Fuel pump spurting fuel -68 Corvair 500

[Kent1915]

Hi. I got to start my ‘vair today to wake it from a mid winter nap. Ran it for a while but when I went to turn it off I smelled fuel. Opened engine compartment and there was fuel that had spurted all over. Would estimate maybe 2-3 ounces on ground under engine, in compartment etc. didnt see it spraying out this time but noticed in fall this happened and saw it spurting out the hole in the fuel pump.

The pump, to my knowledge, hasnt been rebuilt or replaced in recent memory (was my dads since he bought it in 69, i grew up with it and took it over when my dad died a few years ago). i did pump the pedal a few times before starting to move fuel... im thinking something messed up with diaphragm but am not sure. anyone have guidance?


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[joelsplace]

If it's leaking out the center top hole on the cover the diaphragm is shot. If it's leaking between the layers the fresh fuel on it may help the rubber and maybe try tightening the screws.

[Jerry Whitt]

Many auto parts stores carry the fuel pumps, or can get one in a few hours. Try Autozone or Oreillys. Other local spots may help also.

[Kent1915]

Was thinking diaphragm. Thanks to you both. I appreciate it.


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[bbodie52]

The illustrations below and the attached shop manual section may help you to visualize your task. The extra small fuel line at the front of the fuel pump tee connector is a fuel tank return line that keeps fuel moving when the carburetor float bowls are full. This was added to Corvairs in 1968-69 to keep fuel moving and reduce the possibility of vapor lock that can occur when fuel is stationary in a hot running engine.

Corvair fuel pump rebuild kits and repair parts are no longer available.

To remove and reinstall the fuel pump, be sure that you have installed it properly. It is important to ensure that the fuel pump is correctly seated and installed. There is a hole in the side of the pump shaft that the tapered bolt tip must seat into. If the pump is sitting too high and the bolt is simply pressing against the side of the pump housing, rather than seating inside the tapered hole, the pump push rod will not be doing its job. Fig. 57 in the shop manual page shows the tapered hole that the tip of the bolt fits into. This ensures proper installation and seating of the pump.






TIP:

A six-point socket usually gives a better grip on a bolt head than a 12-point socket.



When working with a tubing fitting, such as those found on fuel lines or brake lines, a full socket tool is not possible — so substituting a flare nut wrench approximates a six-point socket grip to avoid damage to the fitting surfaces...


Here are a few options, including a unique wrench shown at the end...

The fuel line inlet fitting size on the carburetor inlet is 7/16".

A five-piece Craftsman set runs about $36.99..



http://www.acehardware.com/product/inde ... a6EALw_wcB

Or $31.91 via Amazon.com

https://www.amazon.com/Craftsman-Flare- ... nut+wrench



For damaged or stubborn fittings, this special tool may help...

Tue Jan 15, 2013 8:44 am

I've had great luck with removing nasty brake line fittings by using a Vise Grips Brand 7LW. They also work well when someone before you has buggered up the hex nut.

These come in three sizes but I use the 7LW (175mm/7 inch) the most. Around $12-$15

http://www.amazon.com/Vise-Grip-Locking ... B00004SBBD

http://www.corvair.com/user-cgi/catalog ... IN&page=65


Part number C3403: NON-GM FUEL PUMP-62-69 WILL FIT 60-61 IF ORDER C259 ROD

Weight: 2 lbs 4 oz
Catalog Pages(s): 65
Price:
1 - 1 $ 65.55
Est. USPS Priority Mail Shipping Cost $ 11.75
Grand Total $ 77.30


TIP: CLARK'S WILL NOT BE CHARGING SALES TAX FOR OUT-OF-STATE SHIPMENT TO WISCONSIN. IF YOU NEED ANY OTHER CORVAIR-SPECIFIC PARTS SUCH AS OIL FILTERS, TUNE-UP ITEMS, A SHOP MANUAL, ETC. CONSOLIDATING YOUR NEEDS INTO A SINGLE SHIPMENT FROM CLARK'S WILL OFTEN SAVE COSTS OVER MULTIPLE SEPARATE SHIPMENTS. MOST OF THESE CORVAIR-SPECIFIC ITEMS WILL NOT BE AVAILABLE LOCALLY, ESPECIALLY FROM IN-STORE INVENTORY.

