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Oil Pump...info


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You need to drop the oil pan,  Other than removing the oil pan, it's 3 bolts.  Replacing your rear main seal while you're there is recommended (by me at least) since it's a $15 part, The labor (if you were to pay a shop to do it) is generally around $5-600 so it's well worth it to replace the seal. Replace the pump and the seal and a new oil pan gasket.  The hardest part is dropping the oil pan...it's a greasy messy job and you'll spend most of the day under the Jeep.  If you have never been under there, maybe longer.  First time I did it, it took me 6 hours one day and 2 the next.  I have done 3...the last one took me 3 hours...it's a learning experience.

 

The pump is turned by a gear on the camshaft, the camshaft is turned by the timing chain. Also the distributor is turned by a gear on the end of the distributor shaft that slips into a slot in the oil pump.

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Alright, thanks for that. However, that brings 2 more questions to mind. Is there any way to mess things up by turning any of those gears while the pump is out? And the pump should be filled with oil when it is put up correct? Primed I believe is the term.

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Priming is a good idea, yes, but not necessary.  You can prime it by turning it over with the coil unplugged to prevent starting.  By "turning gears in there", do you mean the camshaft gear?  Because you can't turn that without turning the crankshaft.  But the pump's shaft does have to line up correctly to properly mate with the end of the distributor (since that's how the pump gets power from the camshaft).

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Alright, thanks for that. However, that brings 2 more questions to mind. Is there any way to mess things up by turning any of those gears while the pump is out? And the pump should be filled with oil when it is put up correct? Primed I believe is the term.

Find TDC and make sure the distributor is indexed to #1

 

There are instructions here on setting up the oil pump so the distributor will slide in correctly.......IIRC......cruiser has the link.\

 

Turn nothing once you pull your distributor.......NOTHING! until have it back in.

 

You can prime the pump using an old long screw driver, cut the handle off and chuck in up in a drill........you can do so after you have installed it and the pan back on with oil in the sump.......then install your distributor.

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Refer to the "random informative picture thread" in the DIY section for photos of things you aren't familiar with. Chock the rear wheels, set the parking brake, jack the truck up and put jackstands under the frame, not the front axle - you'll need for the axle to drop in order to get the pan off (two wheel drive). I haven't done this on a four wheel drive truck but I've heard that you'll need to disconnect some suspension components to get enough axle drop on a four wheeler (could be wrong about that and if so I'm sure someone will clarify that item).

 

1. Disconnect the battery.

2. Mark your plug wires as you remove them from the plugs (a strip of masking tape on each wire numbered appropriately), mark the location of the #1 plug wire on the side of the distributor body and remove the distributor cap with the wires still attached to the cap.

3. Remove the spark plugs (not absolutely necessary but will make it easier to turn the crankshaft and a good time to replace them).

4. I turn the crankshaft (using the bolt on the crankshaft pulley/harmonic balancer) until the distributor rotor is pointed at where the #1plug wire would be and the timing marks are lined up correctly (probably not necessary, but the way I like to do it).

5. Get under the truck and take a photo of the oil pan on both sides and front and back. These will come in handy when you start to put it back together and forget how it was when you took it apart.

6. Remove starter (again, maybe not necessary but it gives you more room to work).

7. Drain the oil and remove the oil pan bolts and studs (I put all of mine in a coffee can filled with solvent to speed up the cleaning process).

8. Using a rubber mallet, hit the oil pan firmly on the side, preferably in the lower curved area. It's less likely to bend if hit in this area with a rubber mallet. If you don't have a rubber mallet, put a block of wood against the pan and hit the wood. Alternate hitting the sides until it breaks loose and comes off. DO NOT, repeat DO NOT try to pry it off. Prying will bend the lip of the pan making it very difficult to get a good seal when you put it back on. If the pan has been on for a while it will probably take some pretty good effort to break it loose.

9. Crawl out from under the truck with the oil pan and put put some cardboard under there to catch the oil drips. Take a short break.

10. Remove the bolts holding the oil pump to the block. Make sure that the oil pickup is thoroughly cleaned before re-installing it on the new pump.

11. At this point, replace the rear main oil seal if that is your preference. I would highly recommend you do so. Use the Fel-Pro double lip seal. Look in the DIY Section for a "how to" on seal replacement.

12. Thoroughly clean the oil pan and install a new gasket on the drain plug. This is a good time to paint the pan for appearance and protection.

13. Prime the new oil pump.

14. Shine a flashlight up the hole and see how the drive slot in the distributor is turned, orient the oil pump shaft accordingly, put it in the hole and bolt it in place.

15. I recommend the Fel-Pro blue gasket when you put the pan back on. There's a photo of the bolt and stud sizes and locations in the DIY picture thread. (This is where the photos you took will come in handy.)

16. Change the oil filter.

17. Replace the starter.

18. Check that the drain plug is in place and tight (don't ask why I included this step)

19. Put oil in the engine.

20. Disconnect the fuel pump (pull the relay), reconnect the battery and turn the engine over a few times to get oil circulating without the engine under load.

21. Re-install the plugs, distributor cap and plug wires (be sure the rotor is still aligned with the #1 plug wire location) and reconnect the fuel pump.

22. Check around for left-over parts - not a good thing!

23. Crank it up and make sure the oil pressure comes up quickly. Listen for any unusual noises. Check under the truck for any leaks.

