AHC very low, will off button keep pump from running? (1 Viewer)

[2001LC]

I've run low on AHC fluid while flushing. So low, it may suck air if pump runs anymore, may have already. I'm out of AHC fluid and can't get for a day or two. I need to move the truck, which means starting.

If I press the AHC off button, will it keep AHC pump from running?

 

[Spike555]

Is the pump electric or belt driven?
If electric unplug it.
I do not know the answer to your question, just throwing something out there that might help.

 

[PADDO]

Height OFF switch will prohibit returning back to N as long as you stay under 30kmh - but if your system is in a transition somewhere between L and N - which by the sounds of it it is - then I'd just unplug the pump to make sure it doesn't run while you move it or just pull the 50A fuse in the main box.

Can I send you a copy of the "can't F it up" bleed process?

 

[2001LC]

Thanks guy's. I do have a copy "bleed process", thanks.

I just did one system (on 07) using less than 3 qts, getting all clear red fluid.

But on this system (with one leaky shock) I've got some air bubbles and nasty looking fluid coming out. Still on DS with accumulator (x3 times) and front glob done (twice). While on DS rear glob after bleeding, I ran out of fresh fluid as I only had 2 1/2 qts in shop. When I started it drew down reservoir more than I thought it would. Off light didn't come on nor did system go into low, but I'm very low (bottom at best)

Just in case I got/get air in system, would you please give me procedure for bleeding off air with dry reservoir? Sooner or later I'll need it!

Accumulator didn't yield much fluid first bleed.

Dumped above jar of old AHC fliud and did accumulator again:

Third time I got clear.

 

[PADDO]

That original fluid is nasty. I sense you're not doing the: "engine off; empty then fill reservoir with fresh; bleed height accumulator + front and rear ccts down to the bump stops/fluid flow stops; then start vehicle to recharge and raise from below L to N" process?

 

[2001LC]

I did stop engine, run down to stops/fluid stop, top then start engine, repeat.

It was just on last bleed (a little to see clear on front PS globe, then rear PS globe) when I had run out of new fresh fluid to pour in. So when I started (without topping) to move out of garage until I can pick-up fresh fluid from Dealer (closed today for holiday), it dew very low (can't see level). I turned off engine, not sure if it's fully in N or not.

I'll pull fuse, so I can move it out of garage.

I saw in my copy of the "flush procedure" warning not to run dry as special bleed procedure may be required.
So @PADDO will you please link me to or post here the air bleed procedure when pump dry and will not draw?

I'm guessing I'll need extra fluid, If pump doesn't draw when I top & start engine again. If so I'd like to be prepared with procedure and extra fluid. For some reason each Dealers is only stocking two of the new 1qts bottle's. So if I'll need to run around and find more bottles if extra is needed for air bleed procedure.

 

[2001LC]

That original fluid is nasty. ***

Notice too the small amount of fluid that came out of accumulator on first bleed to stop (first pic). Would the system being full of air explain this?

 

[flintknapper]

Thanks guy's. I do have a copy "bleed process", thanks.

I just did one system (on 07) using less than 3 qts, getting all clear red fluid.

But on this system (with one leaky shock) I've got some air bubbles and nasty looking fluid coming out. Still on DS with accumulator (x3 times) and front glob done (twice). While on DS rear glob after bleeding, I ran out of fresh fluid as I only had 2 1/2 qts in shop. When I started it drew down reservoir more than I thought it would. Off light didn't come on nor did system go into low, but I'm very low (bottom at best)

Just in case I got/get air in system, would you please give me procedure for bleeding off air with dry reservoir? Sooner or later I'll need it!

Accumulator didn't yield much fluid first bleed.

Third time I got clear.

Maybe its just the photo, but compared to what mine looked like when I did my flush, I'd say you are nowhere near "Clear" yet.

Less nasty, but not clear.

