What to use as a pressure gauge?

A

AdelphiJim

New member
2017 RTV X1100... when the trouble shooting guide says to "check charge pressure", can I simply use the compression testing instrument I use for checking my pickup truck's cylinders? It comes with a few different adapters.
 
Yes I have. It is fine. Thanks for asking.
Looks like I need to check the charge pressure but I want to know if I require a special tool and if so, what is it and where to obtain it?
 
I just went through checking the charge pressure, the traveling side limit pressure, and the braking limit pressure. Charge pressure is checked with a low scale (I used a 200 psi hydraulic test guage) and G1/4 test adapter. Adjustment is made by removing the tamper proof cap just to the right of the test port.

The limit pressures are both on top of the HST and have G3/8 ports. I used G3/8 adapter and 4000 psi guage for those. Those can be adjusted but you need to remove the check valves. Instructions for that procedure are in the WSM.

Guages, test adatper fitting, and test hoses can be found on Amazon.
 
Great info. You should make a detailed post for the sticky section with the test port identification thread size adapters and adjustment procedures. Please
 
aurthuritis said:
Amazon has a test kit for 160 dollars.
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Awesome. I looked and saw a bunch. Any chance you can provide a link to the one you recommend? I am in the dark here, the machine is down, and I don't want to order the wrong thing.
I really appreciate everyone's contributions!
 
Island Runner said:
Guages, test adatper fitting, and test hoses can be found on Amazon.
Click to expand...
Thank you for your input. If I could trouble you for links, I would really appreciate it. This is not my area of expertise. I can rip a SBC down with my eyes closed but I am just getting into hydraulics.
 
For a quick procedural rundown on checking and adjusting charge pressure from memory, here we go.

1. Get the HST up to operating temp by driving around. HST fluid temp should be 113 to 131 degrees give or take.
2. Remove any guards or aftermarket armor pieces from the rear of the HST so you can access the plug on the lower rear of the HST.
3. Remove the plug and screw in your G1/4 test adapter and attach guage and hose.
4. Start engine and set idle to 1400 rpm.
5. WSM states charge pressure to be between 63 and 120 PSI.
6. Remove tamper proof cap on the lower right side of the HST near the test port.
7. Loosen lock nut and turn screw in for more pressure, out for less pressure. More pressure = more aggressive feel. I went with 115 psi. By the way, my machine was set at 76 psi from dealer.
 
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That is very helpful, thank you so much! Often manuals indicate what to do, but not under what circumstances or why.
Here is a link to the test kit I purchased (in Canada). The link you sent unfortunately would not deliver here, but they seem to be the same kits, just under a different name. It should be here Wednesday (fingers crossed).

YFIXTOOL Hydraulic Pressure Test Kit with 5 Gauges, 5 Test Hoses and 13 Couplings and 14 Tee Connectors Hydraulic Test Gauge Kit Pressure Gauge Used for Excavators : Amazon.ca: Industrial & Scientific

YFIXTOOL Hydraulic Pressure Test Kit with 5 Gauges, 5 Test Hoses and 13 Couplings and 14 Tee Connectors Hydraulic Test Gauge Kit Pressure Gauge Used for Excavators : Amazon.ca: Industrial & Scientific
www.amazon.ca
 
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Island Runner said:
For a quick procedural rundown on checking and adjusting charge pressure from memory, here we go.

1. Get the HST up to operating temp by driving around. HST fluid temp should be 113 to 131 degrees give or take.
2. Remove any guards or aftermarket armor pieces from the rear of the HST so you can access the plug on the lower rear of the HST.
3. Remove the plug and screw in your G1/4 test adapter and attach guage and hose.
4. Start engine and set idle to 1400 rpm.
5. WSM states charge pressure to be between 63 and 120 PSI.
6. Remove tamper proof cap on the lower right side of the HST near the test port.
7. Loosen lock nut and turn screw in for more pressure, out for less pressure. More pressure = more aggressive feel. I went with 115 psi. By the way, my machine was set at 76 psi from dealer.
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Does adjusting the charge pressure by itself affect the power of the machine, or must other adjustments be done with that?
 
Charge pressure increase will definitely put more power to the ground and give the HST a more agressive feel. I ended up at 135 PSI for my charge pressure but I have my low idle set at 1550 RPM. WSM states that charge pressure be checked at 1400 RPM. I found when adjusting mine, for every 100 RPM increase in idle the charge pressure increased 5 PSI. I used my hand throttle to dial up RPM in 100 RPM increments and the 5 PSI increase in charge pressure stayed true from 1550 to over 3600 RPM. At 135 PSI charge pressure at 1550 RPM my machine felt way way better. I feel I could go more as nothing ever seemed to bog the engine down. Maybe because I have a turbo? But make sure all your linkages are in time and get your servo piston neutral. I bought an extra G1/4 and G3/8 fitting so I could hook up guages to all 3 ports at once and was helpful.
 
Island Runner said:
Charge pressure increase will definitely put more power to the ground and give the HST a more agressive feel. I ended up at 135 PSI for my charge pressure but I have my low idle set at 1550 RPM. WSM states that charge pressure be checked at 1400 RPM. I found when adjusting mine, for every 100 RPM increase in idle the charge pressure increased 5 PSI. I used my hand throttle to dial up RPM in 100 RPM increments and the 5 PSI increase in charge pressure stayed true from 1550 to over 3600 RPM. At 135 PSI charge pressure at 1550 RPM my machine felt way way better. I feel I could go more as nothing ever seemed to bog the engine down. Maybe because I have a turbo? But make sure all your linkages are in time and get your servo piston neutral. I bought an extra G1/4 and G3/8 fitting so I could hook up guages to all 3 ports at once and was helpful.
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So you are not worrying about damage to the transmission by being over the 120 at 1400 rpm? Increasing 5psi per 100 RPM would put you at 127.5 psi at 1550 rpm. Being slightly chicken, I was going to stay down around 110 psi at the 1400 rpm
 
I'm not worried on charge pressure as much as the high pressure relief which I adjusted to 4100+/- PSI. I think the more charge pressure the more you will bog the engine as you load the HST to the point of too much charge pressure you can actually stall the engine under load. I haven't even came close to this even with a bed piled high of firewood pulling my woodsplitter and driving up steep dam walls in my wetlands. I would advise to test your current charge pressure, adjust it, and test it out. If you get the results you want leave it alone. If not adjust charge pressure higher and test again. Maybe my turbo helps with the bogging down of the engine under heavy HST load as I feel I could easily go 140 - 150 PSI at 1550 RPM but I think you will notice when you get the charge pressure too high.
 
All of this has been tried before. Look in the sticky section and use the search function and read everything from adams repairs. He experiment on charge pressure and hst high side pressures and found the limit will be a cracked broken case so be careful. I don't remember the exact numbers but i think you are in danger at 4100 lbs. Extra charge pressure just pre charges the fill speed and internal pressures of the rotating valve block and allows the hst to build more high side. Your turbo is making more hp and that helps also. For the common man adjusting the low idle rpm for smooth non shake and 3800 high idle loaded along with adjusting the linkages to spec will get about all there is out of a stock unmodified rtv. As climate change progress ktc derated these machines quite a bit so there's alot of room to adjust the smoke screw also.
 
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