hydraulic clutch engaging high

[Troyport]

Hi all, 1987 3/4 ton pickup, hydraulic clutch. The clutch engages very high. Does not slip. I have read that it needs to be bled, but if there was air in the system wouldn't it engage very low in that a lot of piston travel would be compressing air which would translate into not much movement of the throw out bearing? I have had (and still have) several Chevy trucks with mechanical clutches, easy to adjust engagement height.. this is my first hydraulic chevy. Thanks for any input.

 

[YakkoWarner]

Has the engagement/disengagement point changed since you've had it? Your logic is sound in that it would disengage and grab with the pedal very close to the floor if there was air in the system (or depending on how bad it was, possibly not disengage at all). There really isn't any "adjustment" on hydraulic clutches. The more concerning possibility is that the clutch pack is becoming worn, that would certainly cause a higher pedal at engagement - and as it wears it will get to the point that it never fully engages and begins to slip.

It might be warning you that a new clutch pack is in your not-too-distant future. It probably won't fail catastrophocally, but it may begin to slip at some point.

I have not had a Chevy with hydraulic clutch, but many other vehicles with them both American and foreign and they all behave mostly the same. I like them as long as the clutch slave is not enclosed inside the bell housing (thanks a lot for that Ford!). If I buy a vehicle now with a hydraulic clutch, the clutch slave location is a definite dealbreaker for me.

 

[Troyport]

Thanks for the reply. The truck is new to me and I knew it felt funny before I bought it, so if I have to replace the clutch that was already considered before the deal was sealed. Since Hydraulic clutches are self-adjusting, I guess I would also assume it would self-adjust all the way to the end, and then just start slipping. (similar to always having proper pedal with a mechanical clutch, as long as you keep manually adjusting it) This is why I wondered if something else was going on here.

 

[SquareRoot]

My 85 has a hydraulic clutch. I converted it from auto so I know it well. I don't know about "self-adjusting" as mine has an adjustable pushrod between the slave cylinder and the clutch arm. Adjusting the length on it moves my engagement point to some degree.

 

[Troyport]

Self adjusting in that as the stroke of the hyd. cyls change due to wear, there is a check valve that regulates it and keeps the pedal height the same. Much like your brake pedal does not change as your brake pads wear. I would think your clutch pedal should be at the same height as it wears out. So, engaging late, is there something else going on here? I did make an error in my first post. Years ago (like 30) I had an 86 Blazer with a hydraulic clutch, and ran that 200K miles and never touched anything with the clutch. Pedal was always the same height.

 

[Troyport]

Finally getting back to this after a lot of other work. Clutch still engages high, and I think it is correct in that I have the proper amount of free play at the top of the pedal per the service manual. My problem is I also have a 1968 GMC with a manual transmission, and it starts to engage sooner so going from one truck to the other really sucks. I really want to lower the engagement point on the hydraulic clutch. I have read where I could shorten the rod between the slave and the clutch fork, but wouldn't that just make the hydraulic system self-adjust? I could play by shimming the slave away from the fork, has anyone done this?
I also thought about messing with the rod between the pedal and the master cyl. Just shortening it would not allow the pedal to go all the way back up, but cutting it, shortening it, welding a thick-walled tube to one end and then sliding the other end into this tube would allow the rod to slide up and down in the tube. pushing the clutch pedal would bottom the rod attached to the pedal in the tube (against the rod attached to the master cyl) and actuate the clutch, then when releasing the clutch after full engagement the rod could slide within the tube and allow the pedal to go all the way back up. Could even thread the rod and use some nuts to provide adjusting.
Has anyone ever done anything to make this adjustable? thanks.

 

[bucket]

You can make the clutch master adjustable:

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But being stock parts used in a stock application, I don't see the point. Sure the engagement height may be different from other trucks, but that doesn't necessarily mean that anything is wrong. Many vehicles through the years have had different feeling clutch pedals.

 

[Ricko1966]

You can make the clutch master adjustable:

You must be registered for see images attach

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But being stock parts used in a stock application, I don't see the point. Sure the engagement height may be different from other trucks, but that doesn't necessarily mean that anything is wrong. Many vehicles through the years have had different feeling clutch pedals.

Who's bracket is that? And for what application? Kinda kicking the idea around of hydralic clutch on the Chevelle instead of zbar.

 

[bucket]

Who's bracket is that? And for what application? Kinda kicking the idea around of hydralic clutch on the Chevelle instead of zbar.

It's a 2nd gen F-body auto pedal box, reproduction clutch and brake pedals, a DSE clutch master firewall bracket and a 4th gen F-body clutch master. I cut the eyelet off and threaded the rod for a rod end from the hardware store. I adjusted it so that the clutch master would have no more travel than the 4th gen pedal and master that I have in my 3rd gen.

 

[Ricko1966]

It's a 2nd gen F-body auto pedal box, reproduction clutch and brake pedals, a DSE clutch master firewall bracket and a 4th gen F-body clutch master. I cut the eyelet off and threaded the rod for a rod end from the hardware store. I adjusted it so that the clutch master would have no more travel than the 4th gen pedal and master that I have in my 3rd gen.

DSE is that Detroit Speed?