 

[looking4lc]

If I were you, I would do a complete flush until I see no bubble in tube and sparkle red.
Last time I did a flush, had some air with black fluid. I am taking @PADDO suggestion and flush it every 30k

 

[PADDO]

Notice too the small amount of fluid that came out of accumulator on first bleed to stop (first pic). Would the system being full of air explain this?

Bulk air is possible but unlikely as it's forced into solution at that pressure - when you bleed you would have a huge amount of foam. More likely you started your bleeding without the height accumulator charged, which can take up to 30 seconds after a raise cycle. Here's the procedure to force the pump to run, shouldn't operate it in this mode for more than 10 seconds or so according to the fsm. Either raising the front or rear will do. This can also be done from DLC3 but DLC1 is easier to access.

 

[2001LC]

Maybe its just the photo, but compared to what mine looked like when I did my flush, I'd say you are nowhere near "Clear" yet.

Less nasty, but not clear.

Some milky fluid came out of bleeder tube at first, then clear red, so jar has a mix ~20/80.

If I were you, I would do a complete flush until I see no bubble in tube and sparkle red.
Last time I did a flush, had some air with black fluid. I am taking @PADDO suggestion and flush it every 30k

View attachment 1468955

30K miles seems like a good interval between flushes.

@PADDO I'm wonder if time interval, say 3 yr would be advisable also?

Bulk air is possible but unlikely as it's forced into solution at that pressure - when you bleed you would have a huge amount of foam. More likely you started your bleeding without the height accumulator charged, which can take up to 30 seconds after a raise cycle. Here's the procedure to force the pump to run, shouldn't operate it in this mode for more than 10 seconds or so according to the fsm. Either raising the front or rear will do. This can also be done from DLC3 but DLC1 is easier to access.

View attachment 1469378

Very possible, although I did wait until I heard the sound of filling stop.
Thanks @PADDO, hope I'll not need, I'll known later today if Dealer(s) has some bottles in stock.

BTW: I pulled the fuse then started, indicated N. Later started to pull back in garage, indicated L.

 

[2001LC]

Pick-up the only 2 liters of suspension fluid my local Toyota parts Dealer had.

Looks like pulling the fuse/disconnecting pump wire saved my bacon. I topped the reservoir and just proceeded with flushing, pump worked without the need to jump DLC1 Or DLC3. I did notice it drop to L while setting out for the night, while I made use of garage to help my son.

I'll probable flush again soon, but for now this along with adjust pressure should help me find if a leaky front shock needs replacing or not.

Thanks everyone for your help!

 

[geanes]

Height OFF switch will prohibit returning back to N as long as you stay under 30kmh - but if your system is in a transition somewhere between L and N - which by the sounds of it it is - then I'd just unplug the pump to make sure it doesn't run while you move it or just pull the 50A fuse in the main box.

Can I send you a copy of the "can't F it up" bleed process?

@PADDO ... you can send me a copy About to do this on Saturday

 

[PADDO]

@2001LC and @geanes Try this.

Here's a quick, easy and efficient 1 can (or 3 bottle) AHC fluid exchange/bleed procedure. By following this process you are very unlikely to get yourself into trouble by accidentally bleeding too much fluid. Furthermore, it's not at all wasteful of new fluid as you remove a considerable amount of the old fluid/gas/air and recharge the whole system with fresh fluid in just one cycle. No wasteful start/stop/bleed/start/stop...... process.

The benefits of periodically changing out the AHC/AVS systems' fluid can't be overstated as this mineral based working oil degrades with time, temperature and use. Fluid viscosity changes, anti wear, anti rust, anti foaming, anti oxidation additives deplete and the fluid picks up particulate and other contamination. Nitrogen from the accumulators permeates into the system over time and virtually all hydraulic systems will allow air to come out of fluid solution and form bubbles with use and time. The combination of degrading fluid and entrained gases affects damping performance and ultimately can't promote the maximum service life of the system. FWIW I change out the systems fluid at half the recommended service interval, or about 30k miles/3 years.

