740 clutch control arm problem

  • Thread starter Thread starter Roy Bolton
  • Start date Start date
R

Roy Bolton

Hi,
Anyone come across this and how did you fix it. Driving along and you push
the clutch in. Clutch pedal goes all the way to the floor and doesn't come
up again. You pull over and stop. On looking at the clutch slave cylinder
and clutch release arm you find that the clutch slave cylinder piston has
pushed it's way through the release arm and the whole slave assembly has
fallen to pieces. This is an inherent fault with 88 740s! Any solutions to
fixing i9t without replacing the whole release arm assembly?
Thanks - Roy
 
Make sure that the clutch control arm has not come adrift from it's pivot
point.

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).
 
Roy Bolton said:
Hi,
Anyone come across this and how did you fix it. Driving along and you push
the clutch in. Clutch pedal goes all the way to the floor and doesn't come
up again. You pull over and stop. On looking at the clutch slave cylinder
and clutch release arm you find that the clutch slave cylinder piston has
pushed it's way through the release arm and the whole slave assembly has
fallen to pieces. This is an inherent fault with 88 740s! Any solutions to
fixing i9t without replacing the whole release arm assembly?
Thanks - Roy
Click to expand...

The only problem I've had with that is a worn assembly that allowed the
piston to push completely out of the bore. When you say it's pushed through,
do you mean the metal of the release arm has actually broken? If that's the
case you'll have to replace it.
 
No, what I mean is that the end of the piston has pushed through the hole in
the arm where there should be a plastic bush that holds the end of the slave
cylinder piston against the release arm. The arm is not broken in any way.
All that is needed is some way of holding the end of the piston in place.
Think of it as a ball joint type assembly where there should be a socket on
the end of the release arm but the socket has worn, fallen off and the end
of the piston has pushed through the hole where the socket connects to. -
Roy
 
Roy Bolton said:
No, what I mean is that the end of the piston has pushed through the hole in
the arm where there should be a plastic bush that holds the end of the slave
cylinder piston against the release arm. The arm is not broken in any way.
All that is needed is some way of holding the end of the piston in place.
Think of it as a ball joint type assembly where there should be a socket on
the end of the release arm but the socket has worn, fallen off and the end
of the piston has pushed through the hole where the socket connects to. -
Roy
Click to expand...


Perhaps I'm missing something, but it seems the obvious solution here is to
get a new bushing, the dealer should be able to order it.
 
James said:
Perhaps I'm missing something, but it seems the obvious solution here is to
get a new bushing, the dealer should be able to order it.
Click to expand...

There isn't a bushing. The rod coming out of the slave cylinder seems
to have worn a hole big enough so it goes right through the release
arm. Sounds like it's time for a new arm (which would require
transmission removal) or someone to patch up the existing arm (custom
work which may end up costing the same as arm replacement).

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)
 
Roy said:
Hi,
Anyone come across this and how did you fix it. Driving along and you push
the clutch in. Clutch pedal goes all the way to the floor and doesn't come
up again. You pull over and stop. On looking at the clutch slave cylinder
and clutch release arm you find that the clutch slave cylinder piston has
pushed it's way through the release arm and the whole slave assembly has
fallen to pieces. This is an inherent fault with 88 740s! Any solutions to
fixing i9t without replacing the whole release arm assembly?
Thanks - Roy
Click to expand...

Would a suitably thick and large enough diameter washer properly fixed
onto the end of the actuator plunger not resolve this? Reading the posts
below, it sounds like you need to investigate how the piston popped
out, it should be securely held in place by a substantial internal
circlip, you also should carefully clean the actuator piston, and it's
bore, there is a long spring in there also which causes the actuator to
maintain a very light pressure against the clutch release arm, after
reassembly, fit the proper internal circlip, then refill and bleed the
hydraulic circuit, I've had one of these badly and suddenly leak,
giving a whole meaning to gear changing.
This fix above won't look very neat, but, it should get you mobile
again, and it's not like you drive around looking under the car all day:-)

Best wishes from blighty,

Ken Phillips
 
The piston isn't held with anything except the pressure of the release arm
against the end of the piston. the end of the piston sits in a cup normally
which sits in the hole at the end of the release arm, this is what has worn
through and this is what needs replacing. it's an extremely bad fault and
one that needs watching out for. If your sat at the lights with the engine
in gear and this fault happens, then the car is suddenly going to lurch
forward and it's bye bye to some pedestrian. Surprised it hasn't been the
subject of a service recall... be warned! The part is not, as far as I know
available from volvo, there is a fix and it does not involve replacing the
release arm. - Roy
 
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