Trailer slacks adjusting too much

I am a municipal mechanic working on a 3 axle RGN. When it was new it came with front axle using size 30 reg stroke full chambers and rear 2 axles used 30 reg stroke service chambers and gunite style slacks. Last year I converted all 3 axles to long stroke and installed meritor asa style slacks only they where fleetrite brand. A few days later got a call the front axle brakes where locking up. Sure enough brakes had over adjusted on front axle and where starting to over adjust on the 2 rear axles. I brought it to shop and was able to get the template out of a meritor asa slack we had in stock. I used the trailer template and adjusted the chamber rods as required. I kept track of it throughout the summer and it was much better but would still over adjust after a few weeks. The trailer gets parked over the winter and I am now doing the annual to prepare for the construction season. I will be double checking the rod lengths again but also wondering if the problem could be the fleetrite brand slacks and if I should just order 6 meritor asa slacks. I have researched meritor info and it looks as I will require the asa slack with the yellow band for trailer with size 30 chambers but there is no marking on the fleetrites and was no install info either. Also wondering why the front axle the one with the full chambers are over adjusting more then the rear 2 axles.

Also does anyone have a preference as to what brand slack works best on trailers eg meritor, gunite etc.

 

The issue it had before was with the brakes adjusted to spec (tighten then back off 1/2) would give me 1/2" wrencch pull but when brakes where applied the stroke would be very close to 2". If I set them tighter being a low boy it had a tendency to lock up tire when empty. It was like this since new so play in bushings or pins is not the issue. This was the reason for the conversion to long stroke gives me a extra 1/2 " of stroke.

 

I have been kinda suspecting a similar idea. Its a rgn float that hauls our equipment to each job. Drive time from shop to jobs is mostly less then an hour. The operator that runs it ( the term operator is being used very loosely) is a clutch and brake style driver. Gearing down is a skill set he is lacking. I have been suspicious since every time the float gets split the parking brakes are applied and brakes will adjust alittle each time aswell as during break applications on the way. Also as mentioned the gunites that were on it stayed in adjustment just was always close to the 2" limit. Think I might order a pair of bendix and install them on the front axle and see how they do.

 

Grapeape would you have a model number by chance? I did a google search and found a bendix versajust LS. Will measure what I need and will be calling our IH dealer to source some. Thanks for the help.

 

Ok thankyou I have 2 on order. I will see if this solves my issue. If so I will order 4 more. Thanks.