What Did you Do With Your Bronco Today???

[johnnyreb]

Not necessarily the pump.
(You didn't indicate what was wrong about them.)

A few things to consider.

2 brand new Melling pumps in a row being bad would be highly suspect-in my experience. But being given the wrong pump for your APPLICATION is quite possible.

You did try priming the pumps by hand before installing-to see if they worked then, right? And also checked the SIZE of the hex recess in each pump, against the OLD rod size, right?

Ford used 2 drive rod diameters in the older cars, 1/4" and 5/16".

The 1/4" rod is used mostly on the 302 and smaller engines, while the 5/16" is mostly used on 351's and and above.

Its not unheard of for a "substitute" pump to be in a factory engine when parts shortages are going on. If, FOR EXAMPLE you were sent a 5/16" drive pump but your particular engine uses a 1/4" drive rod, that would be the simplest explanation. Whether it came that way from the factory or someone put the wrong pump in for the application, or someone swapped DISTRIBUTORS at some point.

(And sometimes aftermarket suppliers will not stock pumps for every year/engine application or show a pump mating with parts where it shouldn't, or have a typo creep in for the pump number.)

Barring that.

Mehanical rotor oil pumps are very simple, they either work or they don't-but the reasons for one no longer working can be one of several.

RARELY, the hex drive ROD right at the pump or distributor end will get rounded off enough to not drive the pump, but if lubrication at both ends of the drive rod is good, if the pump jams, usually the drive rod will snap before then.
MANY PEOPLE NEVER LOOK CLOSELY AT OR **** THE TOP END OF THE DRIVE ROD because if the original thin push nut/clinching washer is still there, it stays up in the engine.

The problems with the drive rod usually stem from hard crud or gasket material making it through the screen, which then puts a LOT OF BACK PRESSURE on the pump and eventually jams the pump rotor. Its also possible from a large accumulation of varnish or metal shavings to do the same thing.

Its not unknown for the hex recess in the distributor or that end of teh rod to wear just enough for the rod to not be turning when the distributor is. Or for the roll pin that holds the distributor DRIVE GEAR onto the distributor shaft to shear. If THAT happens the gear is no longer locked onto the shaft and the drive rod won't be turning.

And then there's the bugaboo of a stuck OPEN oil pressure relief valve not allowing oil pressure to build sufficiently.....
If you have one of those, and it went on for some time with the engine running, there may have been be a lot of engine damage happening to bearings.

We never started it yet.

 

[johnnyreb]

We never started it yet.

One pump lasted about a month. This one--is not pumping at all---with being primed a good bit.,. I even unhooked the line from the top of the oil filter .Now it between the pump and the mount where the oil filter goes on. Either the mount bis stopped up or the pump is not pumping.

 

[goodO1boydws]

Back up one step.

What, if anything, happened specifically to cause you to want/need to put on the FIRST new pump? And if something oil system related DID happen that caused you to get a new pump, instead of reusing the old one, do you still have the ORIGINAL (old) pump on hand? (I figure that you're reusing the old pickup arm, most people do.)

I forgot to mention (as additional possible suspects) bad gaskets that don't seal properly a pump or pickup arm that is just loose enough to leave an air pathway, or tight enough to deform the gasket. A pickup arm that is will not SEAT properly on the new pump, th epickup being blocked with crud or a piece of old gasket inside, or has a crack somewhere on it just big enough to break suction.

 

[johnnyreb]

Back up one step.

What, if anything, happened specifically to cause you to want/need to put on the FIRST new pump? And if something oil system related DID happen that caused you to get a new pump, instead of reusing the old one, do you still have the ORIGINAL (old) pump on hand? (I figure that you're reusing the old pickup arm, most people do.)

I forgot to mention (as additional possible suspects) bad gaskets that don't seal properly a pump or pickup arm that is just loose enough to leave an air pathway, or tight enough to deform the gasket. A pickup arm that is will not SEAT properly on the new pump, th epickup being blocked with crud or a piece of old gasket inside, or has a crack somewhere on it just big enough to break suction.

The oil pressure dropped way down. We tore it down. Took the pump apart and the spring was blocked off and some light scratchs on the pump plate. So we replaced the pump with a new one and new screen and tUBE, All the parts matched the other one we took out--but as said earlier--they could have sold us a wrong pump---since I put a 390 motor in it. WHICH I TOLD THE PARTS MAN---IT HAS A 74---390 IN IT NOW. ,But you know how they are now days----I,ll take it back out--or have it taken out. Since I have to go into the hospital Tuesday,but when I get out. Hopefully I can watch my cousin tear into it.Raining hear now.

