On Wed, 13 Aug 1997 23:39:27 -0400 "Dustin Howarth"
<howarth@pulsenet.com> writes:
>Hi everyone,
>
>Thanks to all who responded to my clutch question (pedal soft,
>difficulty
>getting into gear, some grinding, whirring sounds in bell housing,
>clunking
>when pedal is released, etc. -- see reprint below). The consensus
>seemed
>to be a faulty throw-out bearing, which made sense.
>
>I now have the engine and tranny out and separated, and have some new
>questions: Just what should I see if the throw-out bearing is in fact
>to
>blame? Should there necessarily be something obvious (broken parts,
>uneven
>wear, etc.)?
>
>Here's what I found:
>
>-- evenly worn clutch disc that should be replaced, but doesn't appear
>to
>be damaged or disfunctional.
>
>-- throw-out bearing looks okay to me -- no uneven wear or broken
>pieces.
>There seems to be a good amount of bearing material (carbon?) left.
>The swivel sockets connecting the bearing to the arm were somewhaat
stiff.
A bit of lube proceeded by a clean up with some fine sand paper should
take care of it. Just don't get carried away with the lube. As the old
commercial said " A little dab'll do you:"
You might consider replacing the retaining clips. Inexpensive, but
irreplaceable if broken.
>-- throw-out bearing arm (fork) had some slop at the connection to the
>transmission housing (maybe 1/4" to 3/8") -- seems like a lot of play.
Definitely a lot of play. Given the mechanical advantage of the fork
arm, that will translate to about 1/2" or so of lost motion before the
bearing applies pressure to the clutch plate. Plan on replacing the
bushings and the pivot pin. Again, inexpensive.
>-- pressure plate looks okay, no evidence of worn springs. There was
>a
>little bit of uneven wear on the throw-out bearing side of the
>pressure
>plate where the bearing meets the plate.
Most likely caused by the excess play in the clutch arm.
>-- the hole in the clutch slave cylinder piston was a bit out of round
>where the throw-out bearing linkage connects, but doesn't seem too
>bad.
Any eccentricity here is not good. there should be no more "play" in the
rod/fork connection than is necessary for ease of movement.
>Does that suggest anything to anyone? My plan right now is to replace
>the
>disc, plate, and bearing, as well as the clutch slave cylinder piston,
>put it together, and hope it's okay. That seems disturbingly
unscientific
>to me, but I can't see anything obviously wrong.
Actually you saw several things wrong, which you laid out above. And
you've made steps to correct those problem areas. Don't sell yourself
short!. You done good!
You'll find that in a lot of cases, there won't be a catastrophic failure
problem with a cars component , but things exactly as you've found. Ie.
little things that add up to cause component malfunction.
>
>Could the problem I described be in the hydraulic system? There were
>no
>obvious leaks, but the fluid level was very low after the initial
>failure.
>After bleeding twice, the car was drivable but still not right. What
>are the symptoms of a bad clutch master or slave cylinder?
>I don't mind replacing the clutch assembly, but I would like to be
>more comfortable about the nature of the problem. Thanks in advance for
>any help or advice.
You've found the basic problem(s). But that's not to say you don't have
others.
A bad slave cylinder will usually manifest itself by leaking. Carefully
peel back the dust cover and check for fluid between the piston and the
cover. There should be none.
A master cylinder (assuming no leaks to the outside) generally falls
into two basic symptoms. 1. No pedal pressure, or 2. A slow release of
the clutch even though the pedal is held down.
Both problems indicate a leakage internally, just a matter of degree.
In both cases, rebuild or replacement is called for.
Hope this helps
Rick Morrison
72 MGBGT
74 Midget
|