air brake conversion

[73m819]

the line I was talking about is on the back side of the service brake diaphram. these play no role in the maxi/parking brake.
turns out they are plumbed this way for a remote vent according to another member who owns a M939 truck. this makes sense to me. so one more question put to rest.

Now i need to sort out what dash valves will work with the axle relay valves. the bendix book only listed 2 that they say will work with this particular relay valve. not sure why yet but Im looking into it.

the good news is-- the relay valves do work even after sitting for a few years. and they are still available thru heavy truck parts suppliers for about $100 if needed.

No pics yet as i seem to have misplaced my patch cord for my camera.

I did however find a photo of an service brake can like im working with.
this is on a trailer axle but is the same type.

you can see the fittings with the blue plugs in them.

Outer cap is for the air to work the brakes, inner cap is a vent line, should go up into the frame somewhere

 

[timothy1]

Your taking parts of a 939 and adding them to a 809 series axle right? Not just swapping out axles? Just wanted to clarify.

 

[DaveP]

Your taking parts of a 939 and adding them to a 809 series axle right? Not just swapping out axles? Just wanted to clarify.

the front is just a backing plate swap.

for the rear Im thinking of just unbolting the suspension from the frame and rolling in the 939 setup. the dog bones and every thing look to be in good shape so this may be the easy way.
besides Im not sure the rear backing plate and drums off the 939 will work on the old style axles.

 

[Derrickl112]

Somewhere on here there is talk that the m809 wheels wont fit on m939 axles..

 

[DaveP]

Somewhere on here there is talk that the m809 wheels wont fit on m939 axles..

I guess In the morning I need to flip one of these wheels around to test fit.
thanks for the heads up.

 

[Derrickl112]

found it. I guess its the m939 wheels that wont fit an m809 front axle...

http://www.steelsoldiers.com/5-ton-up/81085-5-ton-wheel.html#post1032917

 

[Latrine_Commander]

Why are you wasting your time with wedge brakes? Commercial trucks stop using those years ago. You should us "S" cam brakes. Someone had a conversion kit. I think it was Memphis Equipmement. Here is the link,

https://polaris.lunasecure.com/MemphisEquipment/ViewPart.aspx?id=10000152

Figure out what "off the shelf" parts they used and you will have yourself an excelent brake system.


About 25 years ago. I so about 30 Mack 5 ton trucks all with the ENDT673 engine that were puchased modified to full air. They even had a hanging brake pedal under the dash.

You might even contact a Rockwell rep who is knowledgable to poke his brain.

John

 

[Trango]

I have one of those Memphis systems. They use 16.5" Arvin meritor q series brakes, paired with the correct drums (I have the part number of the drums, somewhere).

The issue is that the Memphis conversion was never offered for the front axle. I made one of work the setups work for the front axle, but not without some pain involved.

I can provide more information if you'd like - just let me know.

 

[DaveP]

I guess at this point I dont see it as wasting my time using the wedge type brake. I understand the simple operation and maintenece of S cam type but I already have these. and they dont have cans that hang down in harms way. I also know they are expensive when it comes to replacing parts but these look to be in good shape like barely used.

Im hoping after everything is disasembled cleaned and lubed it works like it should with out giving me to much trouble.
I know special lube is recomended for some parts of this system.

I have a treadle valve and will need to fab the brackets for hanging pedal and valve mount.

the relay valves got pulled apart and are clean and look new inside. hooked them up to shop air and they work as they should. thats good news.

I am the only driver so I dont think the anti compounding valve will be needed.

I may regret the wedge type and if I do I will post up why.

I have a engine brake so they wont really be used very much. plus I prob only put 3000 miles a year on this truck.


Thanks for the link to the memphis S cam kit. the price took me by surprize!

the crazy thing is these axles will prob only be under this truck for a year. then another phase of this project will take place once all the rite parts are located. then these parts will be installed on a different set of axles on another project.


it never ends with me. cant leave things alone.

 

[quickfarms]

Wedge brakes are fine until you have to rebuild them. The only way to make them work up to factory spec is to replace everything and that is not cheap.

 

[DaveP]

Wedge brakes are fine until you have to rebuild them. The only way to make them work up to factory spec is to replace everything and that is not cheap.

Rite you are! checked on parts prices and they are high! good thing these look like they have never been used. just need cleaned and lubed.

 

[Csm Davis]

found it. I guess its the m939 wheels that wont fit an m809 front axle...

http://www.steelsoldiers.com/5-ton-up/81085-5-ton-wheel.html#post1032917

Read the post that you linked only the nonstandard M-809 series rims are Different like the bridge trucks and the m-819. I have M-939 rims on my M-816.