Cable vs hydraulic clutches

JamesShort · **Posted:** Tue Jul 24, 2012 2:03 pm

Why in the world did auto manufacturers go to a hydraulic clutches?

Since buying the CRX, I'm very much liking the cable clutch: its nearly maintenance free, adjusts in seconds, if it breaks it's cheap to replace, it allows for fast and mess free transmission removal, and it feels no better and no worse than a hydraulic clutch.

We talked about it at lunch a few weeks ago and Rich said that older cars had the cables right near the exhaust and they'd fail because of that but that seems easy to work around....having hydraulic fluid near exhaust really isn't any better

.

jeremy gast · **Posted:** Tue Jul 24, 2012 2:10 pm

that is with a stock clutch set up. If you went to anything real big if feels terrible. I had a cable b series transmission in my del sol. It was ok but eventually I went with two strong of a clutch and it was a pain in the butt.

But definately ease of adjustment is so much better!!!

and James I am jealous of you car, I had one just like it back when I first started working for Japan Direct

JamesShort · **Posted:** Tue Jul 24, 2012 2:21 pm

jeremy gast wrote:

that is with a stock clutch set up. If you went to anything real big if feels terrible. I had a cable b series transmission in my del sol. It was ok but eventually I went with two strong of a clutch and it was a pain in the butt.

But definately ease of adjustment is so much better!!!

and James I am jealous of you car, I had one just like it back when I first started working for Japan Direct

Hmmm, I see, so when going with a heavy duty pressure plate, the cable housing can't withstand the cable tension required to actuate the clutch? I can see that. There is likely a point that the housing starts to compress too much and makes for unreliable/mushy pedal feel.

Anyway, I'm talking more from a stock clutch perspective anyway. I'm not really to into big fancy HD clutches/pressure plates anyway.

Vincent Keene · **Posted:** Tue Jul 24, 2012 3:03 pm

I have no problem with hydraulic clutches. I do have a problem with the advent of the internal slave cylinder. It was likely introduced to save 10 seconds on the assembly line or some crap, which is fine until it needs replacement and the transmission needs to be removed to do so.

I'm fairly certain all moder GM cars use the internal slave as does my Z-24. The Miata and Prelude have an external slave and fixing those is easy peasy.

JamesShort · **Posted:** Tue Jul 24, 2012 3:17 pm

Vincent Keene wrote:

I have no problem with hydraulic clutches. I do have a problem with the advent of the internal slave cylinder. It was likely introduced to save 10 seconds on the assembly line or some crap, which is fine until it needs replacement and the transmission needs to be removed to do so.

I'm fairly certain all moder GM cars use the internal slave as does my Z-24. The Miata and Prelude have an external slave and fixing those is easy peasy.

I'm quite the opposite. I have problems with all cylinders: slave or master. Think of how many times people talk about them failing. They are brain dead simple and I just don't understand why they fail so frequently.

Vincent Keene · **Posted:** Tue Jul 24, 2012 3:20 pm

JamesShort wrote:

I'm quite the opposite. I have problems with all cylinders: slave or master. Think of how many times people talk about them failing. They are brain dead simple and I just don't understand why they fail so frequently.

Since the hydraulic system of a clutch is basically the same as brakes, which rarely fail IME, so I don't understand either.

JamesShort · **Posted:** Tue Jul 24, 2012 3:22 pm

Vincent Keene wrote:

JamesShort wrote:

I'm quite the opposite. I have problems with all cylinders: slave or master. Think of how many times people talk about them failing. They are brain dead simple and I just don't understand why they fail so frequently.

Since the hydraulic system of a clutch is basically the same as brakes, which rarely fail IME, so I don't understand either.

Exactly.

JamesMilko · **Posted:** Tue Jul 24, 2012 3:24 pm

The pistons in the clutch system move significantly more than the ones in a brake system.

RickyBeam · **Posted:** Tue Jul 24, 2012 5:32 pm

Vincent Keene wrote:

Since the hydraulic system of a clutch is basically the same as brakes, which rarely fail IME, so I don't understand either.

Answer: cheap, Chinese re-manufactured parts.

BretLuter · **Posted:** Tue Jul 24, 2012 8:45 pm

Vincent Keene wrote:

I have no problem with hydraulic clutches. I do have a problem with the advent of the internal slave cylinder. It was likely introduced to save 10 seconds on the assembly line or some crap, which is fine until it needs replacement and the transmission needs to be removed to do so.

