Should Hub and Drum Assemblies Have Wheel Bolts That are the Same on Both Sides of the Axle?

Question:

I recently purchased a trailer with two 7k Dexter axels. At some point some changes have been made to either the left or the right side of the trailer. The drum assemblies on the right have larger diameter and longer studs 9/16” I believe. The left side has drums with shorter 1/2” stud. Is there any way to tell what should be on the axel? And more importantly does it matter if they are both rated the same? Both sides have 8-219 stamped on the drum. Trailer manufactured in May of 2000.

asked by: Brian

Expert Reply:

You should have the same wheel bolt sizes on your hub and drum assembly; parts should be uniform on both sides of your suspension to minimize any potential issues as well as rectify those issues should they occur. Since you know you have axles rated for 7,000 lbs and you know that your drums have 8-219 stamped on them, replacement assemblies are available, though I highly recommend confirming what you need by taking apart your hub assembly and looking at the bearings themselves; wipe away the grease and you should be able to see the part number stamped directly on them.

If you are unable to find them, you need to use a digital caliper to measure your spindle to the hundredths of an inch where the bearings ride. You can use the photo I've attached to see exactly where you need to measure.

Should you have inner bearing # 25580 (1.75" inner diameter), outer bearing # 14125A (1.25" inner diameter) measure 2.25" where the grease seal rides your two options are Hub and Drum Assembly # 8-219-13UC3, which has 9/16" wheel bolts, or # 8-219-4UC3, which has 1/2" wheel bolts. Please keep in mind that if your seal does measure 2.25" you would need to use Grease Seals # RG06-070 with the latter assembly.

Both of these hub and drum assemblies have an 8 on 6-1/2" bolt pattern and will work with axles that are 5,200 lbs to 7,000 lbs, like your tandem Dexter 7k axles.