DIESEL PUMP FIXES TO AVOID EXPENSIVE REBUILDS AND CURE LEAKS!!!!

[oli larsen]

Hey everyone. Recently my Jdm Townace developed a selection of diesel leaks after a stint of cold weather. I have owned a few diesels now and dread the day I smell diesel. If your lucky its a pipe, if your unlucky it's something to do with the pump!!!

I have the RM025E service manual but that aside no other literature on the pump. The manual has schematics which are invaluable. It is however designed to explain a rebuild of the pump. That is a last case resort if you can't fix the leaks that I will explain in this little guide.
From extensive researching on old defunct forums and what I could dig up I found it's very common for the pumps to start leaking between 60 thousand miles and 95. Not an exact science but it's a common problem.
Mine is on around 80 thousand so fits the bill!

I will cover the 4 fixes you can relatively easily do at home.
They DO NOT require the pump to be removed and can be done in situ using parts that are pretty easy to get hold of at little cost!

First up are the two pages of the manual that are vital for part location reference!
Following these I will break each section down.

[oli larsen]

LOWER PISTON COVER PLATE.
This is the plate that is held on with two m6 cap head bolts on the low side of the pump facing away from the engine. It's by far the easiest. you will only need an Allen key or as I used a 1/4 ratchet with an extension and the correct Allen key bit. I think it was a "5" in the end.
To ease access remove the header tank (expansion tank) for the radiator.
Make sure the Allen key is fully seated with pressure on it to keep it in the bolt and crack off the two bolts.
Really put pressure in on it and make sure the Allen key is in good condition. you don't want to round these off!!!
it will drop a little fuel but not much so have a rag under it.
when it's loose keep hold of it and slide it carefully out. There id a spring inside so draw it out.
You need not touch the adjuster and lock nut!
Then simply select the correct o-ring and replace. refit is simply the reverse.

***** I flatted my cover plate as it was a bit corroded*****

[oli larsen]

2. THERMO WAX COUPLING COVER.
Next tup is the thermo wax coupling cover, It's very similar and uses the same o-ring.
It is however a little more fiddly. First remove The two m6 cap head bolts that hold the throttle stop plate nearest the thermo wax coupling down. they are on the top of the pump.
Then look down on the same piece to the side of the pump. there is another m6. this one is a bit longer. mine rounded and had to be drilled out. luckily once the head was gone it unscrewed easily. a huge relief!!! once these three bolts are out lift the throttle stop plate out.
You are now left with the two m6 cap heads that hold the thermo wax coupling in. undo them and ease it out.
I left it assembled and wriggled an Allen key around the spring. I had to leave the top bolt in and ease it off with the unit. this saves a lot of time as depicted. You will lose a lot of diesel when this comes out. the pump will drain as its like a little tank inside. once its stopped replace the o-ring in the pump body and refit.
Do not be tempted to over tighten any of these bolts. they don't need much torque and stripping the thread in the soft alloy casting is far to easy to do!

[oli larsen]

3. Top cover gasket.
This is where it gets a little more complex, but don't be put off. it's pretty simple once you get into it. first off you will need to unclip the throttle cable. simply push it to open and lift the cable out. much liken a push bike brake lever! Next disconnect the fuel return line on the back of the pump. it has a 17mm banjo bolt. don't drop the copper washers as you slide the bolt out!
Next up take the two 10mm headed bolts out of the top holding a little cylinder with a wire coming out of it. it opens the throttle a bit when the ac is put on. mine was jammed and rusty so I've chose to leave it off! especially as I don't have AC anymore anyway!
Disconnect the vacuum line to the boost diaphragm and put it to one side.
Next up remove the throttle stop bracket that you took off for the thermo wax coupling. two cap head m6 bolts on the top cover and one long one on the side of the pump. The thermo wax coupling is not disturbed by this!!!
Next up are the two throttle stop screws. one nearest the engine controls maximum engine speed. it has a wire tie on it. mark up the adjusting side of the bolt with paint or something visible. crack off the 10mm lock nut just enough to free it then undo it by hand. try and leave the nut in the same place to make things easier when you put it back together!!
The one on the other side of the top cover is the idle adjust. it looks the same minus a locking wire. repeat the process.
Now you need to remove the throttle spindle. This is a part that can cause you a lot of problems. I strongly suggest you do as I did here to save yourself a nightmare!!!!
First scribe a line across the spindle, across the nut and across the centre of the thread in its middle!
It is splined and this makes getting it in the right position way easier upon reinstallation.
Next get some wire, garden wire works great. Look down on top of the spindle and you will see 2x return springs. Now you want to hook the wire around them and pull them back one at a time. then thread the wire through the eye where the throttle cabe locks in and tighten the wire. do this to both and the spindle should now move freely back and forth.
Double check that they won't get free of the wire!!!!!!
Now crack off the 10mm nut on the spindle and undo it. lightly wriggle it off the splines and set it aside. don't knock it!
With that done you can now access the 4x M6 cap head bolts holding the top cover down.
try and undo them evenly. you will need an Allen key for the two nearer the rear as the boost diaphragm will be in the way. again try and keep pressure on them to stop them rounding!!!!!!
******PLEASE NOTE*******
Leave the boost diaphragm attached. the service manual says to remove it. this is not necessary as you are not rebuilding it. it is adjustable and to avoid an additional task leave it alone!!!

[oli larsen]

This will save you no end of time and stress upon the rebuild!

[oli larsen]

3 TOP SEAL.
once the 4 m6 cap heads are removed from the top cover gently wriggle it to break the seal. Now place rags all around the top and either have the van on flat clear ground or put a sheet under it. There is a spring and cap that may try and escape and you don't want to lose it!
as you lift it up you will fell resistance. lift it gently up and back a bit. have a light to hand and look in the side of the pump. there is a spring from the spindle attached to a little cap in a lever that sticks up.
Either try and unclip the spring if you can reach or if possible gently press the throttle spindle down, if you get about 10mm of it to go down you can reach in and hold the spindle and slide it out. try and keep a little tension on the spring. with the cover lifted free you can now unclip the spring and very carefully holding the damper spring slide it out.
This is the trickiest part of it.
I dropped mine but luckily found it straight away. there is a spring from the spindle, then a little spring and a cap that holds it together. its an evil little thing but quite simple when you figure it out. set it aside and wipe it down. don't get any dirt or fluids in the pump as there is no filter after it and its all to easy to get dirt in the injection pump. Now simply install the new top gasket and you are away!!!!
REFITTING.
It's all the same but a helpful thing I found was to install the damper spring and spring seat and jam my glove behind it. otherwise it will slide out.
then connect the spring to keep it together.
I will now jump to the 4th seal as it makes sense to do it at this point!!!!