repairs to save 644 loader

bthomas · Nov 21, 2009

repairs to save 644 loader (from basket case to fully functional)

Picture of 644 in its “BEFORE” condition. (that’s also its NOW condition until I have dealt with its repairs I haven’t started on the painting it so desperately needs)

the NEW QUESTION: following recommendation from another thread I temporarily mounted a T fitting with a 3000 psi gauge to the loader bucket lift cylinder (checked both in and out) and also placed it in the cylinder used to roll and dump. All readings when load was fully applied were 1000 psi. This was steady and did not drop off until the load was released on the joystick control. BTW the gauge came from Ebay this week…was $12.75 w shipping included and is excellent quality (made in Italy by division of WATTS) http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200405110796&ssPageName=STRK:MEWNX:IT

Is the 1000 psi reading evidence to suspect hydraulic pump? (should I be seeing 2000 psi?)

Note another recent thread was a link to an instrument to check engine rpm…I have my order in…when it arrives I will check and report regards whether my Kohler K321 is at or near 3,600 rpm. [thanks Bart--- http://www.mytractorforum.com/showthread.php?t=102883&highlight=engine ]

SKIP the next post in its entirely unless you want background on this tractor or are looking for more power.

bthomas · Nov 21, 2009

I had originally hijacked a thread from a prior inactive post because it dealt in some detail with lack of power in a 600 series loader …I chose it because a lot of forum members had generously invested their time troubleshooting in a methodical informative way the problem of lack of power (646 but applicable generally).

To date I have addressed (3) points in detail and describe below as a reference to others who may undertake a similar quest.

If your 600 series tractor is lacking power suggest you start by reading

http://www.mytractorforum.com/showthread.php?t=68676
http://www.mytractorforum.com/showthread.php?t=72576&highlight=loader

Those threads are two of several archived that are packed with solid recommendations. They guided me through what is really basic maintenance steps
1. changing oil thoroughly/completely (including pumping out the cylinders---very noticeable improvement BTW)
2. adjusting the control arm linkage to the spool on the lift/drive valve (and yet more improvement)
3. they got me to stare at the underside the banana plate long enough that it is no longer a mystery. (and eventually got me to go back remove 2 cotter pins and one nut allowing me to remove the banana shift plate and truly inspect for wear in the plate).

My experience was that just following the basic maintenances (changing oil and adjusting linkage) realized huge gains….it went from a tractor that couldn’t pull itself on level pavement in HI to a tractor that can climb a long steep grade (my winding driveway) in HI , stop along the way and start right back up and get quickly back to speed in short order. And it has power enough to spin the rear tires in LO when the bucket is driven into a obstruction. At this time I had nearly 2” pedal travel (about 1/3 of its travel) before any movement whatsoever was showing at the spool valve.

But having never owned or seen a 600 series in action I don’t know what is to be expected but remained not completely satisfied. My seat of the pants impression was that my 644 loader tractor was not as gutsy relative to other Case and Ingersoll 200 and 4000 series tractors I own.

At this stage while I pondered hydraulic pump/ hydraulic drive motor / engine (rpm) I began going back over the sequence of what had already been done and most importantly continued to read and re-read archived threads.

I began thinking the pedal free travel might yield some more performance (meaning more travel at spool valve if I did not have so much lost motion in the pedal) … I removed the banana plate to be able to more thoroughly inspect all surfaces. Visually from beneath the tractor I had previously dismissed the banana plate as “not worn”.

I had been wrong when I had previously given this part and its components a clean bill of health….while the curved slot does measure pretty uniform .510” and that is about all you can see clearly looking at it installed:

The bushing (which fits on the linkage “Rod –valve control” and rides in this curved slot F/N/R) was worn tapering from .490” to .460”.

The “Rod-pedal control” which is .375” diameter in visible areas shows no wear but when taken out for inspection was very clearly worn in the contacting area and measured .320 (it moves /operates in the elongated hole in the Arm control [shift plate or banana plate]). From beneath the tractor this piece showed no witness marks (but where it counts in the elongated hole section) it is very visibly worn.

I measured the width of the elongated hole , in the banana plate, as .423” and its length as .560”.