=========================================================================================

The link below will provide you with a list of useful websites that are Corvair-related. Some of the links will lead you to an extensive technical library that will allow you to download shop manuals and other technical references in Adobe Reader format at no cost. You will also find a list of essential Corvair parts suppliers. Clark's Corvair Parts is the biggest and oldest Corvair supplier in the world. You will find a link that can provide you with a series of videos that amount to a tour of the Clark's Corvair Parts facilities. I think you will be amazed at the quality of the reproduction components they offer — particularly the interior carpeting and re-upholstery items. Parts suppliers such as this truly make our Corvair hobby possible.

Common and Useful Corvair Websites

viewtopic.php?f=225&t=6007

[Kent1915]

Thank you! Appreciate the help. I had been looking for rebuild kits last night and found out it’s gotta be a replacement. It’s good to have projects I guess to keep me out of trouble. [emoji4]


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[66vairguy]

Thank you! Appreciate the help. I had been looking for rebuild kits last night and found out it’s gotta be a replacement. It’s good to have projects I guess to keep me out of trouble. [emoji4]


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Yes "rebuild" kits have not been available lately. Sadly the replacement Corvair mechanical fuel pumps have had a history of issues. The latest problem is excess fuel pressure. Please use a fuel pressure gauge and correct test fittings to check the fuel pressure with the engine running. It should not exceed 5PSI. Some have reported pressure readings as high as 9PSI. The Corvair fuel pump specification is 4.0 - 5.0 PSI and should remain steady between engine idle speed and 1,000 RPM. Excess fuel pressure can result in rich operation or flooding of the carburetors.

Some have posted that they take apart the new fuel pump and cut the inner spring until the pressure is correct, others try another pump.

[joelsplace]

Keep the springs from any old pumps. You can use the old spring in the new pump and have spares to experiment with.

[VairsRule]

If the pump is bad, an electric fuel pump is a very nice upgrade. I prefer the Facet brand electrostatic pumps (the low pressure ones) over other brands and any type of rotary pump. The electrostatic pumps are rather noisy, but can be made quieter by mounting them on a very solid part of the car and using rubber shock mounts of some sort to isolate the pump from the chassis.

When installing an electric pump, most, recommend placing it up near the gas tank, or in the left-rear wheel opening. Avoid placing it in the engine compartment UNLESS you attach it with hard lines (NO RUBBER HOSE!). Rubber fuel lines are the number one cause of engine fires in Corvairs and other air-cooled vehicles, because if there is a fuel leak, there is nowhere for the gas to go (cooling shroud prevents it from running onto the ground) and it will pool up and vaporize.

I've mounted Facet electrostatic fuel pumps both behind the gas tank on a Corvair, and in the engine compartment in a VW Beetle, and they worked perfectly in both locations. For convenience, I'd much prefer locating the pump in the engine compartment and using hard lines, but it takes more careful planning and more parts to pull it off. There is precious little space to run fuel lines in there!

Also, you will need to do a couple of extra things when changing to an electric fuel pump:

Plug the hole for the old mechanical fuel pump, or modify it to act as a plug. You can buy a plug made for the purpose, but they are rather costly, so I modified my fuel pump by replacing the diaphragm with a piece of aluminum plate cut to match the shape of the fuel pump. This permitted me to keep the old fuel lines running through the mechanical pump.

The electric pump simply won't fit where the mechanical pump is/was, so if you choose to remove the old pump and block off the hole, you will need to modify the two sections of fuel lines that run to/from the old pump. Be sure to use steel fuel line and the proper interconnects. NEVER use fuel hose here! Even if the fuel hose does not rot (and it WILL), there is a big risk that the fan belt and/or some other moving part on the engine will come into contact with the fuel hose. Corvair fan belts need a certain amount of slack, and can bounce up and down a bit in this area.

[bbodie52]

I posted this a few years ago with a discussion on Corvair mechanical fuel pumps...

I dunno... the mechanical pump alone is perfectly capable of doing the job, and you can buy two mechanical pumps for considerably less than one electric pump and the necessary conversion lines and safety interlocks. (One active mechanical pump and one spare in the trunk in your emergency spares kit).

Replacement mechanical fuel pumps are reliable and relatively inexpensive. A good electric pump, with proper safety switching can cost many times the price of a new mechanical pump. Corvair mechanical fuel pumps have been widely tested in hundreds of thousands of Corvairs for 40-50 years, and they are a proven product with good reliability. They are also easy to remove and replace. I would recommend against a conversion to an electric fuel pump. It is not worth the expense. As I said above, you could purchase two mechanical pumps and keep one in the trunk as part of a spares kit, and still spend significantly less than the cost of an electric pump conversion.

Here is something I wrote about this last year. Notice that Clark's also offers a mechanical fuel pump bypass plate, to easily connect to existing steel fuel lines and to use with an electric fuel pump source.

