Slave cyl

Maybe it would be a good idea to first some how test if extra throw would actually help your problem or not. Maybe your problem is not the amount of throw. I would assume you could manually give your slave more throw by turning in the set screw on the arm so that there is not much play at the slave, and then go in your car, pump the pedal and then try reverse to see what happens. If it helps the situation, then long throw slave may help. But don't leave the adjustment there, as it will most likely ride the throw out bearing. So, return it to the required spacing. Also, you could check the clutch plate measurement when pedal is pressed in (I believe Jack has indicated the minimum measurement in another post). I also have some difficulty getting into reverse, and have not figured it out yet, but had suggestions to check into from other posts...but it is not due to not enough throw.

On my ZF the shifting is excellent, except for getting into reverse. I found if I stop the car, briefly select second, and THEN go for reverse the grind issue goes away. I suspect someone else can tell me what exacly is going on inside the tranny, but since this works fine and solves the problem, I have not searched further for a solution. No sense making work for myself; I still have to mount the CB antenna plate, add a second throttle return spring, paint that awful gold anodized air cleaner, clay bar and Zaino the paint, and clean the undercarriage - and Vegas is only two weekends away!

Larry

[This message has been edited by LF - Teach Peace (edited 04-06-2003).]

With an OEM slave attached to an OEM master cylinder, about the best separation of clutch & flywheel you can get is 0.040" as measured thru the bellhousing hole with a feeler gauge (with the engine OFF) This means the clutch disc has 0.020" of clearance on each of its sides- not much to compensate for disc wobble, thermal expansion etc. A long-throw slave will increase the disengagement to about 0.055" More disc separation= less clutch drag on your tranny synchros, which are VERY expensive to replace- upwards of $1500 for each assembly. Grinding going into reverse will happen on most trannys since reverse has no synchro assembly. The method some of us use is to shift into second, then into reverse. This more closely matches gear speeds & no grinding occurs.

Jack, I measured about .022 through the bellhousing hole with the wife at work on the pedal. Is that enough, or should I be getting about .040?

Sorry- 0.022" divided by 2 (since the disc works on both its surfaces), means only 0.011" of friction-surface separation. You will have massive drag on the gear synchronizers, I'm afraid. Either the multiple steel-on-steel contact points in the clutch linkage is badly worn, especially in an 'L' model with the over-center mechanism under the dash. the needle bearings on the bellhousing cross-shaft or the adjustment on the slave cylinder is not correct. For loose under-dash linkage, the only fix is to remove it, weld up the holes & re-ream to size plus replacing the worn shafts. This means pulling the dash as theres no access otherwise. OR, it may mean internal leakage in the master cylinder and/or slave. You can install a long-throw slave, in stainless steel, and I suggest a new ss clutch master as well. Believe me, the car will shift better, and its an investment in NOT spending thousands for a ZF overhaul later.

Thanks Jack. Yes it is an L model, and the slave is adjusted properly & the pedal is stiff, etc, and it also shifts great in all gears, but some problem only in reverse on occasion. So I thought everything was ok, until I did the measurement at the bellhousing. If I am shifting in gears smooth as butter (except for reverse), I didn't think there would be drag on the synchros, no?

Jack, even though I have 0.022" through the bellhousing measurement, I shift with no drag at all by feel of the shifter. Do you think I could still be having drag on the synchros? I would think that I would feel some effect on the shifting if I had a problem, but I certainly am no mechanical genious.

Does anyone know the difference in travel between a stock slave and a long-throw measured at the slave itself?

The measurement of slave throw of my stock unit is about 5/8".

Due to the numerous links, bell cranks, seeping hydraulic seals in the clutch, and the deflections one gets with the overly- stiff clutches used on many cars, it really doesn't matter what the cylinder travel is. What matters is the final disengagement at the flywheel as-measured. Even when the Pantera was brand-new (32+ years ago) and factory-adjusted, clutch disengagement was marginal IMHO.