V-band clamp for GM fuel pump

[Bitsyncmaster]

I have the Bosch 67317 fuel pump and was looking how the V-band clamp works with our tank.

Our tank lip where the V-band clamp mounts has a taper (wider near the tank, getting narrow at the top). So the V-band clamp will tend to pull up as it is tightened until it hits the little lip at the top of the tank opening.

My fuel pump thickness with the gasket non-compressed is 0.275".

My measurement with the V-band clamp (DMCH part) with the clamp lifted to the tank lip is 0.43". So if you press down on the pump as you tighten the clamp, that clamp will try to lift because of the taper. So have people had any leaking when you overfill the tank?

By the way my pump plate is 4.58" dia. and the gasket which came with the pump is a perfect fit for our tank. I was wondering if the DMC pump thickness is more than mine.

V-band clamps can be bought with that "V" thickness less then the DMC part. Was wondering if I should get another V-band clamp with that thickness (known as INSERT APEX WIDTH).

What V-band clamp part numbers have you users that bought for your GM fuel pumps?

[dmcnc]

I have the same DMCH clamp, and I usually hold the clamp itself down instead of the pump with the top end of the V-clamp flushing with the top of the pump (but over it, since it has a smaller diameter). I then tighten while holding the clamp to where the bottom side of the V-clamp will squeeze the neck enough against the pump to where neither will move. It will slip if you over-tighten. I've never had leaks (knock on wood).

I've seen folks use other style clamps like Hervey uses a flat one.

[Bitsyncmaster]

I have the same DMCH clamp, and I usually hold the clamp itself down instead of the pump with the top end of the V-clamp flushing with the top of the pump (but over it, since it has a smaller diameter). I then tighten while holding the clamp to where the bottom side of the V-clamp will squeeze the neck enough against the pump to where neither will move. It will slip if you over-tighten. I've never had leaks (knock on wood).

I've seen folks use other style clamps like Hervey uses a flat one.

That is probably the best way to hold it down. My rubber ring on the pump fits in the tank very tight so probably not much would splash out. It's just if someone overfills the tank where the seal is important.

[Bitsyncmaster]

I gave this some more thought and there really is no way the V-band clamp can apply downward force on the pump except for you putting pressure on the pump as you install it. These clamps are designed to apply clamping force when both sides have a large taper so when the clamp is tighten it clamps together without bottoming out on the "pipes".

I may come up with something but it seems to be working for others as is.

[Bitsyncmaster]

I pulled the OEM baffle out of the tank and put the new pump in. It is really tight and did not seem to get the pump seaded down all the way. I will have to look closer when I get time.

By the way this pump has the pickup cylinder offset from center. The DMC pump is centered. I wonder if the offset is enough to clear that stud that holds the OEM baffle. The offset can be removed by carefully taking the pump apart an putting the guide rods into the other holes.

Have any of you owner cut that stud out of the tank? I would guess is limits how low the new pump will sit.

By the way this pump has only one spring on one of guide rods.

[Bitsyncmaster]

Well I pumped the tank "dry" with the new pump. The tank was about half full and pumping was pretty quick then but the flow slowed quite a bit as the level got low. Not sure if that is normal or something is wrong with my setup. What I plan to do it test primary pressure when I have everything ready to start testing the fuel sender values.

That offset of the pump may be a good thing. I pulled the old fuel sender so I could look into the tank and that stud has about one inch of clearance from the new pump pickup fixture. That is when the pump pipes are pointed to the drivers side of the car like the DMCH pump is orientated.

I have not put the sender float on yet so that is my next test to verify it does not have clearance problems with the sides of the tank.

[dmcnc]

The tank was about half full and pumping was pretty quick then but the flow slowed quite a bit as the level got low. Not sure if that is normal or something is wrong with my setup.

Mine did this as well when I emptied the tank at the very end. Likely too much air in the pump to push the very last bit?

[Bitsyncmaster]

Mine did this as well when I emptied the tank at the very end. Likely too much air in the pump to push the very last bit?

It was pretty much a dribble at the end. It do however pretty much empty the tank. This was pumping into a 25 foot hose. It's nice to have the hose quick release so you can move from the drain hose to the car's hose.

