Hi All

I tried 2 liters of fluid with turkey blaster
Method:
Empty power steering reservoir
Add new fluid
Start the car
Rotate the steering side to side lock
Remove more fluid
Repeated same process like 6-8 times
Fluid is still dirty

Can I remove hose from the bottom
The hose which returns the fluid to reservoir
Hook up an extension hose,
Put a cap on reservoir tube hole
Fill up reservoir
Start the car
Turn the steering wheel side to side
Fill the reservoir
Cont same till fluid is clean
Air will probably get in but what I read is
That system self bleeds air and will get the air out by itself
Only thing we need to do is start the car
For few seconds turn off , fluid level will drop
In reservoir as air comes out
Keep adding fluid and all will be good

Does this method apply to DB9 too?

 

160 views and no reply?
guys , experts speak up please.

 

Most of the guys on this forum are not DYI'ers.

I haven't really looked at the steering rack setup on our cars, but what you seem to have outlined seems logical. The main thing is making sure the reservoir does not run dry on fluid. Will you have another person keeping the fluid level topped off while someone is turning the wheel? If it were me I would just unhook the connection at the rack to let it drain, than refill, than do it again in 500 miles for a complete flush (one man job). The only way I would feel comfortable doing it your way is if I had an extra guy helping me.

 

Why are you flushing, are you converting to CHF 11S?

 

No I am using GM cold climate part # 12345867 which is texaco cold climate equivalent.

I am flushing it because it's so darn dirty almost black in color.

 

Aston was using ATF for cold climate like Texaco, they realized it was still to thick and would not lubricate the lower pinion seal in the rack, which at times would cause a faint squeak noise to travel up the steering column. The thicker fluid would also increase force and heat in the pump which caused premature failure

Aston switched to CHF 11S which is a thinner fluid, Aston also added a Lubrizol additive to help delete any concern of the lower pinion seal lacking lubrication...all the newer Aston's come standard now with CHF11S

The procedure you wrote out will work, just don't let the pump run dry. I suck out the reservoir, disconnect the return and cap off the reservoir. I then put the return hose in a bottle to collect the waste fluid. I pour new fluid into the reservoir and run the run the engine. Keep pouring in the new fluid, once a Liter is gone you will already notice the new fluid color in the waste fluid bottle, shut off the engine and close everything up, bleed any possible air and top up...done

 

Excellent info, will switch to CHF 11s then.

Yes sometimes on turning steering it makes a squeaky noise, but I think after I attempted to flush with GM cold climate fluid it may have gone away.

BTW how to bleed air, just start the car and turn steering wheel side to side and refill fluid if level drops right?

 

Resurrecting a old thread, but I found it helpful, and many of our cars are due for power steering service.

Aston has a service bulletin that describes the recommended fluid change process, and seems like the way to go if you can get the front wheels up in the air. A word of caution if you attempt to drain/bleed/fill by simply starting the engine (as mentioned by Irish07). While this definitely works, it *quickly* depletes the reservoir. Like goes-through-a-liter-in-a-few-seconds fast. Be prepared for this. For this reason, having a helper start/stop the engine would be really helpful.

 

I have a V8 Vantage not a DB9, but AFAIK the PS systems are similar, so I thought I would say this here to keep the DIY knowledge together. I thought this job would be easy so I decided to DIY using the factory service bulletin instructions, but I actually spent 3 hours (working by myself with a lot of cleaning and hand washing in the process, it would be faster with an assistant turning the steering wheel) going through 4 cycles of it using up 2L of fluid, so I feel like using a vacuum pump on the return line to suck the lines completely clean is a better way as you get nearly all the fluid out in one go. With the return line under constant suction, I think the most efficient procedure would be to turn the wheel to full lock and keep it there for a bit to allow the fluid from the reservoir to pump to rack all drain and get replaced with air, then turn the opposite way to full lock to suck the fluid out the other side of the piston. At this point, there is probably a little bit of fluid left in the rack, but the pump and all the lines should be empty, and it would only take a small amount of fluid to flush what's remaining and make the system very clean.

I used a Mityvac to pull fluid out of the reservoir. I found that I could only get about 8oz out thanks to the baffle plate. Then I noticed I could stick the tubing through the gap along the side of the baffle and get the last 2oz out of the reservoir. I pulled the return hose off the bottom of the reservoir and put it into a bottle, and was able to get maybe 6oz or so. That's a little under half the fluid in the system between the reservoir and what comes out of the rack.

I thought about it for a while, and realized that if you start with the wheel locked to the left or right, you can get a little more fluid out of the rack because then you can go through the entire displacement of the rack without changing the rotary valve's position. By contrast, if you start with the wheel centered then turn one direction, when you reverse direction a little bit of fluid will leak back into that side from the return line. I want to say around 2-3oz extra came out when doing this. Now that I think about it more, turning the wheel a few extra times might pull more fluid from the pump's output line, which I didn't do and which might explain why I ended up with less than 0.75L.

So basically, the factory bulletin claims you can get 0.75L out of the system whereas I was only finding 0.5-0.6L, but they think a single flush is enough. I read somewhere that the system capacity is 1.1L, so according to them, leaving (0.35/1.1)^2=10% of the original fluid in there is okay, while I left approximately 6% of the original fluid in there with my triple flush. I remember seeing 1.3L somewhere else, which would make the numbers come out to 18% of old fluid remaining vs 11%. My fluid actually still has a bit of a brown tinge, but I figured if the factory thinks it's okay to leave some old fluid in, it shouldn't be a big deal.

Alternatively, if you don't want to disconnect the return line and potentially get messy, you could use a little more fluid or accept more old remaining fluid by just sucking the reservoir dry. I think the best way to do that is turn the wheel to full lock, empty the reservoir, turn it to full lock the opposite direction, and you'll have gotten around 1/3 of the fluid out of the system. 5 flush cycles using 2 bottles will get the old fluid % down to 10%.