# Massey ferguson 135 cav pump problem



## Jeremy sheally (Oct 17, 2021)

to followed the bundy bears shed tear down and rebuild of the massey ferguson cav pump tear down and rebuild and am having problems getting to tractor to run. It's a 1969 massey ferguson 135 perkins ad3.152 with a cav pump ro3923xu model number and a dpa number 3230f190. I'm a diesel mechanic on on highway and off highway trucks and equipment but this is my fist time trying to rebuild a pump. Just rebuilt the engine on this tractor. Had the local tech school pop test my injectors 2 were good one popped at a lower pressure so they fixed that and if I remember correctly they all pop at 25 bar but don't hold me to that it has been several months ago but do remember the teacher telling me they are all set at the top end of the spec and had a really good spray pattern. But here is my pump problem at first I was only getting fuel to #2&3 cyl and hardly any to #1 removed the fuel lines from the pump and #1 would only shoot out like 4 inches while 2 and 3 had a good strong steady stream of fuel at cranking speed so I tore the pump down again and took every thing back apart and cleaned everything again made sure my arrow on the cam ring was pointing in the direction of rotation which viewed from the rear of the pump would be to the left. The pumping plungers are free in the housing and yes I did turn the fuel up when I put it back together but I only moved the ring maybe the thickness of a aluminum can tab thickness but did find that the plunger in the end cap pressure regulator valve was sticking and not moving freely so I cleaned that up real good and got it moving freely put everything back together installed it on the tractor 24 degrees btc with pump on the E mark bleed the fuel system and my manual pump is bad I have one on order but have a electric pump supplying 7 psi to the injection pump I got good fuel pressure to the injectors but tractor would not start hit it with a little starting fluid and I fired up it would not idle only way it will run is holding the throttle wide open then it only turns 1700 rpm and that is with the throttle stop screw backed all the way out.it ran like that for about 10 mins sounded good but then started acting like it was starving for fuel and slowly died out and would not restart again with out starting fluid I checked and I'm still getting 7psi to the pump when it starts to slowly die out. I was going to take it to the shop where we get some of our pumps rebuilt at but they said it would be 4 to 5 weeks before they could look at it and another shop said they could look at it this week but it would be 650$ for them to check it out on there machine and then what ever parts and labor on top of that to fix it. I'm glad I was sitting at my desk for that. So with all that I'm at a loss and need my tractor to get my final cutting of hay. Help!!!!


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## thepumpguysc (Jan 25, 2015)

Ahhh.. old Bundy bear strikes again.!!
Lol..
He’s been great for my business..


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## Jeremy sheally (Oct 17, 2021)

Do you have any idea what might be the problem? Other than I may have gotten in a little over my head lol.


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## thepumpguysc (Jan 25, 2015)

There’s 50 little things u could have missed.. but the main one I see from mechanics watching the BB video is, the regulator plug is turned up side down and driven into the reg. sleeve.
The plug goes, short side down and big side up so the spring can sit on it..
If ur going to send the pump, send the injectors too..
They should open somewhere around 172-175 bar..
Contact me directly by tapping my screen name..


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## ropeman (Jul 15, 2020)

Jeremy sheally said:


> The pumping plungers are free in the housing . . .


I seem to be having a problem with the pumping plungers in my fuel pump. I rebuilt the pump and discovered that the plungers were stuck. Got them freed up and the tractor ran great. Now 6 months later it's not pumping fuel so I think the plungers are stuck again. Did you ever resolve your issue?


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## thepumpguysc (Jan 25, 2015)

The only cure is preventing the problem.
U have to take it apart, clean the goo off the plungers and anything else that requires movement.. and run some kind of additive in the fuel..
6 months.?? That’s some kinda record.!! I’ve seen’m stick in at little as 30 days..with no use..


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## ropeman (Jul 15, 2020)

thepumpguysc said:


> The only cure is preventing the problem.
> U have to take it apart, clean the goo off the plungers and anything else that requires movement.. and run some kind of additive in the fuel..
> 6 months.?? That’s some kinda record.!! I’ve seen’m stick in at little as 30 days..with no use..


Yeah, it might have been stuck 3 months ago  I think I'll tumble the plungers in my walnut media tumbler to clean them up nice and shiny. Most likely there is some moisture (or other nasty stuff) in the fuel causing this issue.


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## thepumpguysc (Jan 25, 2015)

I’ve never used a walnut tumbler, so I can’t say how intrusive it is.. all I can say is, the plungers are very unforgiving & u can’t buy them separately..
I do use a walnut “sand blaster” on the pump hsgs and other metal bits.. and it works great without being intrusive..
I don’t like the idea of them bouncing off of each other tho..
I use a special lapping compound on the plungers..38-1200..& push them thru the hole in the rotor.. [email protected] a time, back and forth until u feel it moving “easier”.. Now do the other one..
Wash everything REAL GOOD and blow the rotor w compressed air..
Wet the rotor and plungers in diesel fuel, seeing u don’t have calibration fluid..and check for plunger freedom of movement.. When correct, they will slide out of their bore if tipped to one side..
Good luck


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## ropeman (Jul 15, 2020)

Thanks for the info! I think I used 1200 grit sandpaper on the plungers last time. They were stuck so bad that I didn't know they were supposed to move until doing more research. What is the "best" additive to use for the fuel? I like Seafoam for gas engines but don't have much experience with diesel.


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## ropeman (Jul 15, 2020)

thepumpguysc said:


> I’ve never used a walnut tumbler, so I can’t say how intrusive it is.. all I can say is, the plungers are very unforgiving & u can’t buy them separately..


The tumbler I'm talking about is a vibrating tumbler for brass shells so they won't be banging into each other like a rotary tumbler.

After thinking about this for days I have an idea that might be good or very bad, I'm not sure. I was thinking about putting some Seafoam or B 12 in the pump inlet and then hooking up the air compressor with about 20 psi. My thought is that the only thing that pushes the plungers out is fuel pressure so a little extra pressure might unstick them. Would pressurizing the pump inlet cause any damage to the seal or gaskets?


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## thepumpguysc (Jan 25, 2015)

I told u how it’s done..
If u wanna go reinvent the wheel, do it at your own peril..


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## ropeman (Jul 15, 2020)

thepumpguysc said:


> I told u how it’s done..
> If u wanna go reinvent the wheel, do it at your own peril..


That's why I love being able to ask questions in a place like this! I feel like I have a good idea until someone with real world experience comes along and reminds me to do it right the first time. Thanks for the info!


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## ropeman (Jul 15, 2020)

thepumpguysc said:


> The only cure is preventing the problem.


Thanks again for the info! After tearing the pump apart and 2hours of polishing with various fine grit sandpaper the plungers were moving freely in the bore. Drained the old fuel out (which smelled like varnish) added some STP treatment and fresh fuel and the old girl fired right up. I think we will start the tractor once a week from now on just to keep the moving parts moving!


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## thepumpguysc (Jan 25, 2015)

If it’s got a pull cable shut off.. ALWAYS push the knob back in to the run position.. 
that way it won’t get stuck in the shut off position..
Good luck


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