24. If good oil pressure and no leaks - good job!

25. Take it off the jack stands (after reconnecting any suspension components), give it a test drive, then have a cold beverage of choice as you clean up the tools and the work area.

 

Everybody else jump in with anything I missed or omitted.

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I was posting while Jeep Driver posted. His post reminded me that I removed my distributor and primed the pump (and engine) by spinning the pump with an electric drill and a long piece of copper tubing with the end flattened to fit the oil pump shaft. That's why I aligned the timing marks with the rotor pointing to #1 - Did not crank the engine over with the distributor out. Duh - must be the onset of senility.

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Edit: [Oops, too late...anyhoo...may be useful...thanks Keyav8r.]

 

The first time I touched an oil pump I had NO idea that I might have a problem with the distributor.  I only pulled the oil pump out so I could get the pan off.  I did it blind, I never got the pan completely off until I pulled the pump by reaching in with a wrench and dropping the pump into the pan.  Like I said, it's a learning experience if you haven't done it before.

 

I guess I got lucky by not screwing up the dizzy, I didn't know.  I just pulled the pump blind, and reinstalled it blind ( that was back when I could actually bend my wrists).  I didn't TURN anything.  Installing a new pump usually (the ones I've done) calls for priming and/or packing the pump "works" with Vaseline or light grease.  After it's installed, and submerged in the sump, you CAN prime it with a drill/driver,   At that point you'll have to re-index the dizzy anyway.

 

If someone else can offer a write-up on how to do it right, you'll be worlds ahead of where I was when I did my first one. 

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Wow I didn't realize It was so intense. Figured it was just a few bolt out, new pump, few bolts in. Thanks. Now can anybody tell me how a pump would ever fail? - Still having never seen one I'm just imagining direct contact gears and mechanicals; what's there to fail about that?

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Your 4.0 oil pump looks basically like this...

 

 

The interior looks like this...

 

 

Those two gears ride on the bottom cover plate of the pump with a film of oil between the gears and the cover plate.  The bottom plate can become worn and or scored over time as can the gears.  That adds to the clearances and would lessen oil pressure at the least.  I'm not sure if that would be sufficient to make it seem like a failure.  The slot in the end of the shaft in the first photo is where the bottom of the distributor shaft fits in to drive the pump.  The distributor is gear driven off of a gear in roughly the middle of the cam shaft.  One side of that slot may have broken or the part it engages on the end of the distributor shaft could possibly break.  No way to know for sure til you get it apart.  They do make rebuild kits for the pump... new gears, pressure relief spring and cup. If the bottom cover plate isn't worn too bad you can sand it wet with wet and dry sand paper.  Lay the sand paper on a plate of glass, wet it with water or oil and sand away.  Start with 220 and work up to 400 or maybe 600 grit.  Get rid of the wear marks then work on a nice smooth finish to the surface.  Take your time.  A pump around here is about $75.  The rebuild kit I have gotten in the recent past is less than $30 from Summitracing.com.   http://www.summitracing.com/parts/slp-224-51198/overview/make/jeep   The photo in that link isn't the right pump but that is stated there also.  It is a Sealed power kit so it will be available other places to.  Hope that helps a bit.

 

Larry

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All things mechanical can fail, that said......

 

Rarely do oil pumps fail, of all the parts in your engine that can fail, the pump should be that last to go.

 

I'm not suggesting that you cannot handle the replacement, but I do suggest you find a buddy with some experience to help you out. If you have a complete loss of oil pressure......you may need someone else's opinion as to why.

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Here's a pic of the oil pan...via Cruiser54

 

For reference:

 

 

Here's a pic of the innards of the oil pump...like Jeep Driver said...anything mechanical can fail due to wear, loss of tolerances and chipped pieces.

 

http://s168.photobucket.com/user/chasdwitt/media/oilpump3_zps1b6ce0a9.jpg.html'>Image Not Found

 

Image Not Found

 

...AND just because I haven't read it here yet...why do you believe your oil pump has failed in the first place??

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Well, this is all in reference to a 1987 MJ that I picked up for 300 bucks. It had sat for 4 years without anything being done to it. I bought it, drug it home, and started it. Everything worked surprisingly, but there was a huge oil leak from the passenger side of the engine. Still don't know where it was from. But anyhow, one time my oil pressure dropped to nothing on the gauge, and the spraying oil leak ceased. So I'm pretty sure. But anyway, if anyone has a definitive test for me to perform, I'm all for it. I am pretty sure the pump went out though. Like I said it had sat for about 4 years too. And how much should an oil pump cost anyway? I was imagining $50, but my local Carquest, cheapest around, quoted me $116, which blew me out of the water. Rockauto has one for $45 though. I don't imagine I really need a new pickup line anyway. Thoughts?

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I did one on a 258 I had in a Grand Waggy. You don't need to worry about the distributor at all assuming the drive isn't broken. If it is OK just bolt the new pump on and as was said crank it for a little while with the coil unplugged to build pressure then you'll be fine. You should confirm the pressure issue and fix the leaks though no matter what.

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Well what I'd like to do is drop the pan, take a look, then see about ordering a new one or a rebuild kit is correspondence with what I find. Though there'll probably be a couple weeks between dropping the pan and putting it back together.

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Well what I'd like to do is drop the pan, take a look, then see about ordering a new one or a rebuild kit is correspondence with what I find. Though there'll probably be a couple weeks between dropping the pan and putting it back together.

Put the pan back on with  4 bolts, do not leave uncovered.

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