Are these Maxi Brakes?

Barn Owl · March 24, 2007, 06:56:19 PM

Finally! Nice weather and time to get working on the bus. The problem is now I will have lots and lots of questions that I will be posting. This will be the first of many. I don't know what Maxi brakes are and how to identify them. The PO said my bus has them but I have had some tell me that I have just plain old spring brakes. Can someone tell me what I have? How do you tell the difference?

prevost82 · March 24, 2007, 07:37:01 PM

Maxi ... spring brake ... park brake all the same thing
Ron

Barn Owl · March 24, 2007, 07:46:42 PM

I thought Maxi-Brakes were shorter and that they are no longer made. Is that true? If so what does one do if they need parts?

bobofthenorth · March 24, 2007, 07:49:03 PM

Those are maxis. The reason - because you clearly have 2 chambers. There are also single chamber brake pots - they are NOT maxis. The 2nd chamber (the big bulge on the back) houses a great big spring. With no air pressure applied to the spring chamber, the spring applies the brakes. When you push the parking brake release knob, that applies air to the rear chamber which cages the spring and releases the brakes. When you push the brake pedal that applies air pressure to the front chamber which houses a diaphragm attached to the brake push rod. The push rod applies the brakes. QED

RJ · March 24, 2007, 07:56:29 PM

Larry -

How many air lines are going into the brake cans? Two or three?

If two, you have spring brakes.

If three, you have DD3 cans.

Function conception similar, yet different design to accomplish the task.

Maxi-brakes is a generic term (like Kleenex) for the air-operated/controlled parking/emergency brake. One of the early designs was manufactured by a company called Maxi, now defunct.

FWIW & HTH. . .

Barn Owl · March 24, 2007, 08:01:08 PM

I have two lines, so that makes them just plain old spring brakes.

Thanks guys.

bobofthenorth · March 25, 2007, 06:03:49 AM

NO - spring brakes ARE Maxi brakes. Same thing - different name. You have Maxi brakes or spring brakes - take your pick.

RJ · March 25, 2007, 12:32:38 PM

Maxi brake = Spring brake, yup.

Same difference. . . but some folk call ANY air-controlled parking/emergency brake, be it either spring or DD3s, Maxi brakes. Just like folk call tissue for blowin' yer nose Kleenex, even if you buy the private label stuff at Target or Wal*Mart.

Doesn't mean they're technically correct for the actual type of brake installed, but for the layman in general conversation, they don't know the difference anyway. It becomes a knowledge thing when you need to service them, however.

So Larry, now you know you've got spring brakes for your Maxis. . .

Nice thing about that, is if you need to replace them, they're quite inexpensive compared to DD3 cans!

FWIW & HTH. . .