I have a slow hydraulic pressure buildup issue on my 1961 JD 3010 diesel that seems to be temperature related. Below are the symptoms, steps I have planned, and questions I have. What am I missing? Thanks in advance for your suggestions.
Problem & Symptoms:
I've noticed it taking longer to build up power steering, brake pedal, and rocker shaft pressure after startup. The problem is worse when the tractor is cold (29 minutes), but still exists even if it's warm (4-5 minutes). This issue is not intermittent, and the timeframes seem to increase since I bought the tractor three years ago.
This spring I decided to time how long it took to get pressure after firing it up (from sitting all winter) vs. when warm.
Cold Start test:
- Prior to start I confirmed hydraulic fluid reads full, cutch depressed in, foot on brakes (no pressure yet), throttle stick set at idle.
- Fired right up after what sounded like 3 to 4 revolutions (gotta love these old tractors)
- maintained throttle at 600-650 RPM idle for remainder of test
- Kept clutch in the entire time, SM-2038 states transmission pump works when clutch is engaged.
- no pressure buildup behind brake pedals or steering.
- at 14 minutes, felt a "flutter" of pressure building up in the brakes where it built up pressure behind the pedal then it slowly dissipated, then back to hard pedal, no pressure. Still nothing felt in steering at this time.
- engine temp starting to warm, barely moving needle on gauge.
- at 16, 18, 24 minutes, another brake pedal "flutter" episode, still no steering.
- engine almost at temp, needle reading between 1/3 to 1/2.
- at 29 minutes, pressure finally came to brakes, steering, and rocker shaft out of no where like a switch was flipped on.
- at 35 minutes, engine at normal operating temp, needle in middle of gauge.
Warm Start test:
Same steps and symptoms as above, was between 4-5 minutes when reliable pressure came on for all three brakes, steering, and rocker shafts.
Things I'm going to try next, in order:
1. Drain hydraulic fluid
2. Replace main hydraulic filter (transmission)
3. Inspect hydraulic Pickup Screen
4. Inspect oil filter surge pressure relief valve
5. Refill hydraulic fluid
6. Re-test how long it takes to build pressure.
I can't overlook the fact that the symptoms seem related more to the temperature of the hydraulic fluid than they do anything else. The observation that all three components receive pressure at the same time is also interesting (suggests issue is earlier up stream of the PCV).
Questions:
I'm assuming the above steps are not going to resolve it (but will update here soon), and I'll be looking at what other components could be contributing to this. From what I can tell, there's really only four options:
- [b:b11d39a7ff]Surge Pressure Relief Valve[/b:b11d39a7ff] SM-2038 says this exists only on 3010's below SN 1T28972 (which mine is) "[i:b11d39a7ff]located between the check valve and filter to relieve momentary surges of return oil, thus providing a protective measure for the oil cooler. It opens between 90 and 130 PSI allowing oil to return directly to the transmission case.[/i:b11d39a7ff]" I wonder if mine is intermittently sticking open until it's hot then it's closing letting fluid up to the front/main pump. Anyone know why JD stopped using these? Can they just be omitted or replaced?
- [b:b11d39a7ff]Pressure Control Valve[/b:b11d39a7ff] Same concern here about temp. Could it begin to stick until fluid is "hot"? SM-2038 states "[i:b11d39a7ff]the steering valve and brakes have priority over all the other functions should there be a drop in pressure[/i:b11d39a7ff]" My symptoms suggest I have low pressure at the the PCV until up to temp. Shouldn't it be high pressure even when cold?
- [b:b11d39a7ff]main pump filter screen[/b:b11d39a7ff] (the little screen filter, inside the pump)?
- [b:b11d39a7ff]transmission pump check valve[/b:b11d39a7ff] Wondering if this can stick or be intermittent due to temp, or do they just work/not work?
Anything else I should consider?
Lastly, anyone had luck installing modern pressure gauge clusters on both the low and high sides of the system? Not a test kit, but the glycerine filled gauges so it can be monitored while in operation? Bad idea? Love older tractors, just not their gauges.
