AHC Fluid Change How To -- Need Input (4 Viewers)
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PabloCruise
SILVER Star
Now they sell it by the liter or quart in plastic bottles.
Another big thank you to @PADDO ! Just followed his procedure on our new-to-us-as-of-last-week-or-so '05 LX470 w/ 135K miles on it. The body and frame are in beautiful shape, but there's a bit of rust on some of the fasteners and such, including the bleeders, but they loosened without any drama after a 30 minute soak in PBBlaster. Before the procedure, we had about 8 marks on the reservoir between Low and Hi height settings. After, 12! The fluid that came out was gross.. grey and a little milky, like old tired dishwater. After the procedure, nice clear pink on the driver's side bleeds.
Two things ..
1. Make sure you have a perfectly sized hose or fitting to put over the bleeders, or are a lot more coordinated than I am. My hose was too big (no comments, please), and I took a pretty good fluid bath when I cracked the bleeder on the big tank in the middle on the driver's side (accumulator? can't remember what it's called.. the cylinder). The hose fell off and the fluid escaped with the glee of a captive dog tasting freedom for the first time.
2. Got a little concerned when I got to Paddo's step 8; starting up the car after draining the fluid from the three points on the driver's side. It took a long time, after starting the car, for the fluid to cycle back into the system when I pressed the button to take the car from Low to N. Plus, I was standing next to the car with the door open, not realizing that the system only works if the door is closed. Didn't want to get in the car (see aforementioned fluid bath). Closed the door, a little patience... and all was well. Just in case anyone else out there is as impatient and stupid as I am.
In any case, the whole thing, even w/ the slight incompetency-induced challenges, took about an hour. It'll be 20 minutes next time, and will definitely do it every 30K.
Thanks again!
Two things ..
1. Make sure you have a perfectly sized hose or fitting to put over the bleeders, or are a lot more coordinated than I am. My hose was too big (no comments, please), and I took a pretty good fluid bath when I cracked the bleeder on the big tank in the middle on the driver's side (accumulator? can't remember what it's called.. the cylinder). The hose fell off and the fluid escaped with the glee of a captive dog tasting freedom for the first time.
2. Got a little concerned when I got to Paddo's step 8; starting up the car after draining the fluid from the three points on the driver's side. It took a long time, after starting the car, for the fluid to cycle back into the system when I pressed the button to take the car from Low to N. Plus, I was standing next to the car with the door open, not realizing that the system only works if the door is closed. Didn't want to get in the car (see aforementioned fluid bath). Closed the door, a little patience... and all was well. Just in case anyone else out there is as impatient and stupid as I am.
In any case, the whole thing, even w/ the slight incompetency-induced challenges, took about an hour. It'll be 20 minutes next time, and will definitely do it every 30K.
Thanks again!
Stupid followup question... the rubber bleeder cap on the accumulator was ... ummm.. no longer rubber, and it crumbled. I'd like to replace all of them to keep road snot out of the bleeder valves. These took a 10mm wrench... others I have on other vehicles are 8mm. Will any standard bleeder cap fit? Don't have any spares on hand to try..
Any standard cap will fit just fine.
Well I too attempted to bleed my AHC this weekend, but I didn't have the luck that everyone else has had. Let me preface this by saying I can screw up a glass of ice water, so I'm not much of a mechanic. I did want to do this myself though, so I attempted it and failed. I don't know how but the bleeder valve/fitting on the accumulator sheared off while I was attempting to turn it. I know what you're thinking, but I didn't put much force on the valve at all. It didn't move immediately but soon did start to turn (or as I know now it actually wasn't). I soaked the fittings in pb blaster for a bit of time...I don't know what the heck happened. How screwed am I? No fluid ever came out of the valve, so as of right now I'm assuming it is still closed. I'll look for any puddles in the morning. Can this be fixed or did I just buy a whole new accumulator? I can ruin anything. Good news: One rubber dust cap now available in the classifieds section.
Get a good night's sleep, and don't worry. I doubt very much you will need a new accumulator. Bleeder valves are common stock parts..just need to make sure you get a replacement bleeder valve with the right threads. The trick is going to be getting the part that sheared off out of your accumulator; I've never had to do that, so hopefully someone else who HAS can chime in. It's probably going to make a pretty good mess because you now have no way of really directing or controlling the flow of the fluid as it escapes, but messes can be cleaned up.
Possible courses of action (and I'm just guessing here... don't do any of these until someone who's a better mechanic than I validates these guesses..)...
1. Carefully drill a small hole in the center of the valve still stuck in your accumulator.. use a cobalt drill bit, maybe 1/8". Go slow. Thread an "EZOut" into it and try and back it out. LOTS of PBBlaster. Let hours, or even days, go by.. let that puppy soak. Less muscle, more patience. If it does loosen and starts to come out, do NOT be in a position to get sprayed by the fluid. It's going to come screaming out.