Bhildret of this forum and a dealer confirmed he has the suitable replacement parts needed in stock ….he kindly researched my old part numbers and worked up a parts solution from more recent vintage versions that bolt in place as direct replacements. BTW the email was replied very fast can’t say enough about the service.

Before I am done I may be buying these NEW parts but admit that evening rather than wait for Brian’s reply I forged on and cut a new .375” Rod-pedal control, and cut out the worn elongated hole and welded in a new piece to the banana plate (that has an elongated hole milled .375” X .500”---I guessed at this based on width of the wear taking it’s ”side” wear of .048” [.423- .375]. And lastly turned a new bushing that is .500” (where the old one had worn to .460”)

Addressing the wear in the bushing for the linkage, the elongated hole in the banana plate and wear on the pedal rod changed the pedal lost motion free play to just shy of 1” travel before the pedal starts to move the spool valve.

I ordered a pressure gauge to diagnose the hydraulic system. A local auto store had a hydraulic fitting which together with a T I had in the loose parts bin lets me check pressures.

Bart · Nov 21, 2009

bthomas said:
the NEW QUESTION: following recommendation from another thread I temporarily mounted a T fitting with a 3000 psi gauge to the loader bucket lift cylinder (checked both in and out) and also placed it in the cylinder used to roll and dump. All readings when load was fully applied were 1000 psi. This was steady and did not drop off until the load was released on the joystick control.
Is the 1000 psi reading evidence to suspect hydraulic pump? (should I be seeing 2000 psi?)

No, the relief valve setting is supposed to be 1150 psi +/- 50 so I think it's pretty close. Now that you have the pressure gauge you can adjust it a little to get it on spec.

If you want to test the pump, connect the gauge to the travel control valve drain plug port or in the pto line and try to push against a tree in hi range. If the pressure is 2400 psi then your pump is good.

bthomas · Nov 21, 2009

Thanks Bart that is the direction I needed to keep moving on the troubleshooting.

I know that trying to push against a tree in HI range will lug my Kohler engine from WOT to a dead stop if the pedal is pushed to the floor and held in that position.

Now I hope to find out how much pressure the hydraulic pump is creating to cause the engine to lug so hard it dies.

Bart · Nov 21, 2009

bthomas said:
Thanks Bart that is the direction I needed to keep moving on the troubleshooting.

I know that trying to push against a tree in HI range will lug my Kohler engine from WOT to a dead stop if the pedal is pushed to the floor.

Now I hope to find out how much pressure the hydraulic pump is creating to cause the engine to lug so hard it dies.

The pressure relief valve on the travel control valve should release at 2400 psi but if your engine is being stopped before the pressure gets that high then it sounds to me like your pump is just fine.

bthomas · Nov 21, 2009

I do not have a PTO line on this tractor so I mounted the pressure gauge in the drain plug port of the travel control valve (using 4" nipple and a ball valve as a union from nipple to pressure gauge...valve is full open).

When pedal is fully depressed the gauge reads 1800 psi.

Takes a long 4 to 5 second count to lug the engine to just near full stop in HI with loader bucket against a tree. 6 long Mississippi seconds or so with pedal held to the floor in HI against the tree will kill engine.

Caseguytoo · Nov 21, 2009

Bart said:
No, the relief valve setting is supposed to be 1150 psi +/- 50 so I think it's pretty close. Now that you have the pressure gauge you can adjust it a little to get it on spec.

If you want to test the pump, connect the gauge to the travel control valve drain plug port or in the pto line and try to push against a tree in hi range. If the pressure is 2400 psi then your pump is good.

What should he do if the tree gets pushed over? :sidelaugh

Caseguytoo · Nov 21, 2009

bthomas said:
I do not have a PTO line on this tratcor. I mounted the pressure gauge in the drain plug port of the travel control valve (using 4" nipple and a ball valve as a union from nipple to pressure gauge...valve is full open).

1800 psi.

Takes a long 4 to 5 second count to lug the engine to just near full stop in HI with loader against a tree. 6 long Mississippi seconds or so with pedal to the floor in HI against the tree will kill engine.

Sounds like the pump is badly worn. I would replace it. Most likely, you have an A-style pump. Grainger's have one for around $200.00. When you pull your existing pump out, measure the distance, center to center across the the two mounting bolt holes and then post that here.

