Air emergency brake

[clarksgocamping]

🤤 I have a 2000 Safari Zanzibar on a magnum chassis. The air parking brake will not hold on a slope. Can anyone advise on what may be wrong. Air seems to engage the brake but not enough to hold. Is there a adjustment. 

[bm02tj]

Yes you can manually adjust but it should have an auto adjust

have repaired asap before any trips 

that is dangerous  

You should know about your air brakes and the slack adjusters 

[clarksgocamping]

9 minutes ago, bm02tj said:

Yes you can manually adjust but it should have an auto adjust

have repaired asap before any trips 

that is dangerous  

You should know about your air brakes and the slack adjusters 

Thanks I don’t have air brakes they are hydraulic only the emergency brake is air. I have it at a repair shop now. He doesn’t seem to be familiar with this system.There are no other shops around and I’m on top of a mountain 

[bm02tj]

Sorry I know nothing about that brake type 

but I would think it would be a spring brake released by air not applied by air 

so back to adjustment  

[dickandlois]

Clarks, I will try to attach a file that offers some information on the type system you have.

Rich.

When the air system fails you need to apply more pressure to get the same response from the hydraulic system with air assist.

The question now is, does the brake peddle pressure have the same results and only the park brake is causing you concern ?  Good wheel blocks could keep the coach from moving.

Chp._29_Hyd.Brake_AirOverHyd.Brake.pdf

[bm02tj]

That does not show e brake system 

if you can find I would like to see how they work 

I am searching net for it as well

Bruce 

[clarksgocamping]

10 minutes ago, DickandLois said:

Clarks, I will try to attach a file that offers some information on the type system you have.

Rich.

Chp._29_Hyd.Brake_AirOverHyd.Brake.pdf 2.64 MB · 3 downloads

Thanks I’ll look this over but I am not a mechanic and much of it looks over my head. I am looking for information specifically on the parking brake to pass along to the mechanic.

[dickandlois]

Clark, I added some questions to my original post. 

 Air pressure holds the brakes off when driving - When the air pressure is removed by the park brake system, the air is removed from the air cylinder that keeps them from applying pressure to the park air cylinder. 

  Sounds like you have a mechanical issue with the rear brake pads, the spring that applies the brakes issue, adjustment issues or warn-out brake pads.

            Emergency/Hand Brakes • Spring Brake Park Brake –What happens 

Air-over-hydraulic systems use vehicle’s air system to hold brake off when vehicle moving. – When actuation valve moved to apply brakes, air pressure is exhausted from spring brake chamber. – Power spring in unit mechanically moves brake components to apply brake.

Park Brake and Emergency Circuits •

All vehicles required to have park brake system that can act as emergency brake should there be failure of service brakes. 

Tandem arrangements: either one or the other part of tandem system designated as emergency brake, depending on which service system fails. 

Hydraulic braking systems:

  Park or emergency brake mechanically operated hand brake 

Air-over-hydraulic systems:

spring brakes often used as parking brakes.

Rich.

      Your Mechanic should be able to see the air cylinder move when the air is released. You have some braking from what you have posted, but the mechanical portion is not applying enough pressure to the brake pads to hold the coach when the air pressure is released in park.

The fallowing information covers the systems with pictures and written information near the end of the file !!!

Air over Hydraulic Brake systems_CDX_Ch33_PPT.pdf

[wolfe10]

I am a little reluctant to have you come to the FMCA Forum and have me/anyone suggest you check elsewhere, but the parking brake system on many of the Magnum chassis is unique enough that I recommend you checking on a Safari-specific forum. 

Very likely this is a drive shaft brake that needs adjustment, rather than a parking brake on the rear disks.

Here is a good one: https://groups.yahoo.com/neo/groups/Safarifriends/conversations/messages

[dickandlois]

Thanks Brett!   Think that is a real good link and helpful.

Glad you are keeping an eye on the kids. LOL

Sending you a PM

Rich.

 

[clarksgocamping]

9 hours ago, DickandLois said:

Clark, I added some questions to my original post. 

 Air pressure holds the brakes off when driving - When the air pressure is removed by the park brake system, the air is removed from the air cylinder that keeps them from applying pressure to the park air cylinder. 

  Sounds like you have a mechanical issue with the rear brake pads, the spring that applies the brakes issue, adjustment issues or warn-out brake pads.

            Emergency/Hand Brakes • Spring Brake Park Brake –What happens 

Air-over-hydraulic systems use vehicle’s air system to hold brake off when vehicle moving. – When actuation valve moved to apply brakes, air pressure is exhausted from spring brake chamber. – Power spring in unit mechanically moves brake components to apply brake.

Park Brake and Emergency Circuits •

All vehicles required to have park brake system that can act as emergency brake should there be failure of service brakes. 

Tandem arrangements: either one or the other part of tandem system designated as emergency brake, depending on which service system fails. 

Hydraulic braking systems:

  Park or emergency brake mechanically operated hand brake 

Air-over-hydraulic systems:

spring brakes often used as parking brakes.

