What to measure when adjusting clutch pedal bolt?

Need help figuring out what to MEASURE when adjusting a self-adjusting
clutch pedal bolt.
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I've adjusted the bolt all the way in, half way, and all the way out:
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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.
Reply to
Mad Roger
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.
Reply to
Paul Hovnanian P.E.
On Fri, 26 Jan 2018 13:13:56 -0800,
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.
Reply to
Mad Roger
The feel doesn't stink just because *you* don't like it.
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.
This is a situation where pedancy will stuff you up right royally.
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 you can't feel the play, it doesn't have any.
If it is meant to have play, then fix it so it does.
For master cylinder clearance - At the pedal pushrod in most cases. For slave cylinder clearance - at the slave cylinder in most cases.
Reply to
Xeno
On Sat, 27 Jan 2018 02:47:48 -0000 (UTC),
I think the problem is mostly that I don't feel any free play.
Here's a screenshot of the manual process.
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And the spec.
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But you have to *feel* that slop in order to measure it. I don't know why I don't feel any slop.
Reply to
Mad Roger
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 écrit :
Reply to
Look165
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*.
Reply to
Xeno
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 be aring is not constantly engaged. The bearing should not be turning most of the time. Not having enough clearance would allow the bearing to spin const antly.
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!
Reply to
dsi1
On Sun, 28 Jan 2018 00:16:13 +1100,
Here's a screenshot of the manual process.
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And the spec.
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The measurement is about 160 mm in the resting position.
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Pushing gently with my finger, I can measure the lower position.
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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.
Reply to
Mad Roger
On Sat, 27 Jan 2018 16:37:44 +1100, Xeno wrote:
Better than 90% of vehicles with standard transmissions today have NO MANUAL ADJUSTMENT PROVISIONS.
Mad MaX is an IDIOT.
Reply to
Clare Snyder
On Sun, 28 Jan 2018 00:16:13 +1100, Xeno wrote:
The poor lad reminds me of the Irisnman I shared the house with in Zambia. Anything more complex than a retractable ball-point pen had him totally flummoxed. To keep his level of frustration below the point of "blowing smoke" he was restricted to using Bic stick pens (pencils were no good because a pencil sharpener was beyond his level of comprehension)
Reply to
Clare Snyder
Yep, had the same experience in Indonesia - with a South African co-worker what's more.
Reply to
Xeno
On Sun, 28 Jan 2018 11:19:41 +1100, Xeno wrote:
It's got very little to do with "manufacturer's tollerances" - althought they ARE a lot better. The main thing is they are "self adjusting"
Reply to
Clare Snyder
Clare Snyder posted for all of us...
I wonder if this is the clutch he "replaced"?
He doesn't know the olde heat and bend the rod trick... maybe use some all thread and burn an adjustment hole in the floorboard.
Reply to
Tekkie®

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