 

[goodO1boydws]

The oil pressure dropped way down. We tore it down. Took the pump apart and the spring was blocked off and some light scratchs on the pump plate. So we replaced the pump with a new one and new screen and tUBE, All the parts matched the other one we took out--but as said earlier--they could have sold us a wrong pump---since I put a 390 motor in it. WHICH I TOLD THE PARTS MAN---IT HAS A 74---390 IN IT NOW. ,But you know how they are now days----I,ll take it back out--or have it taken out. Since I have to go into the hospital Tuesday,but when I get out. Hopefully I can watch my cousin tear into it.Raining hear now.

For a 1974 390-out of a pickup, there is only one standard Melling pump shown, (the M-57) The only other listing they showing the 390 that year is the P-350 step van and its showing the same pump number.

Here's a link to the M-57 to check specs against what you have.

More Information for MELLING M57

In looking up the 390 pump it reminded me that it was one where the oil was biased to the top end enough that it was considered to be overoiled there. I don't remember if Ford ever fixed that or not. Some people, especially those who wanted to run a high volume pump used to put in gallery restrictors to reduce that tendency and also do other things to improve bearing oiling. The restrictors, being smaller diameter than the galleries, are an even better place for stoppages if there are pieces of gasket material or other crud getting circulated.

On a related note, you just mentioned the oil pressure as originally having dropped way down.

If that happened fairly rapidly, besides it being posssible that the relief valve was stuck OPEN, its also possible that the old pump's pressure relief valve was stuck CLOSED.
If THAT happens its possible to raise the oil pressure high enough to force out one or more oil gallery plugs if they are the pressed-in-type.

If that did happen, the oil pressure will be "way down" from then on, making it difficult to force oil up into the top of the engine for ANY oil pump.
And especially difficult when turning the pump by hand.

 

[johnnyreb]

Back up one step.

What, if anything, happened specifically to cause you to want/need to put on the FIRST new pump? And if something oil system related DID happen that caused you to get a new pump, instead of reusing the old one, do you still have the ORIGINAL (old) pump on hand? (I figure that you're reusing the old pickup arm, most people do.)

I forgot to mention (as additional possible suspects) bad gaskets that don't seal properly a pump or pickup arm that is just loose enough to leave an air pathway, or tight enough to deform the gasket. A pickup arm that is will not SEAT properly on the new pump, th epickup being blocked with crud or a piece of old gasket inside, or has a crack somewhere on it just big enough to break suction.

Well I got the base where the filter screws on--off and the oil passage IS OPEN. So that leaves the pump----I ,ll take it off or have my cousin take it off and check it out.

 

[Jimbo26]

It took 4 GALLON?

Hey J/R,
Just a bit over 3 gal.
Did a complete system purge- drain converter then took the lines loose and aired out the rad. cooler, since the oil looked to be very dated.
>adding a external cooler next.
Da n g it if the starter didn't stick On (key off) yesterday. I hate it when that happens!
Another thing to replace.

 

[johnnyreb]

For a 1974 390-out of a pickup, there is only one standard Melling pump shown, (the M-57) The only other listing they showing the 390 that year is the P-350 step van and its showing the same pump number.

Here's a link to the M-57 to check specs against what you have.

More Information for MELLING M57

In looking up the 390 pump it reminded me that it was one where the oil was biased to the top end enough that it was considered to be overoiled there. I don't remember if Ford ever fixed that or not. Some people, especially those who wanted to run a high volume pump used to put in gallery restrictors to reduce that tendency and also do other things to improve bearing oiling. The restrictors, being smaller diameter than the galleries, are an even better place for stoppages if there are pieces of gasket material or other crud getting circulated.

On a related note, you just mentioned the oil pressure as originally having dropped way down.

If that happened fairly rapidly, besides it being posssible that the relief valve was stuck OPEN, its also possible that the old pump's pressure relief valve was stuck CLOSED.
If THAT happens its possible to raise the oil pressure high enough to force out one or more oil gallery plugs if they are the pressed-in-type.

If that did happen, the oil pressure will be "way down" from then on, making it difficult to force oil up into the top of the engine for ANY oil pump.
And especially difficult when turning the pump by hand.

When I first put the motor in. I wanted a high volume pump---to make sure it got plenty. I never started the motor with the orignal pump in it. When it went low--we tore into the pump and seen something had blocked the spring from working. and it has ssome rough mark inside the pump,but the pan was clean. Now we have the new pump in and its not pumping and all the gallery are open--no restriction at all.. it is pointing to he pump. Any ways---I won,t be on it for awhile,. I go into the hospital for surgery and hope to be out soon and in good health to start back on it--with some help from my cousin.As THEY SAY. i,M NOT SUPPOSE TO LIFT ANYTHING HEAVY. Thanks alot for your help friends

 

[goodO1boydws]

When I first put the motor in. I wanted a high volume pump---to make sure it got plenty. I never started the motor with the orignal pump in it. When it went low--we tore into the pump and seen something had blocked the spring from working. and it has ssome rough mark inside the pump,but the pan was clean. Now we have the new pump in and its not pumping and all the gallery are open--no restriction at all.. it is pointing to he pump. Any ways---I won,t be on it for awhile,. I go into the hospital for surgery and hope to be out soon and in good health to start back on it--with some help from my cousin.As THEY SAY. i,M NOT SUPPOSE TO LIFT ANYTHING HEAVY. Thanks alot for your help friends

I hope the surgery goes smoothly-getting and keeping YOU running well is a much higher priority.

