Tram Issue on 1845

[MikeOConnor]

The "pressure on the brake tender will vary quite a bit" thing has me interested. First off, I'm struck by how absolutely steady your pressure is. Mine has always varied, depending on what I'm doing (steering, lifting, turning on PTO, whatever). And a couple hundred PSI (up to 1700) happens all the time on mine. Heck, if I want to, I can run that pressure up to 2500 PSI just by going to full-lock on the steering. Does yours tend to stay absolutely pegged at 1500 PSI the way it mostly was in the video? That's in the "really interesting, but not necessarily helpful" department.

The second interesting thing is that the pressure appears to jump up *after* you've gone through the surge and then drops back to 1500 PSI over the next few seconds. That kind of variation (both the increase to 1700 and the gentle drop back to 1500) is normal behavior on my 1850 (which has hydraulics rather than cables, so your mileage may vary). If I were guessing, I'd think that the pressure-change is coming from something else, and the brake-tender behavior is the charging-valve/accumulator doing it's thing and bringing pressure back down to normal.

That surge is pretty spectacular. I loved your swivel theory. Your forehead-based test-instrument looked painful.

 

[ponytug]

Marrt,

Did you run the surge by Terry? It sounds to me like a charging valve/accumulator issue. Does this happen when you have the engine at mid to high rpm?

All the best,

Peter

So close. I put the tractor on blocks and disconnected the tram cable. I found Power Trac had attached the 1/4 inch swivel for the cable through a 3/8 inch hole on the pump. And, the swivel was not very tight so I assumed it would slip from time to time. Further, when I would tram the pump by hand, everything was smooth (with the wheels in the air though). I was SO sure I'd found the problem. I fixed the issue with the swivel and reassembled everything and...it didn't make any difference at all. Rats.

However, I did notice something. The pressure on the brake tender will vary quite a bit. When the pressure is 1500 or below, I'll get the "surge." When the pressure is 1700, no surge. You can see this clearly in the third video above. After the initial surge, I can stop and go smoothly if the pressure is 1700 or so. Not sure what is causing this pressure variation but I think this is the root cause of my problem.

 

[marrt]

Did you run the surge by Terry?

I did but haven't had a chance to check his recommendation yet. Terry says to take a look at the shuttle valve. Fortunately, Sedgewood still has some excellent pictures up. I'll try to get to it this weekend.

Tom