Convert to spring brake chambers rear axles 55 LJSWX

[FBGNO]

Is there a conversion set up on the market to retrofit spring brake chambers to the rear drive axles of my 55 Mack LJSWX, or do I have to fabricate my own set up?

[mechohaulic]

don't know of a "conversion set up". looking to go period correct , the spring brake set up was the addition on two chambers with rods connected to through shafts  from outside frame to inside which rods connected to vehicle brake chambers, for safety and simplicity ; install a basic two chamber system such as todays units. depending on the clearance factor of chamber mounting. 

[Geoff Weeks]

Well I think you have to start with Bolt type chambers or clamp type?  Then there is the issue of clearance.  Both have to be looked at.

 The remote chambers were because there wasn't room on the heavier axles for "piggy-backs". There were piggy back conversions for the bolt together chambers, although I haven't seen one in decades.

[terry]

Does the LJXWX have the roto chamber brake cans, i believe they used them because of not enough room.  terry. 

Edited November 23 by terry

[FBGNO]

All,

Thank you for the response, it has roto chambers on it now. I'll have to look into the space issue, to see what will actually fit. I remember 20 years ago, there was a place in New Jersey that came up with retrofit kits to convert just about all of the stock applications, from the old wedge brakes all the way through, over to spring brake canisters. It's been soo many years that I lost track of them. I found out about them because I was doing a complete brake job on an R model tandem tractor and it made sense to go the extra expense to change out the spiders, and whatever else necessary, to accept the kit to convert to spring brakes.

[67RModel]

On 11/23/2025 at 12:17 PM, FBGNO said:

All,

Thank you for the response, it has roto chambers on it now. I'll have to look into the space issue, to see what will actually fit. I remember 20 years ago, there was a place in New Jersey that came up with retrofit kits to convert just about all of the stock applications, from the old wedge brakes all the way through, over to spring brake canisters. It's been soo many years that I lost track of them. I found out about them because I was doing a complete brake job on an R model tandem tractor and it made sense to go the extra expense to change out the spiders, and whatever else necessary, to accept the kit to convert to spring brakes.

I'll say that I tried to use "off the shelf" parts a couple years back to convert Rotochambers on a 1962 B81 to 30/30, 24/24, and even 20/24 chambers. Offset slack adjusters, rotating the spiders, didn't matter. I determined it to be impossible without a bunch of "design" and fabricating to relocate the chambers to a more inboard location on the axle housing. The only solution I determined would "easily" work was to obtain single acting, pull type, Haldex Maxibrake chambers ($$$$$$$$$$) and mount them to the frame on the opposite side of the slack adjuster as the Rotochamber and connect them to the slack adjusters with grade 80 chain. This would still require plenty of thinking, planning, and some fabrication to make happen but I figured was much less involved then trying to reposition 30/30 cans on an axle not originally set up as such. I never did undertake the project and have since sold the truck. 

Haldex | MAXIBRAKE® R-Series Pull Type Spring Brakes

 

Edited Tuesday at 05:38 PM by 67RModel