[Bitsyncmaster]

I measured the clearance from the pump to the stud with my unmodified Bosch pump and it is 0.8".

So if the pump is modified putting it directly under the tank opening it would not clear unless you can rotate the modification to where there is the flat areas of the pump pickup. I may need to do that depending on how the float sits in the tank with the unmodified setup.

You can see if there is a clearance problem by looking in the OEM sender hole but you may need and empty tank to see it clearly. The other option is to cut off that stud. Remember you don't want any sparks made by a cutting tool. I would guess you could just use a hack saw blade cutting it by hand.

I also really had to pull hard on the pump to remove it from the tank. I think I will try some grease on the rubber ring to see if that will let it install and remove with less force.

[Bitsyncmaster]

Well there is only 4 inches of clearance at the front and passenger side of the tank from the pump opening. So if you want to use the sender, you have to rotate this pump pickup so the sender is facing the back of the tank. You pull the bottom white plastic off (held by two clips) and rotate the bottom to existing "rod holes". I also pulled the pump hose clamps off so I could rotate the hoses but you may be able to rotate them with the clamps on (wish I checked that). The bottom of those hoses are not clamped and wonder if they should be.

So it's not for a lot of owners since you have to be very careful not to break that plastic with the rework. If you need a replacement on the road you would install it as it comes and not put the float on until you get home to do the rework.

I wonder if there is a model that comes already pointed the correct way. Does the DMCH pump have the sender at the back?

This rework did put the pump directly under the tank hole. The large flat is at the back and it does just hit that stud in the tank. You can tilt the pump a little to clear the stud and probably be fine but then the pump sits at a very small angle from perfectly vertical. Not sure if I will cut that stud yet.

[Bitsyncmaster]

My pump is ready to install but I will need 10 mm hose clamps for the ones I removed. Don't really need the clamp on the return hose so wonder why they put one there. These "plastic" flex hoses must be heat pressed onto the pump and pipes.

I did cut that stud off but it was a PITA to cut with a hacksaw blade.

Edit: Forgot to state this pump only needs to compress about a half an inch to seat onto the tank.

[Bitsyncmaster]

Forgot to attach a photo

[Chris 16409]

Dave, this is the pump I am using.

https://www.rockauto.com/en/moreinfo.php?pk=1330512&cc=1353721&jsn=492

It's an AC Delco brand Made in Mexico unit. It does not have that offset like you mentioned. Maximum pressures is rated at 109 PSI (750 KPA). Most pumps aren't listed with a max pressure rating.

[Bitsyncmaster]

Dave, this is the pump I am using.

https://www.rockauto.com/en/moreinfo.php?pk=1330512&cc=1353721&jsn=492

It's an AC Delco brand Made in Mexico unit. It does not have that offset like you mentioned. Maximum pressures is rated at 109 PSI (750 KPA). Most pumps aren't listed with a max pressure rating.

Looks good. I think all the GM pumps will work fine. Just make sure the float (if your using the sender) is pointed to the back or drivers side. Our tank opening is near the front and near the passenger side of the tank. My pump looks the same but has a metal plate and metal pipes. I also think there are two types of 4 pin connectors. Mine is the flat 4 pin type. I have seen some double rows of 2 pins.

I ordered some hose clamps 8mm to 10 mm on ebay. Nobody had those small sizes with screw clamp in my area. When I get those I can finish my install. I had 1/4" hose on my pump lines and decided to keep that hose. I think most people are using 5/16" hose.

[Bitsyncmaster]

I thought of a better test of these fuel pumps. Easy with these quick connect hoses, pull the return hose and measure the flow without the engine running (Fuel pump powered). So that would measure the flow at 75 PSI.

[Bitsyncmaster]

Today was nice and I wrapped up soldering inventory for now. So I did a leak test by filling the tank past full (about 6 inches above the tank) and waited about one hour and had no leaks.

Then I cut my closing plate to clear the new pump. My Dremal broke (I think the armature broke wires) so I will have to finish another day. Not much clearance needed. It does sit right on the V-band clamp but did not need to cut for that.

[Bitsyncmaster]

I just thought of something I should have tried. To use a heat gun to see if I could have molded that plastic panel rather than cut it.

