Asking a quick question to doublecheck clutch engagement in pedal travel

[harry newton]

If the clutch engages late in the pedal uplift cycle, if I want the clutch to engage sooner, do I move the master cylinder rod locknut stop point toward the firewall, or toward the driver's foot?

[Gary]

How tall is the driver?

[Iggy]

replying to harry newton, Iggy wrote: Yes or whichever way works, there are different setups. But, you need to leave some slack so the pressure plate can release, so you don't burn through the clutch very prematurely. However, if everything was fine up until recently then you need a clutch-job as your pressure plate's springs are fatigued and it's nothing to do with cable stretch.

[Clare Snyder]

Neither. The adjustment needs to be made at the slave cyl end - if adjustment is even possible. Most current vehicles are "self adjusting" - in which case you need a new clutch.

[Clare Snyder]

There goes Iggy again -- if there is a "master cyl" there IS NO CABLE

- and it's not weak clutch springs, it's a worn out clutch disk.

[harry newton]

He who is Clare Snyder said on Sat, 11 Nov 2017 15:19:54 -0500:

Thanks for your advice, which I appreciate, and where I relize I provided no pictures so everyone had to guess, which won't help so here are some photos.

Here is the clutch slave cylinder:

Here is a picture of the only adjustment there is in the clutch mechanism:

To get rid of a spongy feel, I rebuilt the slave cylinder:

And I rebuilt the clutch master cylinder:

And then I bench bled both:

Using high quality DOT 4 fluid:

But the clutch now suddenly engages late in the pedal uplift cycle.

There is nothing that can be adjusted at the slave cylinder.

The only adjustment is the bolt that attaches the clutch pedal to the clutch master cylinder.

The only adjustment there is to twist the rod and lock it in place with the locknut.

But which way engages the clutch sooner?

[Terry Coombs]

  Shorten the rod . BUT as Clare said , some are self-adjusting and it may come right back to where you are now . I had an 89 Chevy p/u that never really released the clutch properly , even after slave/master replacement . I figure the arm was bent inside the bell housing or something . FWIW I discovered with that truck that the best way to get ALL the bubbles out of the system was to pump fluid in thru the slave bleed port . Pushes them up to the master , a direction they want to go anyway .   --   Snag

[Iggy]

replying to Clare Snyder, Iggy wrote: Wow, not at all correct! But, that's all I get from you any which way. By the way, clutch disks are meant to be ground all of the way down and more with no driver perception by a working-properly pressure plate.

[Clare Snyder]

Like I said. Youhave a "self adjusting" hydraulic clutch. There IS NO height adjustment. The pedal adjustment is toi be set so there is a small clearance between the push-rod and the push rod seat of the M/C. "shortening" the push rod will drop the pedal but will have no effect on the clutch engagement.Your clutch is worn out

(retired auto mechanic speaking)

[Clare Snyder]

Believe what you want. I've been a mechanic for decades, and replaced a LOT of clutches on vehicles from Minis to Loadstars, and small tractors to large loaders. The first symptom of a failing clutch is engaging close to the top. The second symtom is not having enough "up travel" to engage. When the pedal gets too high on any vehicle with a non-adjustable (aka "self adjusting") hydraulic linkage, it's clutch time - pure and simple.

[Ed Pawlowski]

Are you saying that with only 50 years experience working on cars you know more than Iggy? Anyone that hangs sheetrock horizontally would be challenged adjusting a clutch.

[Iggy]

replying to Clare Snyder, Iggy wrote: Yes, you agreed with my conclusion that he needed a clutch-job and no fooling around with the pedal. And FYI, Volvo, Ford, Honda, etc. all had cables as well as both cylinders at some time. I tried to cover all bases with no year, make, model, pictures nor experience level known. But, to say the clutch isn't a system and you'd only pop in a new clutch disk is ridiculous, foolish and professionally irresponsible.

[harry newton]

He who is Clare Snyder said on Sat, 11 Nov 2017 17:36:46 -0500:

Thanks. I admit. I'm confused. I obviously need to read up on clutches because I did not realize that my clutch is a self-adjusting clutch.

And, to tell you the truth, honestly, I understand your words, but I don't understand the adjustment at all.

Now I'm more confused than ever, because I don't see the difference between a "self adjusting clutch" and a "not adjusting clutch".

I understand your words, but I don't understand (yet), why they bother with a pedal adjustment then.

