Stiff Pedal Fix

[anmagro]

I have been driving my 98 A4 2.8L 30V Manual Quattro for 6+ years now (that i can remember), and have put on about 100,000 miles. Long story short my left knee is starting to get pretty sore from using the clutch. I know it sounds odd but after extended driving or a lot of holding the clutch in heavy traffic my knee begins to ache. And i sometimes even feel the pain the next day. As a side note, i am only 22 years old. And it just so happens that my knee has had enough of this particular motion considering how much driving i do at any given time.

So my question now is....

... can the pressure of the clutch pedal be adjusted? Or is this abnormally stiff pedal just something im going to have to deal with? I was even thinking of making some like of modification to the pedal to make it easier to press. Such as an assist spring or even a lead weight attached to the under side of the pedal.

Tell me what you think.

[walky_talky20]

There is an assist spring (it's called an "over-center spring"). It's main job is to reduce the effort needed to hold the clutch pedal to the floor. It also helps to give the pedal motion a more "linear" feel, rather than an "additive" feel as you push it down further.

In my car, I'm using a heavier B5 S4 over-center spring with a stock B6 1.8T pressure plate. This has the effect of making it a very "easy" clutch as far as force applied. Indeed easier to hold to the floor than a stock 1.8T setup. Other people complain that my clutch is "too light!". Like you, I do a lot of driving so I very much prefer it.

There are 3 different over-center springs for the B5 chassis, based on engine: 1.8T, 2.8, or 2.7T. The spring "assist" is increased to help with the added clamping force (and thus pedal effort) required with the higher torque engines. The heaviest spring is used on the S4, and is also used on the C5 A6 2.7T and Allroad 2.7T (6-speed of course).

I think this would be the easiest and simplest thing to try first. Swap to the heavier spring and see how you like it. If that didn't do it, you could probably fashion an additional spring - perhaps something more like the "external" spring design used on the B6 chassis.

EDIT:
Here's a link to the B5 S4 spring: http://www.ecstuning.com/Search/8D0_721_449_Q/ES430248/

I will say it's not super easy to change the spring. I removed and installed the spring outside the car with a good amount of effort. There is a lot of spring load to deal with. I think I used a pair of pliers to get it in there. I don't know how much of a pain this would be under the dash.

[Mad Cow]

I had no issues with installing that spring, I just detached the clutch master from the pedal first. This was with the pedals out of the car but shouldn't be much more difficult without pulling them.

So my stock 2.8 spring will make my now 1.8t clutch lighter? That's a pretty good side effect, traffic can get annoying at times.

[034Motorsport]

I run a stock S4 clutch in my '99 A4 V6. I also used to have a stock clutch in my S4. The clutch pedal in my A4 has always been stiffer than my S4, even with a Southbend aftermarket clutch. In fact, my A4 clutch isn't all that different compared to my old SPEC Carbon twin disc. I've bled it a few times, always just feels solid. I really wish I could have "swapped" that feel over to my S4, as the S4 never felt so solid.

Stock S4 clutch to stock S4 clutch, the A4 was stiffer than me S4, and harder to hold the pedal down.

Some cars are just stiff it seems. I've driven other V6's that weren't like mine.

[anmagro]

Walky, check me on my logic here. The way the clutch pedal seems to work....wouldent a stiffer spring make it harder to press the clutch in? Maybe im a little backwards.

[Mad Cow]

The spring pushes the clutch pedal outwards, so a stiffer spring provides more assist. It would also explain why an S4 clutch in a 2.8 is stiffer than on an S4.

[walky_talky20]

Walky, check me on my logic here. The way the clutch pedal seems to work....wouldent a stiffer spring make it harder to press the clutch in? Maybe im a little backwards.

That's a very good observation. However, the "center" switch over point for the spring is quite high. Only the very top movement of the pedal would show the increased tension. That part of the motion has very little required effort from the hydraulic side of things. So the effect is mostly just decreased pedal effort overall.

With the S4 spring and a 1.8T clutch in my car, the pedal is almost "stupid light". Every other person that drives my car thinks there is something wrong with it, it's that light. But you adjust quite quickly, and I really like it. I think it makes it easier to handle the engagement. You aren't fighting a high spring rate so you can be more precise.

[ricekikr]

Or is this abnormally stiff pedal just something im going to have to deal with?

How old's the pressure plate (mileage-wise)? I ask, cause pressure plates, normally, get stiffer as it ages.

If it's old, its probably not abnormally stiff, and a new pressure plate would fix it. (even though clutch isn't sliding yet)