Hi all,
I have seen a couple of threads where people are trying to replace their ROPS bolts without having to pay the hundreds of $ for the official Kubota TA24048752 set. The official bolts do come with holes for retaining clips drilled in the end and handles on the heads for turning by hand. Of course, Kubota advise not modifying the ROPS or its components so this is very much at your own risk.
I have replaced my set with aftermarket bolts and wanted to share what the sizes are.
Pivot joint
The pivot bolts are M16 x 100mm Hexagon Head Part Threaded Bolts, Bright Zinc Plated, High Tensile 8.8, DIN 931.
You will also need 6 x M16 washers - either 6 x Form A or 4 x Form A and 2 x Form C (hardened). I have got hardened washers for under the head and you will need Form A washers for inside the ROPS between the top and bottom pieces of the ROPS. The hardened (Form C) washers are too thick to put both inside the pivot joint so I will need to get thinner ones for inside the joint.
Instead of drilling a hole through the bolt end for a retaining clip I have instead put a Stover nut on. I don't take this bolt out regularly (or ever) so the locking nut should resist the vibration on the ROPS and can also be taken off with a bit of force if ever needed. I got a spare set of nuts just in case.
Locking joint
The locking bolts are 5/8-18 UNF x 4" Hexagon Bolts - Part Threaded - Grade 5 (8.8) High Tensile Bright Zinc Plated.
I have also put a M16 hardened washer under the head as the original comes with a washer incorporated. This bolt screws into the nut on the opposite of the ROPS so you don't need another nut to secure this. I may drill a hole at the end of this bolt as it comes out regularly to lower the ROPS when putting the tractor in the barn.
I struggled initially to get these bolts into the thread and was worried that I would strip the thread - but fear not! - these are definitely 5/8"-18 threads. The thread in my nuts was gunked up from over the years and once I had cleaned these up it fits snug.
I also filed down the threads slightly on the bolt as the original Kubota bolt looked to have a "flatter" thread but the same pitch. It may be that the accumulation of dirt in the nut did this over time so you may find this helpful too.
You obviously don't get the handles or grips on the end of the bolts so you may want to weld a washer on to each bolt head to turn by hand. I just have a size 24 spanner stuck on my wall in the barn to use on the bolts when I need to get them out. I have included a pic of the original pivot bolt and the replacement so you can see the thread pitch. Both of the original bolts are around 95/96mm long so the 100mm and 4" equivalents are the closest fit and allow you to drill the end holes if you wish.
I sourced these from Boltworld in the UK. You can buy just individual bolts and a complete set should come to just under £10 with £5.95 shipping.
Hope this helps someone out in the future.
boltworld.co.uk
boltworld.co.uk
boltworld.co.uk
boltworld.co.uk
boltworld.co.uk
I have seen a couple of threads where people are trying to replace their ROPS bolts without having to pay the hundreds of $ for the official Kubota TA24048752 set. The official bolts do come with holes for retaining clips drilled in the end and handles on the heads for turning by hand. Of course, Kubota advise not modifying the ROPS or its components so this is very much at your own risk.
I have replaced my set with aftermarket bolts and wanted to share what the sizes are.
Pivot joint
The pivot bolts are M16 x 100mm Hexagon Head Part Threaded Bolts, Bright Zinc Plated, High Tensile 8.8, DIN 931.
You will also need 6 x M16 washers - either 6 x Form A or 4 x Form A and 2 x Form C (hardened). I have got hardened washers for under the head and you will need Form A washers for inside the ROPS between the top and bottom pieces of the ROPS. The hardened (Form C) washers are too thick to put both inside the pivot joint so I will need to get thinner ones for inside the joint.
Instead of drilling a hole through the bolt end for a retaining clip I have instead put a Stover nut on. I don't take this bolt out regularly (or ever) so the locking nut should resist the vibration on the ROPS and can also be taken off with a bit of force if ever needed. I got a spare set of nuts just in case.
Locking joint
The locking bolts are 5/8-18 UNF x 4" Hexagon Bolts - Part Threaded - Grade 5 (8.8) High Tensile Bright Zinc Plated.
I have also put a M16 hardened washer under the head as the original comes with a washer incorporated. This bolt screws into the nut on the opposite of the ROPS so you don't need another nut to secure this. I may drill a hole at the end of this bolt as it comes out regularly to lower the ROPS when putting the tractor in the barn.
I struggled initially to get these bolts into the thread and was worried that I would strip the thread - but fear not! - these are definitely 5/8"-18 threads. The thread in my nuts was gunked up from over the years and once I had cleaned these up it fits snug.
I also filed down the threads slightly on the bolt as the original Kubota bolt looked to have a "flatter" thread but the same pitch. It may be that the accumulation of dirt in the nut did this over time so you may find this helpful too.
You obviously don't get the handles or grips on the end of the bolts so you may want to weld a washer on to each bolt head to turn by hand. I just have a size 24 spanner stuck on my wall in the barn to use on the bolts when I need to get them out. I have included a pic of the original pivot bolt and the replacement so you can see the thread pitch. Both of the original bolts are around 95/96mm long so the 100mm and 4" equivalents are the closest fit and allow you to drill the end holes if you wish.
I sourced these from Boltworld in the UK. You can buy just individual bolts and a complete set should come to just under £10 with £5.95 shipping.
Hope this helps someone out in the future.
M16 x 100mm Hexagon Head Part Threaded, Bolts, Bright Zinc Plated, High Tensile 8.8, DIN 931 - Bolt World
Material:Steel Class / Grade 8.8 Surface Treatment:Bright Zinc Plated Thread Diameter:M16 Thread:Metric Thread Thread Direction:Right Pitch:2.00 Head Shape:Hexagon Bolts Thread Length (Minimum):38mm Total Length:100mm (Total length does not include head) Code:DIN 931 Please Click For Complet
boltworld.co.uk
M16 Through Hardened Flat Washer - Bright Zinc Plated
M16 through hardened flat washer to DIN 6916 / EN14399-6 300HV. Bright zinc plated, Grade 10.9 steel. 17mm bore, 30mm OD, 4mm thick — for use with M16 bolts.
boltworld.co.uk
M16 Flat Washer DIN 125 – Mild Steel Zinc Plated
Mild steel M16 flat washer to DIN 125 (Form A). 17mm ID × 30mm OD with bright zinc plating — for general engineering and metric bolt assemblies.
boltworld.co.uk
M16 All Metal Stover Self Locking Nut | Grade 8 Zinc
M16 all‑metal Stover self‑locking nut (DIN 980V) in Grade 8 steel with bright zinc plating. Reusable prevailing torque nut resistant to vibration and shocks.
boltworld.co.uk
5/8-18 UNF x 4" Hexagon Bolts - Part Threaded - Grade 5 (8.8) High Tensile Bright Zinc Plated - Bolt World
Material: Hexagon Zinc Plated BZP Grade: Grade 5 (8.8), High Tensile Thread Type: UNF Imperial Thread Thread Direction: Right Head Shape: Hexagon Bolts Threads Per Inch: 18 Head Hight: 25/64" Head Width (Across Points): 1.083"
boltworld.co.uk