I'm fairly certain all moder GM cars use the internal slave as does my Z-24. The Miata and Prelude have an external slave and fixing those is easy peasy.

Yah, Hans und Franz never use ze internal slave zylinder. I can swap out a slave cyl on most BMW's in about 15 minutes, including 5 minutes looking for my jack and jack stands.

:thumbsup:

Charlie Guthrie · **Joined:** Thu Aug 28, 2003 8:14 pm **Posts:** 832

The reason that clutch cylinders fail is the same as for brakes except that while a few folks replace their brake fluid (mostly at the harassment of their mechanics), almost no one replaces clutch fluid until it self-drains.
I hate cable clutches for maintenance reasons. The ones I have had to deal with were buried under other stuff and suffered wear. Most newer hydraulic clutch slaves are self adjusting. Of course I would never own one of those crummy ahmerikun cars with the internal slave cylinders....only a cheapskate engineer could have come up with that one. Wasn't the first one on a Jeep or other Chrysler product? Admittedly it does away with the bearing actuator fork, but at what a cost in repair when it fails before the clutch.
The only bad clutch slave replacement was on the MG Midget which totally refused to be bled after replacement (until vacuum bleeders came along).
Charlie G

George Bright · **Posted:** Wed Jul 25, 2012 7:56 am

JamesShort wrote:

Vincent Keene wrote:

I have no problem with hydraulic clutches. I do have a problem with the advent of the internal slave cylinder. It was likely introduced to save 10 seconds on the assembly line or some crap, which is fine until it needs replacement and the transmission needs to be removed to do so.

I'm fairly certain all moder GM cars use the internal slave as does my Z-24. The Miata and Prelude have an external slave and fixing those is easy peasy.

I'm quite the opposite. I have problems with all cylinders: slave or master. Think of how many times people talk about them failing. They are brain dead simple and I just don't understand why they fail so frequently.

The original clutch master cylinder finally failed a month ago on my 81 Datsun with 165k miles. The slave cylinder failed about 3 years ago. :poke:

Matt McGrain · **Posted:** Wed Jul 25, 2012 10:42 am

I'd say half my cars have had leaky clutch master cylinders and the AP2 is leaking too but I've been too lazy to put the new one in but I hope it improves the horrid launches, but I'm still skeptical. BTW, thanks for the tip on the gravity bleed James.

Also, I can just use the Honda Dot 3 brake fluid on the AP2 right?

JamesShort · **Posted:** Wed Jul 25, 2012 10:46 am

Matt McGrain wrote:

I'd say half my cars have had leaky clutch master cylinders and the AP2 is leaking too but I've been too lazy to put the new one in but I hope it improves the horrid launches, but I'm still skeptical. BTW, thanks for the tip on the gravity bleed James.

Also, I can just use the Honda Dot 3 brake fluid on the AP2 right?

3, 4 or 5.1

If you replace the CMC, then bench bleed the sucker first as a gravity bleed probably won't be sufficient.

JamesShort · **Posted:** Wed Jul 25, 2012 10:55 am

Charlie Guthrie wrote:

The reason that clutch cylinders fail is the same as for brakes except that while a few folks replace their brake fluid (mostly at the harassment of their mechanics), almost no one replaces clutch fluid until it self-drains.
I hate cable clutches for maintenance reasons. The ones I have had to deal with were buried under other stuff and suffered wear. Most newer hydraulic clutch slaves are self adjusting. Of course I would never own one of those crummy ahmerikun cars with the internal slave cylinders....only a cheapskate engineer could have come up with that one. Wasn't the first one on a Jeep or other Chrysler product? Admittedly it does away with the bearing actuator fork, but at what a cost in repair when it fails before the clutch.
The only bad clutch slave replacement was on the MG Midget which totally refused to be bled after replacement (until vacuum bleeders came along).
Charlie G

I agree that few people replace/flush their clutch fluid, but very few people do their brake fluid as well, despite mechanic harassment.

I think James Milko likely nailed it. The pistons in the CMC/SC move significantly and are actuated many times per braking incident and brake cylinders hardly move at all. It probably just comes down to the manufacturing tolerances on the piston bores coupled with seals that don't last forever when they get slightly deformed due to a non perfect cylinder on every actuation of the clutch pedal.

Anyway I still think cable clutches are winning

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Cable vs hydraulic clutches

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