Materials required. One can of fluid (Toyota suspension fluid, AHC 08886-01805) or three of the new 1L bottles, clear pvc pipe that's a snug fit (3/16 ID) on the bleeders, 10mm spanner/box wrench/crows foot and a suitable waste fluid container.

This process assumes the fluid level in the reservoir is between max and min when the vehicle is at Normal height before commencing. Clean around the reservoir cap and the spout of the AHC fluid can before opening and avoid introducing any contamination into the reservoir.
This maintenance activity needs to be done with the vehicle on flatish, level ground and not on a lift or with the wheels off the ground as you need the vehicle's weight to compress the shock actuators down to the bump stops to remove the maximum amount of old fluid:

1. Lower the vehicle to LOW and wait 30 seconds for the AHC system to settle and then turn the vehicle OFF, do not restart the engine until step 8. The fluid in the reservoir will now be at its highest level. Using a turkey baster or similar suction device remove as much of this old fluid as practical from the reservoir. The amount removed should equal, or be slightly over, 1 liter [if you were between Max and Min at N].
2. Pour the the entire contents of a 2.5 liter can [or 2 1/2 x 1 liter bottles] of new fluid into the emptied reservoir. It will be very close to completely full.
3. Now we know that the reservoir's "normal" contents is ~ 1 liter (vehicle in L when fluid level is correct at N) and you have just filled it with 2.5 liters so you don't want to drain/bleed more than 1.5 liters or else you may end up with insufficient fluid on completion.
4. Starting at the height accumulator (12 inch long cylinder on DS outer frame rail, between front and rear damper assemblies) connect your drain tube, crack the bleeder and commence draining fluid, closing the bleeder as fluid flow stops. You should drain ~0.3 liters.
5. Move to the front LH damper assembly, connect tube, crack the bleeder and drain until the front has dropped down to the bump stops. Both sides of the vehicle will lower together (because they are hydraulically connected) and you should drain ~0.4 liters. Again close the bleeder as fluid flow stops.
6. Move to the rear LH damper assembly, connect tube, crack the bleeder and drain until the rear is close to/on the bump stops. Both sides will lower like the front did and you should drain ~0.3 liters. Again close the bleeder as fluid flow stops.
7. Now you should have drained very close to 1 liter (0.3+0.4+0.3 for healthy damper accumulator spheres; if you have degraded or blown spheres then you'll likely drain less fluid as there's limited/no nitrogen charge to expel the spheres fluid contents) leaving you about 0.5 liters "excess" in the reservoir.
8. Start the vehicle, let it idle for 30-60 seconds and then press the UP button to raise to NORMAL height. The whole system will refill and recharge with new fluid from the reservoir and the level in the reservoir will be drawn down to slightly over the max line if everything has gone as expected.
9. Turn the vehicle OFF and do a small, quick bleed on the PS front and rear damper assemblies just to check that there isn't any gas trapped. You don't need to remove very much at all from the PS as essentially all available fluid (there will always be a small residual in each shock actuator/damper that we can't access) is forced out when you do the DS dropping the vehicle down to the bump stops.
10. You're done, confirm that the reservoir fluid level is correct - between max and min at N height with the engine running. There is nothing wrong with leaving the level slightly over the max line.

As long as you don't drain more than 1.5 liters you can't mess up and accidentally draw air into the pump/system through the reservoir or be left short of fluid.

This approach is simpler than others, but slightly more elaborate than the FSM. It is intended to remove as much old fluid as practical in a quick and efficient manner. It doesn't waste new, fresh fluid like the drain/start/stop/drain/start etc method. Hopefully this method fills an information gap by associating approximate quantities drained to the height accumulator and the front/rear hydraulic circuits and gives people the confidence to undertake this simple yet critically important maintenance procedure.

 

[2001LC]

Thanks a million.

 

[Raptor555]

@PADDO Thank you for the clear instructions. Most helpful.

 

[Dannyboy lx470]

Bleeding is on all 4 globes right and height accummulator correct.

 

[stratus]

@2001LC and @geanes Try this.

