Allis Chalmers B hydraulic pump

[dcwatson84]

So Ive had my Allis B for probably a year or two, and I always assumed that it did not originally have a hydraulic pump, since there was a GM power steering pump bolted on near the engine. However browsing online recently I discovered that what I *thought* was an old broken PTO accessory (I didnt know what type) is probably the factory hydraulic pump that came on some model B's.

Below is a link to a photo album of the piece, which is mounted on the right side of the PTO casing.

Album:
https://plus.google.com/photos/1025...ms/5706956263713520385?authkey=CIXPtpG6l4y6FQ

My current hydr. cylinder is also in the picture, but its connected to the aforementioned GM power steering pump.

Can anyone confirm that this is indeed the factory installed hydraulic pump? And if so - is there any reason (other than it being broken) that I shouldn't be able to just hook my lift cylinder up to it, and scrap the power steering pump? Would hydr. hoses be the same as back then?

Does anyone have any info on these pumps, and whether they are powerful enough to lift standard implements?

FYI - the reason I ask is that im currently replacing the alternator, and the old one was setup in such a way that it needed a double pulley, and a second belt, which powered the GM power steering pump & hydraulics. The new alternator does not have a double pulley, so the GM pump wouldnt have any power. Using internal hydraulics would solve that issue!

Thanks!

 

[RodNH]

Yes, your photo shows the original, standard AC hydraulic pump that was used on Bs and Cs. It is a HIGH PRESSURE (3200 psig), low flow pump that is intended to work with only single acting cylinders. There is no separate return line to the sump, which has a rather limited volume available. That pump was used with no more than 2 of the standard AC hydraulic cylinders - single acting, small bore (3/4 inch diameter) and about a 6 or 8 inch stroke. The pump ONLY works when the PTO is engaged as it is driven off two cams on the PTO output shaft. It looks like you are using a 2 or 3 inch diameter bore cylinder (to operate a 3pt hitch?).

I'd be concerned about three things if you try and use that pump with your existing setup: 1) You MUST have the PTO engaged in order have any hydraulic power, 2) The high pressure of the AC pump is nearly three times that of a typical power steering pump. With that much pressure over that large a cylinder, concern would be potential damage to equipment due to excessive forces and 3) As the limited oil supply for the pump also provides lube to the PTO gearing, you could start sucking air if more than the original design capacity is exceeded when using cylinders larger than originally intended. If I can help with any specifics, let me know. Check out my AC-B page here:

http://personalpages.tds.net/~thompson_wp/

I should add that not only does the PTO need to be engaged in order to get hydraulic power with that pump, the clutch needs to be engaged also. No PTO spinning, no hydraulics. No live or independent PTO on the B!

 

[dcwatson84]

Firstly, thank you! That's exactly the sort of info I was looking for about this pump.

Secondly - Coincidentally - I actually found your page a couple days ago and was specifically using your alternator conversion guide for my current project! Its an extremely well done set of guides and will be invaluable in the work I need to do to my model-b, so another thank you for that as well!

Lastly - So considering those points, which all sound completely valid, It sounds like it would be better to continue to use the power steering pump to power my hydraulics? Being that the factory pump isnt very well suited for this purpose, I would assume that this is a fairly common scenario (A power steering pump (or other) bolted on to supply a more common double-acting hydr cylinder)?

To the broader issue - Im having some problems with the GM hydraulic pump - foamy fluid in the reservoir, and overflows . It would lift smaller implements, but its refused to lift an 8 disc harrow, which seemed to be well within the range of weight for the tractor. So i was looking for a way to get around having to service that pump. Since it worked for most implements, I was told the problem is probably air in the lines? And that it shouldnt be too hard to fix that problem. If so - then sticking with the Power steering pump might be the best choice?

 

[RodNH]

Could you explain a little more about your exact setup? For instance, are you using a double acting cylinder as double acting or is the brass thing I see on the rod end port just a vent fitting? If it's a vent fitting, then you are using a double acting cylinder as single acting with no pressure ever being applied to the rod end. I'm assuming you are using some type of control valve between the pump and cylinder? The standard AC-B pump has the control valve built into it. As far as lifting ability goes, a lot depends on the linkage arrangement as well as the pressure and cylinder size. Have you tried installing a pressure gauge to check what pressure the power steering pump is actually producing? A typical power steering pump should provide somewhere between 1000 and 1300 psig maximum. That should be a first check to verify pump capability. What kind of oil reservoir are you using? If it's like most power steering pumps, it has a self-contained reservoir of limited capacity. If you are using that DA cylinder as single acting, you may have a oil capacity problem. If that's the case and you fill the reservoir when the cylinder is partly or mostly extended, it could overflow when the cylinder is retracted. Any overflowing is generally be a sign of overfilling a reservoir.

Also make sure the pump drive belt is not slipping, especially around any small diameter alternator pulley. Most power steering pumps have fairly large diameter driven pulleys that are driven by an equally large diameter crankshaft drive pulleys. More belt surface contact around the pulley equates to no/less slippage.

Before you seriously consider any use of the stock AC pump, make sure you will be satisfied with hydraulics that only work when the PTO shaft is spinning. That in itself is a significant deficiency in my opinion. Plus the fact that it may be expensive and frustrating to fix if it doesn't work at all.

Just some thoughts after reading your post.