Rich.

      Your Mechanic should be able to see the air cylinder move when the air is released. You have some braking from what you have posted, but the mechanical portion is not applying enough pressure to the brake pads to hold the coach when the air pressure is released in park.

The fallowing information covers the systems with pictures and written information near the end of the file !!!

Air over Hydraulic Brake systems_CDX_Ch33_PPT.pdf 1.39 MB · 1 download

Thanks I’ll pass this along to the mechanic 

[kaypsmith]

Clarksgocamping, how do you apply the emergency brake on your unit, lever, foot pedal, or some sort of switch, or release valve? This info can help us identify what type emergency brake system that you have, just in case you do not find help otherwise. 

[clarksgocamping]

58 minutes ago, kaypsmith said:

Clarksgocamping, how do you apply the emergency brake on your unit, lever, foot pedal, or some sort of switch, or release valve? This info can help us identify what type emergency brake system that you have, just in case you do not find help otherwise. 

It is a yellow button that you pull on the dash, when pulled it makes a air sound, when pushed in to release it makes another air sound. Similar sample shown

[richard5933]

When is the last time the brakes were inspected? Sounds like your rear brakes are far enough out of adjustment that the shoes are no longer reaching the drums fully.

They should self adjust, but those can get stuck.

 

[desertdeals69]

14 hours ago, clarksgocamping said:

Thanks I don’t have air brakes they are hydraulic only the emergency brake is air. I have it at a repair shop now. He doesn’t seem to be familiar with this system.There are no other shops around and I’m on top of a mountain 

Should be an adjustment for the cable on the end of the cylinder.

[clarksgocamping]

Thanks that sounds like what I’m looking for 

[clarksgocamping]

16 minutes ago, richard5933 said:

When is the last time the brakes were inspected? Sounds like your rear brakes are far enough out of adjustment that the shoes are no longer reaching the drums fully.

They should self adjust, but those can get stuck.

The brakes are disc front and rear, would that still be the case?

 

[richard5933]

If they're disc, probably not...

[kaypsmith]

One more crazy question from me, do you have a brake treadle (one that looks similar to the accelerator), or a brake pedal that looks similar to an automobile? That type actuator does look like a standard air brake, and if this is the case, Richard is correct, the drive axel brakes need to inspected because they probably are spring loaded, which means that there is no adjustment.  I have been searching the internet and it does look as though your brakes are air over hydraulic, and Brett is probably correct that the emergency brake is located on the drive shaft. If this is correct, there will be a drum mounted on the drive shaft with drum brake shoes. If this style, there will be a slack adjuster behind the plate behind the drum with an air piston that actually works the parking brake, biggest problem with this style park brake is that only one wheel actually locks because of the way a differential works, also if this is a diesel pusher with this style park brake, there is a high probability of grease buildup within the assembly causing slippage, brake shoes rarely wear out on this style but if grease is the problem, then a thorough cleaning of the assembly and new shoes should be used.

1 hour ago, clarksgocamping said:

 

The brakes are disc front and rear, would that still be the case?

Sorry I did not see this earlier because it appears within the quote. If the brakes are disc both front and rear, no that is not the case but most likely just as I described above referring to Brett's quote. Only other scenario is that there may be small brake shoes incorporated within a small drum that is made onto the rear wheel rotors, in which a cable may have been used, and I highly doubt this is your style as I have never seen this style used on anything larger than a 3/4 ton pickup. And yes, disc brakes are always self adjusting, and it is illegal to incorporate an emergency brake system into disc style brake, they must be able to be actuated either by hand or foot, and separate from the normal braking system.

[clarksgocamping]

The pedal is like a car brake pedal 

[kaypsmith]

8 hours ago, clarksgocamping said:

The pedal is like a car brake pedal 

I believe that is truly air over hydraulic, be sure to look on the drive shaft for a drum, and if it is there and air activated, there will be a spring that engages when you set the brake, be sure to check for that grease buildup that I mentioned inside the drum.

[clarksgocamping]

6 hours ago, kaypsmith said:

I believe that is truly air over hydraulic, be sure to look on the drive shaft for a drum, and if it is there and air activated, there will be a spring that engages when you set the brake, be sure to check for that grease buildup that I mentioned inside the drum.

 

[rsbilledwards]

Ok guys, here it is tried-- earlier but did not post. First is hydraulic over hydraulic for the service brakes. Park Brake is Air actuated there are no hydraulics to to it. Two types drum and disc you need to discover which it is or this is going to be a long dissertation. Clarksgocamping Feel free to call and I will share the details 303 807 7975 I have a 2001 Z and a 1999 Panther with the same stuff you have, been there and done that. Yes it should adjust as it is used

Brett is correct...it is unique And most of what has been speculation. No parking or brakes on the rear calipers. It is all disc front and rear, hydraulic over hydraulic. Disc is problematic drum pretty straight forward. Either is located on the drive shaft drum and disc are large! Foot pedal does not come into play, manually set with pictured yellow knob.