[Chris 16409]

Like I mentioned before, I just added an extra layer of foam insulation tape to the closing plate. It raised it up enough to give me enough clearance. I then just had to drill a couple new holes so it would align with the rivnuts in the tub.

[dmcnc]

I pushed the connector to rotate and face the rear of the car, giving me just enough clearance to close.

[Chris 16409]

Dave did you have a part number/size/brand of V-band clamp you are using?

[Bitsyncmaster]

Dave did you have a part number/size/brand of V-band clamp you are using?

I bought the V-band clamp from DMCH which has a part number that does not seem to be a standard part. I did some research on stock clamps and there are a lot of variables you can choose from.

I was ready to try the Breeze VT10469 but decided that DMCH must have done a lot of testing for the proper clamp. But after finding out your not going to get a clamp that will compress the pump down since the ridge on the tank is so little I think it's not that critical. So if your a gambling man, try that VT10469

https://www.ebay.com/itm/Breeze-VT10469-V-Band-Coupling-Clamp-4-69-Nominal-Clamp-Diameter/312439775683?epid=1726609868&hash=item48bedca1c3:g:NO8AAOSwrVRcR2-y&frcectupt=true

[Josh]

This clamp works fine

https://www.rockauto.com/en/moreinfo.php?pk=132515&jsn=254&fbclid=IwAR23Fu3cnzNn1C5XGKB2SikqeOPQOXejVKzpuIFbI xJdhe5ZcyyR6ZP25do

Running it on two cars without issue

[Bitsyncmaster]

The pump plate and tank opening are 4.5" dia. But like I said I don't think the band size is that critical.

[dn010]

What are your plans for wiring in the gauge? I know the DMCH pumps come with their own logic box or whatever and I'm not sure if this is just to prevent sudden swings on the gauge due to inclines or what. With all the threads about these newer style pumps, I wouldn't mind transitioning over eventually, especially since I don't need to worry about high pressure pumps for K-jet.

[Bitsyncmaster]

What are your plans for wiring in the gauge? I know the DMCH pumps come with their own logic box or whatever and I'm not sure if this is just to prevent sudden swings on the gauge due to inclines or what. With all the threads about these newer style pumps, I wouldn't mind transitioning over eventually, especially since I don't need to worry about high pressure pumps for K-jet.

http://dmctalk.org/showthread.php?16911-New-Fuel-Gauge-Circuit

[Bitsyncmaster]

I got my new Dremal and finished the cutting for clearance onto the closing plate. Then I put some thin foam over the pump and a layer of Saran wrap. Bolted the plate down and wet 3 layers of 6 oz. glass. To wet the glass you lay Saran wrap on your table, lay the first layer, pour some epoxy on the glass and spread it over the glass. Then lay the next layer over the first, epoxy, next layer. Then you can lift that built up glass and lay it over where you want it. Leave the Saran warp on it an you can just use your fingers to press the build into place. Keep pressing every hour or so until your epoxy hardens. My T88 epoxy takes 24 hours to get real hard but starts setting 2 to 3 hours after the mix. The Saran warp will pull off after the epoxy sets.

[Bitsyncmaster]

I recently was helping another owner installing an all in one fuel pump. His pump was a GM MU1777. That pump functions fine but getting the float for the fuel sender to clear the tank walls is a problem. The problem is for our tank setup, you have to position the pump in one position to clear the closing plate (where the spare tire goes). That sets the float interfering with the fuel tank walls.

It's been since early 2018 since I installed a Bosch 0 986 580 992 all in one pump in may car. That pump is also known as a Bosch 67317 type. I was working with another owner who installed that pump and he wanted me to design the ECU to drive the stock fuel gauge for that sender. Now that pump comes with an offset of the pump location relative to the top mounting. I was able to rotate that pump to remove the offset. You take the pump apart and use different holes already in the pump for the two mounting rods. The result was the float for the sensor was pointing correctly (to the drivers side) to clear the tank walls.

I was thinking the MU1777 may work if I make a new float arm that puts the float on the other side (180 deg out from norm). I'm still working on that but the result is the sensor values get reversed. So you get 40 ohms at full tank and 248 ohms at empty. The norm is swapped 248 ohms full and 40 ohms empty. This is no problem with my ECU since I can program my software to use either direction.

