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Posted by: SKL1 Apr 25 2015, 08:03 PM

In troubleshooting a binding throttle cable, after removing the old cable I was trying to fish the new Terry cable thru the tunnel tube and it kept getting caught up about 2 1/2- 3 feet in towards the front. Could fish a stiff wire through fine but the bigger threaded end would not go past that point. Could also get the old cable end back thru but the new one must be slightly bigger diameter and will NOT go. Looking thru the little holes by the shifter and heater lever (which is removed anyway as I'm not using a heater) I can't really see the tubes anyway so can't see from the front if something is partially blocking it.
I remember helping my son clean the SAI ports on his 993 with an old bicycle brake cable and a power drill and wondered if I fish something like that through it may clean something out left from the restoration and painting. Since I'm not using tubes from the heater cables I thought about using one of those but the flared ends don't fit the throttle cable end that well.

Any ideas of what to use on a drill etc to "clean" things out?? I don't want to destroy another cable trying to "force" it through...

This throttle linkage project is going to be the end of me...

Posted by: mgp4591 Apr 25 2015, 08:07 PM

Maybe an old fat guitar string? I'm sure there's plenty available at your local music store... How long do you need it to be?

Posted by: SKL1 Apr 25 2015, 08:08 PM

not 914 content, but thought it was worth seeing- PCA event today at shop who did the restoration on my '73. Pre A split windshield- I think the tires on my bicycle are wider!!

Posted by: McMark Apr 25 2015, 08:15 PM

Was there any welding in that area?

I just had to cut the tube out of a car and replace it because of a stuck cable. My biggest advice, think long and hard about how to backtrack from any step. Ive heard of multiple 'fixes' that can leave you worse off if they fail.

Posted by: SKL1 Apr 25 2015, 08:40 PM

I remember seeing an image of the tubes exposed to show what they look like but search didn't help. Anyone have that??

Posted by: dangrouche Apr 25 2015, 08:47 PM

I guess you need to determine that your tube is nice and clean. push a copper 12 or 14 gauge copper wire from the rear to the front. once you have determined you have a clear path, then you can try this technique: By hand, push and rotate the new cable in a clockwise direction. Perform the push and turning simultaneously. I had a GEMO brand accelerator cable that I had a hard time installing until I did the push/twirl technique. A small spray of WD40 on the head of the cable also helped let the cable ease forward. let us know how it works out

Posted by: 76-914 Apr 25 2015, 08:53 PM

Push it till it stops then lightly pull back on it, then twist it slightly while gently pushing and it should slip thru.

Posted by: altitude411 Apr 25 2015, 08:59 PM

That split window is beautiful
If you want pictures of the inside of the tunnel Google is your friend...search { tunnel Porsche 914} select images

http://www.pelicanparts.com/techarticles/914_center_tunnel/911_center_tunnel.htm
(Thanks Dave)

Posted by: Socalandy Apr 25 2015, 09:08 PM

pics when my pans were being replaced


Attached image(s)

Posted by: Mike Bellis Apr 25 2015, 09:41 PM

Get a steel fish tape. These are made for pulling electrical wires through conduit.

Cut a 8' section off the reel. Place one end in a drill motor. Get a friend to help. put on gloves and take the loose end and push it into the tube. Have the friend start the drill motor while pushing forward. You will corral the fish tape with your hands to keep it from flopping all over the place.

The spinning fish tape will loosen debris from the tube. If it binds, back it out and slowly move forward again. Once you get the fish all the way to the throttle pedal, pull it out and blow the tube with compressed air.

If the fish tape will not go through, you may have more than debris and may have to cut and weld.

Many times, the hard plastic sheath will break off chunks in the tube and prevent new cable installation.

Tip: When cutting the fish tape, bend over the end of the remaining tape or it will unwind like a clock spring inside the carrier.


$7.99 at Harbor Freight
http://www.harborfreight.com/50-ft-fish-tape-38156.html

Posted by: Jeff Hail Apr 25 2015, 10:33 PM

Clean the tube out first. Some cables had liners that disintegrate and pieces get stuck in the tube.

If it still wont pass through -

Sounds like its hanging up at the bend under the floor crossmember.
A trick I learned twenty something years ago.... cut a 1/16 or 1/8 inch off the threads on the pedal end of the cable. Put a nut on it first to chase the threads/ debur after trimming.

The crimped section on the usual suspect aftermarket cables is a little fatter and sometimes longer than the factory cables and hangs up at the tube bend not wanting to make the turn.

Posted by: Dave_Darling Apr 25 2015, 10:36 PM

I have also heard of people grinding off the corners of the ferule on the end of the throttle cable to let it fit through the tube a little more easily.

--DD

Posted by: Mr.242 Apr 26 2015, 12:01 AM

Perhaps you can get a small caliber gun cleaning kit with a flexible shaft that you can push/pull the small brass brush into the and through the tube? Putting it on your drill to spin as you press it in...

Posted by: 914Sixer Apr 26 2015, 06:16 AM

I would take a air compressor and see if i could blow the problem out in either direction. You will need it cranked up to at least a 100 psi. Might be stuck in one direction.

Posted by: Racer Chris Apr 26 2015, 08:03 AM

A good tool for tube cleaning is a 1/8" dia steel welding rod hammered flat on one end and shaped like a spade drill.

Posted by: Mblizzard Apr 26 2015, 09:35 AM

Exactly what I had to do. Took a long time to get all of the stuff out but it works.

Posted by: Jeffs9146 Apr 26 2015, 10:36 AM

I had the exact same problem on my 75! I ended up measuring the point the cable stopped and found that at the exact point inside the tunnel was a weld that had blown through the inside of the tunnel. I ground off the top of the tube next to the weld and used a screw driver to bend the bad metal out of the way. I left the tube open and I can now see the wire moving freely through the tube.

Posted by: worn Apr 26 2015, 03:01 PM

I cut through a tube accidentally and swaged a copper sort of bullet onto steel cable as a backer for weld repair. The idea is that if you do weld, you need a copper backing. Or low penetration of the weld.
The spade bit also works and if properly attached can work on a flex cable.
But Dave is right. You need to know how the sucker is coming back out. No matter what.
Good luck!

Posted by: HarveyH Apr 26 2015, 03:15 PM

What Dave said!
I seem to have heard that sometimes there is a slight ovaling of the tubing where it is bent, or that the crimping is slightly larger than the original cables.


A few minutes gently filing.

Harvey

Posted by: SKL1 Apr 26 2015, 08:18 PM

Now I remember I saw those images at pelican! Looking at those pix it is probably binding at that slight turn near the level of the shift lever.

I've already tried compressed air and lots of WD40 so some of these other ideas sound promising.

Thanks for the suggestions!

Posted by: r_towle Apr 26 2015, 10:03 PM

Posted by: altitude411 Apr 26 2015, 10:07 PM

Posted by: dcecc1968 Apr 27 2015, 07:38 AM

Thanks for posting. I'll be installing my new Terry cable this weekend....now at least I know what I'm up against.

-Don

Posted by: SKL1 Apr 27 2015, 07:59 PM

Good luck Don- it was the Terry cable I couldn't get through... the cheaper cable did make it but seems to bind. Will try cleaning out with electrical fish wire as suggested above.

Posted by: 914werke Jul 8 2018, 01:46 PM

Resurrecting this old thread. Went through this ...again, with a GEMO cable.
Took a bit of "contouring" for the new cable end to pass the bend/obstruction.
Suggest that this be moved to classic area for future peeps.