2. If no joy, increase the bit size. Choose a bit that is almost as big as the body of the valve would be if there were no threads... in other words, you're trying to drill out the solid portion of the valve, but leave the threads intact, mated to the receiving threads of the accumulator. Once the solid part is drilled out, you'll experience the screaming fluid escape. Again, take care. Then you may be able to use a dental pick to extract the remaining threads. If you booger up the threads in the accumulator, you'll have to rethread them with a tap.
OR...
If you haven't leaked any fluids yet, your system still works, and your car is driveable, take it to any reputable garage. Those guys will have had to fight battles like this many times, and will know how to get it out and get a new bleeder valve installed. They might grumble and act all superior and stuff, but that's OK. Maybe have them check the other bleeders too to make sure they're not seized.
A hint when dealing with seized, rusty stuff... in another thread, someone mentioned using constant, steadily applied and increasing pressure. That person has obviously never lived anywhere near the rust belt, USA; that's terrible advice, and a sure fire way to end up with your current problem. What you want to do is break the bond the rust has. You're on the right track w/ PBBlaster... soak it, tap it lightly with a ballpene hammer (or anything metal, really), then walk away. Do that several times over a few hours. Next, and VERY important.. make SURE you have the correct size wrench, and that it's FULLY seated flush over the nut/bolt/bleeder/whatever you're trying to turn. If that area is rusty, scrape the rust off. Get the bolt/nut/bleeder looking as clean and hexagonal as humanly possible, and get the wrench SEATED without any play. If the bolt/nut is BADLY rusted and misshapen, you may be able to get the next size smaller wrench on it. If it's a metric bolt and your metrics are either too lose or won't go over, try an SAE. GET IT ON with the best fit possible. Now, when you're ready to give it a try, jerk it suddenly, like you're trying to sort of karate-chop it off, not lift a heavy object. You could try tapping the handle of the wrench or ratchet with your ballpene hammer.. not whacking it really hard sledge-style, but just a solid tap. Repeat. THIS IS WHY impact wrenches work so well, and why you're less likely to break things taking them off w/ an impact driver than you are with a ton of leverage. If it doesn't come out after a few taps or you find the wrench starting to round off the bolt, step away, soak some more, and try again later.
If all that doesn't work, then you're looking at heating things. That's a whole other discussion, and I'll defer to those more knowledgeable there, too.
But no, in terms of your accumulator, all is not lost. Just not as easy as originally hoped.
Possible courses of action (and I'm just guessing here... don't do any of these until someone who's a better mechanic than I validates these guesses..)...
1. Carefully drill a small hole in the center of the valve still stuck in your accumulator.. use a cobalt drill bit, maybe 1/8". Go slow. Thread an "EZOut" into it and try and back it out. LOTS of PBBlaster. Let hours, or even days, go by.. let that puppy soak. Less muscle, more patience. If it does loosen and starts to come out, do NOT be in a position to get sprayed by the fluid. It's going to come screaming out.
2. If no joy, increase the bit size. Choose a bit that is almost as big as the body of the valve would be if there were no threads... in other words, you're trying to drill out the solid portion of the valve, but leave the threads intact, mated to the receiving threads of the accumulator. Once the solid part is drilled out, you'll experience the screaming fluid escape. Again, take care. Then you may be able to use a dental pick to extract the remaining threads. If you booger up the threads in the accumulator, you'll have to rethread them with a tap.
OR...
If you haven't leaked any fluids yet, your system still works, and your car is driveable, take it to any reputable garage. Those guys will have had to fight battles like this many times, and will know how to get it out and get a new bleeder valve installed. They might grumble and act all superior and stuff, but that's OK. Maybe have them check the other bleeders too to make sure they're not seized.
A hint when dealing with seized, rusty stuff... in another thread, someone mentioned using constant, steadily applied and increasing pressure. That person has obviously never lived anywhere near the rust belt, USA; that's terrible advice, and a sure fire way to end up with your current problem. What you want to do is break the bond the rust has. You're on the right track w/ PBBlaster... soak it, tap it lightly with a ballpene hammer (or anything metal, really), then walk away. Do that several times over a few hours. Next, and VERY important.. make SURE you have the correct size wrench, and that it's FULLY seated flush over the nut/bolt/bleeder/whatever you're trying to turn. If that area is rusty, scrape the rust off. Get the bolt/nut/bleeder looking as clean and hexagonal as humanly possible, and get the wrench SEATED without any play. If the bolt/nut is BADLY rusted and misshapen, you may be able to get the next size smaller wrench on it. If it's a metric bolt and your metrics are either too lose or won't go over, try an SAE. GET IT ON with the best fit possible. Now, when you're ready to give it a try, jerk it suddenly, like you're trying to sort of karate-chop it off, not lift a heavy object. You could try tapping the handle of the wrench or ratchet with your ballpene hammer.. not whacking it really hard sledge-style, but just a solid tap. Repeat. THIS IS WHY impact wrenches work so well, and why you're less likely to break things taking them off w/ an impact driver than you are with a ton of leverage. If it doesn't come out after a few taps or you find the wrench starting to round off the bolt, step away, soak some more, and try again later.
