How to tight the in-tank fuel pump up to the assembly?

  • Thread starter Thread starter martinxue
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M

martinxue

Hi,

In order to investigate a fuel system problem (the car stopped after
using 1/3 of the fuel in the tank), and after for the first time taking
out the in-tank fuel pump for my 1988 240GL Volvo on this Sunday, I
found out that the in-tank fuel pump was only connected to the assembly
line by one cobble line (to one of the pump's electric connector). The
fuel hose connecting between pump and the steel fuel line was
completely broken and disconnected, and the pump can move up and down
inside a plastic gasket without any constrains (luckly it did not slip
into the tank)!

After I removed the gasket from the assembly and took out the fuel
pump, the cobber line connect to the pump was also broken. I think I
can later on connect the cobber lines to the 2 electric connectors in
the pump. And I also tested the pump with a 12-Volt electricity
withouth problem, the pump works fine.

I am going to buy a new fuel hose, but the question worries me now is
that: how to connect the pump to the assembly? If I only put it into
the gasket it can still move up and down, and it will be only
physically connected by the fuel hose and 2 electric lines to the
assembly. Is that correct? Or I missed something important that tight
the pump up to the assembly?

I search the Hayne's manual and Internet, but still could not find a
explict description on how to tight the pump with the assembly?

Can anyone shed any lights on this issue? I'll be greatly appreciated.

Thanks very much.

Regards

Martin
 
Hi,

In order to investigate a fuel system problem (the car stopped after
using 1/3 of the fuel in the tank), and after for the first time taking
out the in-tank fuel pump for my 1988 240GL Volvo on this Sunday, I
found out that the in-tank fuel pump was only connected to the assembly
line by one cobble line (to one of the pump's electric connector). The
fuel hose connecting between pump and the steel fuel line was
completely broken and disconnected, and the pump can move up and down
inside a plastic gasket without any constrains (luckly it did not slip
into the tank)!

After I removed the gasket from the assembly and took out the fuel
pump, the cobber line connect to the pump was also broken. I think I
can later on connect the cobber lines to the 2 electric connectors in
the pump. And I also tested the pump with a 12-Volt electricity
withouth problem, the pump works fine.

I am going to buy a new fuel hose, but the question worries me now is
that: how to connect the pump to the assembly? If I only put it into
the gasket it can still move up and down, and it will be only
physically connected by the fuel hose and 2 electric lines to the
assembly. Is that correct? Or I missed something important that tight
the pump up to the assembly?

I search the Hayne's manual and Internet, but still could not find a
explict description on how to tight the pump with the assembly?

Can anyone shed any lights on this issue? I'll be greatly appreciated.

Thanks very much.

Regards

Martin
Click to expand...
The pump assembly I'm used to working with on my 760 is different, I know,
but on the 240s I seem to recall people saying it was held down by a
castellated nut - a large nut with bumps like the top of a Spanish castle.
Mostly I recall complaints about how hard it is to get loose. Are there
threads around the pump area that would suggest that nut is missing?

Mike
 
Hi,

In order to investigate a fuel system problem (the car stopped after
using 1/3 of the fuel in the tank), and after for the first time taking
out the in-tank fuel pump for my 1988 240GL Volvo on this Sunday, I
found out that the in-tank fuel pump was only connected to the assembly
line by one cobble line (to one of the pump's electric connector). The
fuel hose connecting between pump and the steel fuel line was
completely broken and disconnected, and the pump can move up and down
inside a plastic gasket without any constrains (luckly it did not slip
into the tank)!

After I removed the gasket from the assembly and took out the fuel
pump, the cobber line connect to the pump was also broken. I think I
can later on connect the cobber lines to the 2 electric connectors in
the pump. And I also tested the pump with a 12-Volt electricity
withouth problem, the pump works fine.

I am going to buy a new fuel hose, but the question worries me now is
that: how to connect the pump to the assembly? If I only put it into
the gasket it can still move up and down, and it will be only
physically connected by the fuel hose and 2 electric lines to the
assembly. Is that correct? Or I missed something important that tight
the pump up to the assembly?

I search the Hayne's manual and Internet, but still could not find a
explict description on how to tight the pump with the assembly?

Can anyone shed any lights on this issue? I'll be greatly appreciated.

Thanks very much.

Regards

Martin
Click to expand...
I'm sorry - I didn't read the post closely enough. You are asking about the
connection *inside* the tank.

That thin bellows usually tears, causing the symptoms you have. I did what
most people do, replacing the bellows (which is not available separately
anyway) with a short piece of fuel hose and clamps at each end of the hose.
Keep the hose short, because if it is too long it will jam against the
bottom of the tank and block flow. Of course, a short hose will keep the
pickup off the bottom of the tank and not allow the very last gallons of
fuel to be used.

Mike
 
Hi Mike,

Thanks very much for your reply.

Just want to clarify the comments, do you mean that there is only the
fuel hose that connects and tight up the in-tank fuel pump to the
assembly (besides the 2 cobber electric lines to the pump's 2 electric
connectors)?

I am wondering if it is like that, the pump can move up and downs
freely inside the gasket, the hoses will always have the "downside"
pressure because of the weight of the fuel pump and it will "tear" off
the hoses sooner or later?

Thanks.

Regards

Martin
 
Hi Mike,

Thanks very much for your reply.

Just want to clarify the comments, do you mean that there is only the
fuel hose that connects and tight up the in-tank fuel pump to the
assembly (besides the 2 cobber electric lines to the pump's 2 electric
connectors)?

I am wondering if it is like that, the pump can move up and downs
freely inside the gasket, the hoses will always have the "downside"
pressure because of the weight of the fuel pump and it will "tear" off
the hoses sooner or later?

Thanks.

