Go Back   iRV2 Forums > MOTORHOME FORUMS > Toads and Motorhome Related Towing
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-15-2014, 11:19 AM   #15
Senior Member
 
Pigman1's Avatar
 
Join Date: Sep 2011
Posts: 1,937
All good points. If SMI is out at Quartzsite this year, I think I'll have a talk with them. Always pays to know a bit more about the inner workings of a system.

Bob, how does your dash light work? On one toad, mine worked off the toad brake light switch, so when the toad brake pedal moved enough to activate the toad brake lights, my dash light came on. In later toads like the Silverado, the brake light switch works off a small computer so SMI recommended putting a pressure switch in the air line going to the brake activation cylinder. Then the light on the dash comes on when sufficient air pressure is being sent to the brake activating cylinder. This is a NAPA switch and is the same one used on some trucks to activate all their brake lights in their air brake system.
__________________

__________________
Pigman
2013 Tiffin Allegro Bus 43QGP
2011 Chevy Silverado 1500 Toad
Pigman1 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 09-15-2014, 12:12 PM   #16
Member
 
Jonnyboy 316's Avatar
 
Join Date: May 2013
Location: Bradenton FL
Posts: 98
The 1/4" slack I mentioned earlier is part of SMI' directions....that's why I mentioned it. Contrary to what one poster mentioned, if you shorten out the 1/4 inch deflection (slack), you hasten the moment when your proportional braking begins.
__________________

__________________
Jonnyboy 316 is offline   Reply With Quote
Old 09-20-2014, 07:54 PM   #17
Senior Member
 
andyh's Avatar
 
Newmar Owners Club
Join Date: Jul 2007
Location: Troy, MI
Posts: 606
I agree. Cable slack adjustment is critical. I have put 74000 miles on the SMI AF1 without any problems on the toad or coach side.
__________________
Andy

2015 DSDP 4369 with HWH Active Air, 2014 Jeep Grand Cherokee, Roadmaster tow bar, SMI AirForce One, Silverleaf VMSPc
andyh is offline   Reply With Quote
Old 09-20-2014, 11:06 PM   #18
Senior Member
 
BobGed's Avatar
 
Tiffin Owners Club
Join Date: Oct 2008
Location: Carson City, NV
Posts: 1,942
Quote:
Originally Posted by Pigman1 View Post
All good points. If SMI is out at Quartzsite this year, I think I'll have a talk with them. Always pays to know a bit more about the inner workings of a system.

Bob, how does your dash light work? On one toad, mine worked off the toad brake light switch, so when the toad brake pedal moved enough to activate the toad brake lights, my dash light came on. In later toads like the Silverado, the brake light switch works off a small computer so SMI recommended putting a pressure switch in the air line going to the brake activation cylinder. Then the light on the dash comes on when sufficient air pressure is being sent to the brake activating cylinder. This is a NAPA switch and is the same one used on some trucks to activate all their brake lights in their air brake system.
My dash light is wired to the cold side of the toad brake pedal and is illuminated whenever the toad pedal is activated.
__________________
Bob, Sherron & Kinsey (Goldendoodle)
2017 Tiffin Phaeton 40QBH
2014 Jeep Cherokee Limited
BobGed is offline   Reply With Quote
Old 09-20-2014, 11:41 PM   #19
Registered User
 
Join Date: Aug 2014
Posts: 608
The reason there is no calibration is simple you don't need it if installed correctly. All of the air systems I have installed work pretty much the same the are driven by a service valve or relay valve which is pretty much the same thing. When you step on the brake pedal you send air pressure to the the valve the valves are rated by crack pressure with them being lighter from the rear to the front. A typical setup would have a 3 on the toad a 5 on the rear axle and a 6 or 7 on the steer axle. This is part of the brake timing so when you step on the pedal and you send 3 psi out the toad would begin braking slightly as you increase to 5 psi the rear axle begins to brake and as you increase pressure the front begins to brake. The actual air going to the brakes is from the output of the service or relay valve and is proportional to the input braking pressure. The rest of the system is designed by the size of the diaphragm used to apply braking force to the actual brakes. On a typical rear axle you have 30in chambers and usually 20in chambers on the steer this is in sqin so a 30in chamber with 5 psi is putting 150lbs of force on the Slack adjuster to apply the brakes. The same 5psi on the steer will not open the valve at all so no braking is applied to them at that pressure. In the toad the amount of brake force will depend on the size of the cylinder or diaphragm used in the system.
__________________
1mainiac is offline   Reply With Quote
Old 09-20-2014, 11:47 PM   #20
Registered User
 
Join Date: Aug 2014
Posts: 608
Quote:
Originally Posted by Pigman1 View Post
All good points. If SMI is out at Quartzsite this year, I think I'll have a talk with them. Always pays to know a bit more about the inner workings of a system.

