correct bolt size

[tcrabtree]

what size bolt is used to mout the seastar hyd steering bracket to the tiller arm on a v-6 merc? (main mounting bolt) thanks

[Thewayweroll]

Try search there is a heap of info .

[mach351]

If you are talking the single bolt that actually goes through the tiller arm it is a 3/8-24, but don't mess around with hardware store junk - go to the merc dealer and order the special ARP hardened stainless bolt - it's about $20 but it will save your azz!

[staylor]

I have SeaStar and bought the Merc ARP bolt which came in with an undercut shank. My steering rigged on an Opti 150 came with a fully threaded factory bolt, and the hole in the connection was fitting on the threaded section. Thus, when I installed the ARP bolt I ended up adding play to the steering system at the connection. My solution was to find a Grade 5 bolt with a non-undercut shank that measured .373 diameter. I selected a bolt with just enough shank to pick up on the steering arm but still have a short enough shank to allow the connection to be torqued properly along the bolt axis. The new bolt was longer than the factory bolt so it had to be cut down. This had to be done slowly to avoid taking the heat treat out of the bolt.
Doug

[XstreamVking]

Correct bolt(very important) is available from teleflex also...imo the weakest link on the whole boat...Get the best you can...

[mach351]

I wouldn't use anything short of a grade 8 bolt IMO - like has been said, this is the WEAKEST link in the system.

[staylor]

..whereas they are just fine in tension loadings. Since the mounting of the steering arm to the motor sees cyclic shear and bending loadings I prefer to use a Grade 5 in this location. The Sea Star factory bolt that came with my rig appeared to be plain stainless with no heat treatment, so I figured that the Grade 5 would be an upgrade.
Doug

[j_martin]

Considering the consequences of a failure at this point, I would think that periodic inspection of aircraft maintenance quality would be in order. I certainly would not use any hardware store or auto store bolt of unknown origin in this application.

my 02
John