The Old Machinery Magazine Forum

Forum Categories => Tractors => Topic started by: cobbadog on 05 September, 2019, 04:02:07 pm

Title: Treating a Rusty Fuel Tank
Post by: cobbadog on 05 September, 2019, 04:02:07 pm
Well as you may know I have had a rust issue in both sides of the TVO fuel tank of our Cropmaster. So I researched the more common sealants to fix it and decided to go with an all Aussie made and sold product made by KBS. They do have a website and is worth a look and make all sorts of coatings for different situations. It you have not heard of them or know of the product it's main competitor is POR products. So hopefully this weekend I will make a start on treating both of the insides of the tank.
Title: Re: Treating a Rusty Fuel Tank
Post by: cobbadog on 07 September, 2019, 03:49:29 pm
First step was to remove the chains that connect the screw on fuel caps, block up the outlets underneath and then get some plastic to use under the fuel caps to seal them off.
I mixed up the Aqua Clean at 1:1 using hot water and poured a litre in the back tank and 3 into the main tank. Kept giving it a shake and rotate every now and then and after an hour I dropped the back tank, smallest, and not much came out. Then the main tank was dropped and boy was there a lot of crap come out the outlet. So much that it was blocking it up so with the use of wire I kept shaking the tank more and kept unblocking the outlet.
As you can see by the colour of the cleaner there was a mess inside but I also got a good 2 handfuls of loose rust out on the first treatment. I flushed the back tank out and it was ready for the next step apart from drying it out with a heat gun. The main tank I had to keep filling it up with rinse water and unblocking the hole for quite some time.
In one of the pics you can see the filler tube and at the bottom of it the bottom of the main tank and it is still a mess. So I have mixed the last of the cleaner and put inside the main tank to soak overnight.
Title: Re: Treating a Rusty Fuel Tank
Post by: cobbadog on 08 September, 2019, 04:29:20 pm
After leaving the cleaner in the main tank overnight I drained a heap more out of the tank. If I had kept it all I could have made another Ford,  a good 2 hand fulls of the stuff. So this afternoon I treated the tanks with the rust converter and should have time tomorrow afternoon to put the sealer in. Something that does take up time is getting the inside of the tank dry before changing from cleaning to rest prevention and then making it ready for the sealant. Because of the filler tube I was using a heat gun for a while then sticking the compressed air down the hole and sealing it with a rag. At first I kept the tank level but as you cannot see what is going on past the bottom of the tube I tilted the tank up at 45' and any moisture would run down beneath the tube. So I kept up the process until it was all gone.
Title: Re: Treating a Rusty Fuel Tank
Post by: Thomas Tisch on 08 September, 2019, 06:43:39 pm
Hi there,
I had rust in the fuel tank of my old Mercedes and just filled it up with Molasses and left it there for three months. After rinsing it was nice and clean and back to bare metal. After it had dried I "coated" it with a mix of Diesel and engine oil. Being slack on that project I haven?t installed it back yet after two years. It is still clean inside with no sign of new rust. I believe these tanks weren?t coated inside from new. The worry I have with acid or caustic cleaning is to get it free of that stuff again before getting the sealer in. Real trouble would start then if you were to get rust later between the sealer and the tank.
Thomas Tisch
Title: Re: Treating a Rusty Fuel Tank
Post by: cobbadog on 10 September, 2019, 10:14:40 pm
G'Day Thomas,
I too have used molasses to clean up rust on parts but inside the main tank was extremely bad and required a tough approach and time is not on my side as we have some treks comming up soon. The process used for the KBS is odd to say the least. Step 1 to use the aqua kleen to wash the insides and to start to pre treat the rust. This got a bit suddsie when the rinsing started and it took a lot of rinsing to get a clean liquid to run out and no bubbles. During this stage I did manage to get some on my hands and it didn't burn.
Step 2 using the rust blaster as it's called. They say this does have an acid in it similar to phosporic acid which is what is used on all rust converters and again this took some doing to get it to rinse clear and it took an overnight soak in the stuff to really shift the scaley rust but it did loosen it and again a lot of rinsing clear. I then let it stand for a day and yesterday afternoon I looked inside and there was still a bit of scale inside and I took the advise and bought a magnet to remove the last bits. So then I poured the sealant into both tanks and rolled it all about and drained out the excess after about 1/2 - 3/4 of an hour of rotating it around. It took around 10 minutes for the excess to stop running and dripping out and I was always clearing the fuel outlets so they did not get blocked. Today I looked inside and all appears to be perfect so soon I can look at respraying the tank again as I scratch it taking the scuttle plate off.
I will post some pics soon.
Title: Re: Treating a Rusty Fuel Tank
Post by: cobbadog on 11 September, 2019, 04:20:51 pm
Here is the result of the messy process but a great result.
Title: Re: Treating a Rusty Fuel Tank
Post by: cobbadog on 29 September, 2019, 04:37:44 pm
Tank resprayed yesterday and everything put back together today. Lock nut fitted to the top link arm but I had to adjust the 3 arms with a length of pipe to ensure it cleared the PTO housing.
Then start up time and no go. This is most unusual for this tractor as he normally jumps to life as soon as you pull the starter knob. Checked for spark, good, fuel in tank, good, fuel in carby, NO.
So what went wrong? Removed the fuel line at the carby and got fuel flowing there so off with the carby. Found no rust or dirt or mud crabs inside but I did find that the needle was stuck in the seat. Looking closer I noticed the finest little retainer spring holding the needle in place and it was as it was holding the needle shut. So I took it off and the needle would open n close no worries. Checked to see if I could put it back together with out the spring and did a bench test and it did not fall out even after a good shaking so I put it back on. Carby is a Solex-FV updraft.
Engine started but it was hunting up and down the rev range which it use to do a little bit but not like this before. So I tried adjusting the spring tension on the rod that goes from the carby to the governor. Thought I was almost winning and it did improve but then it started backfiring a bit and it was going to die so I pulled the choke on and it sorted of recovered and backfiring  a little bit but still wanting to die so I kept pulling the choke and then it seemed to settle a bit. So while it was running badly I parked it back in his shed so I can work on him again there.
I am going to check the adjustment of the governor but I have never done this before and the workshop manuals written in fluent POMMY and once you decipher the terminology I think I understand it. But this does not explain the back firing and it has not done this before.