Bob, how does your dash light work? On one toad, mine worked off the toad brake light switch, so when the toad brake pedal moved enough to activate the toad brake lights, my dash light came on. In later toads like the Silverado, the brake light switch works off a small computer so SMI recommended putting a pressure switch in the air line going to the brake activation cylinder. Then the light on the dash comes on when sufficient air pressure is being sent to the brake activating cylinder. This is a NAPA switch and is the same one used on some trucks to activate all their brake lights in their air brake system.
The one issue I could see by using air psi to let you know the toad brakes were applied is it would not tell you if the pedal on the toad was stuck causing you to burn up your toad brakes. On many of the newer cars and trucks we add a second brake switch and wire it up so that way we don't touch the factory wiring at all and avoid issues with factory warranty and problems down the road from tapping into their system.
__________________
1mainiac is offline   Reply With Quote
Old 09-21-2014, 08:33 AM   #21
Senior Member
 
Tiffin Owners Club
Freightliner Owners Club
Join Date: Aug 2014
Posts: 1,845
I finished my install yesterday. The TOAD brake pedal does move different amounts (according to my wife who was watching the pedal).
But I still don't know if the amount of brake pressure on the TOAD is correct.
Yes, the indicator light comes on...but if the pressure is too much, the Toad will be trying to stop the motorhome.

Guess I need to disconnect the air line and drive so that I can tell the difference with/without TOAD brakes.

Dan
__________________
2014 40QBH Phaeton DP Cummins 380HP ISL, Freightliner XC, 2014 Jeep Trailhawk TOAD
Blue Ox Aventa tow bar, SMI Air Force One -South Orange County Ca.
dpinvidic is offline   Reply With Quote
Old 09-24-2014, 02:13 AM   #22
Senior Member
 
sfischer's Avatar
 
Tiffin Owners Club
Join Date: Nov 2006
Location: Fulltimers-could be anywhere
Posts: 171
Concerning the amount of slack to be left in the cable, this is a direct quote from SMI's manual:

Tighten but do not over tighten leaving approximately ”- ” of slack in the cable. The amount of slack has no effect on the amount of pressure or proportionality. It only reduces the available stroke of the cylinder. Excessive slack will result in premature wear of the cylinder and cable.
__________________
Steve and Karen Fischer
2010 Tiffin Phaeton 40QTH on Powerglide chassis
http://www.gonebyrv.blogspot.com
sfischer is offline   Reply With Quote
Old 09-24-2014, 07:05 AM   #23
Senior Member
 
andyh's Avatar
 
Newmar Owners Club
Join Date: Jul 2007
Location: Troy, MI
Posts: 606
Adding a second brake switch on some vehicles can be very difficult or dangerous, because it can cause dragging brakes on the toad. The air pressure switch is a much cleaner solution. There is nothing in the AF1 cylinder setup which can cause sticking pedal without air pressure to the cylinder.
Many Jeep and Doge toads will require secondary means for brake indication. The OEM brake switch will have power for only 10 minutes after shutdown.
__________________

__________________
Andy

2015 DSDP 4369 with HWH Active Air, 2014 Jeep Grand Cherokee, Roadmaster tow bar, SMI AirForce One, Silverleaf VMSPc
andyh is offline   Reply With Quote
Reply

Tags
brake



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
SMI Air Force One versus US Gear Unified Brake System rvMadness Toads and Motorhome Related Towing 23 06-15-2015 10:58 PM
can you identify this parking brake system 1994 Georgie boy Aeronaut Spartan Motorhome Chassis Forum 4 07-10-2014 01:38 PM
Brakes ?? Bulldog74 Ford Motorhome Chassis Forum 7 07-07-2014 11:32 AM
88 Fleetwood Limited Parking Brake jmerritt Vintage RV's 1 05-29-2014 09:16 PM
Brake system needed on toad? CC Rider Toads and Motorhome Related Towing 33 01-24-2014 09:40 PM

» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:10 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.