 

[Jimbo26]

Addressed fried starter issue (after taking care of the valve cover gaskets change on the other halfs 4.0L- a 'fun' sort of chore)
Bing! Junk trucks at work-
Went and collected a newer style p/m starter with all the trimmings and converted up from the old style. Much better winding up again & 8 lbs lighter.
Total cost= $ time invested.
I guess '91 was the last round for the old style starters, as my 250 is a '92 and has the same 351/E4Od setup with the p/m type from the factory.

 

[Jimbo26]

Today was change out rear wheel brake cyls and JB the bosses back in the dash panel that hold the OD cancel switch in. Nice to have a complete dash again.

Edit-7/13
Changed out the old oem headlight switch.
Acquired a salvage F4 engine last week for the project and slowly going into it to get it ready for the ❤ transplant.
installed some used window ventshades. Blends right in with the rest of the fade.

 

[Jimbo26]

Service the rear diff fluid. Looked to be 31 yrs. old.
Found a few small pieces in the pit that I really didn't want to find.
It is a 'L' unit (3L55)
Didn't see any damage to the R&P so, clutch plate leftovers?
(Educated guess the previous management had to get rev-happy and slam it into D from N at about 3k+ rpm)

 

[goodO1boydws]

I'd say those ARE likely to be the tabs from a differential clutch plate.

If so, its possible that they could be from the same one, (and it might still be in there), or as you said, may be leftovers from a clutch pack replacement-pieces that got stuck somewhere and were missed when doing the swap. Take a very close look at what is in there now to see if any tabs are missing.

If that limited-slip rear end was run without friction modifier, it could have chewed up the clutch pack over time.

Here's a link to An F150 REAR END TEAR DOWN/REBUILD VIDEO, (about 15 minutes in it shows the clutch pack).

 

[Jimbo26]

I'll have a look at that vid, thx.
The fluid I drained out definitely had the fric-additive in it. No mistaking that Smell!
Glad I drained that stuff outside the garage- it still reeked up the area pretty well.
I refilled the diff with RP 75-140 that already has the additive mixed in. Been years since I had serviced a 8.8
Didn't remember those held 3+ quarts!
If the 'lock' does fail, have another one on the shelf that's fresh, so will swap it out.
Edit- 7/21:
Got the loudmouth toned down. Flowmaster 50 installed. Better.

 

[goodO1boydws]

You've got an extra l-s on the shelf?
Must be nice.

 

[Jimbo26]

Yea, just happened to be in the right place @ the right time.
It happens, just have to enjoy the grin while it lasts. More knuckle-bustin eventually.

 

[goodO1boydws]

I'll have a look at that vid, thx.
The fluid I drained out definitely had the fric-additive in it. No mistaking that Smell!
Glad I drained that stuff outside the garage- it still reeked up the area pretty well.

If the 'lock' does fail, have another one on the shelf that's fresh, so will swap it out.
Edit- 7/21:
Got the loudmouth toned down. Flowmaster 50 installed. Better.

"I refilled the diff with RP 75-140 that already has the additive mixed in. Been years since I had serviced a 8.8
Didn't remember those held 3+ quarts!"

It holds even more if you forget to put one of the axles back in.....
Don't ask.

 

[Jimbo26]

Sounds like a 'Miller hilife' evening.
It's always fun- until the next morning.

 

[Jimbo26]

More brake work, parking linkage adjusted out good. Checked ohms on the rear axle ss at the access point under the hood- OFL, not surprising. Parts, parts & mo-parts!
Another round of bleeding, better but still not quite there with the rear cyls yet. Rabs valve just barely giving anything.

 

[L\Bronco]

More brake work, parking linkage adjusted out good. Checked ohms on the rear axle ss at the access point under the hood- OFL, not surprising. Parts, parts & mo-parts!
Another round of bleeding, better but still not quite there with the rear cyls yet. Rabs valve just barely giving anything.

Hey Jimbo, check the wires to the sensor near where they go by the park brake cable. (They used to rub through there a lot)
If you need to fix the wiring, make sure to twist them at least 9 twists per foot.
EMI really causes havoc in the old control system, (especially the trans!)
PS, heres a pict of the guy that ran just before us in round one. Had a huge backfire at the top end. 3”hole blown in the intake!