C50 fuel tank

[paulxjen]

I bought a 1971 C50 grain truck that sat for 12 years and the fuel tank is full of crap. I have been running out of an fuel can and engine runs great. Has anyone replaced the behind the seat fuel tank? It looks like the same as tank in a C10 but there is no cross reference information. Any experiences or info will be greatly appreciated.

[Bob B.]

I am almost positive it's the same as a pickup truck. Being that your truck is a '71, it probably has the evaporative emission control. If it does, be sure to get the 'evap' type tank, not the '67-'69 style.

[paulxjen]

Thanks Bob, that is what I am thinking but I wish there was some way to verify.
I called about having the tank acid dipped and cleaned, the cheapest is $350.00 can buy a repop tank at LMC for $150.00.

[jocko]

I believe only 1/2 ton trucks got the evap tanks in 71/72, C20/30 did not - so am assuming a C50 didn't either - but it's worth asking when you order one just to be sure.

[dmjlambert]

I bought a new tank, but that was before I read about cleaning the old one. So, if I had to do it again I would get some chain and vinegar and swirl it around in there and clean it out. I read a post on another forum where a guy strapped the tank on his tractor wheel, added gravel to the tank, and when he got back from plowing a field for an hour or so, the tank was like new on the inside. I thought that was funny.

[LockDoc]

-
The guys in the Heavy Haulers Forum should know. I will move it there....

LockDoc

[paulxjen]

Funny you mention the tractor, I just watched that video on YouTube a bit ago, looks like it would work but I don’t have a tractor. Watched videos using muriatic acid (pool ph acid) and that worked super-fast and cut to the metal but comes with a lot of steps and the metal is stripped bare and will rust quickly. The problem with the vinegar is it takes a week, I have used that method on small engine tanks before, it really takes a while and you have to fill the tank completely with vinegar. Not sure yet which way to go.

[CarolinaHD]

I'm in the process of cleaning out the tank in my 67 c50 right now. According to Wes at Classic Heartbeat Parts, the tanks will interchange with the smaller trucks. 6 cylinders have 1/4" line and 8 cylinder has 3/8". My sending unit float was rusted out so I ordered a new one and some other parts from him.

A pressure washer got most of the crud off the tank floor and walls. I plan on using some pea gravel and muriatic acid to knock out the rest then use KBS coatings 3 step tank sealer. I had the first 2 steps from a previous project so figured I'd try it out.

https://www.kbs-coatings.com/tank-sealers.html

[paulxjen]

Ok, I looked at the block today, guess what...not a 307 as I was told, it’s a 350 #3970010.

[jdl71]

I've cleaned 2 or 3 tanks with various degrees of success, none of them getting anywhere near as clean as a new one. The one I'm currently using has 3 fuel filters between it and the carb. If the repops fit, just buy one. If you do decide to try cleaning it I would recommend not using rocks or gravel. Use chain, nuts and bolts, anything metallic so you can get the last few out with a telescoping magnet if needed. The last 2 or 3 rocks can roll back and forth for hours before finding their way out. Ask me how I know this.