What to measure when adjusting clutch pedal bolt?

Need help figuring out what to MEASURE when adjusting a self-adjusting
clutch pedal bolt.
http://www.bild.me/bild.php?file=3835507bolt.jpg

I've adjusted the bolt all the way in, half way, and all the way out:
http://www.bild.me/bild.php?file=8057083bolt2.jpg

No matter whether I adjust the bolt all the way inside the clutch pedal
(turning it CCW facing the pedal like a foot would).

Or if I turn the adjusting bolt all the way out of the clutch pedal
(turning it CW).
Or halfway between...

I don't feel any "slop" anywhere (e.g., between the rounded tip and the
master cylinder piston cup). The *feel* of the clutch pedal engagement
changes drastically between all the way in and all the way out though.

But clutch pedal feel is not the question (mainly because I don't know how
it "should" feel). So the question is only about what to measure, and how.

The question is only about WHAT to measure with a ruler and how to measure
it.

On Fri, 26 Jan 2018 20:30:48 -0000 (UTC), Mad Roger
> wrote:

>Need help figuring out what to MEASURE when adjusting a self-adjusting
>clutch pedal bolt.
>http://www.bild.me/bild.php?file=3835507bolt.jpg
>
>I've adjusted the bolt all the way in, half way, and all the way out:
>http://www.bild.me/bild.php?file=8057083bolt2.jpg
>
>No matter whether I adjust the bolt all the way inside the clutch pedal
>(turning it CCW facing the pedal like a foot would).
>
>Or if I turn the adjusting bolt all the way out of the clutch pedal
>(turning it CW).
>Or halfway between...
>
>I don't feel any "slop" anywhere (e.g., between the rounded tip and the
>master cylinder piston cup). The *feel* of the clutch pedal engagement
>changes drastically between all the way in and all the way out though.
>
>But clutch pedal feel is not the question (mainly because I don't know how
>it "should" feel). So the question is only about what to measure, and how.
>
>The question is only about WHAT to measure with a ruler and how to measure
>it.

Why is it you think the clutch pedal "feel" is not an aspect of the
adjustment? The throw out bearing needs to release from the clutch
plate in the bell housing. You can't adjust it by a ruler. You need
a little slop in the pedal so the plate is not always engaged at the
risk of burning the plate.

....at least back in the day. Two cents.

The rod (bolt) needs to be adjusted so that there is about 0.1" clearance
between the end of the rod and the clutch master cylinder piston with the
pedal 'up' (not pressing it). You can't see the piston or where the rod
contacts it, so you have to do it by feel. Push the pedal gently by hand*
until the space is taken up. If you can't feel any space, you might have it
too tight. Back the rod out of the master cylinder until the clearance is
obvious and then gradually extend it. When it's correct, tighten the jamb
nut to keep it in place.

The idea is that the clutch master cylinder has to be able to 'relax' all
the way rearward when not pushing on the clutch. At the last point in it's
travel, the piston opens up the port to the fluid reservoir and lets fluid
in to make up for leakage.

*Feeling the rod clearance is easier by hand. Your foot isn't sensitive
enough to judge the small amount of play.
--
Paul Hovnanian
------------------------------------------------------------------
Never put off till run-time what you can do at compile-time. -- D. Gries

On Fri, 26 Jan 2018 13:13:56 -0800,
Oren wrote:

> Why is it you think the clutch pedal "feel" is not an aspect of the
> adjustment? The throw out bearing needs to release from the clutch
> plate in the bell housing. You can't adjust it by a ruler. You need
> a little slop in the pedal so the plate is not always engaged at the
> risk of burning the plate.
>
> ...at least back in the day. Two cents.

It's not my vehicle, and the "feel" stinks no matter what position it's in.

What changes is that it engages early, or late, but not in a way that I
like either way.

So I can't adjust it by feel because there is no position that feels right
to me.

Therefore, I just want to adjust it by the book.

