I suppose that is a theoretical issue to consider. But Tilton is a tier 1 supplier to new car manufacturers and I think the likelihood of failure is similar to what you would see on a new cars brakes and manual clutch. I have been a Land Rover and Toyota dealer for 25 years and the incidence of that type of failure is staggeringly low. I would bet that the failure of the the clutch cross/fork/tapered bolt is way higher. In fact that is the reason that my 140 OTS was garaged from 1971 until this year when I bought it. Recurrent clutch fork failure. The original owner just got frustrated and put it away. Additional benefit is the way better feel of the clutch pedal.
Brucerudin, I was hesitant to modify my car to the point where it couldn’t be returned to original spec, but I am interested to know, if you don’t mind, what you did to convert your 140 to a hydraulically operated clutch. Jim
I have had to deal with one Tilton and one other make annular release bearing mechanism, both of which suffered hydraulic failures. It’s a right pain having to pull the gearbox, or in the 289 Cobra’s case, the engine, just to replace a seal. It may be that aftermarket applications do not have the reliability of units fitted as manufacturer’s OE.
The pedal feel with the extended lever, as designed by Jim above, feels just right to me, but we’ll see how things go on the road. The pins are a weak point, but I’m hoping that by using the best quality I could get, all from the same supplier, coupled with the reduced pressure required to operate the diaphragm clutch cover, will provide decent longevity. Hope I’m not proved wrong!
Jim, that was important to me, too. The only modified part on mine is the pedal lever, for which I used a Coventry Auto steel repro and kept my original on the shelf.
I went with the Coventry Auto pedal box. I needed more room in the cockpit and after a failure of a single circuit braking system on a 356 Speedster I swore I would NEVER have that on another car. So it checked multiple boxes. Hydraulic clutch, dual circuit braking and about 3 inches more room. You guys can wax prolific about an original XK. Too me the steering is heavy, the brakes fair and the clutch brutal for long events. It made no sense to me to keep the mechanical clutch system and go with a 150 slave cylinder. I am willing to take my chances on a failure over the cross shaft and fork.
My experience of fitting a Mcleod co-axial slave cylinder to my Iso Grifo (with Tremec TKO600) was not without problems. After a time it suffered seal failure which turned out to be the O-ring seals having swollen due to not being compatible with Dot 5 silicone fluid. The ATE braking system never had any issues with silicone. Once new seals were fitted (after pulling engine & box!) everything was fine with normal hydraulic fluid. Maybe something to bear in mind?
Fluid incompatibility seems to be a regular topic here. Curious if the Macleod part said not to use silicone fluid? I have found with my older cars and the mismatch of seals that I am safer with regular fluid. Love the Grifo. Beautiful car.
So…
The McLeod spec sheet says compatible with DOT 3 & 4. Incompatible with DOT 5. After resolving that did you like the action of the clutch?
I’m very lucky, in that at 5’ 8" I fit pretty much everything without the need for modifications. I find I can live with single circuit cars - my Cooper S, Healeys, TRs, all had this arrangement and, touchwood, no problems so far. As for heavy clutches - don’t try an original Cobra 289. It’s hydraulic, but with the cylinder bores AC chose you almost need both feet, but I did manage to pedal mine around Europe for 15+ years OK. It’s probably down to the adrenaline! …or Epinephrine, in American. I don’t know anything about the 150 hydraulics though, my 140 is purely mechanical.
I must have missed that info when I read the instructions (if I did…) I think it did turn out to be an improvement on the previous external slave cylinder and fork. Hardly worth the extra expense and invonvenience if anything went wrong, though. The feel of the conventional diaphragm clutch over the previous twin plate Mcleod was quite an improvement. It would apparently have taken up to 1300hp, and I only had 500! It wasn’t the street version with spring steel straps locaing the centre metal disc but the racing type with three “ears” with holes which slid up and down on “stands” like smooth faced bolts with a PTFE coating, Trouble is, the PTFE wore, causing steps, resulting in an unpredictable clutch engagement. And, it was noisy! The Grifo was a great car, though. It was the big-block version.
I have always thought that sixties Italian styling coupled with large cast iron V8 technology was the way to go. I loved my 440 Jensen Interceptor - couldn’t afford an Iso or Monteverdi - but at the end of the day the Chrysler slushbox was not very involving. I’d have another Interceptor over anything built by Aston, though, any day of the week. And Eric Morecambe had one…
I think we’re in danger of hijacking this thread! I’ll finish by saying that it was owning a Jensen CV8 Mk III which got me into Euro-American hybrids in the first place. Before that I was a Jag man pure and simple, and would look down my nose at anything with a crude cast-iron V8 (little did I know!). I then got my Grifo 7L which I kept for nearly 30 years, before it became too valuable for me to justify owning any more. So, it was back to my first love, the XK120, having finally got the speed bug out of my system!
A similar story to mine, with my '64 leaf-spring Cobra 289. It’s no fun when you can’t leave them anywhere.
I don’t feel too bad about hi-jacking my own thread…
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