How many of you release the fluid inside the strut during your abc fluid drain and refill? If so where is the valve on the strut?

 

There's no drain valve on the struts - only on the pipes that feed them.


Nick

 

Ahh okay, I was just trying to figure out the most efficient way without rodeoing. I assume you have access to star?

 

I don't have STAR but have worked on my ABC without any problems (so far).

The pipes that Nick mentions are the metal ABC lines to each wheel well where you will find the bleed nipples. They look similar to bleed nipples on brake calipers, except they can be under tremendous pressure during operation. The fluid out at the wheel wells never gets cycled back to the pump to be filtered so it could be good idea to bleed some out.

If you want to "drain out" some old Pentosin at each wheel, start by driving the car into the garage at max height, then turning it off. Lift and support the entire vehicle on jack stands at the frame lifting points, allowing all 4 wheels to hang. (Easy to do at a shop or if you have a lift in your garage) After 10 minutes, the pressure should be low enough for you to safely do the bleed process. Pick a wheel and position a jack below the hanging tire, and attach a drain tube to the bleed screw nipple. While a friend slowly jacks up the wheel, you open the bleed screw to let the fluid out. (Be careful not to jack so much that you lift the car off the jack stands.) When the wheel is jacked up to slightly beyond what would be normal right height position, close the bleed screw. Then you can slowly let the jack down and leave that wheel to hang again. You have successfully drained out some old black fluid.

These nipples can be hard to see/reach with the wheels on. So you could take them off for better access, and jack up against brake rotors (keep some lug bolts screwed in).

When you are done bleeding out all four wheels, you have to be very careful when you lower the vehicle back to the ground. Since there will be very little fluid left in each ABC strut, the car will settle quite low, nearly to the bump stops. You don't want to drop it too fast because it could damage components (ride height position sensors, shock seals...your fingers). Once back on the ground, start the car. Press the ride height button and ABC should pump the fluid back into the shocks and immediately raise the vehicle. Add Pentosin CHF11S to the ABC reservoir to top off at correct fill level. You can manually hit the ABC height button a dozen times to cycle through more fluid.

 

Wow thank you for the detailed information, this is exactly what i was looking for! I do have access to a lift which is great. I did a fluid flush manually with the ride height button around 10k miles ago. But obviously i did not do the struts so i may do this asap. About how much fluid will be drained out of all four struts?

 

Not very much comes out. Approximately 1-3 ounces per strut, depending on how much you try to compress it.

 

Thread hijack to ask a simple ABC-related question:

Who made (or hopefully still makes) the original fittings used on the MB ABC Hydraulic hoses? I have seen the LUK name for the pump and valve bodies. And you can find several vendors for the accumulators like Corteco.

But who is/was the vendor of the fittings at the ends of all these hoses?

The reason I ask is that I will someday want to take a hose to a local hydraulic repair shop (assuming I find a good one) and ask them to rebuild a hose for me with new fittings. I will want to give them the vendors' names or possibly buy my own fittings that they could crimp on for me.

 

Unless somebody rounded them off using the wrong tool why would you want to replace them?

 

Because stripped threads. Because poor mechanical skills. Because cross-threaded. Because a hydraulic repair shop would not crimp new line in the middle my OE line, but would make a new one if I had the connectors at both ends. Because I could make new ones as backups/spares for if and when I decided to swap out the OE lines.

Parker has a huge selection of screw on connections. But I'm not sure who made the originals. Just looking for some part numbers and a vendor that supplied them or the vendor that.built the OE complete lines.

 

I think the best option is to cut out the flexible hose sections and fit new sections with either flared or compression joints.

I've been doing that for a few years now, and never had a problem.

Standard hoses, standard fittings. Cheap & available in any large town.





Nick