C240 Brakes, Bleeding

[c240yaz]

Hi All,

Just replaced my rear brake pads on my 2001 C240 tonight. Noticed that OSR bleed nipple leaking fluid, seeping very slightly. (before the replacement operation started). Tried to tighten bleed nipple, used deep socket, but corners of hex rounded off. Rust. Will order new bleed nipples tomorrow x 4.

Should I replace brake fluid (56K miles) and is there any set procedure for bleeding. ie, furthest away wheel cylinder or closest first ?

Also, you technical guys, any idea of how much fluid and make is required for complete replacement ?

 

[television]

You start at the rear, then do the front, 1 tin of 4 dot will do the job, it is better practice to either clamp the pipes or undo the bleed nipple when changing pads as this stops any rubbish messing up the expensive ABS pump

 

[c240yaz]

You start at the rear, then do the front, 1 tin of 4 dot will do the job, it is better practice to either clamp the pipes or undo the bleed nipple when changing pads as this stops any rubbish messing up the expensive ABS pump

Malcolm. 4 Dot, not familiar with this term. Make, specs ?

 

[television]

4 dot is the specification. I liter of bendix,lockheed,castrol and others are all made to the same spec

 

[c240yaz]

Just a thought...are brake caliper bleed nipples not universal ? Do I need to buy MB originals...anyone ?

 

[Patronfrey]

I don't know but I can't imagine that M-B brake caliper bleed nipples are unique. I'd try removing the OSR rear nipple with a pair of mole grips then clean up the thread using a wire brush. The thread is probably rusted and contaminated with dirt which will make it impossible just to tighten. Cleaned up it will most probably be ok again. Happened to me with one of my cars after it had been into the garage at MOT time. It needed new flexys and I told them to renew the fluid while they were at it. Ended up finishing the job myself as I had the same problem as you. I did what I described above and no further problems or leaks.
Ron

 

[television]

I believe that all of the threads are the same, they should be TMD on your car available from any motor factor

 

[c240yaz]

Follow up to earlier queerie. Tonight I changed my brake fluid after 52K miles. I also replaced the bleed nipples on each caliper, as a feel good precaution.

Purchased these from MB Inchcape on line @£2-3 each. I am glad that I replaced these as they were extremely rusty and the tapered end that seals inside the caliper was indented, with previous torque applied, (dont know when).

I used up a total of 1 litre Dot 4, as suggested earlier. Started on the rears, ended with the fronts. There was no foreign matter on the emptied fliud. Took me approx 30 mins. I used aquatic clear rubber hose purchased from the local pet shop. Perfect fit on the bleed screws !

I also painted the calipers red with Halfords high temp paint afterwards. Looks nice and clean all round.

Thanks to everyone for the advice I get on this forum.

 

[Glenn Smith]

a good idea is to smear a little silicone sealant around the nipple to prevent water going down the threads, this can be peeled away next time you bleed the brakes, you should replace the fluid every two years.

 

[c240yaz]

a good idea is to smear a little silicone sealant around the nipple to prevent water going down the threads, this can be peeled away next time you bleed the brakes, you should replace the fluid every two years.

Glen, I never thought of that. Silicon sounds a good idea. Will remember for next time. The rubber boots on the nipple, why dont they design these so that they cover the exposed thread on the bleed nipple also. It would give better thread protection.

Rather than start a new thread. Does anyone have any idea on this. After changing my rear pads a few weeks ago, noticed tonight that the OSR disc, on the outer diametre, new rust developing on the outer 5mm circumference. Obviously new pad is failing to make contact on the outer 5mm. From a visual through the wheel slots, wife pressed brake pedal for me, you can see the pad moving, so does not seem to be sticking, just not making contact on the outer 5mm. I did not have time to teardown.

I did use MB pads from Inchcape, and I am sure that everything is in line. Strange. Brakes are really sharo also when driving.

Anyone any ideas ?