Crown 20MT Walkie forklift (lift-lower valve problem)

[Sodo]

Sodo,
When looking at this manifold could you check a few items.
1) Is plug "D" directly inline with the pressure or pump supply port. If i would suspect there would be a check valve behind this.

Hi oldnslo

I finally had time to open up this manifold again. Yes there is a spring and check valve behind the "D" plug. It is inside, as in my (red) drawing. The 3 places in the manifold, that it could leakdown are here: A, B, C. How I can figure out which one is leaking?

=============

I decided to first inspect the B) Hold valve. It's a spring-loaded check valve. The spring is very light.

Looking at the seat, the contact ring where the ball would seal against the Aluminum manifold has a small lump in the worst place. The black is not corrosion. The black looks like there was galling, which rolled up a small 'burr' at the yellow arrow. This would definitely make it leakdown, but I can't imagine what could lift up a burr (other than a mfg error, at which the Walkie would have leaked down from day1).

I can see the burr with a magnifying glass, and I can feel it with a screwdriver probe, it can't possibly seal tight.

But what to do about it? Can I lightly "peen" the Aluminum seat with the checkvalve's ball, and smash the burr down? By driving the the ball with a light hammer blow. What do you think?

The ball does not appear to be inconsistent in any way, do they wear out? --i.e. should I replace the ball? it's 0.34" dia. The spring appears to be OK.

I don't see anything wrong with valves A) & C) by the naked eye nothing looks out of order. But this ball-seat sure looks like the leak.

 

[wdchyd]

If the ball is bright and shiny then the ball likely is good.....I'd do a light coin or peen with it on a clean seat

The solenoid "C" would be the most likely culprit to give you a creep down.....are the threads on the valve cartridge 5/8-18?.....the dia of the smaller oring area .498"?

If looks like a common normally closed 2-way cartridge (not repairable but easily replaceable)

It may help if you connect a hydraulic hand pump w/guage to the lift cyl port when doing repairs....you'll be able to monitor real time leakdown when adjusting things

 

[Sodo]

If the ball is bright and shiny then the ball likely is good.....I'd do a light coin or peen with it on a clean seat

Can you explain this again, before I go after it with a hammer?? Would I use a brass punch and give the ball a light tap to mash down that burr?

The solenoid "C" would be the most likely culprit to give you a creep down.....are the threads on the valve cartridge 5/8-18?.....the dia of the smaller oring area .498"? If looks like a common normally closed 2-way cartridge (not repairable but easily replaceable)

Another option. The reduced diameter is .50" (don't have .xxx caliper). But the thread seems to be 5/8-16 (same as a 3/8 bolt).

It may help if you connect a hydraulic hand pump w/guage to the lift cyl port when doing repairs....you'll be able to monitor real time leakdown when adjusting things

Yes I think that would help, but I don't have that tool. Just want this walkie to hold its load!

Really hoping for some way to fix that checkvalve seat. The creep rate is about an inch every 5 seconds. If I can reduce that by 75%, or an inch every 20 seconds I will consider it good enough.

I have high confidence that this is it!

But if not….probably can buy a pump for less than the repair bill to take the walkie to a shop. If the peen (coin?) process doesn't solve my creep problem I may be bugging you about how I might find a replacement for this solenoid valve.

 

[Sodo]

Can you explain this again, before I go after it with a hammer?? Would I use a brass punch and give the ball a light tap to mash down that burr?

I gave the ball some taps with a hammer & punch and I think it worked, I can't feel the 'burr' anymore running a screwdriver over it. Also just a little oil holds the ball in its 'seat' against gravity. I am pretty confident that the check-valve seals tight now but have no way to know.

The reduced diameter is .50" (don't have .xxx caliper). But the thread seems to be 5/8-16 (same thd as a 3/8 bolt)?.. I might find a replacement for this solenoid valve.

Well I put it all back together and it still creeps down at one inch in 5 sec, same as before.

Wdchyd, can you suggest where I might get ahold of a new solenoid valve? I searched the web with these numbers below, found nothing. The reduced diameter section (left of the holes) is 0.50" . The thread diameter is about 5/8, and appears to be 16tpi not 18. I don't know if it's metric or imperial.

Parker
Model: VNUP8C-012
Part No.: 765129
12.0 VDC 1.75 AMPS

 

[mikeinwi]

A possible equivalent would be:

Delta- Power MA-S2A-00-SS-12

You can get it from Trausch Dynamics (Hydraulicstore.com - Call toll-free 800-323-5749 Mon-Fri 7:30-5:00 Sat 7:30-11:30 Central Time -)
Their part numbers are:

Valve: 7010003
Coil: 7013524

This is a double spade coil so you will have to ground one of the spades.

