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On the 1996 - 2000 Magnum B-series chassis (Magnum Air) who is the manufacturer of the "Air-over-Hydraulic" brake system (specifically who makes the master cylinder - pressure assist component.

For example, I know Bendix-Bosch makes the "Hydraulic-over-Hydraulic" brake system (Hydro-Max), but I cant find anything on the "Air-over-Hydraulic" setup. I would like to locate a service manual.

If anyone has the Air-Over-Hydraulic brakes, can you post a photo of the master cylinder - booster assembly? I think I can find the manufacture if I have a photo of the setup. Someone said this setup used Bosch brake calipers. But I could not find anything on the master cylinder or air chamber booster Googling it. A photo would help.
Thanks

Mike,

I now you have me (and likely others) stumped.

Familiar with the hydraulic over hydraulic used on many SMC coaches.

And straight air.

But not air over hydraulic.

Can you post a picture of yours or link to one? Inquiring minds want to know.

Mike
A web search for "air over hydralic brakes" finds this: https://learning.hccs.edu/faculty/hugh. ... hyd-brakes
And this: https://kor-pak.com/air-hydraulic-brake-system-work/

And this was used by SMC?

wolfe10 wrote: ↑Sat Nov 16, 2019 8:45 am And this was used by SMC?

Brett
Not that I know of....(I'm one of the "stumped").

Some of the early coaches built from 1996 -2000 (maybe later) that where built on the Magnum Air chassis had "Air-over-Hydraulic" brakes where a brake treadle valve (or similar valve) was used to apply air to a brake chamber that applied (pushed on) the rod for the hydraulic master cylinder.

I've read that there were usually two air chambers and two master cylinders (separately mounted on the front left frame) so as to be a "split system" (front system. and rear brake system). These coaches also had an air operated parking brake (driveshaft mounted).

There is plenty of discussion on this, but not any mention of specific manufacturer's name.

I see several companies made Air-over-Hydraulic brakes (Wagner, Hadlex, Bendix) but no one has said what was installed on these coaches.

A photo of such a setup would help me identify the system by comparing to manufacturer's catalog photos.

Someone posted in another thread the master cylinder replacement (roe 1996-1998 Patriot) is a Centrix 13079025 (that is a dual master cylinder) which doesn't fit the other description I read about it being two separate air chambers/cylinders. So a photo from someones coach would help. Possibly several different designs were used over the years.

The Air-over-Hydraulic brake system used on the early Patriot is a Haldex Series III.

BeaverOwner wrote: ↑Mon Nov 18, 2019 4:10 am The Air-over-Hydraulic brake system used on the early Patriot is a Haldex Series III.

BeaverOwner
Which of the 10 Haldex Series IIIs pictured here? https://www.haldex.com/en/na/vacuumhydr ... ries-iii-/

The part number I was given for the replacement master cylinder and air chamber is N37216C
The item in the attachment above.