the big bang

[benzbiz]

hi all i think i need new flexi disks as my 123 230e is starting to bang
when you put her in drive or reverse, i don't think it is the gearbox
question is are they hard to put in and are they expensive to buy?
thanks. leo

 

[tom7035]

I assume you mean the rubber 'donuts'. Provided you can access the car from below, the answer to both questions is no.

 

[TimN]

Original MB parts are about £80 each. GSF or Eurocar Parts are about £25 each. Simple to fit. Just remove the central prop bearing and that should give you enough slack.

I have a couple of spare original couplers for a reasonable price. PM me if interested.

 

[Amphiscian]

I have an '85 230ce that goes into "D" with a bit of a thump. More so when hot. Goes into "R" more gently. Was wondering whether it was the donuts, or gearbox internals. Somebody mentioned the word "bands" in connection.... Car's only done seventy thousand-odd miles, so hope it won't turn out to be the 'box. Donuts more likely to deteriorate in a quarter of a century?

 

[tom7035]

I have an '85 230ce that goes into "D" with a bit of a thump. More so when hot. Goes into "R" more gently. Was wondering whether it was the donuts, or gearbox internals. Somebody mentioned the word "bands" in connection.... Car's only done seventy thousand-odd miles, so hope it won't turn out to be the 'box. Donuts more likely to deteriorate in a quarter of a century?

I'm not an autobox specialist but I think the gearbox brakebands would be more likely to slip than grab. 'Donuts' a distinct possibility, or what about tickover speed being a little too high? This would exaggerate engagement.

 

[benzbiz]

thanks for the input, looks like the old girl will be of the ground for
a while.

 

[Amphiscian]

Looking for a gentle slide into 'drive'

I'm not an autobox specialist but I think the gearbox brakebands would be more likely to slip than grab. 'Donuts' a distinct possibility, or what about tickover speed being a little too high? This would exaggerate engagement.

Thanks for that, Tom. No, tickover speed is very restrained, 650 rpm or so and I did try reducing it even further; no real benefit. Seem to remember that there's an adjustment that can be made but maybe that's for gear changes (which are fine) rather than going into "D". Perhaps I should/shall do a search ...

 

[tom7035]

Thanks for that, Tom. No, tickover speed is very restrained, 650 rpm or so and I did try reducing it even further; no real benefit. Seem to remember that there's an adjustment that can be made but maybe that's for gear changes (which are fine) rather than going into "D". Perhaps I should/shall do a search ...

May be worth spending a few quid on a visit to an autobox specialist who can do some pressure testing, or even just have a chat to one. I remember on the old British Borg-Warner (sounds German but were British, when that meant something!) autoboxes you could adjust brakebands. However I don't know if that's the case any more - the old story that in my day 'repair' came before 'replacement' which is not the case nowadays.

 

[Amphiscian]

I shall do a bit more research.

- the old story that in my day 'repair' came before 'replacement'.

I can identify with that! We're a fine vintage....

 

[Ian B Walker]

If the rear diff has a bit of play in it this will also cause a "Bang" when you put it into gear.

 

[kiwi_bloke]

hoist

I would suggest putting the car up on a hoist.

Put it in neutral.

grab the drive shaft with your hands. Move it back and forth, and you should be able to see where the play is.

Ussually the flex disks or play in the diff. Very very rarley is it a trans problem.

 

[Amphiscian]

Flex discs'd be easy to do. But the diff.. ? Is that when thoughts turn to sawdust???

 

[tom7035]

I don't personally think the fault is in the diff. If it was so bad other symptoms would be apparent IMO. Be optimistic!

 

[Amphiscian]

I (optimistically) don't think it's the diff. either. No howls or rumbles from there. As said earlier, it's really a case of going through the driveline and then, if necessary, having a word with an auto box man. Which I will do next time I'm back in England. Meantime I raise a glass to you for your positive approach, especially with blacksmiths and brake discs. Cheers!