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Just a re-post for those wanting to know where the fluid line can be and not have leaks. Mine crosses the middle of the "X" in "MAX". I have never had leaks, but still monitoring.
As I said, I never personally changed my fluid level. The system "pushed out" fluid until it was lowered to the mid seam level. If you have no leaks at your mid X level, great, but I'm more comfortable leaving it at the seam level as long as everything still works properly.
Another factor that I'm not going to investigate is temperature affect. It's obviously warmer in my location than NC. How that affects operation is for GM to decide.
Fyi, after every drive prior to reaching this lower level, I used to hear the lift system "running" for a time after I parked and went around to the passenger side to get inside. I no longer hear it running after I park. I don't know, but with the extra air volume it may be easier to return fluid or equalize pressure. Again, something for GM to investigate. I'm very comfortable with my situation now.
^^^
Try some full throttle accelerations to ~60 mph as that will cause whatever fluid is in the upper reservoir to surge back as if parked on a ~45 degree incline!
Starting to wonder why the master cylinder isn't having the same leak issue with fluid sloshing around, ~45 degree inclines and hard stops. The master cylinder uses the exact same cap and there is very little "free space" in the master cylinder so the brake fluid is almost always in contact with the cap.
Starting to wonder why the master cylinder isn't having the same leak issue with fluid sloshing around, ~45 degree inclines and hard stops. The master cylinder uses the exact same cap and there is very little "free space" in the master cylinder so the brake fluid is almost always in contact with the cap.
I don’t think the brakes generate the large amount of air entering and leaving the reservoir that the front lift does. It’s the large amount of air being forced out of the cap when lowering the lift that is “grabbing” little droplets of fluid on the diaphragm and eventually forcing them out the slot in the cap.
Starting to wonder why the master cylinder isn't having the same leak issue with fluid sloshing around, ~45 degree inclines and hard stops. The master cylinder uses the exact same cap and there is very little "free space" in the master cylinder so the brake fluid is almost always in contact with the cap.
Very little Fluid movement in the Brake system. Doubt the CAP inner parts move very much unless the pads wear and the fluid level changes. That movement of the rubber internals may what causes Brake Fluid to leave the Lift reservoir cap?
Starting to wonder why the master cylinder isn't having the same leak issue with fluid sloshing around, ~45 degree inclines and hard stops. The master cylinder uses the exact same cap and there is very little "free space" in the master cylinder so the brake fluid is almost always in contact with the cap.
Originally Posted by 16falcon
I don’t think the brakes generate the large amount of air entering and leaving the reservoir that the front lift does. It’s the large amount of air being forced out of the cap when lowering the lift that is “grabbing” little droplets of fluid on the diaphragm and eventually forcing them out the slot in the cap.
Originally Posted by JerryU
Very little Fluid movement in the Brake system. Doubt the CAP inner parts move very much unless the pads wear and the fluid level changes. That movement of the rubber internals may what causes Brake Fluid to leave the Lift reservoir cap?
Yep, the reservoir is the wrong part for the lift application.
Since you live in Florida your results may not be representative for cars that are driven in areas with slopes. If you are accelerating while going up a slope fluid will migrate towards the cap. If the lift is lowering under these conditions fluid will be expelled.
......Even with the fluid level lowered. Think about this....... When driving in mountainous terrain, your car has the GPS set for a grade that calls for the lift to be activated. Once past that spot your car begins to lower, which it does so automatically without having to hit 24 MPH. During this lowering process, the car is still heading up a mountain and the fluid is still near the cap. There is simply no place for the fluid to go but...OUT! I've been saying this all along. Even with the fluid level lowered, the ending results are the same. The reservoir is incorrectly designed to accomodate this scenario. The cap is in the wrong location in orientation to the fluid. Folks that drive in flat areas of the country that might incur a speed bump or two may never see any leakage in comparison.
^^^ I'm in Florida and have leaked to the seam level. Location is probably irrelevant. Florida has interchanges by default have hills (elevation) and some are significantly above sea level starting from ground level. The cause of the fluid reaching the cap may be individually varied, but the results are all the same. A revisit to the design by GM is necessary to have a final satisfactory solution. Something that they should have done with the Frunk too.