I hear what you're saying below though, and I'm trying to faithfully figure out why you adjust what you adjust.

Here is a picture of what you're saying, I think, the adjustment is for:

Hmmm.... how do we MEASURE what it should be when we're upside down in the footwell?

What do we measure?

I'm not at all disagreeing since I clearly don't know what I'm doing. I'm also clear that I'm confused because I _thought_ the one adjustment there is was for when the clutch engages.

If that one adjustment is only for the master cylinder pushrod clearance, what's the implication if it's adjusted wrong versus right?

[harry newton]

He who is Iggy said on Sun, 12 Nov 2017 03:44:05 GMT:

Since there is this discussion which I didn't understand at first, I just now did some looking up on this cable things where it seems there are two completely different clutch systems.

1. mechanical
2. hydraulic

Where it says, with respect to adjusting: "Mechanical clutches have a cable for actuation, and typically need adjusting throughout the life of the clutch. Hydraulically actuated clutches tend to be self-adjusting"

[harry newton]

He who is Clare Snyder said on Sat, 11 Nov 2017 19:33:08 -0500:

I agree with Clare that there are no wires in this setup that I can see.

Following what I can visually see, there is just the clutch pedal, the pedal-to-master-cylinder adjustable pushrod, then the clutch master cylinder, and then the slave cylinder, and then a lever sticking out of the transmission.

I'm listening to this conversation with rapt attention though, because I had a spongy pedal which sometimes had no back force until I pumped the pedal, which was solved by rebuilding both the clutch master cylinder and the clutch slave cylinder.

My inspection of the slave cylinder seal condition lends me to believe that my original problem may have been that fluid was leaking past the seals, since the fluid level in the clutch master cylinder was stable (but blacker than black).

It's only after solving the spongy pedal that I noticed that the clutch is engaging at almost the last inch or two of the pedal return cycle.

Obviously I thought this was an adjustment problem, which Clare tells me it is not.

I don't know the history of this car so I can't assume anything about the clutch other than what I can measure or feel.

The clutch engages late, but it engages without slipping (I think). At least if it's slipping, I'm not noticing that it's slipping.

I'm not sure what do to, but I guess only a visual inspection will tell for sure, is that my only option?

[harry newton]

He who is harry newton said on Sun, 12 Nov 2017 05:49:00 +0000 (UTC):

I just watched this video, which explains what happens after that lever.

[harry newton]

He who is harry newton said on Sun, 12 Nov 2017 05:23:21 +0000 (UTC):

I google around based on your hints, where I think you might be trying to tell me about what this guy calls "end play" here.

[Iggy]

replying to harry newton, Iggy wrote: Yep, Clare was right that you don't have a cable and I, of course, agree after receiving the pictures. But, we differ on what a Clutch-Job entails, which we both agree should remedy your now single problem. I feel any Clutch-Job should include a complete Clutch Set and not just the Clutch Disc.

In light of this being a used car you've recently acquired, I'd strongly suggest that you get a Professional Clutch-Job performed. As, it requires proper disassembly, experience, handling and installation. They may find your fork, flywheel, transmission shaft and/or a seal need attention.

[Dean Hoffman]

Why not try adjusting it to see what happens? Mark the nut and rod with a Sharpie or a paint marker. You'll be able to keep track of how much you've changed things and will be able to return them to their original position.

[Clare Snyder]

No difference. There is no manual adjustment. Period

That adjustment is for initial setup so the cyl returns to it's fully returned position, so the compensating ports in the master cyl are not covered by the "cup" or "seal" on the piston with your foot off the clutch.

Tou just wiggle the rod. It should be free of the cyl piston "socket". On manycars there is a "return stop" that adjusts the hight of the un-depressed pedal by limiting how high the return spring can pull the pedal. On some cars it is incorporated with the "clutch safety" starter inhibit switch, which also chuts off cruise control when you step oin the clutch.

If the clutch return stop is adjusted, the push rod must also be adjusted to maintain that small clearance between the rod and the M/C

Too loose and the rod will fall out of the cyl, and you will alsp loose "stroke" on the cyl - meaning you may not be able to fully release the clutch. Too little clearance (negative clearance, or preload) prevents the slave cyl from fully returning, because the fluid pressure in the system is never released. This can cause the release bearing to wear out and can also, in severe cases, prevent the clutch from fully engaging