If only I knew what to measure as I think it's for a millimeter or two of
'slop' between the rounded end of the bolt and the master cylinder piston
cup.

But I don't feel that slop in any case.
And I don't know where to measure it either.

Hence the question.

On 27/01/2018 1:47 PM, Mad Roger wrote:
> On Fri, 26 Jan 2018 13:13:56 -0800,
> Oren wrote:
>
>> Why is it you think the clutch pedal "feel" is not an aspect of the
>> adjustment? The throw out bearing needs to release from the clutch
>> plate in the bell housing. You can't adjust it by a ruler. You need
>> a little slop in the pedal so the plate is not always engaged at the
>> risk of burning the plate.
>>
>> ...at least back in the day. Two cents.
>
> It's not my vehicle, and the "feel" stinks no matter what position it's in.

The feel doesn't stink just because *you* don't like it.
>
> What changes is that it engages early, or late, but not in a way that I
> like either way.

It will either take up early or it will take up late. It cannot do both,
either one or the other. Clutches simply cannot work the way you are
imagining they do.
>
> So I can't adjust it by feel because there is no position that feels right
> to me.

This is a situation where pedancy will stuff you up right royally.
>
> Therefore, I just want to adjust it by the book.

Do you have the *book* handy? If not, you are lost.

The method used to adjust a clutch will depend entirely on the mechanism
employed. There are 3 general possibilities in common use; hydraulic,
cable, mechanical linkage. Each of those will have variants and the
differences will make a difference to how and where it is adjusted.

Best you get to it and RTFM.
>
> If only I knew what to measure as I think it's for a millimeter or two of
> 'slop' between the rounded end of the bolt and the master cylinder piston
> cup.
>
> But I don't feel that slop in any case.

If you can't feel the play, it doesn't have any.

If it is meant to have play, then fix it so it does.

> And I don't know where to measure it either.

For master cylinder clearance - At the pedal pushrod in most cases.
For slave cylinder clearance - at the slave cylinder in most cases.
>
> Hence the question.
>


--

Xeno

On Sat, 27 Jan 2018 02:47:48 -0000 (UTC),
Mad Roger wrote:

> I agree that even my hand isn't sensitive enough, so a foot will never do
> it.

I think the problem is mostly that I don't feel any free play.

Here's a screenshot of the manual process.
http://www.bild.me/bild.php?file=2707505pedal1.png

And the spec.
http://www.bild.me/bild.php?file=4030196pedal2.png

But you have to *feel* that slop in order to measure it.
I don't know why I don't feel any slop.

Normally, there should be about 1/2 inch between the resting position of
the pedal annd its thrust position (completey up. This is for preventing
continuous fricton inside the clutch.

Mad Roger a écritÂ*:
> Need help figuring out what to MEASURE when adjusting a self-adjusting
> clutch pedal bolt.
> http://www.bild.me/bild.php?file=3835507bolt.jpg
>
> I've adjusted the bolt all the way in, half way, and all the way out:
> http://www.bild.me/bild.php?file=8057083bolt2.jpg
>
> No matter whether I adjust the bolt all the way inside the clutch pedal
> (turning it CCW facing the pedal like a foot would).
>
> Or if I turn the adjusting bolt all the way out of the clutch pedal
> (turning it CW).
> Or halfway between...
>
> I don't feel any "slop" anywhere (e.g., between the rounded tip and the
> master cylinder piston cup). The *feel* of the clutch pedal engagement
> changes drastically between all the way in and all the way out though.
>
> But clutch pedal feel is not the question (mainly because I don't know how
> it "should" feel). So the question is only about what to measure, and how.
>
> The question is only about WHAT to measure with a ruler and how to measure
> it.
>

On 27/01/2018 10:52 PM, Look165 wrote:
> Normally, there should be about 1/2 inch between the resting position of
> the pedal annd its thrust position (completey up. This is for preventing
> continuous fricton inside the clutch.

