| Author | Message | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 90 Registered: 5-2009 Posted From: 65.92.48.78 Rating: N/A |
This is kind of for posterity, for the next guy that tries to find out how to do this. Also posted on BNO. I installed a new throttle cable in my 1980 MC-5C yesterday, after struggling for some time with it, so here is the story. The stock throttle cable is a Morse cable, and runs about dead straight front to back in the duct chase that all the plumbing runs in down the center of the bus. I could not find a stock replacement cable, so I pulled the old one out, pulling a pull-cord behind it, and sent it off to a control cable place to have it duplicated. I got the cable back and noticed immediately that the swaged on ends were larger than the ends on the stock cable. Maybe it won't matter, sez I. Yes, it matters. The cable runs through a series of supports, which are grommeted holes in flanges or bulkheads that run across the duct. The holes are about .6" in diameter. The stock cable is about .510" in diameter at the swaged end, and can be pulled through. Anything larger cannot. The tightest part is at the heater core bay, where there is a section of tube that the cable runs through, and the entrance to that little bit of tube is a tight pull fit over the swaged end. Your replacement cable MUST have no larger than .51" diameter or it won't go through. Next thing is pulling through. In my case I had removed my original cable to have a new one made to match. I tried to pull the new one, with the larger .65" ends, and it hung up about three feet in. I could tell that it was hanging up on the ends by the scuff marks. I tried pulling the original cable back in as a test, which is when I found the thing about the tight tube entrance in the heater bay. I had a few wraps of tape over the swaged end to hold the pull cord tight, and the wraps of tape and the pull cord were enough to hang up the cable and jam it. I had to pull it back out, take that tape off, trim the pull cord, lube the heck out of it and try again. Even then it was a tight pull past that bulkhead. After I got the original cable back in and found that tight spot in the heater bay, I ground and filed the swaged end on the new cable to .5" diameter from it's original .65" diameter. I made up a coupling bolt and bolted the new cable to the end of the old cable, taped up the sharp transitions, lubed it up and pulled it through. Again quite hard to get the ends past that tight spot, but this is really the best way to do it. So there you go. If you are having a new throttle cable made for your MCI, specify that the swaged ends and the cable itself can be .5" diameter, no larger. If you are pulling an air line through for an air throttle, same deal - pull it through but no larger than .5" OD. And if you ever pull the throttle cable out for any reason, pull a strong pull-cord through behind it - you could spend a month of Sunday's trying to fish a line through the twenty odd support bulkheads that it has to run through! Hope this helps someone sometime! Pretty mundane, run of the mill, PITA project otherwise... Roll Eyes Brian | ||
| David Dulmage (Daved)
Registered Member Username: Daved Post Number: 286 Registered: 12-2003 Posted From: 174.136.114.96  Rating: N/A |
Good to know. Thanks. Dave D |