Here's a quick, easy and efficient 1 can (or 3 bottle) AHC fluid exchange/bleed procedure. By following this process you are very unlikely to get yourself into trouble by accidentally bleeding too much fluid. Furthermore, it's not at all wasteful of new fluid as you remove a considerable amount of the old fluid/gas/air and recharge the whole system with fresh fluid in just one cycle. No wasteful start/stop/bleed/start/stop...... process.

The benefits of periodically changing out the AHC/AVS systems' fluid can't be overstated as this mineral based working oil degrades with time, temperature and use. Fluid viscosity changes, anti wear, anti rust, anti foaming, anti oxidation additives deplete and the fluid picks up particulate and other contamination. Nitrogen from the accumulators permeates into the system over time and virtually all hydraulic systems will allow air to come out of fluid solution and form bubbles with use and time. The combination of degrading fluid and entrained gases affects damping performance and ultimately can't promote the maximum service life of the system. FWIW I change out the systems fluid at half the recommended service interval, or about 30k miles/3 years.

Materials required. One can of fluid (Toyota suspension fluid, AHC 08886-01805) or three of the new 1L bottles, clear pvc pipe that's a snug fit (3/16 ID) on the bleeders, 10mm spanner/box wrench/crows foot and a suitable waste fluid container.

This process assumes the fluid level in the reservoir is between max and min when the vehicle is at Normal height before commencing. Clean around the reservoir cap and the spout of the AHC fluid can before opening and avoid introducing any contamination into the reservoir.
This maintenance activity needs to be done with the vehicle on flatish, level ground and not on a lift or with the wheels off the ground as you need the vehicle's weight to compress the shock actuators down to the bump stops to remove the maximum amount of old fluid:

1. Lower the vehicle to LOW and wait 30 seconds for the AHC system to settle and then turn the vehicle OFF, do not restart the engine until step 8. The fluid in the reservoir will now be at its highest level. Using a turkey baster or similar suction device remove as much of this old fluid as practical from the reservoir. The amount removed should equal, or be slightly over, 1 liter [if you were between Max and Min at N].
2. Pour the the entire contents of a 2.5 liter can [or 2 1/2 x 1 liter bottles] of new fluid into the emptied reservoir. It will be very close to completely full.
3. Now we know that the reservoir's "normal" contents is ~ 1 liter (vehicle in L when fluid level is correct at N) and you have just filled it with 2.5 liters so you don't want to drain/bleed more than 1.5 liters or else you may end up with insufficient fluid on completion.
4. Starting at the height accumulator (12 inch long cylinder on DS outer frame rail, between front and rear damper assemblies) connect your drain tube, crack the bleeder and commence draining fluid, closing the bleeder as fluid flow stops. You should drain ~0.3 liters.
5. Move to the front LH damper assembly, connect tube, crack the bleeder and drain until the front has dropped down to the bump stops. Both sides of the vehicle will lower together (because they are hydraulically connected) and you should drain ~0.4 liters. Again close the bleeder as fluid flow stops.
6. Move to the rear LH damper assembly, connect tube, crack the bleeder and drain until the rear is close to/on the bump stops. Both sides will lower like the front did and you should drain ~0.3 liters. Again close the bleeder as fluid flow stops.
7. Now you should have drained very close to 1 liter (0.3+0.4+0.3 for healthy damper accumulator spheres; if you have degraded or blown spheres then you'll likely drain less fluid as there's limited/no nitrogen charge to expel the spheres fluid contents) leaving you about 0.5 liters "excess" in the reservoir.
8. Start the vehicle, let it idle for 30-60 seconds and then press the UP button to raise to NORMAL height. The whole system will refill and recharge with new fluid from the reservoir and the level in the reservoir will be drawn down to slightly over the max line if everything has gone as expected.
9. Turn the vehicle OFF and do a small, quick bleed on the PS front and rear damper assemblies just to check that there isn't any gas trapped. You don't need to remove very much at all from the PS as essentially all available fluid (there will always be a small residual in each shock actuator/damper that we can't access) is forced out when you do the DS dropping the vehicle down to the bump stops.
10. You're done, confirm that the reservoir fluid level is correct - between max and min at N height with the engine running. There is nothing wrong with leaving the level slightly over the max line.