Bart · Nov 21, 2009

Caseguytoo said:
Sounds like the pump is badly worn. I would replace it.

If the engine can't turn the existing pump I don't think a new pump will improve anything. Sounds to me like the engine is more worn than the pump. Of course that doesn't mean that the pump is perfect but I'd give attention the engine first.

bthomas · Nov 22, 2009

I surprised with the 1800 psi. I was sort of thinking if the pressure was enough to stall the engine that I would see higher pressure.

That said I can't verify the rpm (until the phototach arrives)

In another archive post I recall reading that 400 rpm slow decreases the hydraulic pump’s flow by nearly 1 GPM (approx 11%).

[1800/2400= .75 so I am 25% shy ]

I have considered a possible engine swap....I have a 20HP Vanguard (used) that is "surplus" to me and in the loader application I could forego the electric clutch without compromising a great deal...(I can't see trying to use the cutting deck which I have for the 644 and manuevering the bucket around all the trees on my property). But I have been trying not to stray so far away from the original by dropping in a V twin.

BTW--this 644 has the hydraulic pump which has a "elbow" which I believe is integral... so on the INLET side anyway ...if I am looking at Grainger right the new pump will require some piping changes [and resemble the pump in the later model 220]...I know because I have eyed cannibalizing the 220 (which I was running the 14 HP in).

Caseguytoo · Nov 22, 2009

Don't confuse pressure with volume. One has little to do with the other for this test. What does matter is whether your Kohler is still putting out a full 14 HP because it does take HP to spin the pump when you are asking it to produce max pressure. If your engine is weak and unable to make the pump reach the pressure needed for the relief valve to open, then you'll never see 2400 PSI on the gauge no matter what you do.

Only you can judge how strong the Kohler is. It should have no problem making the relief valve open up and squeal.

bthomas · Nov 22, 2009

Well I am not experienced enough to "verify" the 14 HP Kohler.

It starts easy, does not smoke and never so much as "coughed" this summer mounted in a weathered 220 I drug home and saw a fair amount of heavy load hill climbing lugging several tons of rock.

Cheapest next move would probably be try the Vanguard in the 644 and put the 14 back into the 220 (I had the filled ag tires and even had the snowblower already mounted before I snatched the engine out of it ...a sudden decision when I got the steering gear worked out).

Check presssure again (w Vanguard) and if its still low replace pump.

I appreciate the input I have been getting...it has been helpful.

bthomas · Nov 23, 2009

Today I started pursuing two paths. engine and pump.

engine: I started making an adaptor/faceplate for the Vanguard that will leave the 1" shaft its full original length but let me use the stock "Case" stamped steel pump mount.

pump: I think it is reasonable to expect a tractor this vintage would benefit from a new pump ...and my objective while I am not intending a restoration is to make this into a solid machine.

The center to center bolt mount distance of the 644 hydraulic pump is 3.250"

My Grainger catalog is old ('98/'99) ...it listed a "Parker" brand hydraulic gear pump with this spacing that is .64 cu.in , it shows 9.99 GPM at 3600 rpm . ( The cost was $163.25 ---10 yrs ago)

Burden Sales Surplus Center online has a .73 cu.in "Dynamic" brand hydraulic pump with SAE 2 bolt "A" spacing priced at $95.95...which is low relative to their other similar pumps. It is CCW rotation, and rated 2900 psi or 5.88GPM at 2000 rpm ..... or 3626 psi {which I assume means pressure when deadheaded and "0" flow} or 10.58GPM @ 3600 rpm max speed]

I think this is about 1 GPM higher than "ideal"[based on reading forum archive] .

https://www.surpluscenter.com/item.asp?UID=2009112021145760&item=9-7150-D&catname=hydraulic

Burden Sales Surplus Center also has a .67 cu.in "prince brand" online....$179.95 ....it does not specify the GPM and pressure at 3600 rpn (but says max speed 4000 rpm). The flow at 5.63 GPM is referenced at 2000 rpm...there is a reference to 3000 psi (but no speed is referenced.) Would this be a better candidate?

https://www.surpluscenter.com/item.asp?UID=2009112021145760&item=9-1897-D&catname=hydraulic

I found a prior thread calling for 8.5gpm (as being used in early models) and 9.5 gpm (in later models)---GPM flow being at 3600 rpm (and presumably 0 psi restriction).

