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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Chaz on October 14, 2021, 07:35:50 AM

Title: Cleaning out brake system - brakes air slow
Post by: Chaz on October 14, 2021, 07:35:50 AM
Hey folks,
  I have had my 4108 for about 15 years now and I have had the same issue from day one - it airs up slow....very slow. Probably 10 -12 minutes kinda slow. That is also an issue when I need to use the brakes alot.
  I have replaced the compressor twice with no luck. I am wondering if I need to clean out the whole air system?? I know I had messed around with just opening a valve in the engine compartment, years ago. It was clogged and when it let loose, WOW!, it was a mess! (Me too!!!)
So, any tips, tricks or videos on how to do this??
I appreciate it!!!
Chaz
Title: Re: Cleaning out brake system - brakes air slow
Post by: chessie4905 on October 14, 2021, 09:07:26 AM
pull the flex line off the comp. cab be carboned up. Also remove muffler and thoroughly clean.
Title: Re: Cleaning out brake system - brakes air slow
Post by: Chaz on October 14, 2021, 09:48:44 AM
Great! Thanks!
(Now I just have to figure out those parts. :) ) lol
I appreciate it!!
  Chaz
Title: Re: Cleaning out brake system - brakes air slow
Post by: belfert on October 14, 2021, 02:07:11 PM
Make sure the air tanks are drained of any fluid built up in there.
Title: Re: Cleaning out brake system - brakes air slow
Post by: Tedsoldbus on October 14, 2021, 02:25:11 PM
I have an air tank up front, one about mid bus, and an accessory tank in the front left compartment pretty much under my butt. There are cables in the wheel wells that you tug and it drains the two main tanks. I have another cable near my accessory tank. Only recently did my mechanic also remind me to drain the "yarn balls". I said, you bet. What's that. There is one in the front left compartment and one in the engine compartment. They are about the size of a softball and have a petcock on the bottom. I opened each and yuck came out. Previous guy did not know they were there. There must be a way to blow the air out of your main tanks. Look for a cable or petcock on the bottom of them, and look for the yarn balls (if your bus has them). All drains are on the bottom. Goal being to get the water out of them. Not sure if that will fix your slow to air problem but it can't hurt.
Title: Re: Cleaning out brake system - brakes air slow
Post by: belfert on October 14, 2021, 02:28:10 PM
My bus had automatic drains in the rear and manual drains in the front when I got it.  You had to crawl underneath and open the front drains by hand.  I went to NAPA and got the cable pull style for the front so I would no longer need to crawl underneath.
Title: Re: Cleaning out brake system - brakes air slow
Post by: Tedsoldbus on October 14, 2021, 03:48:58 PM
I'm new at this and you are not, but does it have yarn balls? Mine were gummed up until I blew them out. I have heard to NEVER take them apart. Best of luck. Has to be frustrating as to why on the slow air fill???
Title: Re: Cleaning out brake system - brakes air slow
Post by: buswarrior on October 14, 2021, 03:50:36 PM
As always, I would be highly suspicious of what a previous owner has done to you...

Somewhere in the supply plumbing is an obstruction. Perhaps a much too small line or fitting has been used, and since it has "always been there" for you, it looks normal.

An experienced eye tracing the entire length and fittings of the supply side would be good, and disassmble everything suspicious to check.

What size compressor were you changing out? Replacing the smallest one?

How old is the line feeding the compressor it's fresh air out of the engine air intake? Correct construction? Could be sucking closed internally.

In this case, tanks full of water would be helping by taking up space for air, speeding the filling...

Keep digging, it really should be better than that, and not letting you down when manouvering.

Happy coaching!
Buswarrior
Title: Re: Cleaning out brake system - brakes air slow
Post by: chessie4905 on October 14, 2021, 04:26:06 PM
you replaced compressor twice. used or rebuilt? Did you replace compressor governor. If installed used compressors, are they the same cfm or higher? A used compressor may have significant carbon build up causing valves not to seat.
Title: Re: Cleaning out brake system - brakes air slow
Post by: luvrbus on October 15, 2021, 07:05:54 AM
A dirty air filter,kinked hose and any obstruction in the air intake will greatly reduce the air compressor performance if one doesn't have a clean supply of intake air it circulates the air it has,1st you check for air leaks they air up faster with a system full of oil   (less space to fill up)