Is bleeding the system necessary. Got new globes at 78k, a flush, I have 126k on the vehicle now. I was think about putting the vehicle in low and just draining the HYD tank and refilling the tank with new fluid. Any recommendations on doing this?
ACH Fluid
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Putting the vehicle in Low and sucking the fluid out of the reservior will probably get less than half of the fluid in the system. If that was your only option, it would be better than nothing. The flush is really an easy job though. I recently did it myself in a little over an hour, and I am by no means Mr Fix-it. It's worth it to me spend a little extra time and know that you got all of the old fluid out, especially with a system that seems to be sensitive to fluid contamination.
To introduce new fluid into the system it's necessary to remove the old stuff, and the most effective and practical way of doing this is the conventional approach of lowering the vehicle, remove the relatively small quantity of fluid from the reservoir, fill it with the entires 2.5L can contents, raise to N and bleed off old fluid from the 5 points until new flows. The design off the system with its single port actuators (shocks) encourages fluid to stagnate at the end of each of the four hydraulic dead legs and even when you bleed each corner down to the bump stops there remains a quantity of old fluid that mixes with the new fluid. I don't see any meaningful point in just changing out the small quantity of fluid that's retained in the reservoir, and as fluid only comes in 2.5L cans I'd recommend running the whole can through to remove as much old fluid as possible in one event. I've done 4 fluid changes now and my most recent I ran a can through, drove a couple of weeks and then put the second can through to help eliminate old residual fluid. I see it as a small investment to maintain an expensive system.
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It's more important to bleed the old fluid out at the actuators than to remove fluid from the reservoir. The fluid doesn't mix much - the fluid at the top stays clean and nice, while the fluid in the shocks and spheres gets all black and murky. And do drain/bleed from Normal or Hi position, not Lo, to get more of the fluid out.
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What is the easiest way to bleed the system. Where aRe the 5 points?
I thought there were only 4 bleed points. One at each corner actuator. Where is the 5th?
5th point is the accumulator cylinder between the front and rear globes on the driver's side IIRC.
I drained and flushed my AHC system two weeks ago after just under 60K.
Started with the system in low position and drained the reservoir. Removed the reservoir and cleaned a bunch of black residue from it.
Refilled with fluid, set the AHC to high position and bled the accumulator. Set the system back to high and bled the front passenger side, went back to high and did the front drivers side, and repeated on the rear passenger and rear drivers side. By then, I had about a quarter-inch of fluid remaining.
Opened another can, filled the reservoir to the "max" line in low position.
One can will work if you don't bleed the accumulator...if you do, you'll need about a can and a half.
Steve
I'm getting ready to do second fluid change since owning. I'm also going to replace globes. Anyway when I looked through FSM, it did not say to bleed the accumulator, just the globes. Perhaps I missed it somewhere in the FSM regarding the Height Control Accumulator?
If your question is "should I also bleed off old fluid from the height accumulator, in addition to the four damping control valve assemblies?" - the answer is yes. The height control accumulator retains fluid, your objective here is to remove old fluid, any contamination suspended in that fluid and any residual air so the more old fluid you can remove the less diluted your new, replacement fluid will be, and that is a good thing.
My '01 FSM makes no reference to the accumulator...so being dumb, I did not drain it the first time ~60K ago...my bad.
You'll get more grungy fluid out of the accumulator than from the 4 globes combined...found out that's why I had to run to the dealer for another can 2 weeks ago.
Definitely do the accumulator.
My initial thought, being that the globes are at the end of the line... surely, fluid get dirty. But not the accumulator because it's in the middle of the system and fluid gets passed through constantly.
But according to two posts above. I'll do this as well.
But according to two posts above. I'll do this as well.
Wanted to vouch for the post that says accumulator should be flushed each time. Very easy to see that fluid was more dirtier coming from accumulator than the 4 globes. Note - I did the fluid change some times ago but not with the accumulator. Those 4 corners has better color to the fluid.