Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: FourTravelers on December 07, 2015, 06:07:42 pm

Title: Accelerator pedal air leak ???
Post by: FourTravelers on December 07, 2015, 06:07:42 pm
I have noticed an air leak coming from around the accelerator pedal. It developed sometime on our last trip and is only noticeable when the engine and generator are off. Being a relatively new FT owner, I was unaware the accelerator  pedal was air operated. Is this a common problem?
I found only one post on this topic and it mentions replacing a base valve?
Title: Re: Accelerator pedal air leak ???
Post by: craneman on December 07, 2015, 07:07:45 pm
Could it be coming from your treadle valve? It is right next to the throttle.
Title: Re: Accelerator pedal air leak ???
Post by: Caflashbob on December 07, 2015, 07:27:40 pm
You may have a Williams air throtte.  Mechanical engine. 
Title: Re: Accelerator pedal air leak ???
Post by: Peter & Beth on December 07, 2015, 07:40:45 pm
Yes, very likely a connection at the treadle valve.
Title: Re: Accelerator pedal air leak ???
Post by: Doug W. on December 07, 2015, 07:58:04 pm
Bendix air throttle on older units not sure when the transition to wire feed King control took place.
Title: Re: Accelerator pedal air leak ???
Post by: FourTravelers on December 07, 2015, 08:26:27 pm
Quote from: Doug W. li date=1449536284
Bendix air throttle on older units not sure when the transition to wire feed King control took place.

It could be..... There is a cylinder (bendix) I believe, under the bed mounted next to the Racor fuel filter. I think there is a cable running from it to the curb side of the 8.3.

Title: Re: Accelerator pedal air leak ???
Post by: Chuck & Jeannie on December 07, 2015, 08:53:08 pm
Here are some photos of the Bendix unit on our coach, located on the forward wall in the engine compartment.  It combines the throttle and cruise control functions.  Also a (corrected) diagram of the air lines in this system.  Your may be similar.
Title: Re: Accelerator pedal air leak ???
Post by: Chuck & Jeannie on December 07, 2015, 09:12:36 pm
Here is a "training manual" for the Bendix unit.  It contains much valuable info, although the system is somewhat modified in the Foretravel dual mode application (which is why I "corrected" the diagram linked above).

http://www.wanderlodgeownersgroup.com/downloads/BendixCruiseCtlManual_Parts.pdf
Title: Re: Accelerator pedal air leak ???
Post by: Chuck & Jeannie on December 07, 2015, 10:03:41 pm
The term "treadle valve" can be associated with either the air brake control or the air throttle control.  My owner's manual has some paperwork referring to the Williams WM453109 Treadle Valve.  Looks like the "gas pedal" in our coach.  The air valve sub-assembly (under the pedal) is a WM90DX.  If yours needs repair parts, or replacement, both should be readily available.

WM90DX by WILLIAMS CONTROLS - Fail-Safe Pressure Modulating Valve (http://www.finditparts.com/products/2057094/williams-controls-wm90dx)
Title: Re: Accelerator pedal air leak ???
Post by: FourTravelers on December 07, 2015, 10:24:26 pm
Thanks for all the info, I'll dig into it this weekend. Hopefully it's just a seal or O ring needed.
Title: Re: Accelerator pedal air leak ???
Post by: FourTravelers on December 08, 2015, 12:32:51 pm
Based on the drawing (S-090) page 6
The air is coming from item 17 (dust boot) won't get the chance to disassemble anything until this weekend.
With any luck there will be an O ring that can be replaced rather than the complete valve assembly.
Doesn't seem to affect anything other than the loss of air in the tank (white needle on pressure gauge) too quickly.
Title: Re: Accelerator pedal air leak ???
Post by: Caflashbob on December 08, 2015, 12:35:40 pm
Based on the drawing (S-090) page 6
The air is coming from item 17 (dust boot) won't get the chance to disassemble anything until this weekend.
With any luck there will be an O ring that can be replaced rather than the complete valve assembly.
Doesn't seem to affect anything other than the loss of air in the tank (white needle on pressure gauge) too quickly.

I have had the pedal assembly make funny noises under my foot during operation after the assembly started leaking pressure
Title: Re: Accelerator pedal air leak ???
Post by: Bill Willett on December 08, 2015, 02:06:50 pm
Williams Controls repair kit #117103