dropped the tank on the td - PeachParts Mercedes-Benz Forum

83-240D · #1 10-31-2005, 06:27 PM

it isn't picking up the last 1/4 tank. must be a fouled strainer.

anyway, besides replacing all the 25 yr old rubber, and some of it looks fabric, with viton, what else should i inspect while the space it free?

t walgamuth · #2 10-31-2005, 06:30 PM

never dropped one. just look around.

as yogi berra used tosay "its amazing what you can see just by looking!"

tom w

dieseldiehard · #3 10-31-2005, 07:17 PM

Quote:

Originally Posted by 83-240D

it isn't picking up the last 1/4 tank. must be a fouled strainer.

anyway, besides replacing all the 25 yr old rubber, and some of it looks fabric, with viton, what else should i inspect while the space it free?

The TD is easy to see into the bottom of the tank using a flash light. Use compressed air to blow the line from the engine side back, if you don't see algae it aint algae.

First, have you got plugged lines from the stuff that results from mixing B100 with diesel or WVO?

If not then have you ruled-out the lift pump (the hand primer pump is located on it)?

If the same symptoms remain after replacing the hoses then you MAY have a tiny hole in the steel supply lines. Put a little air pressure on the tank after its reinstalled and put some fuel in it. just a gallon is enough and use just 1 or 2 psi of air, that is sufficient, look for fuel coming out of a section of line where internal rust might have made it thin. A rubber glove over the filler cap might serve to form a seal I haven't done this but someone indicated they did and found a tiny leak.

How does the 1/4 tank come into play? Well, with more than 1/4 tank there is enough pressure from the weight of fuel and gravity that it will prevent the hole from drawing in air bubles yet never causes a major leak because the pressure is small compared to the size of the tiny hole. When it gets down to 1/4 full the pressure from fuel is dimminished to the point that air is drawn in, at least that is the theory I heard on this.

Also, I wonder what sizes of Viton you found that fit? The screw-in hose piece I suppose you made-up somehow, using the old part and Viton? tell us more. Inquisitive minds want to know!

83-240D · #4 11-01-2005, 10:56 AM

at 1/4 tank the engine is running rough and stalls. i am just thinking that the bio d has cleaned the tank and left stuff around the strainer that won't go thru the holes. if when the tank is full anything around the strainer would float in the body of fuel and everything is fine until the fuel resettles to 1/4 tank. this has happened tow or three times so that leads me to think it is tank gunk.

i had the same problem with blondie and after dropping and cleaning the tank(easier in a sedan by the way) black semi soft globs came out and no more problem.

dmorrison · #5 11-01-2005, 01:37 PM

Yes check everything you can see while it out. Why drop the tank for the straininer. It just a 22 mm bolt with 2 nuts jambed on it to remove. Inspect it and if algea or dirty, then clean the tank.

Dave

83-240D · #6 11-01-2005, 01:39 PM

are you sure its a 22mm hex head?

the tank is hung up with what looks like a fuel overflow loop that will not come off the filler neck. i hesitate to cut it for fear of not finding a replacement.

been around town and found a 22mm hex head but its too large.

thopught i saw a post stating 13/16 which might be 20 mm.

dmorrison · #7 11-01-2005, 11:10 PM

IF THIS IS A station wagon. 300TD. Buy a bolt whos head width is 22 mm across. Jamb 2 nuts on it and the head will fit in the reciever of the screen. if it is a sedan then this does not work.

Dave

Just measured the one I use. Its 22mm

83-240D · #8 11-02-2005, 02:26 PM

i bought a 7/8 allen wrench. bmwrench it is. strainer came out. clean. no it came out easily but is clean. replacing the frayed 25 yr old hoses at the tank. when i can get pics of 25 yr old hose i will post them.

viton here

http://www.mcmaster.com/

type in page 97 and scroll.

will this work? it says not pressure rated but isn't all hose under some pressure?

dieseldiehard · #9 11-02-2005, 03:09 PM

Clean strainer, huh? I thought so!
What do you do now on my list of possibilities?

re: hoses
How much pressure? I don't consider the tank supply hose to be under pressure. It should work, but again, What sizes are you going to buy?

83-240D · #10 11-02-2005, 07:15 PM

well let me pick your brain.....how thin a wall is safe? the 5/16 comes in two wall thicknesses but the diff is 8 bucks a foot!!

the goodyear tubing i have new is 5/16 id with a 1/8 wall. the viton walls are waaaay different.

the hand pump works fine. i had to stop and check the primary a couple times and it was okay. the car even ran better after doing that. ya' know i just don't want you to be right about pin holes in the steel. thats more work than i planned. but then what isn't??

dieseldiehard · #11 11-02-2005, 07:22 PM

I only have experience with Viton in the fuel return lines, what 3 mm?
Viton seems like a softer rubber and is not made in layered hose, that is with a nylon reinforcing web inside like other hoses.
If they made Viton inner hose with a nylon innner reinforcing layer and Buna outer rubber that would be the best of both worlds. Maybe someone should invent a new hose?

I did a search and found this info re: Viton hose sizes (and lengths?) Length/sizes of rubber->viton fuel hoses?

83-240D · #12 11-03-2005, 01:39 PM

so is the vent line hose the same as fuel hose? it sure goes on really easily with no force whatsoever. it is hard to tell from the old dry hose what diameter they were to start.

i think i found my problem. the feed hose has delaminated badly at the metel line and i think i saw inner mesh so maybe it was sucking air at the bottom of the tank.

now can i get a paint brush in there to paint the lines with that miracle paint to prevent rusting> hmmmmmm. maybe the spray instead.

kip Foss · #13 11-03-2005, 08:49 PM

83-240d

You are obsessing about something that is not that important. Today fuel line is fuel line. It will basically handle anything that comes out of a gas station fuel pump. Wall thickness is really not important since there is NO pressure on the line coming out of the tank. That is a suction line. There is a return line but the pressure is minimal. If you had an in tank fuel pump on a gas car you might rightfully worry about pressure but not in an old Diesel MB.

Austin85 · #14 11-03-2005, 09:35 PM

What happens when you run regular Diesel???

83-240D · #15 11-04-2005, 11:18 AM

the vent line is much smaller than fuel line. i couldn't get the clamp tight enough to keep it on the nipple so its off to checker again. maybe after work today. i really want to get this DONE!! i may have to give up first friday gallery night tonite and the wine and cheese excursion of downtown racine.