Hydraulic Block Rebuild

[Clownfish]

I am in the process of rebuilding the hydraulic block for my 1949 Cub ( Block NO. 351981R1—Pict 1). I have completed rebuilding/restoring most of the other major items. This cub had not been operational for many years when I started working on it a couple of years ago so I do not know if the hydraulics were working or not. I have removed all of the parts from the block--I hope-- with help from the How To’s on the forum. I am having a problem with the Allen Head plugs in the bottom of the block—Pict. 2. Two of the 3 plugs were only screwed in a few threads but they were very difficult to remove. When I finally got them out the threads on the plugs and the threads in the block were damaged. I have some plugs from a parts tractor I can use but I would like to also get some new plugs. Are these standard pipe plugs or, are they a special plug? I believe they are available from IH Case dealer for about $4.00 ea but I also see 1/8” pipe plugs from McMaster Carr. McMaster has standard and high pressure plugs. Could one of these be used? The second question is about cleaning up the threads in the block. I plan to use a pipe thread tap but what can I do to lessen the amount of metal particles that get into the block? I know that I’ll need to do a good job of flushing it out and blowing it out with compressed air but is there anything else I should do?

Picture 1--Block Number

Picture 2--Allen Head Plugs

[staninlowerAL]

The allen head plugs look like they might be bolt threads and after cleaning should screw into a regular bolt die nut. Also you might try a regular nut of appropriate size. If they are bolt threads, a good hardware store will have them. I think you've got it covered on the threads in the TC block. Stan

[Clownfish]

Stan
Based on what I see in the parts manual and other posts on the forum I believe the plugs are 1/8"pipe plugs. One post did mention that some very early models did use standard threads. A forum post from 2012 says the plugs are available from NAPA and I try that later today. If they don't have them I'll pick up some next time I go to the Case IH dealer but that is a 60 mile RT. In the meantime I'll use plugs from my spare block and get a 1/8" pipe tap to try on the block. Thanks for the suggestions.

[staninlowerAL]

Hi Glenn, Lowes should have the 1/8 pipe plugs in plumbing as well as the allen head bolt thread plugs in fasteners/hardware. They usually have a gage there that you can screw yours into to check the thread size/count/pitch to see if it matches. BTW you probably already know that pipe threads are tapered whereas bolt threads are not. This might account for the fact that some of your plugs were not screwed in very deep, i.e. bolt thread plug into a tapered pipe thread hole. Also if you know someone with millright skills/tools he might have a thread gage. Stan

[Clownfish]

Stan,
My lack of knowledge makes me too cautious at times. On the McMaster Carr site they show black iron and steel 1/8" pipe plugs but these are only good for 150 psi and I assume that the hydraulic system is over this. They also have high pressure plugs good up to 5000 psi. I don't know what the pressure rating of the Lowe's/Home Depot plugs would be. I am not sure I trust my local Lowe's/Home Depot stores to know the difference.

[staninlowerAL]

Sorry, can't help you on the specs. Way beyond my knowledge level, I was just trying to think of what might work. Maybe someone else will chime in on this one. Have you checked with Hendrix Tractor at Atmore? Phone 800-338-5696 or 334-368-2189. Good Luck, hope it goes well. Stan

[Smokeycub]

black iron and steel 1/8" pipe plugs but these are only good for 150 psi and I assume that the hydraulic system is over this.

A Cub's hydraulics is around 1500 psi max. The following is from Rudi's Manuals listed above, Blue Ribbon Service Manuals. http://www.cleancomputes.com/Cub/Blue%2 ... e%2004.jpg

[Clownfish]

Picked up a 1/8" pipe tap today and cleaned up the threads in the block. Plugs from the spare block now screw into the block but not very far. They go in only about half as far as the other plugs in the block. Hopefully everything will work ok. Did not have any luck getting plugs at NAPA. All they had were for low pressure. A local industrial supply house had some that they called high pressure plugs but "thought" they were good up to 1000 psi. I'll get new plugs for the spare block from CaseIH.

[Clownfish]

I have completed the rebuild of the TC Block and pump. Everything was reinstalled and I added 4 pints of HY-Tran which filled the block to the bottom of the fill plug. Started tractor and was cycling the TC lever, with fill plug out, to bleed the air out when the engine started really loading up finally to the point of stalling out. Fluid level in the block had dropped and I added another 1/4 pint which brought it back up to the bottom of the plug. The engine was hard to restart but it finally started. The rock shaft movement was not smooth. Several small movements of the TC lever would produce no movement in the rockshaft and then with the next small movement there would be a large movement in the rockshaft. One or 2 times the engine stalled again but with the lever in about the mid position it ran ok. All of this was at about 10:00pm. The next morning I tried to continue but the engine would not run. On the first try it started and ran for about 3 seconds but since then no luck. It seems to be turning over good and tries to start but when the starter disengages the engine stops. From outward appearance everything looks ok. I have made all adjustments that I know of with the exception of the "Control Valve Operating Lever Stop" (Picture and page from parts manual below) and I don't know what to do to it at this point. Is it possible that hydraulic pressure is too high and the load prevents the engine from starting? Is there a position of the TC lever where pressure would be at a minimum? When the engine is turning over when trying to start the rock shaft will move if I move the lever.

When reinstalling the TC block I removed the dash but did nothing else. The day before the tractor was running great but with no significant load. It is a 6 V system with magneto. I have checked fuel flow by removing the carb plug and got a steady stream of fuel. I also cleaned the carb jet. There is good fire at the plugs. My first thought is to remove the TC pump, install a cover and see if it will start. I don't know if the problem is the TC or if there if another problem came up at the same time as I was working on the TC. The jerky movement of the rockshaft tells me that there is at least some problem with the TC system. Any suggestions would be appreciated.

[baldwindiesel]

Did you check the engine oil ? Is it way past the fill mark ? If so, your hydraulic pump is leaking and letting hydraulic oil into the engine oil. Not good.

Baldwindiesel

[Clownfish]

There is no change to the engine oil level at this time.

[staninlowerAL]

Your idea of removing the TC pump and try to see if it will start will positively tell if the problem is in the TC rebuild. Good Luck, Stan.

[Matt Kirsch]

Be careful. The oil is under pressure now and when you start disconnecting things, you're gonna get sprayed.

I suspect that something is not right with the TC rebuild. When the TC gets to the desired position set by the lever, the spool should move to its neutral position and put the system back to circulating the oil under low pressure.

[Clownfish]

Matt,
Thanks for the warning. I will drain the block and CAREFULLY disconnect the lines from the pump and block. I am hoping that the TC block isn't the problem but I'll disconnect it and find out today.

[Don McCombs]

Open the fill cap before you open the drain. Don't ask why I know that.