312-8 Seat support repair

[mrc 724]

hi all, the typical 3,4,500 series wh seat support cracked and broke on my 312. i welded in thicker metal and added gussets. love my hobart mig!  mike in mass.

[AMC RULES 36,942]

 Nice repair there...

& a good application of "the finger" too.  

[Sparky-(Admin) 19,446]

Wonder if there is something that could prevent that, for those of us with seat supports that have not busted yet.

I have a couple of the 300 style machines that I should check on.

[ohiofarmer 3,156]

36 minutes ago, Sparky said:

Wonder if there is something that could prevent that, for those of us with seat supports that have not busted yet.

I have a couple of the 300 style machines that I should check on.

I like to use bed rails for things like that. Thin, but very strong. The steel is bent really tight on the inside corners [unlike an a standard angle iron] ,and you might get by placing it over or under the existing frame with just bolts or a plug weld. I also have used circular saw blades cut up with a mini grinder to reinforce things.  Bed rails are easy to find as they are often thrown away, especially in college towns

 I get all i need when tenants move out, so talk to a landlord if you know one.

Edited October 24, 2017 by ohiofarmer

[cleat 4,936]

The later 520's came with a larger seat / fender support which may help with this.

 

I have converted all of my machines to this style.

 

It is a direct bolt in replacement to the original using the 2 rear bolts that secure the tunnel cover plate as 2 additional support points.

 

Tunnel cover is then supposed to have a step in it to go over this support but your existing cover will still work.

 

Here is your regular seat support.

 

Here is the larger support.

 

Here is a picture showing the stepped cover and larger support installed.

 

The larger supports are on ebay (not by me).

 

Cleat

Edited October 24, 2017 by cleat

[Wishin4a416 2,185]

Looks good. I had to do 2 of mine also. The Achilles heel.

[Lee1977 6,211]

On 10/24/2017 at 3:40 PM, cleat said:

The later 520's came with a larger seat / fender support which may help with this.

 

I have converted all of my machines to this style.

 

It is a direct bolt in replacement to the original using the 2 rear bolts that secure the tunnel cover plate as 2 additional support points.

 

Tunnel cover is then supposed to have a step in it to go over this support but your existing cover will still work.

 

Here is your regular seat support.

 

Here is the larger support.

 

Here is a picture showing the stepped cover and larger support installed.

 

The larger supports are on ebay (not by me).

 

Cleat

That won't work on an eight speed with out a lot of modification. First it would need to be notched for reverse and low gear. then the shiftier plate would not fit level, it would need a piece of metal the same thickness on each side. On a hydro you would still need the strips of metal to level the plate.

[cleat 4,936]

I have never had an 8 speed so I can't comment and will take your word on that.

But as far as the plate goes, I had one of my 520's with the flat plate and unless you looked really close, you would not notice.

 

I later bought the proper plate just because I am sort of anal about details.

 

 

[Lee1977 6,211]

It's diffidently a way to fix the breakage or to reinforce one that's not broken, It's just not "plug and play" on an eight speed.

[mrc 724]

thanks for the info about the larger seat support cleat. i never knew that wh made such a thing.  i can see where that would help. i sometimes add 1/4 thick strips of metal under the tunnel area to add some extra support. also on a hydro there is a bracket for the hydro pump 3/16 of an inch under the seat support bracket. its almost in the middle of the 2 tabs that usually break. i weld in a piece of 3/16 metal there, kind of a 3rd, middle extra support spot. regards mike in mass.