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DBGraves

Mack rears with walking beam suspension

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Hello everyone,

i have a question my 99 rd688s has walking beam suspension with Mack rears. My rear rear driver side spendle snapped off Friday. It’s been fixed before so the axle doc says I need a new housing. My question is it the same 44 k housing that the camel back uses or different. Both looks the same where the suspension bolts to the housing. 

Thanks in advance 

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Put the older banjo with cone axle  .....if you put same back brake again

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Are they made out of different steel? Black dog2

its a quint axle dumptruck it hauls 23 tons so I’m putting 44k suspension to the limit as is.  I was just wondering if they where the same housing so I could get it back on the road ASAP. 

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The rear axle all break its 2-halfs welded together verse the others are 1-piece  with quills spindle s 

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Posted (edited)

The banjos used both for Camelback or Walking beam are the same. Even those were used for Neway airride at certain applications with bolt on brackets for equalizer beams (normaly they are welded to banjos).

Another point earlier 44 banjos were cast iron (up to about 1990) and than later they became a welded steel style. Look the same as 38's but (too probably) harder to bend and heavier. From what I saw about the attachments you can swap cast housing with fabricated and vice versa. And no big issue is seemed if you even put one cast and another steel in the same bogie.

Of broken axle spindle i saw at one of those a marking was stamped into its surface with a part # and "replacement spindle" or so. From that I suggested you can (or could) order such part and change it right on the truck. That one with the marking had a massive weld seam where inserted into the banjo housing, looked like someone did that in a shop. And that weld was initial reason to note the marking.

Edited by Vladislav

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Are they made out of different steel? Black dog2

its a quint axle dumptruck it hauls 23 tons so I’m putting 44k suspension to the limit as is.  I was just wondering if they where the same housing so I could get it back on the road ASAP. 

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Vladislav,

thanks for the info. If I’m getting it right. I can just buy a 44k housing or (banjo) it will work. 

My housing had been fixed before and it was a hack job and the axle doc doesn’t want to try it due to safety reasons. 

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we are running 24.5 ton on tri-axle  up to 76500 in conn mass 77000 with permits

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On 10/6/2019 at 11:41 PM, DBGraves said:

 If I’m getting it right. I can just buy a 44k housing or (banjo) it will work. 

 

I never checked the parts ## since have no access to Mack parts list but the attachments of the carrier, lower spring (walking beams) clamps (elephant pads), brake spiders and the sizes of spindels to suit bearings are the same. So if you know the rating I see no reason avoiding swap one by the other.

If you go that way note the size of the spindel to accomodate a hub seal. Typically Mack axle has one of "typical Mack" seals but once I got a housing where additional sleeves were installed (and I couldn't remove them) so larger ID seal went there, that one crossed to some trailer axle.

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Wow blackdog2 that’s a payload. I Va we have the bridge law. So my tri grosses at 59325=17.25+. The quint grosses at 72450=22.70+ -

 

so so update got a banjo. I’ll let everyone know how it turns out in a couple days. 

 

Thanks for the info Vladislav. 

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10 hours ago, DBGraves said:

Wow blackdog2 that’s a payload. I Va we have the bridge law. So my tri grosses at 59325=17.25+. The quint grosses at 72450=22.70+ -

 

so so update got a banjo. I’ll let everyone know how it turns out in a couple days. 

 

Thanks for the info Vladislav. 

I don't think its to safe but it is legal we have a DM-686 58k-20k-20k-front  good for 98,000 but only good for 76,500 pay-load  23.8 ton .

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I believe on the Eisenhower interstate system, the roads are designed to federal weight limits unless the state had even heavier weight limits, i.e. in Mass with the 77k permits. In such a situation the federal highway system is built to state standards.

In PA a triaxle is good for 73,280, and a standard tractor trailer 80k. On bridge laws in PA a short tractor trailer with 5 total axles cannot gross as much as a triaxle can, which is irrational because you're longer than the triaxle and you have an extra axle.   

That 98k DM686 is safe so long as you have the heavier brakes and you maintain the truck in good working order. I have a retired dm686sx with 58k rears and 20k front, had a lift axle. It was always able to stop faster than our other triaxle with 44k rears, with a load on, even with the lift axle up. Bigger circumference on the brake drums means more surface area and better mechanical advantage to slow down.

If your lift axle has the bigger brakes as well as the drive axles then you should have no problems stopping 98k. Getting it moving with an endt676 on the other hand is another matter. It'd go but not in a hurry!

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Here in Conn. double steer- tamden axle good for 80,000 no lift they average 26.5 ton  but get stuck on banana peal .

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