Volvo B12BLEA Brake Blending Problem

[Conor]

It disappears gradually with reducing input shaft speed, yes, much as
the effectiveness of an exhaust brake does. I can live with that, on our
Volvo autoboxes. On the Scanias, it's still quite noticeable in low
gears down to about 750rpm.

TBH on lorries, I found the Scania systems to be so effective as to not
be worth bothering with - you could turn it off and there was no
noticable difference apart from a reduction in noise. The Volvos OTOH
could hold a 44 tonne artic at a constant speed going down Windy Hill
on the M62.

 

[Ivor Jones]

In Conor <[email protected]> typed, for some strange, unexplained
reason:
: In article <[email protected]>, John Williamson
: says...
:
: > It disappears gradually with reducing input shaft speed, yes, much
: > as the effectiveness of an exhaust brake does. I can live with
: > that, on our Volvo autoboxes. On the Scanias, it's still quite
: > noticeable in low gears down to about 750rpm.
:
: TBH on lorries, I found the Scania systems to be so effective as to
: not be worth bothering with - you could turn it off and there was no
: noticable difference apart from a reduction in noise. The Volvos OTOH
: could hold a 44 tonne artic at a constant speed going down Windy Hill
: on the M62.

You can't turn it off on our Scanias, there isn't a switch (or if there
is, they've hidden it very well..!) On the Mercedes O405N's there's a
switch but if you turn it off a horribly loud alarm buzzer goes off
continuously until you turn it back on again.

Ivor

 

[John Williamson]

In Conor <[email protected]> typed, for some strange, unexplained
reason:
: In article <[email protected]>, John Williamson
: says...
:
: > It disappears gradually with reducing input shaft speed, yes, much
: > as the effectiveness of an exhaust brake does. I can live with
: > that, on our Volvo autoboxes. On the Scanias, it's still quite
: > noticeable in low gears down to about 750rpm.
:
: TBH on lorries, I found the Scania systems to be so effective as to
: not be worth bothering with - you could turn it off and there was no
: noticable difference apart from a reduction in noise. The Volvos OTOH
: could hold a 44 tonne artic at a constant speed going down Windy Hill
: on the M62.

You can't turn it off on our Scanias, there isn't a switch (or if there
is, they've hidden it very well..!) On the Mercedes O405N's there's a
switch but if you turn it off a horribly loud alarm buzzer goes off
continuously until you turn it back on again.

On our Scania coaches, it's hidden on the manual retarder stalk. I've
not looked at our buses lately.

As for effectiveness, there's a very noticeable lurch as it comes on
with brake application in town, & a very noticeable lurch as it cuts off
again at 20kph or so. It does very little in higher gears, in my
experience. Comparisons with chocolate teapots come to mind....

I'm told it can be reprogrammed by the agents, though.

A feature of the B12 auto I like is the full cruise control, which lets
you set a speed & if you start overspeeding for any reason,
automatically engages the retarder. Very handy on those long French
motorways.

That's only holding 17 tonnes or so back, though.