 

[dcwatson84]

The current setup is a double acting 1-3/4' hydraulic cylinder with a control valve between the cylinder and the power steering pump. (You can ignore whats in the pictures as im currently in the process of installing a newer hitch, so the cylinder is disconnected) The power steering pump does have a rather large pulley, and the alternator a rather small one. From the way its bolted to the tractor im not sure that the crankshaft pulley could be setup to hit both in the current config, but ill look into it, I guess thats the ideal situation. And the only time i noticed the belt slipping was when it hit the top/bottom and the relief valve started whistling.

I havent tested the pressure from the pump yet, as I dont have a gauge (and dont really know how) - but ill look into that as well.

I have filled the pump reservoir with the cylinder extended, but it should definitely be setup as double acting, so that should mean the level in the reservoir shouldn't change much, correct? I guess I need to check and make sure its setup correctly.

I do agree that needed to have the PTO engaged is a major downside. Thats going to put *way* more hours on the PTO than if I used an independent pump. So i think sticking with the power steering pump is the way to go. On that note - Is it a fairly common case to have the double-pully on an alternator to power a pump (or other) - or should I really try and get them both on the crankshaft belt?

 

[RodNH]

The reason I ask about how the cylinder is setup is even though it is a double acting cylinder, it can be setup to function as a single acting cylinder with just a vent fitting in the rod end cylinder port. I take it then that you have two hoses going from two separate ports on your control valve - one to each of the two cylinder ports. Assuming that is the case, the volume in the pump reservoir must, at the very minimum, have the same volume above the oil pickup level as the volume in the piston rod when fully extended. Otherwise, you run the risk of the pump sucking air into the system. You should always fill the reservoir with the piston rod retracted to avoid the possibility of any overflowing of oil. If you suck air then, you know the reservoir is simply too small for use with that particular cylinder arrangement.

There shouldn't be a problem with using a double pulley if it is large enough or has enough wrap of the belt(s) to transmit the power needed by the pump. Do you have any pictures you could post of how your pump is driven, relative to your alternator? The belt should never slip, even when the pump is developing maximum design pressure. Can you be sure the noise you hear is the pump relief valve and not belt squeal?

You should get and use a hydraulic pressure gauge. It's a basic tool for troubleshooting hydraulic system problems. You need at least a 2000 psig, glycerin filled gauge. You can get one from Surplus Center (https://www.surpluscenter.com/pages/Catalog284-092.pdf) for less than $20. If you think you might want to use that AC-B hyd pump sometime in the future, get the 5000 psig model. That and the necessary fittings to quickly and easily tee into one of the lines between your control valve and your cylinder would enable you to test what pressure you are actually getting. Here's what the setup I have looks like:

The other thing I could suggest is to perform a force/moment analysis of the linkage between your cylinder and your harrows to see what kind of force is really needed from the cylinder to lift the harrows to the maximum point. I'd do such an analysis at cylinder full retracted, cylinder at mid extension and cylinder at full extension. That is unless you know the existing system has satisfactorily lifted the harrows at some time in the past and the inability to do so now has suddenly resulted without any physical changes being done to the system.

 

[dcwatson84]

So Ive done quite a bit of work on the hydraulic system, replaced hoses, fittings, etc, and I think ive probably corrected some of my problems.

However, now Im having some issues with starting the tractor, ive always had minor issues, but theyre getting to be more and more annoying. I just recently replaced the alternator, the old one was producing no amperage and batteries were getting drained. Many times when I try and start the tractor, if it doesnt start on the very first attempt, it seems like it temporarily burns out the starter switch or something?? ie on the next few attempts nothing happens, the engine doesnt turn over at all. I have to disconnect the battery and let it sit a little bit before trying again. The battery has voltage, confirmed with a voltmeter.

(So now im trying to solve this issue since Its hard to fully repair the hydraulics without being able to reliable start/stop the tractor)

Im thinking of replacing the starter switch first, to see if its shorting internally or something??? However I read your page on your 12v conversion and saw that you switched to a push button start. Mine is currently a foot pedal to starter switch setup, but I think a push button on the panel would be nice. I dont really understand how to do that from the details on your page. Do you think you could provide a few more on instructions on what you did and what parts were needed??

With that said, if my starting issues sound like theyre not at all related to the starter switch, then any comments you have about that issue are welcomed as well.

Thanks!

 

[RodNH]

You certainly need to take the starter switch apart and see what the copper contacts are like. There is a flat, rather thick copper bar in the switch that makes contact with both the starter lug in the starter body and the lug in the switch when the switch is depressed. If that bar is anything like what mine was, it will be pitted pretty bad. You can either replace the switch with a new one of grind that bar on the same bevels until the pitting is gone.

The thing that I didn't cover well on my webpage about adding solenoid start was the method I used to keep the existing starter switch in constant contact. I disassembled the switch and removed the spring return plunger that the above bar is attached to. I used a brass 1/4" IPS pipe cap, drilled the internal thread outs to 1/2" diameter such that it would just slide over the protruding portion of the starter switch. I epoxied that pipe cap in place. I then drilled and threaded the center of that cap for a 1/4-20 unc long set screw. That set screw is then used to press the copper bar down into contact permanently. I can't really remember how the set screw is insulated from the copper bar but that must be done or everything will short out to ground. Here's a closeup picture of the pipe cap and set screw installed on the starter switch:

If you go to the following site and scroll down about half way, you'll see reference to NAPA Echlin part number SF139.

Allis Chalmers Page 1

That is presumably a standard part that you can get that will do essentially the same thing I did. I can't vouch for that part however as I have never purchased or tried it.