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Well, 2511 has never let me down and stranded me away from home. But Sunday was almost the end of that reality.

After putting about 400 miles on an anniversary trip up to the California Gold Country, with many hills, corners, and a lot of shifting, I started having problems about five miles from home.

Barely got it backed into the garage.

First thing yesterday morning, I ordered rebuild kits for the CNC master cylinder and the McLeod hydraulic throw out bearing. They should arrive today or tomorrow.

I was pretty sure the MC was doing an internal bypass, so I pulled it this afternoon.

I think I found my problem. What do you think? Wink

Larry

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quote:
That thing is nice...

That's what YOU think... Wink

I'm not going to look up Dennis' current cost, in fact, I'm not sure he even will sell it anymore.

It was a work-around, in the days before the long throw slave, to improve clutch action.

The seals are known to fail from non use - they dry out too much. That happened with 2511 shortly after I purchased it, requiring the removal of the ZF.

The set up is intense and time consuming. We are talking 1000's of an inch here, and of course, there is no method to adjust anything once it is all put back together.

In my case, the threaded aluminum adapter ring which was intended to resist rotation (and loss of set-up measurements) because of its two inner o-rings (not visible) and their friction on the ZF input shaft housing managed to rotate anyways, probably a result of vibration....so, out came the ZF.

I devised a system using three 4-40 allen head set screws that has proven effective at holding things in place.

In my talks with Dennis about this system, he says it is okay for a racer that expects to be removing the ZF with regularity, or someone like me that actually puts regular miles on the car - 700 or so in the last two weeks, and headed to Reno next week.

But with long throw slaves now available, and the adjustment hassles of the internal unit, he no longer thinks it is a good choice.

Larry
Last edited by lf-tp2511
I made a few of these for our car and a couple of friends using Tilton's racing throwout system- different from Dennis' rig. Besides what Larry says about the seals, the biggest single problem with all such throwouts is getting enough free play. The quad-rings on which the system depends must have enough free pay WHEN HOT so the piston doesn't bottom. The quad ring seals linear back-and-forth motion only. If the piston bottoms, it will spin with the clutch and a few miles of that will destroy the ring. And you aren't gonna find parts at a roadside Kragens even if you could pull the ZF! Nevertheless, I have 20,000 miles on ours and Larry has at least that much, so if set up properly, they work fine, remove over 6 lbs from the powertrain and with a stock master, act like a long-throw slave cylinder. My rig gives 0.075" of throwout bearing travel, which a stocker gives maybe 0.035" and a long throw about .050" This extra distance prolongs the life of your ZF synchros by reducing clutch drag when shifting
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