Hydraulic Welch plug popped

[55cubster]

Hello Everbody. New to forum but have had my "55 cub for approximately 30 years. Main chore of mowing. Had a hydraulic control valve leak that I addressed when putting in new clutch. Decided to do rebuild kit since the cub is older than me even though lift appeared ok. Following rebuild the engine sounded a little labored at operational speed and a little lacking in power. Then "pop," Welch plug blew. What did I do wrong with rebuild or can you direct me.to the cause? If it ain't broke...don't TRY to fix it. Thanks in advance for any advice!

[Glen]

Hi,
The 1955 Cub operator's manual says to fill the Touch Control system the last time after removing the air, with the arms in the rear or down position. The fluid level rises in the unit as the arms go to the rear.
If you filled it with the arms ahead, it is overfilled.
When you move the arms to the down position with too much fluid in it, it might make enough pressure to blow out the plug on top of the block, that's a guess.

[Jim Becker]

Yes, what Glen said could be the story or a piece of it. However, the sounding labored and lacking power leads me to think the stops that limit movement of the control lever were not correctly adjusted. If so, the control may have been pushed beyond the proper end of movement. This could leave the system trying to push the rockshaft too far and leaving the system at high pressure with fluid flow going through the pressure control valve. This will quickly overheat the system. Higher temperature causees higher pressure in the reservoir.

[55cubster]

Thanks for your input. The fluid was filled as per manual. The lever was " midrange" and no adjustments were made to stops / linkage of rod. Any chance one of the valves could be stuck and if so which one?

[Jim Becker]

As long as the engine isn't laboring from a hydraulic load, I'd put in a new plug and forget about it. If it happens again, I would start digging deeper.

[55cubster]

Thank-you Jim for your support. Will get back to it hopefully next week. Been studying the TC manual. I have 2 questions: 1. Do you think the o-rings would be fried and need replaced? And 2. The two openings on the Control valve - should they be oriented to the outside of the unit (drivers left)? That's how I placed it. Thanks again for your help. Dave.

[Jim Becker]

I wouldn't worry about o-rings as long as they are still doing the intended job. That would be no external leaks, the lift not settling down when it is parked, and fluid isn't leaking from the pump into the engine.

I don't have the answer to the second queston. Maybe someone that has had one apart recently can answer.

[55cubster]

Thanks. I'l l keep you posted here as to how it goes when I get.back to it in the next.week or so. Dave