As long as you don't drain more than 1.5 liters you can't mess up and accidentally draw air into the pump/system through the reservoir or be left short of fluid.

This approach is simpler than others, but slightly more elaborate than the FSM. It is intended to remove as much old fluid as practical in a quick and efficient manner. It doesn't waste new, fresh fluid like the drain/start/stop/drain/start etc method. Hopefully this method fills an information gap by associating approximate quantities drained to the height accumulator and the front/rear hydraulic circuits and gives people the confidence to undertake this simple yet critically important maintenance procedure.

Thank you very much for these clear and easy to follow instructions!

I started it today, but stopped as I ran into a problem and thought I better ask before make a (expensive or irreparable) mistake.

I noticed that my suspension level is lower then Min when in Normal position. Ok, I thought, I am putting new fluid anyway, so might as well continue following instructions. So I put the car in Low, the level reached Max. But I measured the height from pavement to fender at "through axis" point, and I have some discrepancies here:
FD(L) - 79cm
FP(R) - 81cm
RD(L) - 84cm
RP(R) - 85.5cm

I thought I would go on even with these measurements, but I have received (today!) my diag cable from China.

So my question is (finally) - should I go ahead and change the fluid or setup the diag software, read the car first and only after that change the fluid if all the checks are OK? I have no idea on how to do this, but there was a thread somewhere here about that, so I hope I will be able to do this. It will take some time

P.S. Between High and Low I counted 9 lines of fluid. Sometimes the car drives nice, sometimes it drives like there no amortization at all and the car "feels" every crack in the asphalt. It is a 2002 European car, but new to me and the PO has no idea when suspension fluid was last changed.

Many thanks!

 

[stratus]

Thank you very much for these clear and easy to follow instructions!

I started it today, but stopped as I ran into a problem and thought I better ask before make a (expensive or irreparable) mistake.

I noticed that my suspension level is lower then Min when in Normal position. Ok, I thought, I am putting new fluid anyway, so might as well continue following instructions. So I put the car in Low, the level reached Max. But I measured the height from pavement to fender at "through axis" point, and I have some discrepancies here:
FD(L) - 79cm
FP(R) - 81cm
RD(L) - 84cm
RP(R) - 85.5cm

I thought I would go on even with these measurements, but I have received (today!) my diag cable from China.

So my question is (finally) - should I go ahead and change the fluid or setup the diag software, read the car first and only after that change the fluid if all the checks are OK? I have no idea on how to do this, but there was a thread somewhere here about that, so I hope I will be able to do this. It will take some time

P.S. Between High and Low I counted 9 lines of fluid. Sometimes the car drives nice, sometimes it drives like there no amortization at all and the car "feels" every crack in the asphalt. It is a 2002 European car, but new to me and the PO has no idea when suspension fluid was last changed.

Many thanks!

UPDATE:

of course 5 minutes after writing my initial post, I couldn't resist waiting and not continuing the job so I went ahead and did it

I had about 830 ml of fluid in the expansion tank, about 400ml in the accumulator and roughly 1l in front and rear globes. So circa 2.2-2.3l of black fluid was drained.
I put approximately 2350-2450ml in the expansion tank to the Max level in Normal position. I can't say exactly how much because I used the 5l plastic bottle available in the UK and it seems to be above the 2.5l mark left in the bottle.

New measurements are now:

FD(L) - 84.5cm
FP(R) - 85.5cm
RD(L) - 88.5cm
RP(R) - 89.5cm

Is the 4cm difference between front and rear normal?


I still have this (annoying) difference of 1 cm between left and right side. When I will occupy the driver's seat, I assume the difference will become even worse. Can someone please help with this? I have heard that this can be adjusted, but have no idea what to search for?