who is the manufacturer of the "Air-over-Hydraulic" brake system?

Pretty much everything on the bottom side of the coach: Steering, wheels, tires, brakes, suspension
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BeaverOwner
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who is the manufacturer of the "Air-over-Hydraulic" brake system?

Post by BeaverOwner »

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.
- Mike
2005 Beaver Patriot Thunder 525HP C13
( SMC Magnum D-series chassis)
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BeaverOwner
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Re: who is the manufacturer of the "Air-over-Hydraulic" brake system?

Post by BeaverOwner »

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
2005 Beaver Patriot Thunder 525HP C13
( SMC Magnum D-series chassis)
wolfe10
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Re: who is the manufacturer of the "Air-over-Hydraulic" brake system?

Post by wolfe10 »

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.
Brett and Dianne Wolfe
Ex: 2003 Alpine 38'. Ex 1997 Safari Sahara. Ex 1993 Foretravel U240
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Re: who is the manufacturer of the "Air-over-Hydraulic" brake system?

Post by stuplich@ymail.com »

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/
Mel
'96 Sahara 3530, mine since '01
250 hp 3126 Cat, MD3060 Allison
wolfe10
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Re: who is the manufacturer of the "Air-over-Hydraulic" brake system?

Post by wolfe10 »

And this was used by SMC?
Brett and Dianne Wolfe
Ex: 2003 Alpine 38'. Ex 1997 Safari Sahara. Ex 1993 Foretravel U240
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Re: who is the manufacturer of the "Air-over-Hydraulic" brake system?

Post by stuplich@ymail.com »

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").
Mel
'96 Sahara 3530, mine since '01
250 hp 3126 Cat, MD3060 Allison
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BeaverOwner
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Re: who is the manufacturer of the "Air-over-Hydraulic" brake system?

Post by BeaverOwner »

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.
Last edited by BeaverOwner on Mon Nov 18, 2019 4:11 am, edited 2 times in total.
- Mike
2005 Beaver Patriot Thunder 525HP C13
( SMC Magnum D-series chassis)
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BeaverOwner
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Question answered: It's a Haldex Series III

Post by BeaverOwner »

The Air-over-Hydraulic brake system used on the early Patriot is a Haldex Series III.
Air-over-Hdyraulic mastercylinder and chamber - Haldex.jpg
Air-over-Hdyraulic mastercylinder and chamber - Haldex.jpg (117.35 KiB) Viewed 6644 times
Attachments
Annotation 2019-11-18 055258.jpg
Annotation 2019-11-18 055258.jpg (41.25 KiB) Viewed 6642 times
- Mike
2005 Beaver Patriot Thunder 525HP C13
( SMC Magnum D-series chassis)
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Re: Question answered: It's a Haldex Series III

Post by stuplich@ymail.com »

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-/
Mel
'96 Sahara 3530, mine since '01
250 hp 3126 Cat, MD3060 Allison
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BeaverOwner
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Re: who is the manufacturer of the "Air-over-Hydraulic" brake system?

Post by BeaverOwner »

The part number I was given for the replacement master cylinder and air chamber is N37216C
The item in the attachment above.
- Mike
2005 Beaver Patriot Thunder 525HP C13
( SMC Magnum D-series chassis)
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