There may be other pumps that will work. Maybe going to a junk yard with a ruler you can choose one. Our Tank from the bottom to the top lip of the mounting is 8.7 inches. So you want to make sure the pump can compress to that height.


Notes:

No matter what pump you use, you want to cut that stud off the bottom of the tank so the new pump will sit on the bottom. If not you will not be able to run your tank as low and that also affects the range of your fuel level sender. I remember I used a hacksaw blade to cut mine. Quite a task working through the tank opening. If your tank could be dry and vented of all fumes you could use a cutoff wheel on with a Dremal. You don't want to try to break it off, that many damage the tank and get a leak.

There is also long "wire" in the tank. Mine ran along the drivers side of the tank. Since my float runs close to that side, I pull the "wire" to the front side of the tank. The wire rotates freely. I just had to bend the end a little to clear the passenger side of the tank.

I really don't like when you tighten the pump hold down clamp, it pulls the clamp up. My pump would probably be fine without the clamp. It sits tight in the tank and very little spring pressure to push it up because the pump is almost the correct height without pushing it down. I wan to someday 3D print a ring to glue on the top of the tank.

Float wire is 2.5 mm diameter. You need about 12 inches long or more. I was able to fine some 400 mm long on Ebay.

[thibaut]

No matter what pump you use, you want to cut that stud off the bottom of the tank so the new pump will sit on the bottom.
That was one of my concerns too, before seeing this @ DCS :
71554
Although I agree w/ you : i'd be more confident w/o the stud... and yet less confident to have removed 100% of the metal residues from the filing/cutting

[Bitsyncmaster]

That was one of my concerns too, before seeing this @ DCS :
71554
Although I agree w/ you : i'd be more confident w/o the stud... and yet less confident to have removed 100% of the metal residues from the filing/cutting

The fuel pump filter would take care of that. Some of the all in one pumps put it on the outside at the bottom. Most put it inside at the bottom. It's a very fine filter.

[dn010]

I never had to remove the stud, it sits next to the pump and doesn't interfere at all.

[WHO1DMC]

I never had to remove the stud, it sits next to the pump and doesn't interfere at all.

I didn't remove mine and had no problems. I got my pump from DMCH and I don't remember it even being in the instructions.




Dave B.

[Bitsyncmaster]

71554

Look at this photo of the DMCH pump. Probably if the pump had the flat side on the rear it would clear. Now is that pump sitting rotated how it has to be to clear the closing plate?

[Bitsyncmaster]

Here is what I have designed right now. Still always thinking about changes. But it looks like this will work. Just a 3D printed ring with 4 holes to press in 8-32 rivet nuts. This ring sits a little below that ridge on the tank so my plan is just to hot glue at that ridge so the ring can't pull up.

I plan to make a top ring out of aluminum or steel that presses the pump down. Could even just use fender washers.

I will position it so one screw is between the two fuel pipes, then the others should also clear.

I was thinking of making a thin ring of metal that would use a regular hose clamp to hold it onto the tank. But I don't think there is enough room for that hose clamp.

As always, suggestions or ideas always welcome.

[82DMC12]

I have the DPI Delphi pump and the stud is a non-issue. it sits under the pump in a sort of recess if I recall.

[Bitsyncmaster]

Here is the finished clamp installed. It should give you a little more clearance since the pump is clamped all the way down.

[Bitsyncmaster]

I just thought of another way to do the clamp. Could probably get enough flex with the 3D printed ring, so cut a slot so you can clamp it under the ridge. Could probably use a normal hose clamp for that.

[Bitsyncmaster]

I just thought of another way to do the clamp. Could probably get enough flex with the 3D printed ring, so cut a slot so you can clamp it under the ridge. Could probably use a normal hose clamp for that.

I'm convinced this is the way to go. It will wait till I get a chance to replace my glued one. I ordered at T- bolt clamp the for the new one and I have a new 3D printed ring ready to go.

I never stop trying to perfect things.

