[SOLVED] W124 e200 b2 piston story.

Discussion in 'Engine' started by E200CT, Jun 6, 2012.

  1. E200CT

    E200CT New Member

    Messages:
    16
    Joined:
    Jun 3, 2011
    Location:
    Chester
    Car:
    2005 CLK320 Cabriolet
    I just thought I would share this story with you guys as the information could be useful in case anybody else is having trouble with their transmission.:thumb:


    Whist driving the other day, I came to a roundabout, paused for the gap, and pressed accelerator to go, and nothing, engine just revved up and didn’t' move, all manner of thoughts went through my mind but especially I have a knackered gearbox, managed to get car moving and it went fine except for the slipping on start off.
    Rang up a mate who owns an auto gearbox rebuild firm here in Chester, and he assured me from the symptoms I had explained that it was a low ATF problem.
    So I discovered that I had been checking the fluid level incorrectly and thought the level was fine, not so, after checking it properly at running temp with the engine running, I had to put 1 ¾ liter of ATF in to get the level up to the 80 degree mark on the dipstick, and as a result, all the gears came back, except for slipping when starting off.

    Net and forums searching told me that it was a b2 piston problem and to do an ATF oil and filter change, but after reading up a lot over a couple of days of how I was going to do the job, I was a bit reluctant to change the oil because Americans especially don’t like changing oil on an old transmission if it hasn’t been serviced on a regular basis as it can make things worse, or the piston itself, if it was broken I would need to replace it, so embarked on a search for a replacement b2 piston in case mine was the plastic one, only to find out they are not available in the UK or Germany and in the region of £130 to get one.
    I was in a bit of a dilemma, what am I going to do as a rebuild was quoted at £1250 + vat, and another couple of hundred to drop and refit the box, second hand boxes were in the region of £150 to £750 + shipping + getting someone to fit it, if I could get a box that would fit which I cant.
    It’s decision time, scrap the car which I don’t want to do, or have a go myself to see what’s what.

    Next morning, ramped up the car, dropped the fluid, and took the pan off ready to check the B2 piston, guess what I found in the pan, the small dog bone from the reactor pin has fell out and was in the bottom of the oil pan, no metal fragments or anything else nasty except the fluid was dirty but doesn’t smell burnt.
    Took out the B2 piston and luckily I have the modified metal piston and plastic liner sleeve already in there, that was a big relief.
    Next job to take off the valve housing to see if I could get the little dogbone back in, but this is where my DIY skills came to an end, I chickened out of dropping the valve body off because all the manuals I was looking at weren’t very clear as to which bolts to undo to remove it, so I didn’t want to have it fall to pieces and the springs balls fly off everywhere, so left it well alone.

    Where I’m at now is, reassembled everything back together, problem is still there, had to use the old pan gasket as the new one supplied was the wrong one, but not leaking.
    Rang up my mate Steve at the gearbox place, and he says they have done this job before whilst the box is still on the car, so for about two to three hours labour @ £65 per hour, I’ve booked it in to get it done, which I think is a relatively cheap fix, It looked like the B2 brake band itself is not broken and the plastic retainers are OK, but if it is the case that the band itself is broken, the box certainly will have to be removed to replace that, which is probably still a cheaper option to full a rebuild, I will have to decide what to do then.

    Here's hoping.
     
    3 people like this.
  2. OP
    OP
    E200CT

    E200CT New Member

    Messages:
    16
    Joined:
    Jun 3, 2011
    Location:
    Chester
    Car:
    2005 CLK320 Cabriolet
    Just an update albeit a bit of time has gone by, I took my car to the mate i mentioned above and left it with him for 3 to 4 hours, and he actually fitted the dogbone rod back in the gearbox with a second hand plastic clip (original one had broke, that's why it fell out) from a box he had scrapped.

    After picking the car up it was running as sweet as a nut, all gears were OK and no slipping, been running perfect ever since and at £200 I wasn't robbed.

    :rock::rock::rock:
     

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