3520 rockshaft problem

[debushau]

I have a 3520 and just installed the power beyond kit this weekend. I installed it by the book and it was a fairly straightforward install. The kit was missing the spring for holding the toplink and seemed to have an extra bulkhead reducer fitting that did not go anywhere.

Anyway, the issue that cropped up after the install is with the rockshaft. The 3 point hitch goes up and down fine but when I set it to a specific height it will pulse up and down slightly. By that, I mean the arms go down slightly (1/8 of an inch) and back up again. This happens every 3 to 4 seconds and I can feel the a pulse move through the piping at the back. When it's fully down, the pulsing stops.

I checked the fluid level and topped it up. I doubt it's air as the system bleeds air very quickly. My only idea is maybe the (new) filter is blocked (I was careful to install it the right way round as the manual warns). Any ideas on what could be wrong?

thanks

 

[debushau]

Reading through some old postings, it looks like the issue might be dirt in the bypass valve.

Is the bypass valve the valve on ball bearings which is on the end of a large hex/acorn nut that screws into the housing under the seat - just above where the rockshaft pipe goes into the block/rear end housing on the starboard side. Sounds like it's time to buy a workshop manual.

 

[Nuru]

Reading through some old postings, it looks like the issue might be dirt in the bypass valve.

Is the bypass valve the valve on ball bearings which is on the end of a large hex/acorn nut that screws into the housing under the seat - just above where the rockshaft pipe goes into the block/rear end housing on the starboard side. Sounds like it's time to buy a workshop manual.

Yep, sure sounds like something is wrong with the valve. they are replacing mine this week and it came from the factory like that.

 

[tjkadar]

Yep, sure sounds like something is wrong with the valve. they are replacing mine this week and it came from the factory like that.

Ditto. My 5425 came from the factory with approximately the same rockshaft issue. Dealer replaced the valve, now all is good.

 

[Nuru]

Ditto. My 5425 came from the factory with approximately the same rockshaft issue. Dealer replaced the valve, now all is good.

Sounds like either defective parts, defective assembly or just a bad day for inspections got us!

 

[debushau]

I will check and clean the pressure relief valve first. Since it was working fine before I put in the power beyond, I am hoping that some dirt got in the system during assembly.

The PB kit is just a bunch of tubes that only go together one way so I figure if it's not leaking, it's assembled okay. The tractor is still under warranty so I guess I could get the dealer to do it if it's not dirt.

 

[debushau]

I pulled out the pressure relief valve and found the remnants of an o-ring in there. Once removed, the rockshaft is back to normal. It's an entirely separate question as to where the piece of the o-ring came from.

 

[Nuru]

Wow, glad you got the issue solved.

 

[GreatWhitehunter]

I added PB when I got my 448. The dealer installed while they added the hoe. The next time put on the 3pt hitch same issue your having. The dealer ended up replaceing the valve. I've heard of this alot so it seems a common issue.

Matt T.

 

[Nuru]

Apparently this issue has occurs through various models and once fixed, then the issue does not return.

 

[WarrenInDe]

I pulled out the pressure relief valve and found the remnants of an o-ring in there. Once removed, the rockshaft is back to normal. It's an entirely separate question as to where the piece of the o-ring came from.

debushau,

How hard is it to get to the pressure relief valve? My 1 week old open cab 3320 has the same issue. I looked at it real quick and it seems like if I take the black plastic cover off that goes around the joystick I could maybe get to it from the top? Haven't look underneath very well. From looking inside the wheel area it looks pretty closed in.

My dealer gave me a coupon for a free warranty repair pickup/return, but If I can fix it easily myself I'd rather save that for someting more severe (which won't happen ). Not to mention that I would be out the use of it for a while.

Thanks,
Warren

 

[debushau]

It's easy to get to. Remove the seat - 4 bolts and the seat weight sensor wire. Then look for what looks like a large black lug nut sticking out of the block. It's on the right hand side, just above where the u-pipe connnects to the rockshaft valve housing. Use a large wrench or adjustable wrench to remove it, it's sealed with an o-ring so it's not on super tight.

 

[Nuru]

Yep, I went a little while, but I eventulaly got a mowing back-up and put off my dirt work for a bit - No problem though, gave me more time to plan.

 

[WarrenInDe]

Thanks, I'll give it a try Friday, when I go back to our property. I tried to do it lastnight while we were there but ran out of time.

Warren

 

[Nuru]

Good Luck!

 

[WarrenInDe]

No dice The valve was easy to get to, but when I took it out it looked clean and I didn't see anything blocking any of the holes or anything. So I guess the valve is bad. I wonder if they could do a warranty repair in the field. Seem a waste to have them come get it and haul it back to the store for a 10 min repair.

Warren

 

[Nuru]

Ask them, they probably can do it.