If all that doesn't work, then you're looking at heating things. That's a whole other discussion, and I'll defer to those more knowledgeable there, too.
But no, in terms of your accumulator, all is not lost. Just not as easy as originally hoped.
I appreciate the words and advice. I figured the accumulator might be toast just because of the drilling of the valve and potentially getting debris in the device. Of course it's under pressure right now isn't it, so even if I screw that up maybe the pressurized fluid will shoot out any metal shavings. Then again I may have to remove accumulator to get access.
Pyrenees
SILVER Star
Anyone know how many quarts I actually need to buy? The original cans are apparently gone.
You'll need 3 liter/quart bottles, and will end up with around half a bottle left over.
Well I did the AHC flush today as part of baselining the LX, and the exact same thing happened to me today with head of the bleeder screw shearing off and leaving the other half in. Did you ever try drilling it out, or how did you end up fixing it?
None of the fluid has leaked out of mine yet...I'm debating just taking it in to the dealership and letting them take care of this one just because I don't want to fool with it.
Thanks in advance!
Peter
I haven't fixed it yet as I'm not sure the best way to do it. I don't want to risk getting any metal shavings into the accumulator, so it sort of makes sense to me to try to drill it while it's under pressure to help expel any shavings. But them I'm gonna make a huge mess I assume. I don't have the extra AHC fluid nor a replacement bleeder to attempt just yet either. Also I don't know what size the bleeder screw is, just that it has a 10mm hex. Do you know where to get a replacement screw?
As I'm now gunshy of the bleeders what I ended up doing in regards to the fluid is just suck everything out of the reservoir then refill with 1 liter of AHC. I let that mix around for a couple of weeks then drained the reservoir again and added a clean 1 liter to it. So my fluid is pretty clean now. I have 1 liter left and will wait about a month and drain and refill again...if I can't get the bleeder fixed. But by doing so my AHC fluid went from oil black to sort of a clearish color. Front and rear AHC pressures lowered from >10 to 6.9-7.1 so I believe it was time. My accumulator pressure is still at 10.9 however.
For those who have to deal with corroded or broken bleeders and are reluctant to try and open them for your fluid exchange then the next best thing is to drive both the front and rear down to the bump stops in manual test [the active test] mode and then remove/replace the fluid out of reservoir. Doing it this way will maximize the volume of old fluid removed in one cycle and therefore reduce the dilution of your new fluid. Not as good as bleeding off from the five bleed points but much better than doing nothing.
Bleeder valves with rubber cap part numbers:
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Thanks for the help and advice! I'm going to purchase a couple of extra bleeder screws before I attempt again.
This may have been mentioned somewhere, I just got the LX570 back from the dealership and the foreman told me "they tried to check for leak, the level is a little bit low, but due to the oil undercoating they couldn't find any".
Now, there might be a lot lost in translation. I went in and told them to "check for rust damage" on the "reservoir/accumulators" as I saw some, and I expressed I wanted to flush the fluid. The car is 82k miles. (later on I decided not to change the fluid).
So, could it be possible that the fluid gets low even though there is no leak? I doubt the truck has AHC leak...despite the surface rust on the cynlinders/accumulators. Height control works fine, rides fine.
Now, there might be a lot lost in translation. I went in and told them to "check for rust damage" on the "reservoir/accumulators" as I saw some, and I expressed I wanted to flush the fluid. The car is 82k miles. (later on I decided not to change the fluid).
So, could it be possible that the fluid gets low even though there is no leak? I doubt the truck has AHC leak...despite the surface rust on the cynlinders/accumulators. Height control works fine, rides fine.
ktmracer01
SILVER Star
Wow! Your old fluid looks exactly how mine looked. I though I was the only one that had fluid that dark. I agree, the ride is night and day difference. I've actually considered keeping my AHC after the flush now.
PabloCruise
SILVER Star
I am not sure about the difference between the 570 and 470.
We primarily discuss the 100/470 in this section
Bleeders are hollow so I don't know that you need to drill them out. I've had good luck using the square type screw extractors like these. Just tap it in and turn (after soaking in PB blaster). If you have to drill, just use some fresh fluid to flush the accumulator immediately after drilling.
AHC fluid is just hydraulic oil, oil doesn't evaporate. So no!
But we can weep a little at shocks (which is ok, if not dripping off shock) and loose some that way. Any other leak would needs repairing IMHO.
How to check if air got into the AHC system? I accidentally allowed the AHC reservoir run low while the truck was rebalancing (was closely watching it, but the dirty residue on the inside walls tricked me into thinking the fluid was still there)?
The truck appears to cycle fine thru L-N-H modes and drives fine. Should I just re-bleed the system to get rid of any potentially trapped air in hydraulic lines?
Anything else I should check or be worried about (besides looking inside the reservoir :-( )?
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