Throttle Cable Rubing, How I fixed that dragg'n feeling Options

[ctc911ctc]

Teeners,

'74 2.0

The pedal assembly was rebuilt, painstakingly cleaned and then powder coated. greased to perfection and then installed.

New Clutch and throttle cable, rebuilt calipers on all 4 corners, brake lines, etc.

All worked great with the exception of the gas pedal. It just seemed to be grabbing when depressed. Ugh

Today I tackled this job, took a few hours - this is what I learned.

First I followed in the previous steps suggested here in 914W

1. Wrapped Around the clutch pedal? No, no throttle movement when depressing clutch and with a mirrored light was able to visually verify.
2. Guide crushed or bent. No
3, firewall to engine turns too tight? Verified long bends, within an acceptable range.

So,

I took the cable off of the throttle body and started to debug.
Seems that the factory that built this cable (German but not stamped as a Porsche part - did not cost a great deal as well) used a bundle of rigid wire as a guide. This guide is then either shrink wrapped or dipped in plastic for the coating.



I found that the cable when pulled across these wires managed to snag every few millimeters. Just enough to provide that dragging feeling.



I decided to push the plastic sleeve shown above down into the wire guide so that all of the guide wires surrounded the plastic sleeve. This removed the opportunity for the wire-against-sharp wire edge to connect thereby removing the snagging that was felt in the pedal. I added a few dabs of epoxy to bond the plastic sleeve to the surrounding wires (careful not to get any on the internal cable) and the results were slicker than snot on a glass door knob! Perfect throttle feel.

Oh, before I did this I also tried to file the wires hoping to remove the sharp edges. Wasted an hour there.

[ctc911ctc]

*****Update*******

Drove the car 20+ miles today - roads are open and free of drivers.

Question: Why wear a mask while driving your car?????

The throttle was smooth as silk, really a major improvement - Suggest you give it a try if you have a dragg'n right foot.

CTC911CTC

[Stltri]

What kind of plastic sleeve is that?

[ctc911ctc]

Came with the cable, very hard and plyable. My guess would be a Nylon mix. Like used on bushings, etc.

What kind of plastic sleeve is that?

[Superhawk996]

Question: Why wear a mask while driving your car?????

Because people blindly listen to the "authorities" and can't do math. Here in Michigan you can no longer buy paint or garden seeds (our commissar has deemed them non-essential) but you can buy lottery tickets that benefit the state. Hmmm. (IMG:style_emoticons/default/idea.gif)


Great job debugging the cable. I've not seen one manufactured that way, where it was possible to drag the cable over the raw wire winding of the housing. That end fitting doesn't seem to be crimped properly. I really shouldn't have been able to be pulled off the sheath. It probably moved and then started allowing the inner cable to drag on the housing sheath.

That would be a tough one to figure out and you nailed it. (IMG:style_emoticons/default/cheer.gif)

[cary]

Gemco cable. I changed out mine this weekend. Found the same issue, used your idea. Added a couple drops of GEL Super Glue and slid the ferrule (?) back on.
The old cable was wearing in that exact spot. But it didn't have a liner.

[FL000]

Thanks for sharing, will have to add this to my list of things to check (IMG:style_emoticons/default/beerchug.gif)

[JamesM]

This is perfect timing as I just put a new throttle cable in a restoration project and its hanging so badly as to not let the throttle return at all. Old pedal cluster bushings on mine are for sure a contributing factor, but even disconnected from the cluster the throttle return is very sluggish and you can hear it dragging in the tunnel.

There was a noticeable quality difference between the new "German" cable and the original cable that came out of the car.

looks like ill be pulling the cable back out again for some fiddling this weekend.

[913B]

Teeners,

'74 2.0

The pedal assembly was rebuilt, painstakingly cleaned and then powder coated. greased to perfection and then installed.

New Clutch and throttle cable, rebuilt calipers on all 4 corners, brake lines, etc.

All worked great with the exception of the gas pedal. It just seemed to be grabbing when depressed. Ugh

Today I tackled this job, took a few hours - this is what I learned.

First I followed in the previous steps suggested here in 914W

1. Wrapped Around the clutch pedal? No, no throttle movement when depressing clutch and with a mirrored light was able to visually verify.
2. Guide crushed or bent. No
3, firewall to engine turns too tight? Verified long bends, within an acceptable range.

So,

I took the cable off of the throttle body and started to debug.
Seems that the factory that built this cable (German but not stamped as a Porsche part - did not cost a great deal as well) used a bundle of rigid wire as a guide. This guide is then either shrink wrapped or dipped in plastic for the coating.



I found that the cable when pulled across these wires managed to snag every few millimeters. Just enough to provide that dragging feeling.



I decided to push the plastic sleeve shown above down into the wire guide so that all of the guide wires surrounded the plastic sleeve. This removed the opportunity for the wire-against-sharp wire edge to connect thereby removing the snagging that was felt in the pedal. I added a few dabs of epoxy to bond the plastic sleeve to the surrounding wires (careful not to get any on the internal cable) and the results were slicker than snot on a glass door knob! Perfect throttle feel.

Oh, before I did this I also tried to file the wires hoping to remove the sharp edges. Wasted an hour there.

In your first pic, how did you pull the metal sleeve to expose the guide pins, did you just simply pull it away and how did you re-install it back over the cable, did you have to crimp a bit or glue that too? (IMG:style_emoticons/default/blink.gif)

Thanks for the debugging!
Ted