Graz Slave cylinder shim?

[Dan Carter]

Just got my Graz back from having the drop gear changed. With the engine running, I am unable to put it into gear. Bleed the &^&%$ out of it so I'm certain its not air. Took all restrictions off the clutch pedal so it has full travel. The only thing I can think of is there was/is a shim to move the cylinder forward.

Does any one if there is supposed to be a shim on the slave cylinder? If so how much of one.

 

[HCF - John]

Hi Dan,
You shouldn't need to do anything with the slave post drop gear install. We've done at least a dozen installs now and all have been plug and play.

Did you already reach out to Heffner and confirm everything with the install went as expected? In particular that clearances were no tighter on the gears going in than those coming out?

Had you already driven the car in its original 1.32 configuration? (IE - that it's not a clutch issue)

Hopefully it's just something simple on the trans-to-vehicle install you can address at home.
Best,
John

 

[Dan Carter]

Unfortunately this was a weekend surprise, but making the call is on my Monday to do list. Yes it did drive prior to the install. Based on the inability to engage with engine running and if I push the shifter a bit hard, the car will move slightly. This makes me focus on the slave cylinder, but with only 5 miles on the drive chain, I’m not looking forward to removing the Graz again. So I too hope it’s a simple oversight on my part.

 

[Joel K]

Dan,

Not sure if this is a similar issue but here’s a link:
https://www.gt40s.com/threads/problem-shifting-into-reverse-graziano.48246/

Hope it’s an easy adjustment. Good luck,

Joel

 

[Johan]

Dan, I have seen this before, if you are a little brutal when installing the transmission you can hurt the pilot bearing in the flywheel/crank and the result will be as you describe, it will pull slightly when in gear with clutch pressed and hard/impossible to engage a gear with engine running.

First, make sure you have sufficient travel on the pedal.

 

[Dan Carter]

I was hoping to not have to pull it out again. It went in very easy and seated against the adapter plate without any bolt pressure. It makes sense unfortunately. I don’t recall but does the bearing have a seat to bottom out on?

 

[Ed Davis]

Sounds like air in the line. How did you bleed it?

 

[Dan Carter]

Update

We bled the system two different ways. I first used a vacuum bleeder, and finished the old fashion way by pressing the pedal and opening and closing the bleeder.

I am able to shift into all gears with the engine off. Shift linkage works as advertised. Jacked the rear off the ground and in neutral, turning one tire does not make the other wheel move. Shifting into any gear and turning one tire made the other rotate in opposite direction.

Used the “peep” hole next to bleeder to visually see slave was activating via pedal. Started engine while jacked up and could not shift into any gear. Dejacked the car, put it into gear held clutch in and started engine. With clutch in car crept forward.

This suggest to me the clutch is not fully releasing. Still thinking air. Going to try and power bleed from reservoir side this time. I want to believe it’s air but my gut says Graz is coming out again. Hefner is providing their expertise and I’m following guidance.

Clutch assembly worked before and was not touched while Graz was out for mod.

Any other ideas to trouble shoot.

 

[Frank Clark]

Did this get solved?

We almost always pressure bleed brakes/clutch on all our cars. We have an assortment of reservoir tops with air quick connect fittings. Dial the air pressure down to 3-5psi, screw on the cap and bleed. Makes it a quick one-man operation.

On the race cars we do it the same, but then start the engine, let it warm up, then do a normal pump-release 2-3 times for each slave. It seems that sometimes there is a stuck bubble or two and the vibration from the engine can free it up.

I did have a similar clutch problem on the SLC. Everything was fine on Friday, then Saturday morning fired it up (it was cold overnight), headed to the starting grid. The clutch felt wonky. Gear shifts where clunky. On track the clutch would slip at higher RPMs/Full Throttle. So seemed like it was not full engaged or disengaged. Pulled the trans, all looked OK. Put it back together and it was fine (after being bled of coarse). Never really figured that one out. Do carry a spare master cylinder in the trailer now.

If anyone needs a WILWOOD reservoir top to make a power bleeder, PM me your address. I have a box of them laying around somewhere.

 

[Dan Carter]

The problem was resolved. I had switched from Wilwood to Tilton master cylinders because I could not get the Wilwood to stop leaking. Discovered that despite the same diameters the Tilton was pushing slightly less fluid and the clutch was not disengaging. Pushed the diameter up in size and no more problems.

Like you, I have a bunch of Wilwood products if anyone is in the hunt.