[lal Naja]

External actuating deviced, machanical & hydraulic have been applying pressure to clutches successfully doing the job for decades on millions of cars. When some of the external components wear out, replacement and adjustment can be simple & quick. So there are some advantages and if you have the space for the external components it could be a wise choice.

On the other hand, Internal HTOB's have also been successfully doing their job of actuating clutches. And I understand that many car manufacturers use the system. I'm not a mechanic, so I can't vouch for failure statistics on production cars. Or for that matter how many million units are in service.

The installation of the HTOB however, needs to be accurate. The system is intolerant to incorrect spacing. No external adjustment is possible and if you get it wrong you have to pull the transmission to correct it. If the hydraulics wear out on the HTOB the transmission needs to be pulled to repair it. That's a lot more work than the external system.

If the throwout bearing fails in either installation the transmission needs too be pulled to replace it.

I tried very hard to get an external system to work in my limited space on my Cobra, but gave up and opted for the HTOB. I was not happy with the design of the shimming system that came with the HTOB. I accurately took all the measurements and made a custom spacer to exactly suit my situation. Net result is that I'm pleased with my HTOB installation. As I do all my own work single-handedly, I'm making sure the transmission removal is made as easy as possible when the inevitable happens.

If you are interested in seeing photos of my installation you can do so in my Profile Album.

Arthur