Mr4btTahoe
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- Indiana
Hey alls...
Just buttoned up the rebuild on my MEP-003a injection pump (Ambac M50) and documented the process. Member "jamawieb" gave me a write up on the tear down and it was very straight forward.
I'll post his write up in steps with pictures from my rebuild and some details on what I had to do.
--
Removed from engine
On the bench ready for disassembly. Be sure to MARK the pump body and housing as far as orientation goes!
Step 1 - Take the throttle linkage out (take the flat head screws out and then it slides out). Mine was stuck pretty good so a couple flat screw drivers and a bit of prying was in order.
Make sure this little piece came out with it. It sticks in the end of the throttle shaft.
Step 2 - Back the inlet and outlet adapters out or take them out completely. (I removed them)
Step 3 - Take the 4 allen screws off the housing and then push the pump out of the housing. (On mine, this took a bit of effort. I used a thin putty knife and tapped it between the pump and housing at the lip where the 4 clamp screws held it in place. Then gradually worked it up taking care not to damage the housing.)
Step 4 - Remove the big c-clip off and separate the pump, you'll have the gear set in one hand and the ports for the injectors in the other.
The gear set will have the plunger sticking out of it and if you look at the end, that the plunger is protruding from, you'll see a flat piece, that is the plunger guide. The plunger guide will be broken in half or it will be rounded off, where the plunger will just spin.
Step 5 - take the cap off the end of the gear set. (Pry it up with a flat blade screw driver carefully. Just an o-ring holding it snug). When you take the cap off you'll see the button under it.
Step 6 - There is a little clip that holds the button in place that has to be removed. I use a little pick to pick it out but be careful because it will fly off and you'll never find it. (I placed the entire assembly in a gallon ziplock bag and used a pick to work the clip loose. When it popped off, it was caught by the bag.)
From let to right... Cap (tappet), wire clip, timing button.
Step 7 - After you remove the button. You'll see the end of the plunger under the spring. It's held in place with 2 half circles (best way I know how to describe), you have to depress the spring and get the half circles out. This is the hardest part of the whole thing. I have a pair of need nose vice grips that I cut the nose off of to make them flat. Then set them far enough apart to go around the plunger so I can put the plunger on a hard surface (Like a desk) and depress the spring with the vice grips to get the half circles out. (This is setup just like a valve spring/retainer. I just used some needle nose pliers to push down on the retainer while the plunger was held in a vice with soft jaws. Then a magnet to pull the little clips up out of the retainer.
The little clips are on the right. Spring/retainer under the tappet and to the left of the spring/retainer is a spring shim (that is under the spring when assembled).
Step 8 - Remove the spring, plunger and guide.
Plunger
Plunger guide. This is the item that likes to fail after the pump sits and gets gummed up. Mine was nearly rounded out in the center and cracked.
Put back together with new plunger guide and everything clean. When I reinstalled the retainer clips, I placed them on top of the retainer. When I pushed down the retainer using the needle nose pliers, I nudged the clips into the hole and they worked themselves into place. Very easy.
New plunger guide in place.
Timing button back in position with wire lock in place.
Tappet back in place.
Delivery valve components. Cap, Holder, Spring, Valve, and tiny spacer (orange piece).
Just buttoned up the rebuild on my MEP-003a injection pump (Ambac M50) and documented the process. Member "jamawieb" gave me a write up on the tear down and it was very straight forward.
I'll post his write up in steps with pictures from my rebuild and some details on what I had to do.
--
Removed from engine
On the bench ready for disassembly. Be sure to MARK the pump body and housing as far as orientation goes!
Step 1 - Take the throttle linkage out (take the flat head screws out and then it slides out). Mine was stuck pretty good so a couple flat screw drivers and a bit of prying was in order.
Make sure this little piece came out with it. It sticks in the end of the throttle shaft.
Step 2 - Back the inlet and outlet adapters out or take them out completely. (I removed them)
Step 3 - Take the 4 allen screws off the housing and then push the pump out of the housing. (On mine, this took a bit of effort. I used a thin putty knife and tapped it between the pump and housing at the lip where the 4 clamp screws held it in place. Then gradually worked it up taking care not to damage the housing.)
Step 4 - Remove the big c-clip off and separate the pump, you'll have the gear set in one hand and the ports for the injectors in the other.
The gear set will have the plunger sticking out of it and if you look at the end, that the plunger is protruding from, you'll see a flat piece, that is the plunger guide. The plunger guide will be broken in half or it will be rounded off, where the plunger will just spin.
Step 5 - take the cap off the end of the gear set. (Pry it up with a flat blade screw driver carefully. Just an o-ring holding it snug). When you take the cap off you'll see the button under it.
Step 6 - There is a little clip that holds the button in place that has to be removed. I use a little pick to pick it out but be careful because it will fly off and you'll never find it. (I placed the entire assembly in a gallon ziplock bag and used a pick to work the clip loose. When it popped off, it was caught by the bag.)
From let to right... Cap (tappet), wire clip, timing button.
Step 7 - After you remove the button. You'll see the end of the plunger under the spring. It's held in place with 2 half circles (best way I know how to describe), you have to depress the spring and get the half circles out. This is the hardest part of the whole thing. I have a pair of need nose vice grips that I cut the nose off of to make them flat. Then set them far enough apart to go around the plunger so I can put the plunger on a hard surface (Like a desk) and depress the spring with the vice grips to get the half circles out. (This is setup just like a valve spring/retainer. I just used some needle nose pliers to push down on the retainer while the plunger was held in a vice with soft jaws. Then a magnet to pull the little clips up out of the retainer.
The little clips are on the right. Spring/retainer under the tappet and to the left of the spring/retainer is a spring shim (that is under the spring when assembled).
Step 8 - Remove the spring, plunger and guide.
Plunger
Plunger guide. This is the item that likes to fail after the pump sits and gets gummed up. Mine was nearly rounded out in the center and cracked.
Put back together with new plunger guide and everything clean. When I reinstalled the retainer clips, I placed them on top of the retainer. When I pushed down the retainer using the needle nose pliers, I nudged the clips into the hole and they worked themselves into place. Very easy.
New plunger guide in place.
Timing button back in position with wire lock in place.
Tappet back in place.
Delivery valve components. Cap, Holder, Spring, Valve, and tiny spacer (orange piece).
Attachments
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