Soft brake pedal?

[studmuffin1]

2006 holiday rambler endeavour 40 pda, 6 wheel , rear radiator Monaco 8 bag chassis. Drove to New Jersey, from fl., near the end of the trip, the brake pedal felt soft, had to push further to get action. Still stops ok, but wondering what is going on. Air pressure is at 120 psi no loss or drops. It is very cold up here, from fl. Should I vent air out the system and start over. Should I bleed the air. Never had anything like this in 25 years of various motorbikes. Any ideas or suggestions, or should I be going to a shop? Help, the soft pedaled
Muffin
Man.

[Mighty_J]

I hope it was a good drive! Usually with air brakes, it’s just a treadle valve, so you generally won’t feel back pressure like a hydraulic system. I’m not familiar with your particular coach though. If it was sitting for a while, perhaps the treadle valve mechanism was sticky and is freed up now? Someone on here will have a better answer than that!

[twinboat]

Every step of the pedal bleads air out of the system. No bleeding needed.

You may have some sticking self adjusters, allowing the brakes to come out of adjustment.

My recommendation is to have them checked by a pro.

[studmuffin1]

That's what I am thinkin beyond my expertise. Thanks.

[153stars]

If you take it in, a good time to supply then with your chassis lube point diagram and have it done.

[YC1]

While sitting with the parking brake on I would press and hold the brakes very hard. Do this several times to exercise the components.

I do this as a preflight exercise before driving each day on the road.

[DiplomatDon]

Originally Posted by YC1

While sitting with the parking brake on I would press and hold the brakes very hard. Do this several times to exercise the components.

I do this as a preflight exercise before driving each day on the road.

Just curious as to what components you are exercising. The only components that would operate are the air supply to the brake pots and extra stress to the diaphragms.

[Mighty_J]

Originally Posted by YC1

While sitting with the parking brake on I would press and hold the brakes very hard. Do this several times to exercise the components.

I do this as a preflight exercise before driving each day on the road.

Spartan recommends doing something similar at each start up to ensure the automatic slack adjusters are engaged, except they say with spring brakes released, 4 full service brake applications in quick succession.

[DiplomatDon]

Originally Posted by Mighty_J

Spartan recommends doing something similar at each start up to ensure the automatic slack adjusters are engaged, except they say with spring brakes released, 4 full service brake applications in quick succession.

Doing this with the maxi's released makes more sense but the only way you would know if they are actually working is by crawling under and physically checking the adjustment. The slack adjuster has to have a certain length of stroke before before the automatic adjuster engages. When I started driving professionally there were no such thing as automatics and when they came into popularity I continued to crawl under, check brakes and still adjusted them as required. With auto adjusters every brake may have a different stroke length.
For anyone joining the IRV2 Monaco group in Quartzite and wants to know how to physically check them search me out.

[YC1]

Don, I didn't want to go too deep on why I press the brakes as exercise but you have so thanks.

I think my front brakes were out of adjustment at one time and providing very little help to the braking. I had babied the coach, not because I was worried about wearing out the brakes but because of the stopping distances with a toad connected. I like to begin my deacceleration early and with the engine brake the use of the service brakes is just for the final stopping needed.

I found my front slack adjusters quite a bit off and adjusted them manually as you stated. It has been several years so I have long forgotten exactly how. I keep everything lubed so it was not a lack of lube. Heck, could have come off the assembly line like that.

[windsorbill]

Originally Posted by DiplomatDon

Doing this with the maxi's released makes more sense but the only way you would know if they are actually working is by crawling under and physically checking the adjustment. The slack adjuster has to have a certain length of stroke before before the automatic adjuster engages. When I started driving professionally there were no such thing as automatics and when they came into popularity I continued to crawl under, check brakes and still adjusted them as required. With auto adjusters every brake may have a different stroke length.
For anyone joining the IRV2 Monaco group in Quartzite and wants to know how to physically check them search me out.

I'll take you up on your offer in Quartzsite. Hope our schedule will overlap.

[nehog]

for air brakes, have a truck shop check your slack adjusters--it does sound like one or more are out of adjustment. Generally automatic slack adjusters (which you have) once they stop working need to be replaced--not expensive or difficult.

The main reason for slack adjuster failure is not greasing them as required.