mrc 727 #1 Posted October 24, 2017 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. 5 Share this post Link to post Share on other sites
AMC RULES 36,945 #2 Posted October 24, 2017 Nice repair there... & a good application of "the finger" too. 1 Share this post Link to post Share on other sites
Sparky-(Admin) 19,540 #3 Posted October 24, 2017 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. Share this post Link to post Share on other sites
ohiofarmer 3,157 #4 Posted October 24, 2017 (edited) 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 5 Share this post Link to post Share on other sites
cleat 4,983 #5 Posted October 24, 2017 (edited) 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 1 Share this post Link to post Share on other sites
Wishin4a416 2,185 #6 Posted October 24, 2017 Looks good. I had to do 2 of mine also. The Achilles heel. Share this post Link to post Share on other sites
Lee1977 6,217 #7 Posted October 25, 2017 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. Share this post Link to post Share on other sites
cleat 4,983 #8 Posted October 26, 2017 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. Share this post Link to post Share on other sites
Lee1977 6,217 #9 Posted October 26, 2017 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. Share this post Link to post Share on other sites
mrc 727 #10 Posted October 26, 2017 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. Share this post Link to post Share on other sites