[Bitsyncmaster]

I 3D printed the top ring at 0.125" thick and I think it will be strong enough rather then make one in metal. I will look if I can make it thicker when I rework my original attempt. These are printed with PLA+ which I think will flex enough to use the hose clamp method. I may try printing in ABS just to see how that works. I could print them with resin but that results in very brittle parts.

[iflights]

Dave, thank you for the continued thought leadership. I have a GM pump with V-clamp, but have never been confident its fully pushed down. My pump avoids the stud but I cannot close the access panel. A previous "GM style" pump was in place previously and allowed the access panel to close. I like the solution you are outlining.

[Bitsyncmaster]

I printed that top plate with ABS. Testing both, it looks like the ABS is very slightly more flexible than PLA. I haven't done a break test yet but they say ABS is stronger.

I did however think of a change I need to do on my design. I need to have the lower ring ID the size of the tank neck, less the ridge. Therefor you make a cut in the ring and expand it over the ridge to install. Have to do that so the screw holes in the top ring will line up. If you were compressing the ring that would change the screw holes a little. I don't think you need much for the "hose clamp". This new change will almost stay put without a clamp.

All this needs to wait till I get time to pull my fuel pump again. So I can measure the exact OD of the tank neck less that ridge.

[Bitsyncmaster]

It works great. Ring has one cut and it just snaps over the tank ridge. Simple hose clamp really locks it in place. Hose clamp bought at ACE hardware.

[Bitsyncmaster]

Here it is with the pump installed. I used a 3D printed top hold down plate that is 0.125" inch thick ABS. It does seem strong enough and much less work than making that plate out of metal.

When your clamping the bottom plate, put the 4 screws in to hold it up against the ridge.

[Bitsyncmaster]

Here is one of those low dollar fuel pumps. This one is to high for our tank. It also has the float for the sender on the wrong side.

It's not hard for anyone that has a vice to make up a new float putting the sender on the other side so it locates it around where the original OEM sender was. This does reverse the resistance which would not be 40 ohms full and 250 ohms empty. My fuel gauge ECU can be loaded with software for that.

Get some 2.5 mm stainless rod (304 is common). It can be bent 90 degrees cold. You may need a few attempts at it. This was my first attempt and it looks perfect. You can make small adjustments with your hands. Remember a longer arm will do less movement of the sender. Your looking for the 250 ohms with the sender sitting on the bottom of tank and 40 ohms with it hitting the top of the tank.

[Josh]

a metal coat hanger works perfectly, and you likely already have it for making a float arm.

[Bitsyncmaster]

a metal coat hanger works perfectly, and you likely already have it for making a float arm.

Probably would work fine. But the 304 SS really holds the bends.

[Bitsyncmaster]

I bought this fuel pump for a backup unit to put on the self. Looks like this will work with the fuel sender. It should put the float close to where the OEM sender is located. It has a lot of range on the height. Our 8.7" tank height seems about in the middle range. I paid $36 for this unit plus shipping and tax made it just under $50. My unit came with the pressure sensor which I will pop off and plug the hole. Looks like a lot of higher grade pumps they sell on parts Geek offer pumps with or without the pressure sender.

2000 Chevrolet Tahoe
DriveBolt is the manufacture
Parts Geek SKU shows A3091M in the shipping cart but I did see 371-02784243 somewhere during the order.

Note the fuel sender has a part number printed on it of S3091M. I wonder if that is the fuel pump part number.

[Bitsyncmaster]

I bought this fuel pump for a backup unit to put on the self. Looks like this will work with the fuel sender. It should put the float close to where the OEM sender is located. It has a lot of range on the height. Our 8.7" tank height seems about in the middle range. I paid $36 for this unit plus shipping and tax made it just under $50. My unit came with the pressure sensor which I will pop off and plug the hole. Looks like a lot of higher grade pumps they sell on parts Geek offer pumps with or without the pressure sender.

2000 Chevrolet Tahoe
DriveBolt is the manufacture
Parts Geek SKU shows A3091M in the shipping cart but I did see 371-02784243 somewhere during the order.

Note the fuel sender has a part number printed on it of S3091M. I wonder if that is the fuel pump part number.

Edit: Get one without the pressure sender. So you don't need to find something to block that 3/8" hole.