cast steel?

Date 11-09-2009 23:01

Anybody out their know what a 5th wheel plate is composed of?

Any recomendations for welding mild steel to a 5th wheel plate?

Friend of mine has four trucks that needed retro-fitted, going to be pulling end dumps that require the 5th wheel to be pinned. Has one peterbuilt that has such a set up we copyied it for our design 3 held, 1 didn't? Looks like the weld pulled out of the material with the crystalized look to it? Almost like cast iron?? All these Trucks have different 5th wheels and all welded differently? 7018 all the way out with a little pre heat just to prep the steel and remove oil etc. The one that failed has international tag and made in america sticker.... The one that failed had very little load put on it all pressure is down when pulling and up when stopping. This one failed backing under rock trailer?

Not my area of expertise and normally would have avioded such a project, but he was going at it anyway and just jumped in to helpout any tips?

By nevadanick (**)

Date 11-10-2009 03:59

ive seen several of these set up with spacers, usually 4, made where they just bolted in place, or welded (if the truck always ran an endump)
and blocked the fifth wheel so it couldnt rock forward or back, and there was no welding to the fifth wheel. the spacers i saw were made of like 2" round solid
and the fifth wheel is cast steel

By bozaktwo1 (***)

Date 11-11-2009 17:59

The problem with cast steel is that you can have large porosity entrapped in the casting and you'll never know it until failure. I would recommend buying new 5th wheels from a reputable manufacturer. That way you're not getting someone's old throw-away garbage.

By weaver

Date 11-12-2009 03:14

every plate is different. If you have to weld it use 11018 rod, and run it hot i've done quite a few of these. It will work perfect. done it many times, (around 15) hope this helps..regards shannon..

By Joseph P. Kane (****)

Date 11-21-2009 16:04

I believe that welding repairs to a 5th wheel plate on a truck component built for travel on public roads in the USA are illegal. Check with DOT.

By low_hydrogen (**)

Date 11-22-2009 04:17

Wasn't actually a "repair", more of a modification. The modification, which we have seen some truck companies do, wouldn't affect travelling down the road. The risk would come when dumping the end dump.

It is a rod that locks the 5th wheel in place, so it can not rock forward or back. The trailer actually pivots, the king pin plate etc.

A guy we hired to haul some rock he took his truck to have it out fitted with wet kit and had the blocks put on his 5th wheel plate. They welded the front ones on and bolted the back ones on.

We liked it so well we cut our pins off and just bolted four blocks on. Some times the simple anwser is the right one and easily overlooked?

As far as legal, I have seen lots of repaired 5th wheels, doesn't make it legal but the trucks we are running will have to pass dot inspection so I'm sure they will let us know. They are pretty strict around here....

Thanks for the info and insight, always appreciated !!

On a side note I did order some of that 11018 rod wow! $5.60 a pound

By Dualie

Date 11-24-2009 07:25

http://ww1.safholland.us/sites/damedit/literature/XL-FW251_en-US.pdf

Doesn't take much, Buy the kit and do it right

By low_hydrogen (**)

Date 11-25-2009 00:35

Wow holland makes it sound simple lol! The kit they show is exactly what we made, and we braced it better than they show in their example and all three have failed. Of course all three are different brands, all a little different design etc. doesn't help that two of the need bushing kits. They finally put four blocks on them and it seems to be the way to go imo. There is just to much pressure on those end dumps when they are in the air with 18" rock in them. Even with the 11018 the porosity in the cast steel of the cheaper brands is just to unpredictable the welds are not failing, either the cast rips out or the rod bends etc.

For his application the blocks seem to be the best solution (other than just buying new 5th wheel plate$)

but thanks for the link, info and response
much appreciated!!