In search of a softer clutch pedal

[BuckShaw]

My clutch pedal is hard to push down. In fact it wears me out shifting. I was considering changing to a pedal & cylinder combo. My pedal pushes an actuator rod to a master cylinder (see pic). I am looking for any option to make the clutch easier to push. Any ideas??????

[peteg59]

A "taller" pedal would in theory give you better leverage potentially reducing the effort needed to work it...

[vw driver]

I'd say the crank needs to be longer and more vertical.

[sonny8l3]

I have my 1st VW trike and have less than 2K miles on it thanks to a much less than honest previous owner in Ok. Also, l am mechanically declined, so I'm no expert. But, when I got mine it almost took 2 feet to push the clutch. The mechanic at Moberly's in Baton Rouge put a pre-load tube on it. It's just a bent piece of tubing that the clutch cable runs through. I don't know why it works, but it now pushes like a VW clutch.
Thanks for your time.

[vw driver]

It sounds like he installed a bowden tube. The adjustment of the bowden tube is very important for correct VW clutch operation. It's the black tube with the cable running through it in the picture.

[sonny8l3]

Yes sir, that's the one. The local independent VW shop here calls it a pre-load tube. I don't understand how it could make a difference, but boy howdy, it sure does.
Thanks for your time.

[Loner]

In reply to the original post, here's some hints for softer pedal:

1. Make sure the leverage of the pedal is minimum 8 to 1 (check the distances from the hinge point to the push rod, and then the hinge point to the pedal that you push). Even 9:1 or 10:1 are feasible, but not lower than 8:1.

2. Get a master cylinder with a smaller bore, like 5/8". I'll bet the one you have has 3/4" bore. The smaller bore will let you move fluid at a softer (lower) rate of flow. The clutch slave cylinder on the market will work perfectly with a good 5/8" bore. Hint: a small Harley brake master cylinder will work perfectly with the aftermarket standard clutch slave cylinders. Or vendors like Jamar offer great master cylinders to fit your needs. If you are using a standard VW master cylinder (as it looks like in the photo), you are trying to move a much higher quantity of fluid at a time whichs means lower pressure. Lower the volume and you lower your pressure required when you push.

Rule: At any given amount of pressure from you on the pedal, you can either move higher volume with less pressure, or lower volume and get higher pressure - and that is all controlled by the bore of the master cylinder for the most part.

3. I can't see how your slave cylinder is set up, but make sure it is a true aftermarket cylinder with proper mounts to attach the slave cylinder with a properly aligned pull rod for your VW application. As a rule, the slave cylinder diameter will be a bit larger than the master cylinder.

I like the build so far.

[vw driver]

[QUOTE=sonny8l3;253265]Yes sir, that's the one. The local independent VW shop here calls it a pre-load tube. I don't understand how it could make a difference, but boy howdy, it sure does.
Thanks for your time.[/QUOTE

Here is some info I found on the bowden tube. It's just one of several unique things VW put on their cars in the past. Don't even ask about the gland nut which is really a bolt.
Bowden Tube

~~~ The "Bowden" tube is the tube through which the clutch cable runs between two welded brackets in the body and the gearbox support arm. These brackets force a "sag" or bend of about 3/4 to 1 inch below the straight line between the body and the support arm. This sag or bend in the clutch cable guide tube is critical -- the friction it imposes on the cable minimizes clutch chatter. If the sag is insufficient, the clutch will jump and shudder when you use it - mostly in first. The Bowden tube allows the engine to rock on it's rubber mounts without pulling on the cable.