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View Full Version : TR2/3/3A Tr-3 fueltank vent tube



AweMan
05-09-2007, 12:04 PM
Does anyone know how this vent tube is routed? How long is it? Does it go down through the body tub?
I have a bundle of old tubing I removed from the car IE> brake lines, fuel line and such, and I am having a hard time determining which piece is the vent tube. Does it have a fitting on both ends? If so what does the "Other" end connect to? {I know the tank end has the banjo fitting}
I seem to have misplaced the banjo bolt that connects it to the tank, does anyone know what size this bolt is. And or where I can {If necessary purchase one}.
Help Im lost here.

Harry_Ward
05-09-2007, 01:34 PM
Mine has a banjo bolt fitting affixed to the right side top of the fuel tank. The bolt has a rather large hex head on it. I think a 3/4 or 7/8ths box wrench fits it but not sure? The tubing is pretty different in that just off the banjo there is an up bend and then a down bend in the tube. I think this is to create an air gap so gas doesn't flow out too freely when the tank is overly full. I don't think it is more than two feet long. After the bends the tube goes more or less straight down through a rubber grommet in the base of the gas tank floor and comes out to just below the axle just to the inside of the spring. I'll have to confirm that view when I get home though.

MGTF1250Dave
05-09-2007, 02:43 PM
Adding to Harry's response, the vent tube is down below the car an can be blocked with road grim. If this happens the vent will not work, so from time to time it needs to be check to make sure it is clear. Also the rear end vent needs to be cleaned up periodically. To clarify the vent tube routing, it goes through the floor pan next to the tank.

YankeeTR
05-09-2007, 02:54 PM
What Harry and Dave said...

Harry_Ward
05-09-2007, 03:09 PM
Just checked, It comes straight down through the gas tank floor close to the right rear inner fender wall and stops just at the bottom of the spring between the road spring and frame. Hangs way closer to the spring than the frame. I'd say about a inch to half inch off the spring. The tubing appears to be 5/16ths ID but everything looks a little bigger to me lately with these magnifying specs. If I remember this correctly you need to have the rear seat out if you have one to get the tank in and out. <span style="color: #FF0000">Make sure the vent tube is roughly in place through the floor and properly hanging between the frame and spring <span style="color: #FFFF33"><span style="color: #FF6666">before</span></span> you put the tank in or you will be having some seriously unhappy discussions with yourself.</span>

Alreadyinuse
05-09-2007, 05:38 PM
For my money, just plug or cap off the vent tube. All of my TR3/As have had a vent hole in the cap anyway; and the vent tube slops fuel on the ground when you turn left.

AweMan
05-09-2007, 05:48 PM
Thanks Guys:
After a Much closer inspection of my discarded {but NOT thrown away, due to my packrat tendancys} parts pile, I DID manage to find both the tube and banjo bolt. Get this! The fiber washer was holding the banjo bolt in the banjo fitting. HOW lucky is that? I recognised it in that jumble of tubing and wireing beacuse of the 7/8 Th`s description, there it was, that huge head glareing right up at me. Although the tubing itself is in pretty sad shape, Im sure I can do something to aleviate that minor problem.
Thanks again!
Kerry

martx-5
05-09-2007, 06:26 PM
Glad you found the vent tube. Being that it is just to vent air from the tank, or the occasional overflow, as long as it's clear and doesn't have holes in it, it should be fine.

Also, there are TWO washers required. One above, and one below the banjo fitting. According to this Moss parts diagram, (https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29125) they are DIFFERENT. See items 8 & 9.

PeterK
05-09-2007, 06:33 PM
Agree, two different sizes of sealing washers. I replaced them when I changed out my tank.

Twosheds
05-09-2007, 09:10 PM
and the vent tube slops fuel on the ground when you turn left.

A friend was following me closely on his '68 Triumph Bonneville. We went around a hard lefthander and, when I looked in the mirror, saw that he was much farther behind me. Slid on the fuel but gathered it up and didn't go down. He stayed back for a while, but then came closer when he realized that fuel didn't spill on righthanders.

I plugged the overflow/vent line after that.

AweMan
05-09-2007, 09:39 PM
A friend was following me closely on his '68 Triumph Bonneville. We went around a hard lefthander and, when I looked in the mirror, saw that he was much farther behind me. Slid on the fuel but gathered it up and didn't go down. He stayed back for a while, but then came closer when he realized that fuel didn't spill on righthanders.

I plugged the overflow/vent line after that.

Interesting!

I doubt I will be driving this 56 Tr in that fassion anymore.
{I use to}
It is however, good to know I can plug the vent tube with no serious consequences. {I was wondering about that when it seemed I could not find the vent tube banjo bolt or line}. I have sence located both! But the line is broken and will need a splice {not a problem} I will either weld/silver solder a splice on or use compression fittings {I havnt decided yet}. It apears that the hold down straps are M.I.A. so I suppose I will have to manufacture those also. Unless one of you good fellows has spares you would part with for a nominal fee of course.
Thanks again for all of your responses
Kerry

mrv8q
05-09-2007, 11:52 PM
Those hold down straps show up on eBay fairly often.....

martx-5
05-10-2007, 06:40 AM
I may have a spare set of straps laying around. Give me a day to check in the loft.

EDIT: I just looked on Moss' site. The extra ones that I have are for TR3A to TS60,000. Moss shows a different number for the TR3 smallmouth.

AweMan
05-10-2007, 10:20 AM
martx-5:
Thanks anyway, I already have a plan formulating.
I`ll make some! Most likely better than what was there originaly. Although I would like to keep this car as original as possible I`m not building a concourse. And besides once the interior is instaled no one but me will know anyway.
Kerry