Opinions wanted on "new" clutch bleeding procedure (was Need help bleeding cutch)

[Avram Dorfman <dorfman@est.org>]

Well, either this will help you, or you'll tell me why not & hopefully
my brother won't get stranded as a result...

We may have found the perfect tool for pressure bleeding the clutch,
because you already have one! Believe it or not, it's the clutch slave
cylinder. (For those new to the thread, this is for an '88 80q)

Here's what we did:

1) remove the slave cylinder (1 bolt, but kinda hard to get to)
2) open the bleeder valve
3) compress the slave cylinder piston (dumping fluid & air out the
bleeder)
    we just pressed it against the subframe, it's a pretty strong
spring.
4) close the bleeder valve
5) let the cylinder piston expand back out (it's on a spring)
    this causes the cylinder to suck fluid in from the reservoir
6) repeat from #2 until only fluid comes out
7) reinstall the cylinder (takes some effort b/c you have to compress it
in an awkward position to get it in place)

it's no surprise that the slave cylinder can create a strong enough
vacuum to suck the fluid in.

Now that I know how it should be done, it would probably be easy to
reverse the procedure, putting a tube from the bleeder into a bottle of
fluid, having the slave suck fluid in from the bottle, closing the
bleeder, and using compressing the cylinder to push fluid through the
system into the reservoir.

What we did seems to have worked find though. Any thoughts?



Todd Young wrote:

> He-he, you need to "pressure" bleed the clutch.
>
> In other words, you need to force the fluid "into" the bleeder screw
> and through the system, out into the reservoir.
>
> So, you will need to rig up a pressure bleeder. Basically some
> container that will hold pressure and has an inlet for pressurized
> air, and an outlet for the fluid. Just make sure not to empty the
> container and force air into the system.
>
> I was going to bleed my clutch and brakes this weekend. I had
> previously bought a MityVac vacuum pump with the brake bleeding
> accessories. I figured I could just use the same container for both
> vacuum and pressure bleeding. Doesn't work. The container won't hold
> pressure, works fine for vacuum. So I spent Saturday evening finding
> an appropriate container and Sunday finding fittings to make it all
> work. Now I just need to "build" the container.
>
> Avram Dorfman wrote:
>
>>  I'm having trouble bleeding the clutch in an '88 80 quattro. Here's
>> what happens: 1) we open the bleeder valve2) we step on the clutch3)
>> Air & a little fluid comes out4) we close the bleeder valve5) we
>> lift the clutch off the floor (it doesn't come up on it's own), and
>> there's a little resistance6) we open the bleeder valve to do it
>> again7) air gets sucked into the bleeder valve as soon as we open it
>> it appears as though we're creating a vacuum in the line when we
>> lift the clutch. For some reason, fluid from the reservoir is
>> apparently not going into the line to replace what came out when we
>> lift the clutch. Here's the background: We just put the transmission
>> back in. We bled the clutch while it was hanging free & the trans
>> was out, and it worked fine. Is it possible that we did something
>> wrong when we put the slave cylinder back in? Can anyone thing of
>> anything else that migh be causing this problem? -Avram
>
> --
> -----------------------------------------------------------
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> -----------------------------------------------------------
> Todd Young              WAM!NET Inc.
> tyoung@wamnet.com       655 Lone Oak Drive, Bldg#A
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