 

[Sodo]

Hi Mike, Thanks for the help. I found some info on the solenoid you listed, it's 5/8-18 thread as WDC mentioned. My Parker valve is possibly 5/8-16 thread. I used 3/8-16 bolt as a thread gauge…….its very likely 16tpi (I used a 5/16-18 bolt to confirm that it's definitely not 18tpi).

The Parker solenoid is a double spade.

I called Trausch, they are going to have a look at my pics. Thanks very much for the help.

 

[wdchyd]

Sodo.....possibly is that valve thread .750 x 16 tpi

If so I have them in stock

If not I would suggest getting a new solenoid cartridge, coil and valve block and put this setup between the existing control valve and the lift cyl....many of these have a built-in check valve for up and energized coil for down....just wire it with the existing wires for the other valve coil....easy peasy

also here's what we use to ream the seats (verrrry gently)

 

[oldnslo]

SoDo,
Measure the OD of the threads like wdchyd shows. Then also measure the length of the valve from the bottom of the hex below the coil to the nose of the valve. Their are two different valve cavity sizes that I know of and they do not interchange. Delta Power, Hydra-Force, Parker & Eaton all make valves that look very similar and may or may not fit in the same cavity.

My first guess would be that this is 3/4-16 threads since the parker model code includes the 8 which is some what of a standard for the 3/4-16 thread cavity size.

The 5/8 thread cavity was more of a odd ball size started by Delta Power and is far less common in the industry.

If you have a lathe that uses collets Vs 3-jaw chuck you could also try dismantling the Parker valve.

 

[js5020]

Just call your local Crown dealer for the solenoid valve they will have it or the updated valve.

 

[Sodo]

Sodo.....possibly is that valve thread .750 x 16 tpi If so I have them in stock

You guys could be right. The reduced diameter (near the holes) is .50, the O-ring seals to a 0.62 bore, so if those threads are 16 then the thd diam has to be 3/4. Can't measure it now because it's all back together.

Sounds reasonable to replace the solenoid valve block, but what if the manual control valve is the culprit?

wdc what's your company, & how much is that solenoid?

 

[Sodo]

Just call your local Crown dealer for the solenoid valve they will have it or the updated valve.

I called them, its $378 for the CROWN part.
I need to invest $600 in new batteries, then this walkie would be worth $1800.

….rather have a $50 solution or I should scrap it.

 

[aczlan]

$55 will get you a new solenoid valve from Surplus Center if you can live without manual lowering or you can install a pair of Tees and a manual valve ($40+ at the same site) to lower: HYDRA FORCE 12 VDC N.C. SOLENOID VALVE

Aaron Z

 

[oldnslo]

You guys could be right. The reduced diameter (near the holes) is .50, the O-ring seals to a 0.62 bore, so if those threads are 16 then the thd diam has to be 3/4. Can't measure it now because it's all back together.


Sounds reasonable to replace the solenoid valve block, but what if the manual control valve is the culprit?

wdc what's your company, & how much is that solenoid?

Sodo,
so we are hopefully talking apples to apples.
The O-ring at the end of the valve is sealing on a .625 diameter? Yes or no

What size is the thread size on the valve? For reference if 3/4-16 a standard #8 SAE fitting should screw right in.

Parker purchased several companies so if we can get the cavity / valve size figured out you should be able to get a replacement valve fairly reasonable. Possibly from wch.

 

[Sodo]

The O-ring at the end of the valve is sealing on a .625 diameter? Yes or no

What size is the thread size on the valve? For reference if 3/4-16 a standard #8 SAE fitting should screw right in.

Measured left & right next to the o-ring, its 0.62, so YES
Using a 3/8-16 bolt as a thread guage, I held it to the threads and concluded the thread is 16. I do not have any #8 fittings to test. Very very likely it's 3/4-16

I would like to know why you guys suspect the Solenoid valve over the manual valve. Its not the electrical part failing, it's the valve part leaking. Can I get a replacement manual valve too?

I suppose I should have another look at the o-rings, maybe they are getting cut on install.

Yeah I've had that thought just replace with off the shelf items, sounds like I can get all the questions answered for that too but first want to try to fix it without changing so much.

 

[js5020]

I called them, its $378 for the CROWN part.
I need to invest $600 in new batteries, then this walkie would be worth $1800.

