Intraax/Vantraax Brake Chamber Replacement
The Hendrickson Intraax and Vantraax trailer suspensions have caused a unique situation in the aftermarket for the replacement of brake chambers. Brake chamber replacement in the typical aftermarket application uses the universal 8-inch threaded rod chamber. However, the Intraax and Vantraax suspensions call for a brake chamber with a rod length of 11.10-inches at the y-dimension. The y-dimension is a measurement taken from the bottom of the NPC to the center line of the yoke pin.
It is critical to maintain the OEM-specified 11.10-inch y-dimension when replacing these Intraax/Vantraax brake chambers in the aftermarket to assure proper brake operation. Standard replacement brake chambers sold in the aftermarket come with rod lengths ranging from 12-inches to 13-inches in the x-dimension, which is the measurement between the base of the non-pressure chamber (NPC) and the end of the push-rod. There is no industry standard for the push-rod length of replacement brake chambers sold in the aftermarket.
Another issue concerning the aftermarket replacement of the brake chambers on Intraax and Vantraax suspensions is how much of the push-rod is threaded. If the 12-inch push-rod on the replacement brake chamber only has 5-inches of thread, this brake chamber can only be used to replace the chambers used on Intraax and Vantraax suspensions. The brake chambers with this type of push-rod would not be able to be cut down and used as a typical tractor OEM replacement brake chamber. This causes an issue when stocking aftermarket replacement brake chambers. You would have to stock two types of brake chambers for every variation of chamber manufactured.
The solution to this issue is to provide a 12-inch fully threaded push-rod on the replacement brake chambers. One brake chamber can be used as a replacement for the Intraax and Vantraax suspensions and tractor suspensions as well. This will help reduce the amount of replacement brake chambers that will need to be stocked.
For those trailers that were specified by the OEM manufacturer with a welded yoke, with a y-dimension of 11.10-inches on the Intraax and Vantraax suspensions, it is critical that they be replaced with welded yoke chambers. This ensures the original y-dimension is met when it comes time for replacement. Inaccurate measurements on cutting the rod and different yoke sizes make it difficult to keep the y-dimension at 11.10-inches when trying to replace welded yoke chambers with a rod and clevis.