Tips From CORVAIR UNDERGROUND...

http://www.corvairunderground.com/fuelpump.htm

Let's Talk About



Corvair FUEL PUMPS

This is always a controversial subject amongst Corvair owners. But a great deal of the controversy is self inflicted. Mechanical or electric fuel pumps? Let's try and sort this out.

MECHANICAL FUEL PUMPS - These are the pumps that came standard with all Corvairs from the factory. The mechanical pump is a simple diaphragm type that is operated by a push rod which rides on an eccentric on the crankshaft. The pump develops suction which draws gas from the fuel tank and distributes it to the carburetors.

It would be simple to say that all mechanical Corvair pumps are the same - but alas, that is not the case. The original 1960 models had a pump that appears to be the same but has a longer rod exiting the bottom of the pump. In turn a shorter pump pushrod was obviously used. This design was carried over into 1961 models for an uncertain period of time. This is why if you own a 1960 or 1961 you should always measure the overall length of your pushrod before you replace the pump.

In that same vein I would highly suggest that if you find you have one of these earlier pumps you should convert it to the 62-69 type. Why? because it's easy and cheap to do and there is never a question in the future as to which pump you're using. If you should be unlucky enough to find an NOS earlier pump do not be tempted to use it!

These 60-61 pumps were last produced well over 30 years ago and that pump will be too old to reply on. To make the conversion simply get one of our part number U-481 pump pushrods.

Now let's go back 18 years ago to 1992. One of the largest makers of Corvair fuel pumps got a defective batch of diaphragms. THIS HAPPENED ONCE and only in 1992. But the repercussions have lasted ever since. The problem was corrected within a few months BUT because this manufacturer sold to many different retailers it made it appear that numerous manufacturers were putting defective pumps on the market. To make matters worse, some of those retailers moved very few Corvair pumps, so for years (even to the present) some "brands" (labels, really) still sell defective Corvair pumps - all ones made in that original batch 18 years ago.

Well, bad enough you say. Oh it can always get worse - and it did. Back in the early 90's a small parts vendor saw an opportunity. Because everyone at the time was in a virtual panic this vendor saw an opportunity to promote their fuel pumps. An abnormal amount of negative advertising and outright nonesense permeated the Corvair grapevine. The claim, of course, was that this vendors fuel pumps were perfect while everyone elses were bad. But there was an irony here.

As time went on it became more than apparent that the vendors fuel pumps were actually worse than everyone elses. Where their pumps came from were anyone's guess, but by hundreds of defective pumps and 3 different, but failing, revisions later the matter was dropped.

But that wasn't enough. During this timeframe numerous Corvair experts (some real some self-proclaimed) wrote articles that only clouded the issue even worse.

Some claimed that rebuild kits were the only answer. Ironic again, because the few remaining rebuild kits also suffered from the diaphragm problem, possibly because they had been the original supplier for this part from the beginning. Some claimed that certain visible features could warn you of doom. Visible reinforcement fibers in the diaphragm, the type of screws holding the pump body together, even the precise length of the lower diaphragm rod were all to be worshipped. While it's true that some of these identities sometimes had validity none of them were absolute. The issue of the diaphragm rod length was especially absurd.

It's true that the rod length has to fall within certain parameters, but the miniscule measuring of this rod was misleading overkill. The amount the rod protrudes from the pump casting can still vary up to at least 1/4 of an inch and still be within specs.

Take all of the above and horsewhip it to death from 1992 to the present and what can you expect? If you study the psychology of panics most of them look a lot like our fuel pump example. An issue can be twisted and confused so much for so long there is no way to untangle it.

Then we have to think that many people quit driving their Corvairs? No, a "white knight" came to some owners rescue. The electric fuel pump is used on nearly all modern cars. Electric pumps are generally reliable, and are readily available. So why isn't that the end of the story?

I have said since Day One that I would never talk a happy electric fuel pump owner out of their pump. That has never really been the issue. The issue are new Corvair owners and what they should feel compelled to do. I think it's irresponsible to tell a new owner that he has to get rid of a perfectly functioning mechanical pump and replace it with an electric.

Electric fuel pumps cost more than mechanical pumps, especially when set up safely, take a bit of work and knowledge to retrofit and have their own problems (as do all mechanical devices). Bottom line - they are unnecessary, but if you really WANT one (as opposed to being convinced that you MUST have one) then that's your decision.

But what if your mechanical pump has failed?