Any Clues???
Title: Re: Treating a Rusty Fuel Tank
Post by: cobbadog on 01 October, 2019, 04:02:42 pm
Maybe, just maybe, I have found the problem/s. A tiny flake of rust inside the fuel tap assembly. Blocked partly off when it felt like it and then the cork disc washer was worn and had broken off the tabs that locate it in place and when you turned the tap on or off it started to move and partially block the hole but not always. A new cork gasket ordered but true to form I have to buy one from a Fergy and reduce the OD of the gasket to suit the D.B. All other holes are exactly the same. So it will be here later this week.
I also stripped the carby and re-fitted the spring on the needle and seat and double checked all galleries, ports and jets for cleanliness and all is good. I once again looked at the air mixture screw set up and it is long enough to go about 3/4 of the way across the body of the carby which puts it into it's own little  area that could possibly control air flow. When it is screwed all the way in it goes about 7/8 of the way across the body. It still doesn't make sense how this regulates much as far as sir mixture but it is how it was made.
Title: Re: Treating a Rusty Fuel Tank
Post by: cobbadog on 09 October, 2019, 09:07:50 pm
New cork gasket arrived yesterday and today I fitted it up simply by enlarginf the centre hole for the tap spindle to fit through and then reduce the od of the gasket using a Stanley knife but leaving the 2 ears in place so the gasket stays in alignment of all the 4 holes for fuel to run through. Fitted everything back together and had a slow fuel flow. Took it apart again and I forgot to check how the fuel got from the top holes to the bottom ones for it to go to the bowl. It has 2 holes in th handle and it was a bit restricted. Fixed that and now have good flow to the carby, but, at low revs all is good pull up to half throttle and above and it starts to starve for fuel so it is back to the needle and seat issue. I will try removinf the spring first and whule I have it out I will take all the measurements of the seat and its thread and if required buy another one. Even at low revs as in the past it doesn't seem to make any difference where the air mixture screw is set but this may be because of the starvation, time will tell.
Title: Re: Treating a Rusty Fuel Tank
Post by: cobbadog on 11 October, 2019, 04:37:18 pm
Well the saga continues. I borrow a couple of carbies, one known to be in excellent condition and on a running tractor and another from a tractor in not so good condition. The idea was to just swap the carby over and give it a run. Not to be. My carby has a different size connection into the bowl and cannot be swapped over to the others so I took the older carby apart and borrowed the needle and seat from it and this improved things a lot. At least it runs and is not hunting anywhere like it was but it is still running very rich. But it is good enough to go to the Taree Show tomorrow and will give me time to order another needle and seat  so I can return the borrowed carby back to being as it was.
Still can't get any difference with the air mixture screw and I have a sneaky suspicion that the needle is not seating as good as it should and allowing more fuel in and so still running rich, well that's my thinking at the moment.