Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 08, 2025 ...

Broken trottle return spring - mechanical C engine

August 04, 2010, 10:30:52 pm

Today when I check oil, etc and did a look around and found one of our two throttle return springs hanging on one end of the spring as the other end had broken off.

I made several replacement springs a while ago as others have broken.  So I had to get them out of my important Foretravel spare parts box.  I decided to replace both at this time, even though one was still good.

Our mechanical C Cummins engine has two throttle return springs that are mounted next to each other, probably more for safety redundancy than offering more spring return strength.
Each of the two springs has its own top & bottom mounting holes. 

Years ago, I found OEM spring replacements impossible to find and have been buying hardware springs and cutting them down to correct length.
In a hardware store, I looked for springs of similar diameter & spring steel thickness, trying many until I found some with same pull resistance and spring return feel, as original spring.
With a metal cutter, I shortened the new spring a couple of turns longer than the original.
With two pliers I gently make a ring loop with the last spring end loop.  This has worked just fine for the 6 or so springs I have made.  None of the loops have broken while I bent them 90 degrees.

The label on the springs I mounted today is:
Hillman, Cincinnati OH 45321
UPC 0-08236-80114-9
Made in Taiwan
HPM# 07828
#543016
Extension
0.44" x 10.25" x 040"
11.10mm x 260.35mm x 1.05mm
Safe working load: 1.4 lbs

Similar springs from other spring manufactures can be used, but here is a Lowe's link:
http://www.lowes.com/pd_246628-37672-543016_4294865718+5003697_4294937087?productId=3115911&pl=1&currentURL=/pl__4294865718%205003697_4294937087_?identifier

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #1 – August 04, 2010, 10:46:42 pm

Cool!  That brings to mind a story from the previous owner and the owner's mechanic.  The coach is 1997 U295 that had King throttle controls.

The story goes something like:  The throttle had exhibited some problems, and FOT worked on it.  It broke altogether in California.  The "Boss" (owner) had the mechanic flown to California from Texas in the company jet.  The "Boss" and driving partner/wife flew home in the company jet.  The mechanic acquired a broom stick and some rope.  The broom stick held the bed up.  The rope extended from the throttle linkage, through to coach, and to the driver's position.  The mechanic drove to NAC, applying throttle control via the rope.

This story was told to me by the wife and the mechanic at different times, and in separate sessions.

Our coach has an air throttle that was installed several years ago by FOT.  My guess is that it was installed immediately after the mechanic drove it to NAC using "the rope."

(Yes, this belongs "Around the Fire Ring," but I just had to respond with the great story.)

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #2 – August 05, 2010, 05:40:09 am

Yours is not the only rope story I have heard over the last nine years of FT ownership.

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #3 – August 05, 2010, 10:46:52 am

Experience dictates the best way to solve the above throttle spring issue is very, very simple, install the air throttle kit and
presto, it all of a  sudden the problem is gone for ever. 
The beauty of the air throttle is with the automatic transmissions. if your using a clutch type, forget the air throttle,it is toooo
slow responding for nice shifting.
Experience again
'Dave

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #4 – August 05, 2010, 06:48:55 pm

For mechanical engines using cables or links to operate the throttle, I add the following,
I should have mentioned the air throttle system is made by Williams,
Surely any truck dealer / shop should be able to help. 
Once you use a properly installed unit, you will be in love with it.
Dave

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #5 – August 05, 2010, 09:47:16 pm

Last year I had the King throttle/Cruise unit bench tested at the factory on a complimetary basis.  It came back 100% okay according to the tests performed.  (Thank you Steve Boller, King CEO)  Some may recall I had an intermittent performance issue "Yahoo, Steady Uphill Climbs" which may have been operator error    on my part (I still don't know for sure) but the transmission would not downshift and I had loss of power.  This may have been the throttle acting up so I had the unit inspected by King.
 
Some day I may have to change to an air throttle.  The units I've seen on the internet (Williams) appear to be a complex chage-out.  But, even with a Williams unit, would I retain the King unit to serve as the Cruise Control for the air throttle?  Does anyone have an estimate for the cost of the conversion?

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #6 – August 06, 2010, 12:10:36 pm

Anyone with a King Control that is in the Minneapolis area would find it a good stop to meet Steve Boller & have him check out the cruise/throttle control. Steve found an overheated spot on our circuit board, even though our unit was working ok. .

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #7 – August 06, 2010, 10:10:24 pm

Peter,I have seen the Williams setup on Detroit Diesel, and also had a crusie control in addition.  I did not look
close at it, so cannot give a good answer, sorry. 
Surely some one here who has played with buses, has a good idea.
I played the bus/rv route for 20 year but never had a cruise nor auto transmission, so I stuck with the mechanical
throttle.
Dave

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #8 – August 07, 2010, 09:29:00 am

Guys,  Bill W in Tampa did his own conversion on his FT to an Air throttle, he may want to chime in on the details. 
I Believe that there are some pic's in the archives.

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #9 – August 07, 2010, 02:20:19 pm

Gary,
 
My '92 has the air throttle.  When did FT convert to the Williams' throttle?

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #10 – August 07, 2010, 04:42:47 pm

Don, I don't know when the Williams came into use but I have it on my 95 and Bill W did not on his bus type ( I Think 95 ).
Gary

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #11 – August 07, 2010, 09:31:31 pm

The springs that I ordered two-three years ago from Century Spring in Los Angeles are exact OEM replacements of the original Foretravel springs.
www.centuryspring.com
Item 119
Whoever orders might want to do a quantity order and resell them to other members as seem to remember a minimum order dollar amount.
Regards,

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #12 – August 08, 2010, 10:02:18 pm

I looked at my throttle today, it says Williams on it.  Does that mean I have the air system?

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #13 – August 09, 2010, 01:08:22 am

The throttle pedal with the name Williams does not indicate that you have the air throttle.
Williams makes the electronic throttle pedal that tells the King electronic throttle/cruise control located in engine compartment what position the throttle pedal is in.
Open bed and look at curb side of engine to determine if you have air or electronic (also called fly-by-wire) throttle system.

Quote Selected

Re: Broken trottle return spring - mechanical C engine

Reply #14 – August 09, 2010, 08:36:09 am

Well now I don't know what I have and at present am not able to easily lift bed and look.  I believe that I can see BENDIX on throttle unit on firewall under the bed. I ASSUME that its an air throttle but now I will have to look closer.

Quote Selected