back.

One thing to note, if I can’t get the Baler door open. I can shut off the tractor wait a couple seconds and restart it and the hydraulics work great

Replacing the top cover is going to be a costly fix, and if there was something else I can do to get me by another year that would be great.

I have attached some pictures as well as the serial number.

I really appreciate everyone’s input and help. This is my first John Deere and I have a lot to learn lol.

 

[rolsen05]

I just checked the SVC pressure at stand by and the best I was getting was 1200 psi. I adjusted the pump screw all the way out well running until the pump stops pumping and then ran it all the way back in. The best I got was 1200 again. I think I’ll go tomorrow and buy a the Destroking kit and see if that helps.

 

[rockcreek4630]

View attachment 65642View attachment 65643I bought a 4630 and didn’t realize there were some welds on top of the rocker arm cover. Please see pictures. The last two years it’s been leaking from that area and increasingly worse hydraulics. It’s to the point now it’s struggling to lift the three point with my 4 bottom plow. Also struggling to open the Baller door.

I’m guessing most of these problems are due to the Weld, however, do you suggest anything else I could check?
I have checked the pressure on the front pump last year with help of the local farmer/friend. The pressure was fine on that.
I have also changed the hydraulic fluid in the back.

One thing to note, if I can’t get the Baler door open. I can shut off the tractor wait a couple seconds and restart it and the hydraulics work great

Replacing the top cover is going to be a costly fix, and if there was something else I can do to get me by another year that would be great.

I have attached some pictures as well as the serial number.

I really appreciate everyone’s input and help. This is my first John Deere and I have a lot to learn lol.

I replaced my housing last fall for that same cracked area. The fitting below the weld in your Pic is the priority valve if your pressure is still good that is where I would look.

 

[rolsen05]

I replaced my housing last fall for that same cracked area. The fitting below the weld in your Pic is the priority valve if your pressure is still good that is where I would look.

Thank you, I’ll check that out. Did you have to pull the cab to replace the cover?

 

[rockcreek4630]

Thank you, I’ll check that out. Did you have to pull the cab to replace the cover?

No

 

[buickanddeere]

I just checked the SVC pressure at stand by and the best I was getting was 1200 psi. I adjusted the pump screw all the way out well running until the pump stops pumping and then ran it all the way back in. The best I got was 1200 again. I think I’ll go tomorrow and buy a the Destroking kit and see if that helps.

You can dial that screw all you want but it won’t make a difference when there is a high pressure leak .
The screw controls max pressure , it does not adjust minimum pressure .
Replace the broken components .

 

[Tx Jim]

I replaced my housing last fall for that same cracked area. The fitting below the weld in your Pic is the priority valve if your pressure is still good that is where I would look.

I agree with rockcreek4630 in that pressure control valve in rockshaft control valve housing could be blocking pressure to rockshaft & scv's. I suggest to check hyd pressure closer to front hyd pump

 

[rolsen05]

Good idea, I’ll try to check closer to the front pump when I get home from work and let you know what I get.

Any recommendations on sites to order a replacement rockshaft cover?

 

[rockcreek4630]

Good idea, I’ll try to check closer to the front pump when I get home from work and let you know what I get.

Any recommendations on sites to order a replacement rockshaft cover?

You need s/n and the casting # to look for one. Than start calling salvage yards .

 

[Tx Jim]

It appears from viewing 4630 parts catalog that there's a serial # break for rockshaft housing. I suggest to check with Salvage yards such as All States parts who owns this discussion forum or other tractor salvage yards.

 

[rolsen05]

Great! Thank you guys! Appreciate the help

 

[tim s]

I just checked the SVC pressure at stand by and the best I was getting was 1200 psi. I adjusted the pump screw all the way out well running until the pump stops pumping and then ran it all the way back in. The best I got was 1200 again. I think I’ll go tomorrow and buy a the Destroking kit and see if that helps.

There is a small junction block on the lower right side below the battery box, remove the rear line, the one that goes to the rock shaft, install a gauge there and see what you have,, if your pressure is still low, the welded rockshaft is not your problem,,at that point I would call it a stuck stroke control valve. Isolating different components is the best way to pinpoint a problem,, and that is easily done on these older closed center systems. If,,and most likely it is a stuck stroke valve you will not get much response from the adjusting screw,,and it appears that you are not..

 

[rolsen05]

There is a small junction block on the lower right side below the battery box, remove the rear line, the one that goes to the rock shaft, install a gauge there and see what you have,, if your pressure is still low, the welded rockshaft is not your problem,,at that point I would call it a stuck stroke control valve. Isolating different components is the best way to pinpoint a problem,, and that is easily done on these older closed center systems. If,,and most likely it is a stuck stroke valve you will not get much response from the adjusting screw,,and it appears that you are not..

Thank you, that’s extremely helpful and makes perfect sense. I’ll get that checked.

 

[used red MN]

If you decide to replace the rock shaft cover and you are near NE KS try Don’s Tractor Salvage

 

[rolsen05]

So I just checked and confirmed I have 2500 PSI here. Looks like I need to replace the rockshaft cover…
Thanks guys for your help!