Thanks in advance,
Ryan
Problem & Symptoms:
I've noticed it taking longer to build up power steering, brake pedal, and rocker shaft pressure after startup. The problem is worse when the tractor is cold (29 minutes), but still exists even if it's warm (4-5 minutes). This issue is not intermittent, and the timeframes seem to increase since I bought the tractor three years ago.
This spring I decided to time how long it took to get pressure after firing it up (from sitting all winter) vs. when warm.
Cold Start test:
- Prior to start I confirmed hydraulic fluid reads full, cutch depressed in, foot on brakes (no pressure yet), throttle stick set at idle.
- Fired right up after what sounded like 3 to 4 revolutions (gotta love these old tractors)
- maintained throttle at 600-650 RPM idle for remainder of test
- Kept clutch in the entire time, SM-2038 states transmission pump works when clutch is engaged.
- no pressure buildup behind brake pedals or steering.
- at 14 minutes, felt a "flutter" of pressure building up in the brakes where it built up pressure behind the pedal then it slowly dissipated, then back to hard pedal, no pressure. Still nothing felt in steering at this time.
- engine temp starting to warm, barely moving needle on gauge.
- at 16, 18, 24 minutes, another brake pedal "flutter" episode, still no steering.
- engine almost at temp, needle reading between 1/3 to 1/2.
- at 29 minutes, pressure finally came to brakes, steering, and rocker shaft out of no where like a switch was flipped on.
- at 35 minutes, engine at normal operating temp, needle in middle of gauge.
Warm Start test:
Same steps and symptoms as above, was between 4-5 minutes when reliable pressure came on for all three brakes, steering, and rocker shafts.
Things I'm going to try next, in order:
1. Drain hydraulic fluid
2. Replace main hydraulic filter (transmission)
3. Inspect hydraulic Pickup Screen
4. Inspect oil filter surge pressure relief valve
5. Refill hydraulic fluid
6. Re-test how long it takes to build pressure.
I can't overlook the fact that the symptoms seem related more to the temperature of the hydraulic fluid than they do anything else. The observation that all three components receive pressure at the same time is also interesting (suggests issue is earlier up stream of the PCV).
Questions:
I'm assuming the above steps are not going to resolve it (but will update here soon), and I'll be looking at what other components could be contributing to this. From what I can tell, there's really only four options:
- [b:b11d39a7ff]Surge Pressure Relief Valve[/b:b11d39a7ff] SM-2038 says this exists only on 3010's below SN 1T28972 (which mine is) "[i:b11d39a7ff]located between the check valve and filter to relieve momentary surges of return oil, thus providing a protective measure for the oil cooler. It opens between 90 and 130 PSI allowing oil to return directly to the transmission case.[/i:b11d39a7ff]" I wonder if mine is intermittently sticking open until it's hot then it's closing letting fluid up to the front/main pump. Anyone know why JD stopped using these? Can they just be omitted or replaced?
- [b:b11d39a7ff]Pressure Control Valve[/b:b11d39a7ff] Same concern here about temp. Could it begin to stick until fluid is "hot"? SM-2038 states "[i:b11d39a7ff]the steering valve and brakes have priority over all the other functions should there be a drop in pressure[/i:b11d39a7ff]" My symptoms suggest I have low pressure at the the PCV until up to temp. Shouldn't it be high pressure even when cold?
- [b:b11d39a7ff]main pump filter screen[/b:b11d39a7ff] (the little screen filter, inside the pump)?
- [b:b11d39a7ff]transmission pump check valve[/b:b11d39a7ff] Wondering if this can stick or be intermittent due to temp, or do they just work/not work?
Anything else I should consider?
Lastly, anyone had luck installing modern pressure gauge clusters on both the low and high sides of the system? Not a test kit, but the glycerine filled gauges so it can be monitored while in operation? Bad idea? Love older tractors, just not their gauges.
Thanks in advance,
Ryan
