What to measure when adjusting clutch pedal bolt?

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.

Thanks for the advice as, well, as I NEED advice.

I can't disagree about the measurement, but I'm not sure how to measure that.

The problem is that I don't *feel* any slop with my hand pushing along the axis of the bolt away and then toward the master cylinder.

I know what it looks like as I rebuilt the master cylinder, so I know what you're talking about.

I just don't feel any slop at all no matter how I adjust the bolt.

I'll have to try this again. Hopefully I can hear a click or feel the "space" being taken up.

I'll try again.

That means to turn the bolt INTO the pedal (and away from the master cylinder), which is, in effect, a shortening of the bolt.

OK. That sounds like a plan. It's a normally threaded bolt which is threaded into the clutch pedal.

Is this a good plan?

1. Shorten the bolt by screwing the bolt into the clutch pedal assembly.
2. Then feel for slop (there "should" be plenty of slop, I would think) between the end of the bolt and the master cylinder (this is on the other side of the firewall so it has to be done by feel)
3. Once I get a feel for the slop, then lengthen the bolt by twisting the bolt OUT of the clutch pedal, which "lengthens" it.

That part I understand! :)

That makes sense. Thanks.

I'll try again now that I understand it a bit more. I agree that even my hand isn't sensitive enough, so a foot will never do it.

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.

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.

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

Here's a screenshot of the manual process.

And the spec.

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 écrit :

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*.

Here's a screenshot of the manual process.

And the spec.

The measurement is about 160 mm in the resting position.

Pushing gently with my finger, I can measure the lower position.

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.

Except you never need to bench bleed a clutch master. Virtually never need to bench bleed a disc brake master either. You CAN get into a world of hurt if you don't bench bleed a drum brake master (it has residual pressure valves onthe outlet) but I've gotten away without bench bleeding even a LOT of drum brake masters.

MOST clutch masters will "gravity bleed"

Clare Snyder posted for all of us...

Sharp as a marble aye?