I have never specified or selected a hydraulic pump and I am asking for recomendations from someone more experienced

Bart · Nov 23, 2009

You have another choice on engines and that would be to rebuild the Kohler, not a particularly expensive proposition. As CGT said the Kohler should be able to easily cause the relief valve to release and, in any event, should not be stopped by the hydraulic load. I'd suggest checking the compression or do a leak down test to determine the condition of the engine.

Caseguytoo · Nov 23, 2009

I'd choose the Prince pump at .67 cu inch displacement. You don't need more GPM than that.

bthomas · Nov 23, 2009

Bart, I Googled "cylinder leak test kohler K" and some of the best hits were on the MyTractor forum.

I have seen the recomendation to "leak test" in many other threads but was not really familar how it differs from compression test ....this link explains the test

http://www.mytractorforum.com/showthread.php?t=96587

http://www.perr.com/tip15.html

Caseguytoo, OK was tempted by lower $95 price of the "dynamic" brand...but will persue Prince. Still intend to check Grainger (sort of hate to...my local Grainger counterman must practice how to ask questions for the purpose of making the customer look foolish...certainly never seen them make an effort to assist).

Caseguytoo · Nov 23, 2009

I'm just guessing but most likely the "Dynamic" pump is made in China. Does that mean "inferior quality"? Not necessarily. Most likely, it has been made to the specs of some American company that is importing them.

My issue with that pump is the GPM. If you stick with the 14 hp Kohler, then asking that engine to produce that much GPM at 2400 PSI might be too taxing and therefore, counter-productive to the hydraulic system as a whole. Now, if you fully intend to re-power the tractor with higher hp engine, then that pump should work just fine. Your decision.

bthomas · Nov 24, 2009

Just reference...I do not want my prior statements to confuse anyone considering the purchase of a new hydraulic pump (and too much time has passed to edit) so I want to make a correction.

The online pumps I had marked from Burden Sales are not good candidates. Two issues:

1. rotation: I had mistakenly selected hydraulic pumps with CCW rotation. This is in error. SPECIFY CW . Viewed from the front of the engine [fan end] the rotation of both the Kohler and the Vanguard is CW (...meaning viewed from the 1" CRANK it is CCW) ...but the hydraulic pump rotation is designated when viewed from the shaft end of the pump ...so will be the same as the front of the engine (or opposite the crank end of the engine)

2. size: I had marked "SAE A" size pumps. These would not be drop in replacements. The hydraulic pump bolt mount spacing on this Case tractor (and on my 220) is 3.25". This is "SAE AA". Caseguytoo tried to keep me on track when he asked for me to measure this spacing.

BTW I got educated at the counter of Grainger...there was a pump i thought was "right"(...I was looking at .67 cu.in. and max speed 3600) but when it was picked and brought up for me to see, it was obviously much larger physically (and used much larger fittings). It was SAE A size. Grainger locally did not have SAE AA (they could one quickly but it is smaller) cu in with less flow ). The SAE A with its larger fittings I think it would be possibly challenging to package without several hard lines being replaced.

I am still looking online for a SAE AA pump.

Meanwhile I am going to try the 220 pump (it does have elbow inlet even though the oil reservior is by the battery). I am also on the path to try the used Vanguard I have.

Caseguytoo · Nov 24, 2009

Go here: http://www.phionline.com/index.htm

Then go "hydraulics" and then "Pumps" and then "Gear Pumps"-

Choose the D27AA2A

bthomas · Nov 24, 2009

Appreciate the link...I am green as grass selecting a pump and probably confusing myself looking at too many different specifications.

As I read the specs are they saying D27AA2A is limited to 1500 psi?

"General specifications:
SAE "AA" 2 bolt mount; 0.50" shaft dia.; Side ports; #10 SAE inlet; #8 SAE outlet; Buna-N seals; Pressure to 2,500 PSI (except D27, 1500 PSI)

repairs to save 644 loader

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