Alright guys, we have beaten this to a dead horse already , and here's hopefully the final explanation of what's going on, what we can do as a "fix" for now, and what GM should have done and should follow...
Alright guys, we have beat this to a dead horse already , and here's hopefully the final explanation of what's going on, what we can do as a "fix" for now, and what GM should have done and should follow...
Great summary. GM can also move the cap to the middle of the reservoir too. Based on the illustrations you provided here, if the cap is in the middle vs at one end, there would be less chance of pushing the fluid out of the cap.
Great summary. GM can also move the cap to the middle of the reservoir too. Based on the illustrations you provided here, if the cap is in the middle vs at one end, there would be less chance of pushing the fluid out of the cap.
Yes, thought about that too after uploaded the image, and made the edit and update the post. But you beat me to the punch!
Alright guys, we have beaten this to a dead horse already , and here's hopefully the final explanation of what's going on, what we can do as a "fix" for now, and what GM should have done and should follow...
GM also needs to address the volume of fluid being displaced when lift is used. Right now, the cap diaphragm is unable to fully compensate for the volume used so air is sucked through the slit to compensate when the front is raised and then the air (and fluid if it is there) is expelled when the front is lowered. This "breathing" of oxygen and moisture will degrade the fluid over time and possibly cause the lift components to corrode internally. I don't see a practical way to compensate for the fluid displacement with the current size of the cap. The cap needs to be much larger with a corresponding increase in diaphragm size or some other type of bladder large enough to compensate for the fluid displacement.
GM also needs to address the volume of fluid being displaced when lift is used. Right now, the cap diaphragm is unable to fully compensate for the volume used so air is sucked through the slit to compensate when the front is raised and then the air (and fluid if it is there) is expelled when the front is lowered. This "breathing" of oxygen and moisture will degrade the fluid over time and possibly cause the lift components to corrode internally. I don't see a practical way to compensate for the fluid displacement with the current size of the cap. The cap needs to be much larger with a corresponding increase in diaphragm size or some other type of bladder large enough to compensate for the fluid displacement.
That's a great point, Sterling! Yes, agreed, they need to take care that, in addition to avoid getting the fluid level close to the bottom of the cap in all driving and incline conditions.
Alright guys, we have beaten this to a dead horse already , and here's hopefully the final explanation of what's going on, what we can do as a "fix" for now, and what GM should have done and should follow...
Great graphic. Just a reminder, accelerating rapidly on a flat surface is like tilting the reservoir at ~45 degrees for ~2 seconds.
That low max fluid level is fine IF it is enough fluid to have the Lift Operate. Since I am in the process of defining the Royalty owed for 2020 sales by a major welding equipment company who license one of my MIG Shielding Gas Saver patents, that product uses a short section of large diameter hose to replace the normal smaller ID hose to hold more volume (in that case Argon based gas.)
So to assure there is enough fluid in the Lift system, GM could replace the hose leading to the reservoir from what looks like 1/4 inch ID to 1/2 inch ID. That will hold 4 times the fluid volume and could compensate for the lower reservoir volume!
Would the change in hose size affect the operating pressure in any way - lowering it? As we (I) have no idea of the actual design/operating specifications of the system aside from lowering to prevent leaks, everything we are doing is second guessing until GM does an engineering look at the system. The least they could do is acknowledge the problem and at least say that they are working on a solution. I'll stay comfortable with my lowered fluid level and sweatband for now. Time for driving.
01-29-2021, 10:27 AM
......Even with the fluid level lowered. Think about this....... When driving in mountainous terrain, your car has the GPS set for a grade that calls for the lift to be activated. Once past that spot your car begins to lower, which it does so automatically without having to hit 24 MPH. During this lowering process, the car is still heading up a mountain and the fluid is still near the cap. There is simply no place for the fluid to go but...OUT! I've been saying this all along. Even with the fluid level lowered, the ending results are the same. The reservoir is incorrectly designed to accomodate this scenario. The cap is in the wrong location in orientation to the fluid. Folks that drive in flat areas of the country that might incur a speed bump or two may never see any leakage in comparison.
, and here's hopefully the final explanation of what's going on, what we can do as a "fix" for now, and what GM should have done and should follow...