It is actually there to guarantee that the piston can fully return to
its stop (circlip usually) and fully uncover the compensating port
allowing pressure in the slave cylinder and lines to release and fluid
to return to the master cylinder reservoir. If this does not happen, the
system may pump up and slave cylinder will not return thus not applying
or only partially applying the clutch. The most common symptom of this,
apart from a lack of pedal clearance, is a clutch that slips.

Also, it is wise not to dick with the pedal height adjustment as you may
end up with more MC travel than previously existed. That can result in a
torn or damaged primary seal if the piston is now traveling over an
unworn part of the cylinder or, worse, a part of the cylinder that has
corrosion buildup on the unworn part.

Frankly, if Roger needs to find out how to do the job from advice here,
he'd be well advised to hand the task over to someone with a clue. This
is basic stuff, hardly high tech, and he's *struggling*.
>
> Mad Roger a écritÂ*:
>> Need help figuring out what to MEASURE when adjusting a self-adjusting
>> clutch pedal bolt.
>> http://www.bild.me/bild.php?file=3835507bolt.jpg
>>
>> I've adjusted the bolt all the way in, half way, and all the way out:
>> http://www.bild.me/bild.php?file=8057083bolt2.jpg
>>
>> No matter whether I adjust the bolt all the way inside the clutch pedal
>> (turning it CCW facing the pedal like a foot would).
>>
>> Or if I turn the adjusting bolt all the way out of the clutch pedal
>> (turning it CW).
>> Or halfway between...
>>
>> I don't feel any "slop" anywhere (e.g., between the rounded tip and the
>> master cylinder piston cup). The *feel* of the clutch pedal engagement
>> changes drastically between all the way in and all the way out though.
>>
>> But clutch pedal feel is not the question (mainly because I don't know
>> how
>> it "should" feel). So the question is only about what to measure, and
>> how.
>>
>> The question is only about WHAT to measure with a ruler and how to
>> measure
>> it.
>>
>


--

Xeno

On Saturday, January 27, 2018 at 1:53:02 AM UTC-10, Look165 wrote:
> Normally, there should be about 1/2 inch between the resting position of
> the pedal annd its thrust position (completey up. This is for preventing
> continuous fricton inside the clutch.
>

I used to set up my VW Rabbit for early clutch engagement. I liked it that way. This was easy to do because the cable was easily accessible under the hood and adjustment could be done in a few seconds. I'd just grab the cable and shake it to make sure there was some play in the fork.

The reason you need some play on the clutch fork is so that the throwout bearing is not constantly engaged. The bearing should not be turning most of the time. Not having enough clearance would allow the bearing to spin constantly.

For my RWD cars, I'd have to get under the car with two wrenches to adjust the clutch pushrod or cable. That's no fun!

On Sun, 28 Jan 2018 00:16:13 +1100,
Xeno wrote:

> Frankly, if Roger needs to find out how to do the job from advice here,
> he'd be well advised to hand the task over to someone with a clue. This
> is basic stuff, hardly high tech, and he's *struggling*.

Here's a screenshot of the manual process.
http://www.bild.me/bild.php?file=2707505pedal1.png

And the spec.
http://www.bild.me/bild.php?file=4030196pedal2.png

The measurement is about 160 mm in the resting position.
http://www.bild.me/bild.php?file=6041860bolt3.jpg

Pushing gently with my finger, I can measure the lower position.
http://www.bild.me/bild.php?file=8845966bolt4.jpg

This #2 measurement seemed to be about 5mm but my only confusion left is
that these two things seem to be the same thing:
A. Pedal freeplay
B. Pushrod play

The reason they seem to be the same thing is that, with one finger on the
pedal, you can push the pedal down about 5mm until you hear and feel the
pushrod hit the master cylinder piston cup.

I can't yet distinguish between the two (freeplay & pushrod play) with my
finger or measurement at the top of the rubber part of the pedal position.