FIRST - Make sure it HAS failed. I believe that many fuel pump "failures" have nothing directly to do with the pump. The most common of these is when you develop an air leak in the incoming fuel line. Spots to look for trouble include the rubber connecting line just behind the firewall (old cracked hose or loose fittings are the culprit) and make sure the fittings where the incoming line connect to the pump are good. These air leaks can be transient or very specific and repeatable - all related to ambient temperature. If you think your fuel pump has quit pumping check these spots first.

And then there's leaks, both internal and external. Of course the biggest boogeyman is the internal leak that pumps gas into your crankcase causing everything from noisy lifters all the way to a trashed engine. This can be serious and I have seen it happen - with both mechanical AND electric fuel pumps - but it isn't so common that you have to spend every day immersed in paranoia about it.

External leaks can happen but they are usually the result of incorrect installation or other misuse of the pump OR you may have purchased one of the brands of pumps that never got sent back from the 1992 recall.

One important point about electric pumps is that if you chose to use one make sure to remember that the incoming line system was not designed to be pressurized.

http://www.corvairunderground.com/pumpleaks.htm

Our own mechanical fuel pump "horror" stories....



As I've mentioned before, I have nearly 2 million miles of Corvair driving on mechanical fuel pumps. I believe them to be totally reliable.

Never the less, we do no one a service by ignoring actual issues. Rather, it's better to get them out in the open and try to analyze them. Here are the ones I have experienced firthand.

Once my stepson and I were driving his 1969 up to a Corvair event in northern Washington. He hadn't put many miles on the new engine but everything was running well. We had stopped at a Wendy's to eat lunch. The 69 was parked on a pretty steep space where the engine was on the downhill side.

After eating we came out and started the 69 up. It was running fine but I was sure I smelled gas. Went to the back of the car and gas was POURING out of the back of the fuel pump. We immediately stopped the engine and pondered our options (I had brought a new spare fuel pump with us - I carry a spare tire and fan belt too).

Because I couldn't explain why the pump was suddenly "leaking" I asked my stepson to start the motor up for just a few seconds so I could see exactly where the gas was coming from. SURPRISE! Gas wasn't coming out of the pump any more. I was baffled.

We watched the pump for about 10 minutes. Not a drop of gas. We proceeded (cautiously) the further 100 miles to the show. No leaks. Then drove home (about 300 miles) no leaks. In fact, this was 10 years ago and the car still has the same fuel pump on it. Not a drop since.

What exactly was going on? I have my theories, but maybe you have an idea.

Another leak story involves my Ultravan. Because it usually sat for months at a time when it came time to start up for a new season I'd have the engine lid off to watch for problems. The last time it had been started was about 9 months before. This time on startup there was a massive fuel pump leak.

I shut the van down and went inside to ponder the situation. About 10 minutes later I went out, restarted the Ultravan, and of course, no leak. The "leak" never came back - even 4 years and 5000 plus miles later.

Our last example is interesting because it just happened to me 2 days ago (August 30th). I had my daily driver 64 Greenbrier down for about 3 weeks while I rebuilt the carbs, distributor, and alternator.

When all the work was done I did the initial startup and SURPRISE the fuel pump that had been serving faithfully for over 60,000 miles was leaking. But this time I thought I'd just shut down for a few minutes and then restart.

Of course the "leak" was gone. And it hasn't come back.

In all the cases above I DID NOT tighten the screws on the pump - In these circumstances many people retighten the pump cap screws and lay the "leak" on the need to do that. But note that, at the same time, there was a short waiting period between "leaking" and not leaking. I'm certain it was the waiting period - NOT the screw tightening that fixed the problem.

But why is it happening? (Even if just occasionally) It appears that modern fuel dries out the rubber diaphragm between extended intervals of operation. Sometimes (but not usually) the diaphragm material will shrink causing a leak at startup. BUT, once the material is re-exposed to the fuel it "swells up" and re seals.

If you have other ideas let me know.

The last example is what I believe to be very typical. Linda and I drove our 67 out to southern Utah for a Corvair event back in 2000. We had already driven 900+ miles without incident but after meeting up with the Bonneville Corvair club we stopped for lunch (At a Wendys again - hmmmmm I wonder...).

As we left we all drove back onto the freeway and the 67 died out. No fuel. Everyone thought it was a failed pump. But I was suspicious. I went back and checked everything over and noticed that the incoming gas line fitting was loose. Upon tightening it up we had fuel pressure again and finished our trip, including a barren 300 mile return across HWY 50 in Northern Nevada (The world's loneliest highway).