Regards

Martin
Click to expand...


Yep, that's how it is. The idea is that the pump floats in the bracket,
so the pickup sock can rest right down on the bottom of the fuel tank
yet not be smashed against the bottom of the tank. Fuel hose is pretty
strong, I think you'd break the plastic fitting on the pump before
tearing the hose.
 
Hi,

Thanks for the ideas and suggestions. Then in that case I suspect that
the fuel hose in my tank was a bad one since it was completed broken
and torn off. The fuel pumps (both internal and external) were replaced
by a mechanics several months ago.

Does anyone know what the hose should be like?

Thanks.

Regards

Martin
 
Hi,

Thanks for the ideas and suggestions. Then in that case I suspect that
the fuel hose in my tank was a bad one since it was completed broken
and torn off. The fuel pumps (both internal and external) were replaced
by a mechanics several months ago.

Does anyone know what the hose should be like?

Thanks.

Regards

Martin
Click to expand...
The original was a thin, folded rubber piece that allowed the pump to move
up and down. That is really too fragile and isn't available separately
anyway. I used standard fuel hose (is that 6mm?) and a pair of worm clamps.
If you take the pump to the auto parts store and say "I want a short piece
of fuel hose to fit this" you will get something that works. I think the
piece I used was something like 5cm long but I had to buy a foot of it.

Mike
 
Hi,

Maybe this is a naive question, but if the goal is to pump the fuel out
of tank, why does it need to let the pump to float on the surface of
the gasoline and not just tight the in-tank fuel pump to the bottom of
the tank?

Unless it is required that the in-tank fuel pump can not be submerged
into the gasoline?

Thanks

Regards

Martin
 
Hi,

Thanks for the ideas and suggestions. Then in that case I suspect that
the fuel hose in my tank was a bad one since it was completed broken
and torn off. The fuel pumps (both internal and external) were replaced
by a mechanics several months ago.

Does anyone know what the hose should be like?

Thanks.

Regards

Martin
Click to expand...


It rots out with age, rubber just breaks down like that.

Just get a piece of standard rubber fuel line of the right diameter,
IIRC it's 5/8", but take the prepump with you to the store.
 
Hi,

Maybe this is a naive question, but if the goal is to pump the fuel out
of tank, why does it need to let the pump to float on the surface of
the gasoline and not just tight the in-tank fuel pump to the bottom of
the tank?

Unless it is required that the in-tank fuel pump can not be submerged
into the gasoline?

Thanks

Regards

Martin
Click to expand...


It doesn't float on the surface, it floats on the bottom of the tank. If
the pump mount and tank dimensions were precision made then the bracket
could be rigid, but things vary so the idea is to give the pump some
slack so the pickup can rest on the bottom of the tank without smashing
against it and clogging.
 
Hi,

I still do not fully understand how it works. If the in-tank fuel pump
was connected to the fuel feed line (mounted on the assembly) by the
fixed-length fuel hose, then how would it move up and down freely,
unless the hose can be "dynamically" shortened or extended?

Or another "explanable" way is that the pump should be tighted up to
the assembly so that its pickup socket can be able to reach the bottom
of the tank, then it pumps gasoline through the hose to the fuel feed
line without moving up and down when the level of the gasoline in the
tank changes.

But it was not like in my Volvo, as there is a gasket which was mounted
to the assembly and the pump was slided into the gasket and can be
moved up and down.

Possiblly there are some parts missing, as the fuel pump was replaced
serveral months ago by a mechnics and I remembered after I ordered the
fuel pump for him, he said that there was something parts was not
fitted for that pump but he somehow "managed" to get it working.

Am I missing something?

Thanks.

Regards

Martin
 
Hi,

I still do not fully understand how it works. If the in-tank fuel pump
was connected to the fuel feed line (mounted on the assembly) by the
fixed-length fuel hose, then how would it move up and down freely,
unless the hose can be "dynamically" shortened or extended?

Or another "explanable" way is that the pump should be tighted up to
the assembly so that its pickup socket can be able to reach the bottom
of the tank, then it pumps gasoline through the hose to the fuel feed
line without moving up and down when the level of the gasoline in the
tank changes.

But it was not like in my Volvo, as there is a gasket which was mounted
to the assembly and the pump was slided into the gasket and can be
moved up and down.

Possiblly there are some parts missing, as the fuel pump was replaced
serveral months ago by a mechnics and I remembered after I ordered the
fuel pump for him, he said that there was something parts was not
fitted for that pump but he somehow "managed" to get it working.

Am I missing something?

Thanks.

Regards

Martin
Click to expand...
No - it sounds like you have it all there. After the repair the pump will no
longer be free to extend to the bottom of the tank, so the last gallon or so
of gasoline won't be picked up. Before the pickup filter sock was able to
rest on the bottom of the tank, but now it won't. But as long as you don't
try to get the last mile or km out of the tank you'll do just fine.

Mike
 
Thanks.

I will buy the fuel hose to connect the pump to the fuel feed line.
The length of the hose will be measured so that the pickup socket would
be able to reach the bottom of the tank. Since the hose's length is
fixed I will secure the pump to the assembly (sending unit) and won't
allow it to move up and down.

Are there any problem with this approach?

Thanks

Martin
 
Thanks.

I will buy the fuel hose to connect the pump to the fuel feed line.
The length of the hose will be measured so that the pickup sock would
be able to reach the bottom of the tank. Since the hose's length is
fixed I will secure the pump to the assembly (sending unit) and won't
allow it to move up and down.

Are there any problem with this approach?

Thanks

Martin
Click to expand...
No. If you're being that particular size the hose length with the tank
about a quarter full, that way as it changes size during filling and
heating you won't be far wrong from ideal a high percentage of the time.

Bob
 
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