CAV Injector Pump Stuck? MF135

[thepumpguysc]

Google: CAV metering valve..
There should be a video on how to lift the top cover and free up a stuck mv..

 

[jrsavoie]

Google: CAV metering valve..
There should be a video on how to lift the top cover and free up a stuck mv..

Thanks.
Do you have any thoughts on installing the lift pump to pressurize things a little as d check for leaks?

Your search found a good tutorial on loosening up the metering valve on yesterday's tractors.

Here is a write-up I made on another board.

"I don't claim to be a pump man but my guess is the problem is your metering valve.
On those CAV pumps it is rather common for them to get stuck in the off position.
Here is a post with a picture I put up on another forum that explains how to free it up.
It has helped many guys get their tractor started.
"First of all CLEAN your pump and its surroundings.
Pressure wash it then use brake cleaner.
You do NOT want any dirt inside.
Shut fuel off at the tank.
Remove the throttle rod and shut off cable.
Cut the wire that has the lead seal on it.
Remove the two nuts that hold the top cover on the pump. There are washers under the nuts. Do not lose them or your cover will leak.
Carefully lift the cover of the pump about 3/4".
Do NOT overstretch or remove the spring that is attached under the cover.
The photo below shows the pump backwards from what you will actually see. Note the slide bar #3. That will be right in front of you when you lift the cover. That slide bar operates the metering valve. See the red arrow. Metering valve has a very weak spring that should return it forward to run position. They get stuck in the off position. Free it up with a small screwdriver or popsicle stick - move it back and forth till it returns forward on it's own.
Get the slide bar located properly - that can be tricky so use due care. Replace the cover. Replace the washers and nuts.
Some say you will ruin the gasket under the cover when you do this. I have done this a half dozen times and gasket was always fine.
Turn on the fuel and bleed the filter/s. Bleed the pump. Crack all 3 injector lines at the injectors, turn the engine with the starter and bleed them all simultaneously. Then retighten the injector lines . It should start then.
Remember this pic is backwards.
It really is Very simple to do so don't be scared of it.
Let us know how it goes."

 

[thepumpguysc]

Let me ask you.. why are you worried about leaks if it won’t start.??
Once u get it running, any leaks will show up.. u don’t need to pressurize the pump.

 

[jrsavoie]

It's been leaking for a few months. The leaks didn't show up yet.

About a 3" spot on a piece of cardboard overnight.

I thought it smelled like diesel.

It drops to the floor about 3" on front of the Cav pump.

 

[thepumpguysc]

It might show up with your electric supply pump..
The problem with that pump is, once u plug 1 leak, another one shows up.. If one seal is hard and flat, they’re all hard and flat..

 

[jrsavoie]

If the pump leaks, it will get a complete rebuild. Once you have it off to fix anything, there's no sense having a 1975 pump installed without having it gone through.

The only seals between the electric pump and the Cav pump are the filter gaskets.
Everything else is compression fittings.

 

[jrsavoie]

It might show up with your electric supply pump..
The problem with that pump is, once u plug 1 leak, another one shows up.. If one seal is hard and flat, they’re all hard and flat..

Found out the electric pump I used has the same pressure rating às the mechanical lift pump on the back of the cav pump. 8-9 psi.

I did find a couple minor leaks.
I had to tighten the fuel filter just a tiny bit - we just changed it.
I use the Baldwin fuel filter.
I found out a while back, the Napa filters don't work on these.

I had a guy service the machine for me and he used the Napa. Immediate issues.

I also did not get the line to the cav pump tight enough, it was leaking a tiny bit also.

I let the electric lift pump run constantly.

Added another battery with jumpers and a booster charger that I flipped on for cranking.

Got it cranking over a lot faster.
Block heater plugged in and it finally popped off tonight.

Never had to pull the top off the cav pump.

I plan on eventually installing the electric lift pump and a relay to run it, permanently

 

[thepumpguysc]

FWIW.. the NAPA filter will work, but u HAVE TO Put the top oring UP IN the groove in the filter head.. NOT ON the filter..
I’m confused on your statement about the supply pump puts out 8-9 psi in the back of the CAV pump..??
R u talking about the old supply pump that runs off the engine cam/crank.??
Glad u got it running..
U might wanna run an injector cleaner thru the system..
And ALWAYS, ALWAYS, ALWAYS push the shut off knob back in to the run position when shutting it down..
Don’t give it a chance to freeze the metering valve in the shut off position..

 

[Swetz]

And ALWAYS, ALWAYS, ALWAYS push the shut off knob back in to the run position when shutting it down..
Don’t give it a chance to freeze the metering valve in the shut off position..

Oh boy, I may be in trouble! I have a 445A that is a project, outside under a tarp for over 5 years now. I know I left the cable pulled cuz it did not return on its own....darn!

 

[thepumpguysc]

No worries.. just go to the beginning of the thread, there’s enough pic and instructions for u to diagnose the problem..
But after 5 YEARS.. I would expect that the pumping plungers are frozen up..& that requires a tear down..& special tools..

 

[jrsavoie]

FWIW.. the NAPA filter will work, but u HAVE TO Put the top oring UP IN the groove in the filter head.. NOT ON the filter..
I’m confused on your statement about the supply pump puts out 8-9 psi in the back of the CAV pump..??
R u talking about the old supply pump that runs off the engine cam/crank.??
Glad u got it running..
U might wanna run an injector cleaner thru the system..
And ALWAYS, ALWAYS, ALWAYS push the shut off knob back in to the run position when shutting it down..
Don’t give it a chance to freeze the metering valve in the shut off position..

I read in the Ford repair manual that the mechanical lift pump built into the back of the cav pump should put out 8-9 psi. I don't remember the number.

I would imagine that could be measured by attaching a gauge at the Cav pump bleeder. I never read any further once I saw the pressure was the same as the electric pump I added ahead of the filter.

The electric lift pump takes the load off the built in Cav pump. Which I'm sure wasn't designed for ULSD.

I always stick the fuel filter seal up in the housing, no matter the brand of filter.

That way, I can't forget to remove the old seal.

I added some fresh diesel
Clear diesel, bio killer and Hotshots.

I also always try to remember to push the fuel shut off to the run position. For me, I was thinking, if there was a very minor leak, the fuel might leak out, instead of air leaking in.

Thank you very much for your advice.

It's much appreciated

 

[Swetz]

5 YEARS.. I would expect that the pumping plungers are frozen up..& that requires a tear down..& special tools..

LOL, it will most probably be over 6 by the time I get to it.


I purchased the tractor for a retirement project. With the value of the dollar dropping so rapidly, I am still working, but plan on retiring in July. The tractor project has to get in line...The good news is if the pump is in fact all mucked up, I got a guy that can fix it.