Vacuum leaks anywhere in the incoming line can cause the pump to quit drawing fuel. These leaks can be effected by temperature and other factors. Check these things first , before you assume the pump has failed.

This might also help with a more-reliable fuel control...

Clark's Corvair Parts offers a replacement for the needle and seat that makes use of a ball in an all-metal assembly. It has many advantages over the standard needle and seat found in carburetor rebuild kits, as shown below...

http://www.corvair.com/user-cgi/catalog ... ow_page=58


Part number C3799: METAL FUEL INLET VALVE-60-69 FITS CARS & TURBOS

Weight: 0 lbs 2 oz
Catalog Pages(s): 48(10),55(12),58
Price:
1 - 3 $ 9.00
4+ $ 8.10


This appears to be a well thought-out solution that provides both electric fuel pump cutoff safety and initial pump priming without all of the added complexity of developing the plumbing for an oil pressure safety switch sensing point and a lot of added rear engine compartment wiring. Most of the wiring could remain under the dashboard and in the front supporting the electric fuel pump were it should be — near the fuel tank. For non-Corsa/Spyder installations, a tachometer pulse sensing wire would have to be routed to the ignition coil negative terminal.

The other thing to consider...

$47.42 + $64.99
= $112.41

= $65.55



Fuel Pump Controller
This universal electric fuel pump controller is designed for cars and trucks being upgraded from a mechanical fuel pump to an electric inline or in-tank fuel pump.

• Pump only runs if there is a tach signal from the ignition.
• Primes the pump for three seconds at initial key-on.
• Includes a 7.5 amp circuit breaker.
• Includes an internal relay.
• Includes 15 feet of 16 gauge wire to energize the fuel pump.

One year warranty
30 day Money Back guarantee
$64.99 PN 12003

http://www.revolutionelectronics.com/Fuel_Pump.html
http://www.revolutionelectronics.com
Cypress, California 90630

https://www.amazon.com/Revolution-Elect ... nics+12003

This Fuel Pump Controller is a “must have” for any electric fuel pump equipped muscle car. It monitors the tach signal to limit when the fuel pump can operate. When the key is first turned on, the fuel pump is allowed to operate for three seconds, priming the fuel system. After these first three seconds, the pump is only allowed to run when the engine is running; if the engine stops, so does the fuel pump. No plumbing into the oil lines or adding an extra priming button under the dash. (If you are converting to an in-tank pump, be sure to check out our Power Isolator.

The attachment Revolution Electronics Electric Fuel Pump Controller — Model 12003 - Installation (pg 1 of 2).jpg is no longer available

The attachment Revolution Electronics Electric Fuel Pump Controller — Model 12003 - Installation (pg 2 of 2).jpg is no longer available

Revolution Electronics Electric Fuel Pump Controller — Model 12003 - Installation.pdf

Revolution Electronics Electric Fuel Pump Controller — Model 12003 - Installation

(200.79 KiB) Downloaded 58 times

[Kent1915]

Thank you all. Had some other stuff to get from Clark's so added new mechanical pump to order.

Now if it would stop snowing long enough for me to get to the car to do some work on it...


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[VairsRule]

Interesting theory, Brad. Seems like the most likely explanation. I've had multiple Corvairs with original mechanical fuel pumps sit for very long periods of time, and none of these has ever leaked coming out of hibernation. I wonder why not??? Virtually all gas sold in my area contains 10-15% ethanol, which is the prime suspect. Weird.

Facet makes several models of electrostatic fuel pumps, with a variety of flow rates and pressure ranges, and cases in the original zinc-plated metal case like the one Brad pictured, or high-impact plastic. Many of the aftermarket electrostatic fuel pumps sold under various brand names are actually made by Facet. Most of these have the black plastic housings. I've used both types, and never had a problem with either. These are often priced around $25 (or were last time I bought one), so I'd shop around for the best price. I think even the "Mr. Gasket" pumps sold at most auto parts stores are now supplied by Facet, as they are a dead-ringer for other brands that I know are made by Facet.

Some Mr. Gasket fuel pumps have been known to be very undependable in the past. However, I believe these were rotary pumps and/or were not made by Facet. The ones I've used or seen used have all worked fine.

Good catch on the fuel pump controller/auto-shutoff safety feature, well worth $65.

[joelsplace]

Keep the old pump for the spring as I mentioned before and the base of the pump may be better also. I've heard of a lot of the newer pumps having issues with the base warping. The fix is an old style base.

[Kent1915]

Was planning on saving old pump in case I needed parts but didn't know about the base. Thanks for the info.

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