240d clutch bleed - Page 4 - PeachParts Mercedes-Benz Forum

rwd4evr · #46 06-11-2019, 04:27 PM

Quote:

Originally Posted by C.Doner

Loop method is still my vote for simplicity. Make a loop in a clear hose connected to the slave cylinder and tie it in a manner so the fluid does not flow out with gravity . Fill the master cylinder and keep topped. Pump until bubbles are gone. See the clear loop to be sure no air comes back in when you return the pedal to the up position before closing the bleeder.

Done . Bleeding should be the same amount of work as jacking up the car. Its a one hour job and works, for me, every time.

Doesn't work if your Mc piston isn't returning to its upper most position when the pedal is up. The internal springs are fairly weak and don't always play nice.

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tsa · #47 06-11-2019, 04:54 PM

Quote:

Originally Posted by rwd4evr

Temperature will have a large effect on the hardness of the PVC allowing it to grip the bleeder and the viscosity of the fluid causing it to create more pressure in the system when freezing cold.

Didn't think of that, perhaps since brake fluid works well enough at even colder temperatures, for braking, that is . . .

Quote:

Originally Posted by rwd4evr

I've never done it but I believe the backlash in the steering gearbox is adjustable for wear to an extent. Also make sure the idler arm mount/pivot bushings are new.

Thanks for the tip - will investigate / check :-)

tsa · #48 06-11-2019, 05:06 PM

Quote:

Originally Posted by C.Doner

Loop method is still my vote for simplicity. Make a loop in a clear hose connected to the slave cylinder and tie it in a manner so the fluid does not flow out with gravity . Fill the master cylinder . . . .

Do you mean you fill the MC via the hose from the brake reservoir? I tried that initially, but that attempt may have failed due to the still fitted piston rod blocking the pathway downwards for the fluid.

Quote:

Originally Posted by C.Doner

. . . and keep topped. Pump until bubbles are gone. See the clear loop to be sure no air comes back in when you return the pedal to the up position before closing the bleeder.

Not sure if I followed you there - if you have to open and close the SC bleeder nipple for every brake pedal pumping, it may be easier to get to and open/close the FR brake caliper bleed nipple, than crawling under the car to get to the clutch SC bleed nipple - ?

C.Doner · #49 06-11-2019, 09:20 PM

Quote:

Originally Posted by tsa

Do you mean you fill the MC via the hose from the brake reservoir? I tried that initially, but that attempt may have failed due to the still fitted piston rod blocking the pathway downwards for the fluid.

Not sure if I followed you there - if you have to open and close the SC bleeder nipple for every brake pedal pumping, it may be easier to get to and open/close the FR brake caliper bleed nipple, than crawling under the car to get to the clutch SC bleed nipple - ?

I use the clutch pedal to pump. I do it by hand, lowering and raising it. Bleeder stays open until the end of the process. No line from the brakes or pressurized containers needed. Those methods always end up with fluid spills when I tried them. The method has worked for me and many others who have struggled for days with all of the other ways. I have done 4 MB clutches and a Nissan this way, all without a hiccup.. One guy was at it for weeks, tried this way, and it was fixed.

vwnate1 · #50 06-11-2019, 09:59 PM

Good to hear you got it finished .

Hydraulic bleeding isn't an exact science, most Mechanics have a method they're good with and prefer, I find some times the back filling method works O.K., mostly I prefer to use a $50 pressure bleeder , sometimes I have to do the old pump, old, bleed, repeat method, it depends on the vehicle and is the master cylinder level or inverted (I hate those) or what .

Once in a while the vehicle is designed with the bleeders lower than the hose connection, those typically need back filling or remove the cylinder, strap it so the guts can't puke out, position it so the bleeder screw is the highest part and bleed away.....

rwd4evr · #51 06-12-2019, 12:57 AM

Quote:

Originally Posted by C.Doner

I use the clutch pedal to pump. I do it by hand, lowering and raising it. Bleeder stays open until the end of the process. No line from the brakes or pressurized containers needed. Those methods always end up with fluid spills when I tried them. The method has worked for me and many others who have struggled for days with all of the other ways. I have done 4 MB clutches and a Nissan this way, all without a hiccup.. One guy was at it for weeks, tried this way, and it was fixed.

Yes it should work this way but it doesn't always. Rust or a ridge of sh|πy crusty brake fluid or a stuck piston seal from sitting will ruin your day if the master piston isn't fully free to return after you push the pedal down.
Alot of the time were taking about cars that have sat for extended periods, at least I am. If the pedal was down while sitting there is a very good chance the piston is going to stay there until you push it back with positive pressure from the slave side.

math · #52 06-12-2019, 12:43 PM

This is the way i have successfuly clutch bled the 300d, 240d ect: multiple times now without a helper

step 1. Put enough brake fluid to fill the res to the very top. leave the cap undone

step 2. undo the 2 bolts that hold the slave cylinder to the gearbox.

step 3. lower the slave cylinder so that the bleed nipple is the lowest point towards the ground.

step 4. loosen the bleed nipple and let gravity do the work.

step 4 part 2 . wait for the bleeding liquid to be the correct colour ( if you have switched fluids ) When correct colour comes through. Tighten nipple and check fluid res in the engine bay is topped up

step 5.

go back under the car and put bleed nipple back to lowest point and loosen nipple to release liquid and let the liquid flow until it's a strong solid line of liquid with no air bubbles.

step 6. Tighten up bleed nipple and reattach slave cylinder to gearbox

step 7. check fluid res level and top up, or drain with glass syringe if needed.

mwagon · #53 06-11-2020, 04:12 PM

Just to add some more info in support of the great advice already posted.
As mentioned there are two different length Push Rods that will typically come with the ATE Clutch Masters. The shorter Rod with the White End Housing works best for me on 5 speed Trans such as the 717.400. See photo
Sonymorrow gave the tip to disconnect the Master Push Rod during bleeding. I never did this in the past, but it did improve the Fluid Flow to the Reservoir, so definitely how I will do future bleeds.
I used a Power Bleeder connected to the Slave Cylinder. There only $50.00 & you'll want one for doing Brakes someday. Using this Bleeder, you don't have to mess with the Brakes & Bleed used Fluid into your Clutch system

Skippy · #54 07-19-2020, 06:45 PM

Mine started to act like it got a big gulp of air into the clutch system, so I decided to bleed it. I wasn't getting results, so I looked up this thread for a better way. Partial success. I got plenty of fluid coming out the bleed screw, along with any air that might have been in there. Then I found the clutch pedal was worse instead of better, so I started looking into the suggestion to disconnect the push rod to the master cylinder. Then I found the real problem: The push rod is broken. I must have driven it a thousand miles like that. I'll be taking the Jaguar to work for a while it seems.