….rather have a $50 solution or I should scrap it.

Holy Jeeze if thats just the valve, they are proud of that valve! I could be wrong but it sounds like they priced the whole asm,,, did they give you a part#?

 

[wdchyd]

$55 will get you a new solenoid valve from Surplus Center if you can live without manual lowering or you can install a pair of Tees and a manual valve ($40+ at the same site) to lower: HYDRA FORCE 12 VDC N.C. SOLENOID VALVE

Aaron Z

Sodo,

I'd buy this valve and install the fitting on the bottom (not pictured) to the original control valve (all put back together).....and the fitting on the side directly to the lift cyl.......if you leave the existing control valve then you won't have to add any tees or check valves ect.....it'll be just an add-on

then wire both solenoid coils to the down switch.....Your problems will be over cuz those cartridges have a built-in one-way check valve in the stem

I could sell you what I have but would cost more than this one

 

[Sodo]

Holy Jeeze if thats just the valve, they are proud of that valve! I could be wrong but it sounds like they priced the whole asm,,, did they give you a part#?

$378 is the entire manifold (complete valving assy). I will call again to get part#, and ask again if they offer the valves separate. Today's Saturday, will be a couple days until I can call, so I have a couple days to grumble about it.

Still curious why everyone suspects the solenoid valve leaks. I can guess that its got only a light spring pressure, but that sounds like something that is then simply fouled, and could be cleaned (?). Of the 3 valves
1) Check/hold valve (its a ball)
2) solenoid lower valve
3) Manual lower valve
Can you guys who have solved a lot of hydr problems tell me why the solenoid valve is the one you suspect?

 

[js5020]

None of us can actually see or hear what is going on with the stacker and the most common part to fail that most technicians would see over the years would be the lower solenoid, if I were able to be at your location I could tell you within a minute if it is actually the solenoid or related to the solenoid. There are many possibilities of why the thing drops, it could be a blown cylinder packing, it could be an internally stuck lower switch, it could be the lower switch is wired wrong, it could be wiring to the solenoid is shorted, it could be the mechanical section of the valve is bad, it could be multiple problems at the same time,,,,, there are so many possibilities and variables, internet diagnosis is difficult at the least. Do you have the ability to make a vid and post it to youtube?

 

[Sodo]

Perfect, need help from those who have seen it all

.....common....most technicians would see over the years would be the lower solenoid, if I were able to be at your location I could tell you within a minute if
......blown cylinder packing
.......internally stuck lower switch
.......lower switch is wired wrong
.......wiring to the solenoid is shorted
....... mechanical section of the valve is bad
.......could be multiple problems at the same time,,,
Do you have the ability to make a vid and post it to youtube?

Would try but youtube hates me!

It operates perfect, all switches all controls perfect.
The only thing it does wrong is creep down at 1" every 5sec when there's weight on the fork (&not when empty).
There is no noise, no vibration on any valve or tube.
The cyl packing is new.
If I run it up then led it creep down with weight (800 lb)then run up again then open a return fitting at the top of the cyl - its dry = zero fluid returning which tells me that the packing is real good.
Using the manual lower, I cant get it to behave any differently under any condition.
And electric lower button works perfect.

Can you suggest any other testing? Pretty sure the hold valve off the pump is good (visual inspection of ball& conical seat).
Would like to figure out betw the mech and solenoid.

Intend to inspect the o-rings again (they are new but its been apart 3x since).

 

[oldnslo]

Sodo,
Not exactly sure how the Parker solenoid valve is made but it has at least one sealing surface and possibly two. Since you say the valve is working perfect does that mean it lowers electrically? Parker DS091C D012HP valves are 3/4-16 threads and have .623 diameter nose for sealing in a .625 diameter hole. This is an odd ball cavity so finding a replacement valve may be difficult.

A concern I have with this electrical valve is what is controlling the lower speed when using the electrical. Is there a metering orifice in solenoid valve or some restriction below the valve. The DS09 is rated @ 5 GPM with @ 70 PSI pressure drop so this would allow the mast to free fall which is not good.

If you want to experiment: Remove the solenoid valve and look at the drill diameter below the valve cavity. Is the hole around 3/8 to 7 /16 in Diameter? Is the nose of the cavity reasonably smooth? If yes get a 1/2" diameter steel ball and a #8 SAE fitting. Put the ball in the hole install the fitting and operate the lift. The ball should seal on the nose of the cavity similar to how the check valve ball seals. You may need a soft spring to hold the ball in place.

This would help identify what is leaking.