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Sat Apr 18, 2009 11:29 pm

Hello I need to know the length of a 71 bus fuel sender. The tube type. Arent they longer than the split bus ones? Is the ohm reading the same or does that change also? Im tired of searching for these specs as I dont think they are available in previous posts. I see they offer a different tube type for 68 and later but I cant tell how much longer it is.

Sun Apr 19, 2009 9:35 am

The length of the tube is exactly 8 1/2". I got the one out of the Safare' right now because it took a dump on me.

Anybody know what the resistance numbers should be with the float at different positions? I would like to know.

Sun Apr 19, 2009 11:19 am

you mean the resistance at full and empty? You can figure this out of noboby responds. Go to radio shack, purchase a really low resistance pot or some resistors and hook them up to the sending unit wire and to frame ground. When the guage pegs out, check the equivalent resistance. When it stops where it does somewhere on empty, measure that resistance too. Are you going to repair yours too? I know where to get the resistance wire. Its almost a no brainer. www.resistancewire.com

Sun Apr 19, 2009 5:08 pm

quartermilecamel wrote: you mean the resistance at full and empty? You can figure this out of noboby responds. Go to radio shack, purchase a really low resistance pot or some resistors and hook them up to the sending unit wire and to frame ground. When the guage pegs out, check the equivalent resistance. When it stops where it does somewhere on empty, measure that resistance too. Are you going to repair yours too? I know where to get the resistance wire. Its almost a no brainer. www.resistancewire.com

Yes, I mean the resistance at full and empty. I know that at full, the resistance is zero, just need to know what it is at empty. I got a whole bunch of resistors here. I think that I will mess about with different combinations of resistors and see what it needs to be at empty. Do you know what the exact type of resistance wire that is needed? I really want to put my bus back together this week, as I got a lot of time to do it. I could go to a hobby shop and get some, I just need to know which one to get. 8)

Sun Apr 19, 2009 6:40 pm

I'm sure the info is out there for these, but I did just come across the similar info in my Bentley manual for one of my Volvos- I have an inop fuel gauge in a 240 and I found the info in the Instruments chapter.

The Bus one being a VDO gauge is probably similar, though I'm not going to suppose it's the same. Volvo's procedure on their old sending units was to install a test plug that consisted of a 68 ohm resistor, from the sender wire to ground. This is supposed to result in a 1/2 scale reading on the gauge. Also works for their engine temp sensors, same gauge, same 10VDC regulated supply in the cluster.

Hope this is some help.

--Rob

busfreak_71 wrote: quartermilecamel wrote: you mean the resistance at full and empty? You can figure this out of noboby responds. Go to radio shack, purchase a really low resistance pot or some resistors and hook them up to the sending unit wire and to frame ground. When the guage pegs out, check the equivalent resistance. When it stops where it does somewhere on empty, measure that resistance too. Are you going to repair yours too? I know where to get the resistance wire. Its almost a no brainer. www.resistancewire.com

Yes, I mean the resistance at full and empty. I know that at full, the resistance is zero, just need to know what it is at empty. I got a whole bunch of resistors here. I think that I will mess about with different combinations of resistors and see what it needs to be at empty. Do you know what the exact type of resistance wire that is needed? I really want to put my bus back together this week, as I got a lot of time to do it. I could go to a hobby shop and get some, I just need to know which one to get. 8)

Thu Apr 23, 2009 8:01 am

Thought i'd piggyback in on this thread....... I have a 73 bay..... with the original gauge........... I ordered a replacement sender for the 73 and installed it..... the gauge reads full when full......... drops to empty when i used about 7 gallons.............. I know '73 was a switch year for many parts......... I'm guessing i have the 68-early '73 sender installed..... my gauge is a late '73-78 ( i've tried both) same result.....

How do you tell what the late '73 and up sender looks like?..... Mine is a tube type.....

Will the earlier '68-72 gauge fit the '73 dash without changing the whole panel?.... I really don't relish the thought of having to pull the tank out again..... :)

Thu Apr 23, 2009 8:16 am

I am going to change the sender on my 71. I am just going to cut hole then patch it. Beats pulling the engine and tank.

Thu Apr 23, 2009 8:17 am

foxtail1 wrote: I am going to change the sender on my 71. I am just going to cut hole then patch it. Beats pulling the engine and tank.

Yeah, I thought about going that route...... hate to have to peel my interior and Dynamat out to get there though..... :(

Thu Apr 23, 2009 9:44 am

fastmc25 wrote: Thought i'd piggyback in on this thread....... I have a 73 bay..... with the original gauge........... I ordered a replacement sender for the 73 and installed it..... the gauge reads full when full......... drops to empty when i used about 7 gallons.............. I know '73 was a switch year for many parts......... I'm guessing i have the 68-early '73 sender installed..... my gauge is a late '73-78 ( i've tried both) same result.....

How do you tell what the late '73 and up sender looks like?..... Mine is a tube type.....

Will the earlier '68-72 gauge fit the '73 dash without changing the whole panel?.... I really don't relish the thought of having to pull the tank out again..... :)

The difference in senders is very obvious, 68-mid 73 are the tube and 73+ are a float on a lever with a twist ring mounting, neiter fits the other hole.
As for the instrument I don't see why one couldn't go into the others spot but I've never done a side by side comparison, no external vibrator on the early ones.

Thu Apr 23, 2009 10:08 am

busdaddy wrote: fastmc25 wrote: Thought i'd piggyback in on this thread....... I have a 73 bay..... with the original gauge........... I ordered a replacement sender for the 73 and installed it..... the gauge reads full when full......... drops to empty when i used about 7 gallons.............. I know '73 was a switch year for many parts......... I'm guessing i have the 68-early '73 sender installed..... my gauge is a late '73-78 ( i've tried both) same result.....

How do you tell what the late '73 and up sender looks like?..... Mine is a tube type.....

Will the earlier '68-72 gauge fit the '73 dash without changing the whole panel?.... I really don't relish the thought of having to pull the tank out again..... :)

The difference in senders is very obvious, 68-mid 73 are the tube and 73+ are a float on a lever with a twist ring mounting, neiter fits the other hole.
As for the instrument I don't see why one couldn't go into the others spot but I've never done a side by side comparison, no external vibrator on the early ones.

See , that's what i thought....(Sender differences). Now when i hooked my gauge up without the vibrator it read correctly...... but for some reason the bus had a vibrator on it and the tube type sender......

Must be a bastard case.... I might try hooking straight up to the gauge and see how it fares on the later model gauge.... I wonder why it had the later gauge w/vibrator..... :? I don't know the operational history of this bus. It was sitting in a pasture for several years..... :roll:

Thu Apr 23, 2009 11:47 am

I just scored a '69 fuel gauge...... i'll see how it fits... 8)

Mon Mar 01, 2010 9:51 pm

Anyone know the length of the late '73 and up fuel sender? Im trying to see if this universal Stewart Warner will work... It says it is adjustable from 4/12-24 in...

http://www.summitracing.com/parts/SWW-114876/